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Sample records for brucei bloodstream form

  1. Non-cytochrome mediated mitochondrial ATP production in bloodstream form Trypanosoma brucei brucei

    NARCIS (Netherlands)

    Bienen, E. J.; Maturi, R. K.; Pollakis, G.; Clarkson, A. B.

    1993-01-01

    The life cycle of Trypanosoma brucei brucei involves a series of differentiation steps characterized by marked changes in mitochondrial development and function. The bloodstream forms of this parasite completely lack cytochromes and have not been considered to have any Krebs cycle function. It has

  2. Particle-bound enzymes in the bloodstream form of Trypanosoma brucei

    NARCIS (Netherlands)

    Opperdoes, F. R.; Borst, P.; Spits, H.

    1977-01-01

    We have screened the bloodstream form of Trypanosoma brucei for the presence of enzymes that could serve as markers for the microbodies and the highly repressed mitochondrion of this organism. None of seven known microbody enzymes were detected at all, but glycerol-3-phosphate oxidase, ATPase,

  3. The phosphoproteome of bloodstream form Trypanosoma brucei, causative agent of African sleeping sickness.

    Science.gov (United States)

    Nett, Isabelle R E; Martin, David M A; Miranda-Saavedra, Diego; Lamont, Douglas; Barber, Jonathan D; Mehlert, Angela; Ferguson, Michael A J

    2009-07-01

    The protozoan parasite Trypanosoma brucei is the causative agent of human African sleeping sickness and related animal diseases, and it has over 170 predicted protein kinases. Protein phosphorylation is a key regulatory mechanism for cellular function that, thus far, has been studied in T.brucei principally through putative kinase mRNA knockdown and observation of the resulting phenotype. However, despite the relatively large kinome of this organism and the demonstrated essentiality of several T. brucei kinases, very few specific phosphorylation sites have been determined in this organism. Using a gel-free, phosphopeptide enrichment-based proteomics approach we performed the first large scale phosphorylation site analyses for T.brucei. Serine, threonine, and tyrosine phosphorylation sites were determined for a cytosolic protein fraction of the bloodstream form of the parasite, resulting in the identification of 491 phosphoproteins based on the identification of 852 unique phosphopeptides and 1204 phosphorylation sites. The phosphoproteins detected in this study are predicted from their genome annotations to participate in a wide variety of biological processes, including signal transduction, processing of DNA and RNA, protein synthesis, and degradation and to a minor extent in metabolic pathways. The analysis of phosphopeptides and phosphorylation sites was facilitated by in-house developed software, and this automated approach was validated by manual annotation of spectra of the kinase subset of proteins. Analysis of the cytosolic bloodstream form T. brucei kinome revealed the presence of 44 phosphorylated protein kinases in our data set that could be classified into the major eukaryotic protein kinase groups by applying a multilevel hidden Markov model library of the kinase catalytic domain. Identification of the kinase phosphorylation sites showed conserved phosphorylation sequence motifs in several kinase activation segments, supporting the view that

  4. Channel-forming activities in the glycosomal fraction from the bloodstream form of Trypanosoma brucei.

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    Melisa Gualdron-López

    Full Text Available BACKGROUND: Glycosomes are a specialized form of peroxisomes (microbodies present in unicellular eukaryotes that belong to the Kinetoplastea order, such as Trypanosoma and Leishmania species, parasitic protists causing severe diseases of livestock and humans in subtropical and tropical countries. The organelles harbour most enzymes of the glycolytic pathway that is responsible for substrate-level ATP production in the cell. Glycolysis is essential for bloodstream-form Trypanosoma brucei and enzymes comprising this pathway have been validated as drug targets. Glycosomes are surrounded by a single membrane. How glycolytic metabolites are transported across the glycosomal membrane is unclear. METHODS/PRINCIPAL FINDINGS: We hypothesized that glycosomal membrane, similarly to membranes of yeast and mammalian peroxisomes, contains channel-forming proteins involved in the selective transfer of metabolites. To verify this prediction, we isolated a glycosomal fraction from bloodstream-form T. brucei and reconstituted solubilized membrane proteins into planar lipid bilayers. The electrophysiological characteristics of the channels were studied using multiple channel recording and single channel analysis. Three main channel-forming activities were detected with current amplitudes 70-80 pA, 20-25 pA, and 8-11 pA, respectively (holding potential +10 mV and 3.0 M KCl as an electrolyte. All channels were in fully open state in a range of voltages ±150 mV and showed no sub-conductance transitions. The channel with current amplitude 20-25 pA is anion-selective (P(K+/P(Cl-∼0.31, while the other two types of channels are slightly selective for cations (P(K+/P(Cl- ratios ∼1.15 and ∼1.27 for the high- and low-conductance channels, respectively. The anion-selective channel showed an intrinsic current rectification that may suggest a functional asymmetry of the channel's pore. CONCLUSIONS/SIGNIFICANCE: These results indicate that the membrane of glycosomes

  5. Trypanosoma brucei FKBP12 differentially controls motility and cytokinesis in procyclic and bloodstream forms.

    Science.gov (United States)

    Brasseur, Anaïs; Rotureau, Brice; Vermeersch, Marjorie; Blisnick, Thierry; Salmon, Didier; Bastin, Philippe; Pays, Etienne; Vanhamme, Luc; Pérez-Morga, David

    2013-02-01

    FKBP12 proteins are able to inhibit TOR kinases or calcineurin phosphatases upon binding of rapamycin or FK506 drugs, respectively. The Trypanosoma brucei FKBP12 homologue (TbFKBP12) was found to be a cytoskeleton-associated protein with specific localization in the flagellar pocket area of the bloodstream form. In the insect procyclic form, RNA interference-mediated knockdown of TbFKBP12 affected motility. In bloodstream cells, depletion of TbFKBP12 affected cytokinesis and cytoskeleton architecture. These last effects were associated with the presence of internal translucent cavities limited by an inside-out configuration of the normal cell surface, with a luminal variant surface glycoprotein coat lined up by microtubules. These cavities, which recreated the streamlined shape of the normal trypanosome cytoskeleton, might represent unsuccessful attempts for cell abscission. We propose that TbFKBP12 differentially affects stage-specific processes through association with the cytoskeleton.

  6. KREX2 is not essential for either procyclic or bloodstream form Trypanosoma brucei.

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    Jason Carnes

    Full Text Available BACKGROUND: Most mitochondrial mRNAs in Trypanosoma brucei require RNA editing for maturation and translation. The edited RNAs primarily encode proteins of the oxidative phosphorylation system. These parasites undergo extensive changes in energy metabolism between the insect and bloodstream stages which are mirrored by alterations in RNA editing. Two U-specific exonucleases, KREX1 and KREX2, are both present in protein complexes (editosomes that catalyze RNA editing but the relative roles of each protein are not known. METHODOLOGY/PRINCIPAL FINDINGS: The requirement for KREX2 for RNA editing in vivo was assessed in both procyclic (insect and bloodstream form parasites by methods that use homologous recombination for gene elimination. These studies resulted in null mutant cells in which both alleles were eliminated. The viability of these cells demonstrates that KREX2 is not essential in either life cycle stage, despite certain defects in RNA editing in vivo. Furthermore, editosomes isolated from KREX2 null cells require KREX1 for in vitro U-specific exonuclease activity. CONCLUSIONS: KREX2 is a U-specific exonuclease that is dispensable for RNA editing in vivo in T. brucei BFs and PFs. This result suggests that the U deletion activity, which is required for RNA editing, is primarily mediated in vivo by KREX1 which is normally found associated with only one type of editosome. The retention of the KREX2 gene implies a non-essential role or a role that is essential in other life cycle stages or conditions.

  7. Zinc finger nuclease technology: A stable tool for high efficiency transformation in bloodstream form T. brucei.

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    Schumann, Gabriela; Kangussu-Marcolino, Monica M; Doiron, Nicholas; Käser, Sandro; de Assis Burle-Caldas, Gabriela; DaRocha, Wanderson D; Teixeira, Santuza M; Roditi, Isabel

    2017-04-01

    In Trypanosoma brucei, the generation of knockout mutants is relatively easy compared to other organisms as transfection methods are well established. These methods have their limitations, however, when it comes to the generation of genome-wide libraries that require a minimum of several hundred thousand transformants. Double-strand breaks with the meganuclease ISce-I dramatically increase transformation efficiency, but are not widely in use as cell lines need to be generated de novo before each transfection. Here we show that zinc finger nucleases are a robust and stable tool that can enhance transformation in bloodstream forms by more than an order of magnitude. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Trypanocidal action of bisphosphonium salts through a mitochondrial target in bloodstream form Trypanosoma brucei

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    Abdulsalam A.M. Alkhaldi

    2016-04-01

    Full Text Available Lipophilic bisphosphonium salts are among the most promising antiprotozoal leads currently under investigation. As part of their preclinical evaluation we here report on their mode of action against African trypanosomes, the etiological agents of sleeping sickness. The bisphosphonium compounds CD38 and AHI-9 exhibited rapid inhibition of Trypanosoma brucei growth, apparently the result of cell cycle arrest that blocked the replication of mitochondrial DNA, contained in the kinetoplast, thereby preventing the initiation of S-phase. Incubation with either compound led to a rapid reduction in mitochondrial membrane potential, and ATP levels decreased by approximately 50% within 1 h. Between 4 and 8 h, cellular calcium levels increased, consistent with release from the depolarized mitochondria. Within the mitochondria, the Succinate Dehydrogenase complex (SDH was investigated as a target for bisphosphonium salts, but while its subunit 1 (SDH1 was present at low levels in the bloodstream form trypanosomes, the assembled complex was hardly detectable. RNAi knockdown of the SDH1 subunit produced no growth phenotype, either in bloodstream or in the procyclic (insect forms and we conclude that in trypanosomes SDH is not the target for bisphosphonium salts. Instead, the compounds inhibited ATP production in intact mitochondria, as well as the purified F1 ATPase, to a level that was similar to 1 mM azide. Co-incubation with azide and bisphosphonium compounds did not inhibit ATPase activity more than either product alone. The results show that, in T. brucei, bisphosphonium compounds do not principally act on succinate dehydrogenase but on the mitochondrial FoF1 ATPase.

  9. Trypanocidal action of bisphosphonium salts through a mitochondrial target in bloodstream form Trypanosoma brucei

    Science.gov (United States)

    Alkhaldi, Abdulsalam A.M.; Martinek, Jan; Panicucci, Brian; Dardonville, Christophe; Zíková, Alena; de Koning, Harry P.

    2015-01-01

    Lipophilic bisphosphonium salts are among the most promising antiprotozoal leads currently under investigation. As part of their preclinical evaluation we here report on their mode of action against African trypanosomes, the etiological agents of sleeping sickness. The bisphosphonium compounds CD38 and AHI-9 exhibited rapid inhibition of Trypanosoma brucei growth, apparently the result of cell cycle arrest that blocked the replication of mitochondrial DNA, contained in the kinetoplast, thereby preventing the initiation of S-phase. Incubation with either compound led to a rapid reduction in mitochondrial membrane potential, and ATP levels decreased by approximately 50% within 1 h. Between 4 and 8 h, cellular calcium levels increased, consistent with release from the depolarized mitochondria. Within the mitochondria, the Succinate Dehydrogenase complex (SDH) was investigated as a target for bisphosphonium salts, but while its subunit 1 (SDH1) was present at low levels in the bloodstream form trypanosomes, the assembled complex was hardly detectable. RNAi knockdown of the SDH1 subunit produced no growth phenotype, either in bloodstream or in the procyclic (insect) forms and we conclude that in trypanosomes SDH is not the target for bisphosphonium salts. Instead, the compounds inhibited ATP production in intact mitochondria, as well as the purified F1 ATPase, to a level that was similar to 1 mM azide. Co-incubation with azide and bisphosphonium compounds did not inhibit ATPase activity more than either product alone. The results show that, in T. brucei, bisphosphonium compounds do not principally act on succinate dehydrogenase but on the mitochondrial FoF1 ATPase. PMID:27054061

  10. Probing the metabolic network in bloodstream-form Trypanosoma brucei using untargeted metabolomics with stable isotope labelled glucose.

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    Darren J Creek

    2015-03-01

    Full Text Available Metabolomics coupled with heavy-atom isotope-labelled glucose has been used to probe the metabolic pathways active in cultured bloodstream form trypomastigotes of Trypanosoma brucei, a parasite responsible for human African trypanosomiasis. Glucose enters many branches of metabolism beyond glycolysis, which has been widely held to be the sole route of glucose metabolism. Whilst pyruvate is the major end-product of glucose catabolism, its transamination product, alanine, is also produced in significant quantities. The oxidative branch of the pentose phosphate pathway is operative, although the non-oxidative branch is not. Ribose 5-phosphate generated through this pathway distributes widely into nucleotide synthesis and other branches of metabolism. Acetate, derived from glucose, is found associated with a range of acetylated amino acids and, to a lesser extent, fatty acids; while labelled glycerol is found in many glycerophospholipids. Glucose also enters inositol and several sugar nucleotides that serve as precursors to macromolecule biosynthesis. Although a Krebs cycle is not operative, malate, fumarate and succinate, primarily labelled in three carbons, were present, indicating an origin from phosphoenolpyruvate via oxaloacetate. Interestingly, the enzyme responsible for conversion of phosphoenolpyruvate to oxaloacetate, phosphoenolpyruvate carboxykinase, was shown to be essential to the bloodstream form trypanosomes, as demonstrated by the lethal phenotype induced by RNAi-mediated downregulation of its expression. In addition, glucose derivatives enter pyrimidine biosynthesis via oxaloacetate as a precursor to aspartate and orotate.

  11. Respiration of bloodstream forms of the parasite Trypanosoma brucei brucei is dependent on a plant-like alternative oxidase

    NARCIS (Netherlands)

    Clarkson, A. B.; Bienen, E. J.; Pollakis, G.; Grady, R. W.

    1989-01-01

    CoQ links the sn-glycerol-3-phosphate dehydrogenase and oxidase components of the cyanide-insensitive, non-cytochrome-mediated respiratory system of bloodstream African trypanosomes. In this and other characteristics, their respiratory system is similar to the alternative oxidase of plants. The

  12. The Phosphoproteome of Bloodstream Form Trypanosoma brucei, Causative Agent of African Sleeping Sickness

    OpenAIRE

    Nett, Isabelle R. E.; Martin, David M. A.; Miranda-Saavedra, Diego; Lamont, Douglas; Barber, Jonathan D.; Mehlert, Angela; Ferguson, Michael A. J.

    2009-01-01

    The protozoan parasite Trypanosoma brucei is the causative agent of human African sleeping sickness and related animal diseases, and it has over 170 predicted protein kinases. Protein phosphorylation is a key regulatory mechanism for cellular function that, thus far, has been studied in T.brucei principally through putative kinase mRNA knockdown and observation of the resulting phenotype. However, despite the relatively large kinome of this organism and the demonstrated essentiality of severa...

  13. Isolation and characterization of kinetoplast DNA from the bloodstream form of Trypanosoma brucei.

    NARCIS (Netherlands)

    A.H. Fairlamb; P.O. Weislogel; J.H.J. Hoeijmakers (Jan); P. Borst (Piet)

    1978-01-01

    textabstractWe have used restriction endonucleases PstI, EcoRI, HapII, HhaI, and S1 nuclease to demonstrate the presence of a large complex component, the maxi-circle, in addition to the major mini-circle component in kinetoplast DNA (kDNA) networks of Trypanosoma brucei (East African

  14. Alkaloids Induce Programmed Cell Death in Bloodstream Forms of Trypanosomes (Trypanosoma b. brucei

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    Michael Wink

    2008-10-01

    Full Text Available The potential induction of a programmed cell death (PCD in Trypanosoma b. brucei by 55 alkaloids of the quinoline, quinolizidine, isoquinoline, indole, terpene, tropane, steroid, and piperidine type was studied by measuring DNA fragmentation and changes in mitochondrial membrane potential. For comparison, the induction of apoptosis by the same alkaloids in human leukemia cells (Jurkat APO-S was tested. Several alkaloids of the isoquinoline, quinoline, indole and steroidal type (berberine, chelerythrine, emetine, sanguinarine, quinine, ajmalicine, ergotamine, harmine, vinblastine, vincristine, colchicine, chaconine, demissidine and veratridine induced programmed cell death, whereas quinolizidine, tropane, terpene and piperidine alkaloids were mostly inactive. Effective PCD induction (EC50 below 10 µM was caused in T. brucei by chelerythrine, emetine, sanguinarine, and chaconine. The active alkaloids can be characterized by their general property to inhibit protein biosynthesis, to intercalate DNA, to disturb membrane fluidity or to inhibit microtubule formation.

  15. Trypanosoma brucei: analysis of cytoplasmic Ca2+ during differentiation of bloodstream stages in vitro.

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    Stojdl, D F; Clarke, M W

    1996-06-01

    The highly regulated intracellular concentration of calcium (Ca2+) is a well-described regulator of diverse cellular events, including cell cycle control. In the present study we have addressed the regulation of cytosolic Ca2+ in differentiation events in the life cycle of the protozoan parasite Trypanosoma brucei. Bloodstream form (BSF) trypanosomes include the mitotically active long slender forms (LS) which differentiate to two nondividing stages--intermediate (INT) which transform into short stumpy (SS) forms. An axenic in vitro culture system was used to cultivate LS to a density greater than 1.0 x 10(6) cells/ml/day. Populations of the intermediate BSF (INT) and SS were derived from cultured LS by treatment with difluoromethyl ornithine (DFMO, 100 microM) for 2 and 4 days, respectively. A semiquantitative reverse transcriptase-coupled polymerase chain reaction protocol (SQ-RT-PCR) was developed to objectively distinguish the three BSF by monitoring the relative levels of stage-specific mRNAs--cytochrome oxidase II (COXII), variant surface glycoprotein, and procyclin during the differentiation of LS to SS, showing an increase in COXII and procyclin mRNA expression during this process of differentiation. Basal cytosolic Ca2+ levels [Ca2+]i of populations of LS, INT, and SS were studied using Indo-1 dual emission fluorometry. [Ca2+]i was maximal in dividing LS cells and was shown to decrease coincidentally with early events in the process of differentiation to INT and SS. Thapsigargin (1 microM), reported to cause the release of Ca2+ from the endoplasmic reticulum, elevated [Ca2+]i by about 30-60 nM in all BSF; however, the total thapsigargin-releasable stores decreased in parallel with the decrease in basal [Ca2+]i. Control treatments verified that elevations in [Ca2+]i in response to thapsigargin were intracellular in origin. These results may reflect the cessation of cytosolic Ca2+ transients involved in the regulation of mitosis as the parasite exits from

  16. Cultivation in a semi-defined medium of animal infective forms of Trypanosoma brucei, T. equiperdum, T. evansi, T. rhodesiense and T. gambiense.

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    Baltz, T; Baltz, D; Giroud, C; Crockett, J

    1985-05-01

    A semi-defined medium for the cultivation of bloodstream forms of the African trypanosome brucei subgroup was developed. Out of 14 different strains tested, 10 could be cultured including Trypanosoma brucei, T. equiperdum, T. evansi, T. rhodesiense and T. gambiense. The presence of a reducing agent (2-mercaptoethanol or thioglycerol) was found to be essential for growth. The standard medium consisted of Hepes buffered minimum essential medium with Earle's salts supplemented with 0.2 mM 2-mercaptoethanol, 2 mM pyruvate and 10% inactivated serum either from rabbit (T. brucei, T. equiperdum, T. evansi and T. rhodesiense) or human (T. gambiense). Although a general medium could be defined for the long-term maintenance of trypanosome cultures, the initiation to culture nevertheless required particular conditions for the different strains. The cultured trypanosomes had all the characteristics of the in vivo bloodstream forms including: morphology, infectivity, antigenic variation and glucose metabolism.

  17. Trypanosoma brucei mitochondrial respiratome: Composition and organization in procyclic form

    KAUST Repository

    Acestor, Nathalie

    2011-05-24

    The mitochondrial respiratory chain is comprised of four different protein complexes (I-IV), which are responsible for electron transport and generation of proton gradient in the mitochondrial intermembrane space. This proton gradient is then used by F oF 1-ATP synthase (complex V) to produce ATP by oxidative phosphorylation. In this study, the respiratory complexes I, II, and III were affinity purified from Trypanosoma brucei procyclic form cells and their composition was determined by mass spectrometry. The results along with those that we previously reported for complexes IV and V showed that the respiratome of Trypanosoma is divergent because many of its proteins are unique to this group of organisms. The studies also identified two mitochondrial subunit proteins of respiratory complex IV that are encoded by edited RNAs. Proteomics data from analyses of complexes purified using numerous tagged component proteins in each of the five complexes were used to generate the first predicted protein-protein interaction network of the Trypanosoma brucei respiratory chain. These results provide the first comprehensive insight into the unique composition of the respiratory complexes in Trypanosoma brucei, an early diverged eukaryotic pathogen. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. In or out? On the tightness of glycosomal compartmentalizatin of metabolites and enzymes in Trypanosoma brucei.

    NARCIS (Netherlands)

    Haanstra, J.R.; Bakker, B.M.; Michels, P.A.M.

    2014-01-01

    Trypanosomatids sequester large parts of glucose metabolism inside specialised peroxisomes, called glycosomes. Many studies have shown that correct glycosomal compartmentalization of glycolytic enzymes is essential for bloodstream-form Trypanosoma brucei. The recent finding of pore-forming

  19. Glucose uptake occurs by facilitated diffusion in procyclic forms of Trypanosoma brucei.

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    Wille, U; Seyfang, A; Duszenko, M

    1996-02-15

    The glucose transporter of Trypanosoma brucei procyclic forms was characterized and compared with its bloodstream form counterpart. Measuring the glucose consumption enzymatically, we determined a saturable uptake process of relatively high affinity (Km = 80 microM, Vmax = 4 nmol min-1 10(-8) cells), which showed substrate inhibition at glucose concentrations above 1.5 mM (Ki = 21 mM). Control experiments measuring deoxy-D-[3H]Glc uptake under zero-trans conditions indicated that substrate inhibition occurred on the level of glycolysis. Temperature-dependent kinetics revealed a temperature quotient of Q10 = 2.33 and an activation energy of Ea = 64 kJ mol-1. As shown by trans-stimulation experiments, glucose uptake was stereospecific for the D isomer, whereas L-glucose was not recognized. Inhibitor studies using either the uncoupler carbonylcyanide-4-(trifluoromethoxy)phenylhydrazone (5 microM), the H+/ATPase inhibitor N,N'-dicyclohexylcarbodiimide (20 microM), the ionophor monensin (1 microM), or the Na+/K+-ATPase inhibitor ouabain (1 mM) showed insignificant effects on transport efficiency. The procyclic glucose transporter was subsequently enriched in a plasma-membrane fraction and functionally reconstituted into proteoliposomes. Using Na+-free conditions in the absence of a proton gradient, the specific activity of D-[14C]glucose transport was determined as 2.9 nmol min-1 (mg protein)-1 at 0.2 mM glucose. From these cumulative results, we conclude that glucose uptake by the procyclic insect form of the parasite occurs by facilitated diffusion, similar to the hexose-transport system expressed in bloodstream forms. However, the markedly higher substrate affinity indicates a differential expression of different transporter isoforms throughout the lifecycle.

  20. Trypanosoma brucei TbIF1 inhibits the essential F1-ATPase in the infectious form of the parasite.

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    Brian Panicucci

    2017-04-01

    Full Text Available The mitochondrial (mt FoF1-ATP synthase of the digenetic parasite, Trypanosoma brucei, generates ATP during the insect procyclic form (PF, but becomes a perpetual consumer of ATP in the mammalian bloodstream form (BF, which lacks a canonical respiratory chain. This unconventional dependence on FoF1-ATPase is required to maintain the essential mt membrane potential (Δψm. Normally, ATP hydrolysis by this rotary molecular motor is restricted to when eukaryotic cells experience sporadic hypoxic conditions, during which this compulsory function quickly depletes the cellular ATP pool. To protect against this cellular treason, the highly conserved inhibitory factor 1 (IF1 binds the enzyme in a manner that solely inhibits the hydrolytic activity. Intriguingly, we were able to identify the IF1 homolog in T. brucei (TbIF1, but determined that its expression in the mitochondrion is tightly regulated throughout the life cycle as it is only detected in PF cells. TbIF1 appears to primarily function as an emergency brake in PF cells, where it prevented the restoration of the Δψm by FoF1-ATPase when respiration was chemically inhibited. In vitro, TbIF1 overexpression specifically inhibits the hydrolytic activity but not the synthetic capability of the FoF1-ATP synthase in PF mitochondria. Furthermore, low μM amounts of recombinant TbIF1 achieve the same inhibition of total mt ATPase activity as the FoF1-ATPase specific inhibitors, azide and oligomycin. Therefore, even minimal ectopic expression of TbIF1 in BF cells proved lethal as the indispensable Δψm collapsed due to inhibited FoF1-ATPase. In summary, we provide evidence that T. brucei harbors a natural and potent unidirectional inhibitor of the vital FoF1-ATPase activity that can be exploited for future structure-based drug design.

  1. How Does the VSG Coat of Bloodstream Form African Trypanosomes Interact with External Proteins?

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    Schwede, Angela; Macleod, Olivia J S; MacGregor, Paula; Carrington, Mark

    2015-12-01

    Variations on the statement "the variant surface glycoprotein (VSG) coat that covers the external face of the mammalian bloodstream form of Trypanosoma brucei acts a physical barrier" appear regularly in research articles and reviews. The concept of the impenetrable VSG coat is an attractive one, as it provides a clear model for understanding how a trypanosome population persists; each successive VSG protects the plasma membrane and is immunologically distinct from previous VSGs. What is the evidence that the VSG coat is an impenetrable barrier, and how do antibodies and other extracellular proteins interact with it? In this review, the nature of the extracellular surface of the bloodstream form trypanosome is described, and past experiments that investigated binding of antibodies and lectins to trypanosomes are analysed using knowledge of VSG sequence and structure that was unavailable when the experiments were performed. Epitopes for some VSG monoclonal antibodies are mapped as far as possible from previous experimental data, onto models of VSG structures. The binding of lectins to some, but not to other, VSGs is revisited with more recent knowledge of the location and nature of N-linked oligosaccharides. The conclusions are: (i) Much of the variation observed in earlier experiments can be explained by the identity of the individual VSGs. (ii) Much of an individual VSG is accessible to antibodies, and the barrier that prevents access to the cell surface is probably at the base of the VSG N-terminal domain, approximately 5 nm from the plasma membrane. This second conclusion highlights a gap in our understanding of how the VSG coat works, as several plasma membrane proteins with large extracellular domains are very unlikely to be hidden from host antibodies by VSG.

  2. Bromodomain Proteins Contribute to Maintenance of Bloodstream Form Stage Identity in the African Trypanosome.

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    Danae Schulz

    2015-12-01

    Full Text Available Trypanosoma brucei, the causative agent of African sleeping sickness, is transmitted to its mammalian host by the tsetse. In the fly, the parasite's surface is covered with invariant procyclin, while in the mammal it resides extracellularly in its bloodstream form (BF and is densely covered with highly immunogenic Variant Surface Glycoprotein (VSG. In the BF, the parasite varies this highly immunogenic surface VSG using a repertoire of ~2500 distinct VSG genes. Recent reports in mammalian systems point to a role for histone acetyl-lysine recognizing bromodomain proteins in the maintenance of stem cell fate, leading us to hypothesize that bromodomain proteins may maintain the BF cell fate in trypanosomes. Using small-molecule inhibitors and genetic mutants for individual bromodomain proteins, we performed RNA-seq experiments that revealed changes in the transcriptome similar to those seen in cells differentiating from the BF to the insect stage. This was recapitulated at the protein level by the appearance of insect-stage proteins on the cell surface. Furthermore, bromodomain inhibition disrupts two major BF-specific immune evasion mechanisms that trypanosomes harness to evade mammalian host antibody responses. First, monoallelic expression of the antigenically varied VSG is disrupted. Second, rapid internalization of antibodies bound to VSG on the surface of the trypanosome is blocked. Thus, our studies reveal a role for trypanosome bromodomain proteins in maintaining bloodstream stage identity and immune evasion. Importantly, bromodomain inhibition leads to a decrease in virulence in a mouse model of infection, establishing these proteins as potential therapeutic drug targets for trypanosomiasis. Our 1.25Å resolution crystal structure of a trypanosome bromodomain in complex with I-BET151 reveals a novel binding mode of the inhibitor, which serves as a promising starting point for rational drug design.

  3. Steroid Alkaloids from Holarrhena africana with Strong Activity against Trypanosoma brucei rhodesiense

    OpenAIRE

    Charles Okeke Nnadi; Ngozi Justina Nwodo; Marcel Kaiser; Reto Brun; Thomas J. Schmidt

    2017-01-01

    In our continued search for natural compounds with activity against Trypanosoma brucei, causative agent of human African trypanosomiasis (HAT, “sleeping sickness”), we have investigated extracts from the leaves and bark of the West African Holarrhena africana (syn. Holarrhena floribunda; Apocynaceae). The extracts and their alkaloid-enriched fractions displayed promising in vitro activity against bloodstream forms of T. brucei rhodesiense (Tbr; East African HAT). Bioactivity-guided chromatogr...

  4. Essential Assembly Factor Rpf2 Forms Novel Interactions within the 5S RNP in Trypanosoma brucei.

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    Kamina, Anyango D; Jaremko, Daniel; Christen, Linda; Williams, Noreen

    2017-01-01

    regulatory checkpoints during ribosome biogenesis. We have previously characterized the 5S RNP in T. brucei and showed that trypanosome-specific proteins P34 and P37 are part of this complex. In this study, we characterize for the first time the interactions of the homolog of the assembly factor Rpf2 with members of the 5S RNP in another organism besides fungi. Our studies show that Rpf2 is essential in T. brucei and that it forms unique interactions within the 5S RNP, particularly with P34 and P37. These studies have identified parasite-specific interactions that can potentially function as new therapeutic targets against sleeping sickness.

  5. Contribution of glucose transport to the control of the glycolytic flux in Trypanosoma brucei.

    NARCIS (Netherlands)

    Bakker, B.M.; Walsh, M.C.; ter Kuile, B.; Mensonides, F.I.C.; Michels, P.A.M.; Opperdoes, F.R.; Westerhoff, H.V.

    1999-01-01

    The rate of glucose transport across the plasma membrane of the bloodstream form of Trypanosoma brucei was modulated by titration of the hexose transporter with the inhibitor phloretin, and the effect on the glycolytic flux was measured. A rapid glucose uptake assay was developed to measure the

  6. Trypanosoma evansi is alike to Trypanosoma brucei brucei in the subcellular localisation of glycolytic enzymes

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    S Andrea Moreno

    2015-06-01

    Full Text Available Trypanosoma evansi, which causes surra, is descended from Trypanosoma brucei brucei, which causes nagana. Although both parasites are presumed to be metabolically similar, insufficient knowledge of T. evansi precludes a full comparison. Herein, we provide the first report on the subcellular localisation of the glycolytic enzymes in T. evansi, which is a alike to that of the bloodstream form (BSF of T. b. brucei: (i fructose-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH, hexokinase, phosphofructokinase, glucose-6-phosphate isomerase, phosphoglycerate kinase, triosephosphate isomerase (glycolytic enzymes and glycerol-3-phosphate dehydrogenase (a glycolysis-auxiliary enzyme in glycosomes, (ii enolase, phosphoglycerate mutase, pyruvate kinase (glycolytic enzymes and a GAPDH isoenzyme in the cytosol, (iii malate dehydrogenase in cytosol and (iv glucose-6-phosphate dehydrogenase in both glycosomes and the cytosol. Specific enzymatic activities also suggest that T. evansi is alike to the BSF of T. b. brucei in glycolytic flux, which is much faster than the pentose phosphate pathway flux, and in the involvement of cytosolic GAPDH in the NAD+/NADH balance. These similarities were expected based on the close phylogenetic relationship of both parasites.

  7. Trans-sialidase-like gene from the bloodstream form of ...

    African Journals Online (AJOL)

    SA) activities. Although many authors reported that TS is not found in the blood stream form (BSF) of African trypanosomes, SA activity has been observed in the sera of infected animals and the BSF parasites, contributing to initial and ...

  8. Adaptations of Trypanosoma brucei to gradual loss of kinetoplast DNA: Trypanosoma equiperdum and Trypanosoma evansi are petite mutants of T. brucei.

    Science.gov (United States)

    Lai, De-Hua; Hashimi, Hassan; Lun, Zhao-Rong; Ayala, Francisco J; Lukes, Julius

    2008-02-12

    Trypanosoma brucei is a kinetoplastid flagellate, the agent of human sleeping sickness and ruminant nagana in Africa. Kinetoplastid flagellates contain their eponym kinetoplast DNA (kDNA), consisting of two types of interlocked circular DNA molecules: scores of maxicircles and thousands of minicircles. Maxicircles have typical mitochondrial genes, most of which are translatable only after RNA editing. Minicircles encode guide RNAs, required for decrypting the maxicircle transcripts. The life cycle of T. brucei involves a bloodstream stage (BS) in vertebrates and a procyclic stage (PS) in the tsetse fly vector. Partial [dyskinetoplastidy (Dk)] or total [akinetoplastidy (Ak)] loss of kDNA locks the trypanosome in the BS form. Transmission between vertebrates becomes mechanical without PS and tsetse mediation, allowing the parasite to spread outside the African tsetse belt. Trypanosoma equiperdum and Trypanosoma evansi are agents of dourine and surra, diseases of horses, camels, and water buffaloes. We have characterized representative strains of T. equiperdum and T. evansi by numerous molecular and classical parasitological approaches. We show that both species are actually strains of T. brucei, which lost part (Dk) or all (Ak) of their kDNA. These trypanosomes are not monophyletic clades and do not qualify for species status. They should be considered two subspecies, respectively T. brucei equiperdum and T. brucei evansi, which spontaneously arose recently. Dk/Ak trypanosomes may potentially emerge repeatedly from T. brucei.

  9. An Atypical Mitochondrial Carrier That Mediates Drug Action in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Juan P de Macêdo

    2015-05-01

    Full Text Available Elucidating the mechanism of action of trypanocidal compounds is an important step in the development of more efficient drugs against Trypanosoma brucei. In a screening approach using an RNAi library in T. brucei bloodstream forms, we identified a member of the mitochondrial carrier family, TbMCP14, as a prime candidate mediating the action of a group of anti-parasitic choline analogs. Depletion of TbMCP14 by inducible RNAi in both bloodstream and procyclic forms increased resistance of parasites towards the compounds by 7-fold and 3-fold, respectively, compared to uninduced cells. In addition, down-regulation of TbMCP14 protected bloodstream form mitochondria from a drug-induced decrease in mitochondrial membrane potential. Conversely, over-expression of the carrier in procyclic forms increased parasite susceptibility more than 13-fold. Metabolomic analyses of parasites over-expressing TbMCP14 showed increased levels of the proline metabolite, pyrroline-5-carboxylate, suggesting a possible involvement of TbMCP14 in energy production. The generation of TbMCP14 knock-out parasites showed that the carrier is not essential for survival of T. brucei bloodstream forms, but reduced parasite proliferation under standard culture conditions. In contrast, depletion of TbMCP14 in procyclic forms resulted in growth arrest, followed by parasite death. The time point at which parasite proliferation stopped was dependent on the major energy source, i.e. glucose versus proline, in the culture medium. Together with our findings that proline-dependent ATP production in crude mitochondria from TbMCP14-depleted trypanosomes was reduced compared to control mitochondria, the study demonstrates that TbMCP14 is involved in energy production in T. brucei. Since TbMCP14 belongs to a trypanosomatid-specific clade of mitochondrial carrier family proteins showing very poor similarity to mitochondrial carriers of mammals, it may represent an interesting target for drug

  10. Characterization of Trypanosoma brucei dihydroorotate dehydrogenase as a possible drug target; structural, kinetic and RNAi studies.

    Science.gov (United States)

    Arakaki, Tracy L; Buckner, Frederick S; Gillespie, J Robert; Malmquist, Nicholas A; Phillips, Margaret A; Kalyuzhniy, Oleksandr; Luft, Joseph R; Detitta, George T; Verlinde, Christophe L M J; Van Voorhis, Wesley C; Hol, Wim G J; Merritt, Ethan A

    2008-04-01

    Nucleotide biosynthesis pathways have been reported to be essential in some protozoan pathogens. Hence, we evaluated the essentiality of one enzyme in the pyrimidine biosynthetic pathway, dihydroorotate dehydrogenase (DHODH) from the eukaryotic parasite Trypanosoma brucei through gene knockdown studies. RNAi knockdown of DHODH expression in bloodstream form T. brucei did not inhibit growth in normal medium, but profoundly retarded growth in pyrimidine-depleted media or in the presence of the known pyrimidine uptake antagonist 5-fluorouracil (5-FU). These results have significant implications for the development of therapeutics to combat T. brucei infection. Specifically, a combination therapy including a T. brucei-specific DHODH inhibitor plus 5-FU may prove to be an effective therapeutic strategy. We also show that this trypanosomal enzyme is inhibited by known inhibitors of bacterial Class 1A DHODH, in distinction to the sensitivity of DHODH from human and other higher eukaryotes. This selectivity is supported by the crystal structure of the T. brucei enzyme, which is reported here at a resolution of 1.95 A. Additional research, guided by the crystal structure described herein, is needed to identify potent inhibitors of T. brucei DHODH.

  11. INFECTED WITH TRYPANOSOMA BRUCEI BRUCEI

    African Journals Online (AJOL)

    v brucei infection where for example tant components of extra-cellular the parasite infectivity potential and toxicological effects have been sues in animal. They are ... homeostasis (1,2, 3). With a unique ability to main- tain the cellular contents and ions stable concentrations, Trypano- soma b. brucei, to which humans.

  12. Interaction between Gallotannin and a Recombinant Form of Arginine Kinase of Trypanosoma brucei: Thermodynamic and Spectrofluorimetric Evaluation

    Directory of Open Access Journals (Sweden)

    O. S. Adeyemi

    2014-01-01

    Full Text Available Current chemotherapies against trypanosomiasis are beset with diverse challenges, a situation which underscores the numerous research efforts aimed at finding newer and effective treatments. Arginine kinase of trypanosome has been validated as target for drug development against trypanosomiasis. The present study investigated the interaction between a recombinant form of the arginine kinase (rTbAK of trypanosome and gallotannin. The interaction between gallotannin and recombinant arginine kinase of Trypanosoma brucei caused significant decrease of enzyme activity. Kinetic analysis revealed the interaction to be of noncompetitive inhibition. Further thermodynamic analysis showed that the interaction between gallotannin and the recombinant arginine kinase was nonspontaneous and involved hydrophobic forces. The Ksv values and the FRET analysis suggest that static quenching of fluorescence intensity by gallotannin was static. Data revealed inhibitory interactions between gallotannin and rTbAK of trypanosome. Although the mechanism of inhibition is not clear yet, molecular docking studies are ongoing to clearly define the inhibitory interactions between the gallotannin and rTbAK. The knowledge of such binding properties would enrich development of selective inhibitors for the arginine kinase of Trypanosoma brucei.

  13. Apocytochrome b and other mitochondrial DNA sequences are differentially expressed during the life cycle of Trypanosoma brucei.

    OpenAIRE

    Feagin, J E; Jasmer, D P; Stuart, K

    1985-01-01

    Cytochromes and Krebs cycle enzymes are not detected in bloodstream forms of Trypanosoma brucei but are present in procyclic forms. We have analyzed transcription of mitochondrial sequences which contain the apocytochrome b gene and several other open reading frames (ORFs). Multiple transcripts map to individual DNA sequences located on both DNA strands. Larger low abundance transcripts map to multiple ORFs and may be precursor RNAs. Small abundant transcripts map to G + C rich sequences that...

  14. Genome-scale RNAi screens for high-throughput phenotyping in bloodstream-form African trypanosomes.

    Science.gov (United States)

    Glover, Lucy; Alsford, Sam; Baker, Nicola; Turner, Daniel J; Sanchez-Flores, Alejandro; Hutchinson, Sebastian; Hertz-Fowler, Christiane; Berriman, Matthew; Horn, David

    2015-01-01

    The ability to simultaneously assess every gene in a genome for a role in a particular process has obvious appeal. This protocol describes how to perform genome-scale RNAi library screens in bloodstream-form African trypanosomes, a family of parasites that causes lethal human and animal diseases and also serves as a model for studies on basic aspects of eukaryotic biology and evolution. We discuss strain assembly, screen design and implementation, the RNAi target sequencing approach and hit validation, and we provide a step-by-step protocol. A screen can yield from one to thousands of 'hits' associated with the phenotype of interest. The screening protocol itself takes 2 weeks or less to be completed, and high-throughput sequencing may also be completed within weeks. Pre- and post-screen strain assembly, validation and follow-up can take several months, depending on the type of screen and the number of hits analyzed.

  15. Mechanisms Mediating Antigenic Variation in Trypanosoma brucei

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    Rudenko Gloria

    1999-01-01

    Full Text Available Antigenic variation in Trypanosoma brucei is a highly sophisticated survival strategy involving switching between the transcription of one of an estimated thousand variant surface glycoprotein (VSG genes. Switching involves either transcriptional control, resulting in switching between different VSG expression sites; or DNA rearrangement events slotting previously inactive VSG genes into an active VSG expression site. In recent years, considerable progress has been made in techniques allowing us to genetically modify infective bloodstream form trypanosomes. This is allowing us to reengineer VSG expression sites, and look at the effect on the mechanisms subsequently used for antigenic variation. We can now begin a dissection of a highly complicated survival strategy mediated by many different mechanisms operating simultaneously.

  16. Trypanosoma brucei CYP51: Essentiality and Targeting Therapy in an Experimental Model.

    Science.gov (United States)

    Dauchy, Frédéric-Antoine; Bonhivers, Mélanie; Landrein, Nicolas; Dacheux, Denis; Courtois, Pierrette; Lauruol, Florian; Daulouède, Sylvie; Vincendeau, Philippe; Robinson, Derrick R

    2016-11-01

    Trypanosoma brucei gambiense is the main causative agent of Human African Trypanosomiasis (HAT), also known as sleeping sickness. Because of limited alternatives and treatment toxicities, new therapeutic options are urgently needed for patients with HAT. Sterol 14alpha-demethylase (CYP51) is a potential drug target but its essentiality has not been determined in T. brucei. We used a tetracycline-inducible RNAi system to assess the essentiality of CYP51 in T. brucei bloodstream form (BSF) cells and we evaluated the effect of posaconazole, a well-tolerated triazole drug, within a panel of virulent strains in vitro and in a murine model. Expression of CYP51 in several T. brucei cell lines was demonstrated by western blot and its essentiality was demonstrated by RNA interference (CYP51RNAi) in vitro. Following reduction of TbCYP51 expression by RNAi, cell growth was reduced and eventually stopped compared to WT or non-induced cells, showing the requirement of CYP51 in T. brucei. These phenotypes were rescued by addition of ergosterol. Additionally, CYP51RNAi induction caused morphological defects with multiflagellated cells (pnifurtimox-eflornithine combinations showed similar improvement in mice survival (p≤0.001). Our results provide support for a CYP51 targeting based treatment in HAT. Thus posaconazole used in combination may represent a therapeutic alternative for trypanosomiasis.

  17. The phosphoarginine energy-buffering system of trypanosoma brucei involves multiple arginine kinase isoforms with different subcellular locations.

    Directory of Open Access Journals (Sweden)

    Frank Voncken

    Full Text Available Phosphagen energy-buffering systems play an essential role in regulating the cellular energy homeostasis in periods of high-energy demand or energy supply fluctuations. Here we describe the phosphoarginine/arginine kinase system of the kinetoplastid parasite Trypanosoma brucei, consisting of three highly similar arginine kinase isoforms (TbAK1-3. Immunofluorescence microscopy using myc-tagged protein versions revealed that each isoform is located in a specific subcellular compartment: TbAK1 is exclusively found in the flagellum, TbAK2 in the glycosome, and TbAK3 in the cytosol of T. brucei. The flagellar location of TbAK1 is dependent on a 22 amino acid long N-terminal sequence, which is sufficient for targeting a GFP-fusion protein to the trypanosome flagellum. The glycosomal location of TbAK2 is in agreement with the presence of a conserved peroxisomal targeting signal, the C-terminal tripeptide 'SNL'. TbAK3 lacks any apparent targeting sequences and is accordingly located in the cytosol of the parasite. Northern blot analysis indicated that each TbAK isoform is differentially expressed in bloodstream and procyclic forms of T. brucei, while the total cellular arginine kinase activity was 3-fold higher in bloodstream form trypanosomes. These results suggest a substantial change in the temporal and spatial energy requirements during parasite differentiation. Increased arginine kinase activity improved growth of procyclic form T. brucei during oxidative challenges with hydrogen peroxide. Elimination of the total cellular arginine kinase activity by RNA interference significantly decreased growth (>90% of procyclic form T. brucei under standard culture conditions and was lethal for this life cycle stage in the presence of hydrogen peroxide. The putative physiological roles of the different TbAK isoforms in T. brucei are further discussed.

  18. The Phosphoarginine Energy-Buffering System of Trypanosoma brucei Involves Multiple Arginine Kinase Isoforms with Different Subcellular Locations

    Science.gov (United States)

    Wadforth, Cath; Harley, Maggie; Colasante, Claudia

    2013-01-01

    Phosphagen energy-buffering systems play an essential role in regulating the cellular energy homeostasis in periods of high-energy demand or energy supply fluctuations. Here we describe the phosphoarginine/arginine kinase system of the kinetoplastid parasite Trypanosoma brucei, consisting of three highly similar arginine kinase isoforms (TbAK1-3). Immunofluorescence microscopy using myc-tagged protein versions revealed that each isoform is located in a specific subcellular compartment: TbAK1 is exclusively found in the flagellum, TbAK2 in the glycosome, and TbAK3 in the cytosol of T. brucei. The flagellar location of TbAK1 is dependent on a 22 amino acid long N-terminal sequence, which is sufficient for targeting a GFP-fusion protein to the trypanosome flagellum. The glycosomal location of TbAK2 is in agreement with the presence of a conserved peroxisomal targeting signal, the C-terminal tripeptide ‘SNL’. TbAK3 lacks any apparent targeting sequences and is accordingly located in the cytosol of the parasite. Northern blot analysis indicated that each TbAK isoform is differentially expressed in bloodstream and procyclic forms of T. brucei, while the total cellular arginine kinase activity was 3-fold higher in bloodstream form trypanosomes. These results suggest a substantial change in the temporal and spatial energy requirements during parasite differentiation. Increased arginine kinase activity improved growth of procyclic form T. brucei during oxidative challenges with hydrogen peroxide. Elimination of the total cellular arginine kinase activity by RNA interference significantly decreased growth (>90%) of procyclic form T. brucei under standard culture conditions and was lethal for this life cycle stage in the presence of hydrogen peroxide. The putative physiological roles of the different TbAK isoforms in T. brucei are further discussed. PMID:23776565

  19. The krebs cycle enzyme α-ketoglutarate decarboxylase is an essential glycosomal protein in bloodstream African trypanosomes.

    Science.gov (United States)

    Sykes, Steven; Szempruch, Anthony; Hajduk, Stephen

    2015-03-01

    α-Ketoglutarate decarboxylase (α-KDE1) is a Krebs cycle enzyme found in the mitochondrion of the procyclic form (PF) of Trypanosoma brucei. The bloodstream form (BF) of T. brucei lacks a functional Krebs cycle and relies exclusively on glycolysis for ATP production. Despite the lack of a functional Krebs cycle, α-KDE1 was expressed in BF T. brucei and RNA interference knockdown of α-KDE1 mRNA resulted in rapid growth arrest and killing. Cell death was preceded by progressive swelling of the flagellar pocket as a consequence of recruitment of both flagellar and plasma membranes into the pocket. BF T. brucei expressing an epitope-tagged copy of α-KDE1 showed localization to glycosomes and not the mitochondrion. We used a cell line transfected with a reporter construct containing the N-terminal sequence of α-KDE1 fused to green fluorescent protein to examine the requirements for glycosome targeting. We found that the N-terminal 18 amino acids of α-KDE1 contain overlapping mitochondrion- and peroxisome-targeting sequences and are sufficient to direct localization to the glycosome in BF T. brucei. These results suggest that α-KDE1 has a novel moonlighting function outside the mitochondrion in BF T. brucei. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  20. Stearoyl-CoA desaturase is an essential enzyme for the parasitic protist Trypanosoma brucei

    Energy Technology Data Exchange (ETDEWEB)

    Alloatti, Andres [Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Santa Fe (Argentina); Gupta, Shreedhara; Gualdron-Lopez, Melisa; Nguewa, Paul A. [Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Universite Catholique de Louvain, Brussels (Belgium); Altabe, Silvia G. [Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Santa Fe (Argentina); Deumer, Gladys; Wallemacq, Pierre [Department of Clinical Chemistry, Cliniques Universitaires Saint-Luc, LTAP, Universite Catholique de Louvain, Brussels (Belgium); Michels, Paul A.M. [Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Universite Catholique de Louvain, Brussels (Belgium); Uttaro, Antonio D., E-mail: toniuttaro@yahoo.com.ar [Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Santa Fe (Argentina)

    2011-08-26

    Highlights: {yields} Inhibiting {Delta}9 desaturase drastically changes T. brucei's fatty-acid composition. {yields} Isoxyl specifically inhibits the {Delta}9 desaturase causing a growth arrest. {yields} RNA interference of desaturase expression causes a similar effect. {yields} Feeding T. brucei-infected mice with Isoxyl decreases the parasitemia. {yields} 70% of Isoxyl-treated mice survived the trypanosome infection. -- Abstract: Trypanosoma brucei, the etiologic agent of sleeping sickness, is exposed to important changes in nutrients and temperature during its life cycle. To adapt to these changes, the fluidity of its membranes plays a crucial role. This fluidity, mediated by the fatty-acid composition, is regulated by enzymes named desaturases. We have previously shown that the oleoyl desaturase is essential for Trypanosoma cruzi and T. brucei. In this work, we present experimental support for the relevance of stearoyl-CoA desaturase (SCD) for T. brucei's survival, in both its insect or procyclic-form (PCF) and bloodstream-form (BSF) stages. We evaluated this essentiality in two different ways: by generating a SCD knocked-down parasite line using RNA interference, and by chemical inhibition of the enzyme with two compounds, Isoxyl and a thiastearate with the sulfur atom at position 10 (10-TS). The effective concentration for 50% growth inhibition (EC{sub 50}) of PCF was 1.0 {+-} 0.2 {mu}M for Isoxyl and 5 {+-} 2 {mu}M for 10-TS, whereas BSF appeared more susceptible with EC{sub 50} values 0.10 {+-} 0.03 {mu}M (Isoxyl) and 1.0 {+-} 0.6 {mu}M (10-TS). RNA interference showed to be deleterious for both stages of the parasite. In addition, T. brucei-infected mice were fed with Isoxyl, causing a reduction of the parasitemia and an increase of the rodents' survival.

  1. NLP is a novel transcription regulator involved in VSG expression site control in Trypanosoma brucei.

    Science.gov (United States)

    Narayanan, Mani Shankar; Kushwaha, Manish; Ersfeld, Klaus; Fullbrook, Alexander; Stanne, Tara M; Rudenko, Gloria

    2011-03-01

    Trypanosoma brucei mono-allelically expresses one of approximately 1500 variant surface glycoprotein (VSG) genes while multiplying in the mammalian bloodstream. The active VSG is transcribed by RNA polymerase I in one of approximately 15 telomeric VSG expression sites (ESs). T. brucei is unusual in controlling gene expression predominantly post-transcriptionally, and how ESs are mono-allelically controlled remains a mystery. Here we identify a novel transcription regulator, which resembles a nucleoplasmin-like protein (NLP) with an AT-hook motif. NLP is key for ES control in bloodstream form T. brucei, as NLP knockdown results in 45- to 65-fold derepression of the silent VSG221 ES. NLP is also involved in repression of transcription in the inactive VSG Basic Copy arrays, minichromosomes and procyclin loci. NLP is shown to be enriched on the 177- and 50-bp simple sequence repeats, the non-transcribed regions around rDNA and procyclin, and both active and silent ESs. Blocking NLP synthesis leads to downregulation of the active ES, indicating that NLP plays a role in regulating appropriate levels of transcription of ESs in both their active and silent state. Discovery of the unusual transcription regulator NLP provides new insight into the factors that are critical for ES control.

  2. Isolation and analysis of the genetic diversity of repertoires of VSG expression site containing telomeres from Trypanosoma brucei gambiense, T. b. brucei and T. equiperdum

    Directory of Open Access Journals (Sweden)

    Becker Marion

    2008-08-01

    Full Text Available Abstract Background African trypanosomes (including Trypanosoma brucei are unicellular parasites which multiply in the mammalian bloodstream. T. brucei has about twenty telomeric bloodstream form Variant Surface Glycoprotein (VSG expression sites (BESs, of which one is expressed at a time in a mutually exclusive fashion. BESs are polycistronic transcription units, containing a variety of families of expression site associated genes (ESAGs in addition to the telomeric VSG. These polymorphic ESAG families are thought to play a role in parasite-host adaptation, and it has been proposed that ESAG diversity might be related to host range. Analysis of the genetic diversity of these telomeric gene families has been confounded by the underrepresentation of telomeric sequences in standard libraries. We have previously developed a method to selectively isolate sets of trypanosome BES containing telomeres using Transformation associated recombination (TAR cloning in yeast. Results Here we describe the isolation of repertoires of BES containing telomeres from three trypanosome subspecies: Trypanosoma brucei gambiense DAL 972 (causative agent of West-African trypanosomiasis, T. b. brucei EATRO 2340 (a nonhuman infective strain and T. equiperdum STIB 818 (which causes a sexually transmitted disease in equines. We have sequenced and analysed the genetic diversity at four BES loci (BES promoter region, ESAG6, ESAG5 and ESAG2 from these three trypanosome BES repertoires. Conclusion With the exception of ESAG2, the BES sequence repertoires derived from T. b. gambiense are both less diverse than and nearly reciprocally monophyletic relative to those from T. b. brucei and T. equiperdum. Furthermore, although we find evidence for adaptive evolution in all three ESAG repertoires in T. b. brucei and T. equiperdum, only ESAG2 appears to be under diversifying selection in T. b. gambiense. This low level of variation in the T. b. gambiense BES sequence repertoires is

  3. Isolation and analysis of the genetic diversity of repertoires of VSG expression site containing telomeres from Trypanosoma brucei gambiense, T. b. brucei and T. equiperdum.

    Science.gov (United States)

    Young, Rosanna; Taylor, Jesse E; Kurioka, Ayako; Becker, Marion; Louis, Edward J; Rudenko, Gloria

    2008-08-12

    African trypanosomes (including Trypanosoma brucei) are unicellular parasites which multiply in the mammalian bloodstream. T. brucei has about twenty telomeric bloodstream form Variant Surface Glycoprotein (VSG) expression sites (BESs), of which one is expressed at a time in a mutually exclusive fashion. BESs are polycistronic transcription units, containing a variety of families of expression site associated genes (ESAGs) in addition to the telomeric VSG. These polymorphic ESAG families are thought to play a role in parasite-host adaptation, and it has been proposed that ESAG diversity might be related to host range. Analysis of the genetic diversity of these telomeric gene families has been confounded by the underrepresentation of telomeric sequences in standard libraries. We have previously developed a method to selectively isolate sets of trypanosome BES containing telomeres using Transformation associated recombination (TAR) cloning in yeast. Here we describe the isolation of repertoires of BES containing telomeres from three trypanosome subspecies: Trypanosoma brucei gambiense DAL 972 (causative agent of West-African trypanosomiasis), T. b. brucei EATRO 2340 (a nonhuman infective strain) and T. equiperdum STIB 818 (which causes a sexually transmitted disease in equines). We have sequenced and analysed the genetic diversity at four BES loci (BES promoter region, ESAG6, ESAG5 and ESAG2) from these three trypanosome BES repertoires. With the exception of ESAG2, the BES sequence repertoires derived from T. b. gambiense are both less diverse than and nearly reciprocally monophyletic relative to those from T. b. brucei and T. equiperdum. Furthermore, although we find evidence for adaptive evolution in all three ESAG repertoires in T. b. brucei and T. equiperdum, only ESAG2 appears to be under diversifying selection in T. b. gambiense. This low level of variation in the T. b. gambiense BES sequence repertoires is consistent both with the relatively narrow host range

  4. An Overview of Trypanosoma brucei Infections: An Intense Host-Parasite Interaction.

    Science.gov (United States)

    Ponte-Sucre, Alicia

    2016-01-01

    Trypanosoma brucei rhodesiense and T. brucei gambiense, the causative agents of Human African Trypanosomiasis, are transmitted by tsetse flies. Within the vector, the parasite undergoes through transformations that prepares it to infect the human host. Sequentially these developmental stages are the replicative procyclic (in which the parasite surface is covered by procyclins) and trypo-epimastigote forms, as well as the non-replicative, infective, metacyclic form that develops in the vector salivary glands. As a pre-adaptation to their life in humans, metacyclic parasites begin to express and be densely covered by the Variant Surface Glycoprotein (VSG). Once the metacyclic form invades the human host the parasite develops into the bloodstream form. Herein the VSG triggers a humoral immune response. To avoid this humoral response, and essential for survival while in the bloodstream, the parasite changes its cover periodically and sheds into the surroundings the expressed VSG, thus evading the consequences of the immune system activation. Additionally, tools comparable to quorum sensing are used by the parasite for the successful parasite transmission from human to insect. On the other hand, the human host promotes clearance of the parasite triggering innate and adaptive immune responses and stimulating cytokine and chemokine secretion. All in all, the host-parasite interaction is extremely active and leads to responses that need multiple control sites to develop appropriately.

  5. Regulation of Trypanosoma brucei Total and Polysomal mRNA during Development within Its Mammalian Host.

    Directory of Open Access Journals (Sweden)

    Paul Capewell

    Full Text Available The gene expression of Trypanosoma brucei has been examined extensively in the blood of mammalian hosts and in forms found in the midgut of its arthropod vector, the tsetse fly. However, trypanosomes also undergo development within the mammalian bloodstream as they progress from morphologically 'slender forms' to transmissible 'stumpy forms' through morphological intermediates. This transition is temporally progressive within the first wave of parasitaemia such that gene expression can be monitored in relatively pure slender and stumpy populations as well as during the progression between these extremes. The development also represents the progression of cells from translationally active forms adapted for proliferation in the host to translationally quiescent forms, adapted for transmission. We have used metabolic labelling to quantitate translational activity in slender forms, stumpy forms and in forms undergoing early differentiation to procyclic forms in vitro. Thereafter we have examined the cohort of total mRNAs that are enriched throughout development in the mammalian bloodstream (slender, intermediate and stumpy forms, irrespective of strain, revealing those that exhibit consistent developmental regulation rather than sample specific changes. Transcripts that cosediment with polysomes in stumpy forms and slender forms have also been enriched to identify transcripts that escape translational repression prior to transmission. Combined, the expression and polysomal association of transcripts as trypanosomes undergo development in the mammalian bloodstream have been defined, providing a resource for trypanosome researchers. This facilitates the identification of those that undergo developmental regulation in the bloodstream and therefore those likely to have a role in the survival and capacity for transmission of stumpy forms.

  6. Regulators of Trypanosoma brucei cell cycle progression and differentiation identified using a kinome-wide RNAi screen.

    Directory of Open Access Journals (Sweden)

    Nathaniel G Jones

    2014-01-01

    Full Text Available The African trypanosome, Trypanosoma brucei, maintains an integral link between cell cycle regulation and differentiation during its intricate life cycle. Whilst extensive changes in phosphorylation have been documented between the mammalian bloodstream form and the insect procyclic form, relatively little is known about the parasite's protein kinases (PKs involved in the control of cellular proliferation and differentiation. To address this, a T. brucei kinome-wide RNAi cell line library was generated, allowing independent inducible knockdown of each of the parasite's 190 predicted protein kinases. Screening of this library using a cell viability assay identified ≥42 PKs that are required for normal bloodstream form proliferation in culture. A secondary screen identified 24 PKs whose RNAi-mediated depletion resulted in a variety of cell cycle defects including in G1/S, kinetoplast replication/segregation, mitosis and cytokinesis, 15 of which are novel cell cycle regulators. A further screen identified for the first time two PKs, named repressor of differentiation kinase (RDK1 and RDK2, depletion of which promoted bloodstream to procyclic form differentiation. RDK1 is a membrane-associated STE11-like PK, whilst RDK2 is a NEK PK that is essential for parasite proliferation. RDK1 acts in conjunction with the PTP1/PIP39 phosphatase cascade to block uncontrolled bloodstream to procyclic form differentiation, whilst RDK2 is a PK whose depletion efficiently induces differentiation in the absence of known triggers. Thus, the RNAi kinome library provides a valuable asset for functional analysis of cell signalling pathways in African trypanosomes as well as drug target identification and validation.

  7. Trypanosoma brucei CYP51: Essentiality and Targeting Therapy in an Experimental Model.

    Directory of Open Access Journals (Sweden)

    Frédéric-Antoine Dauchy

    2016-11-01

    Full Text Available Trypanosoma brucei gambiense is the main causative agent of Human African Trypanosomiasis (HAT, also known as sleeping sickness. Because of limited alternatives and treatment toxicities, new therapeutic options are urgently needed for patients with HAT. Sterol 14alpha-demethylase (CYP51 is a potential drug target but its essentiality has not been determined in T. brucei. We used a tetracycline-inducible RNAi system to assess the essentiality of CYP51 in T. brucei bloodstream form (BSF cells and we evaluated the effect of posaconazole, a well-tolerated triazole drug, within a panel of virulent strains in vitro and in a murine model. Expression of CYP51 in several T. brucei cell lines was demonstrated by western blot and its essentiality was demonstrated by RNA interference (CYP51RNAi in vitro. Following reduction of TbCYP51 expression by RNAi, cell growth was reduced and eventually stopped compared to WT or non-induced cells, showing the requirement of CYP51 in T. brucei. These phenotypes were rescued by addition of ergosterol. Additionally, CYP51RNAi induction caused morphological defects with multiflagellated cells (p<0.05, suggesting cytokinesis dysfunction. The survival of CYP51RNAi Doxycycline-treated mice (p = 0.053 and of CYP51RNAi 5-day pre-induced Doxycycline-treated mice (p = 0.008 were improved compared to WT showing a CYP51 RNAi effect on trypanosomal virulence in mice. The posaconazole concentrations that inhibited parasite growth by 50% (IC50 were 8.5, 2.7, 1.6 and 0.12 μM for T. b. brucei 427 90-13, T. b. brucei Antat 1.1, T. b. gambiense Feo (Feo/ITMAP/1893 and T. b. gambiense Biyamina (MHOM/SD/82, respectively. During infection with these last three virulent strains, posaconazole-eflornithine and nifurtimox-eflornithine combinations showed similar improvement in mice survival (p≤0.001. Our results provide support for a CYP51 targeting based treatment in HAT. Thus posaconazole used in combination may represent a therapeutic

  8. Programmed Cell Death in Procyclic Form Trypanosoma brucei rhodesiense - Identification of Differentially Expressed Genes during Con A Induced Death

    Directory of Open Access Journals (Sweden)

    Welburn Susan C

    1999-01-01

    Full Text Available Trypanosoma brucei rhodesiense can be induced to undergo apoptosis after stimulation with Con A. As cell death in these parasites is associated with de novo gene expression we have applied a differential display technique, Randomly Amplified Differential Expressed Sequence-Polymerase Chain Reaction (RADES-PCR to the study of gene expression during Con A induced cell death in these organisms. Twenty-two differentially displayed products have been cloned and sequenced. These represent the first endogenous genes to be identified as implicated in cellular death in trypanosomatids (the most primitive eukaryote in which apoptosis has been described. Evidence for an ancestral death machinery, `proto-apoptosis' in single celled organisms is discussed.

  9. High-confidence glycosome proteome for procyclic form Trypanosoma brucei by epitope-tag organelle enrichment and SILAC proteomics.

    Science.gov (United States)

    Güther, Maria Lucia S; Urbaniak, Michael D; Tavendale, Amy; Prescott, Alan; Ferguson, Michael A J

    2014-06-06

    The glycosome of the pathogenic African trypanosome Trypanosoma brucei is a specialized peroxisome that contains most of the enzymes of glycolysis and several other metabolic and catabolic pathways. The contents and transporters of this membrane-bounded organelle are of considerable interest as potential drug targets. Here we use epitope tagging, magnetic bead enrichment, and SILAC quantitative proteomics to determine a high-confidence glycosome proteome for the procyclic life cycle stage of the parasite using isotope ratios to discriminate glycosomal from mitochondrial and other contaminating proteins. The data confirm the presence of several previously demonstrated and suggested pathways in the organelle and identify previously unanticipated activities, such as protein phosphatases. The implications of the findings are discussed.

  10. The inositol pyrophosphate synthesis pathway in Trypanosoma brucei is linked to polyphosphate synthesis in acidocalcisomes.

    Science.gov (United States)

    Cordeiro, Ciro D; Saiardi, Adolfo; Docampo, Roberto

    2017-10-01

    Inositol pyrophosphates are novel signaling molecules possessing high-energy pyrophosphate bonds and involved in a number of biological functions. Here, we report the correct identification and characterization of the kinases involved in the inositol pyrophosphate biosynthetic pathway in Trypanosoma brucei: inositol polyphosphate multikinase (TbIPMK), inositol pentakisphosphate 2-kinase (TbIP5K) and inositol hexakisphosphate kinase (TbIP6K). TbIP5K and TbIP6K were not identifiable by sequence alone and their activities were validated by enzymatic assays with the recombinant proteins or by their complementation of yeast mutants. We also analyzed T. brucei extracts for the presence of inositol phosphates using polyacrylamide gel electrophoresis and high-performance liquid chromatography. Interestingly, we could detect inositol phosphate (IP), inositol 4,5-bisphosphate (IP2 ), inositol 1,4,5-trisphosphate (IP3 ), and inositol hexakisphosphate (IP6 ) in T. brucei different stages. Bloodstream forms unable to produce inositol pyrophosphates, due to downregulation of TbIPMK expression by conditional knockout, have reduced levels of polyphosphate and altered acidocalcisomes. Our study links the inositol pyrophosphate pathway to the synthesis of polyphosphate in acidocalcisomes, and may lead to better understanding of these organisms and provide new targets for drug discovery. © 2017 John Wiley & Sons Ltd.

  11. NIMA-related kinase TbNRKC is involved in basal body separation in Trypanosoma brucei.

    Science.gov (United States)

    Pradel, Lydie C; Bonhivers, Mélanie; Landrein, Nicolas; Robinson, Derrick R

    2006-05-01

    The NIMA-related kinase 2 (NEK 2) has important cell cycle functions related to centriole integrity and splitting. Trypanosoma brucei does not possess centrioles, however, cytokinesis is coupled to basal body separation events. Here we report the first functional characterisation of a T. brucei basal body-cytoskeletal NIMA-related kinase (NRK) protein, TbNRKC. The TbNRKC kinase domain has high amino acid identity with the human NEK1 kinase domain (50%) but also shares 42% identity with human NEK2. TbNRKC is expressed in bloodstream and procyclic cells and functions as a bona fide kinase in vitro. Remarkably, RNAi knockdown of TbNRKC and overexpression of kinase-dead TbNRKC in procyclic forms induces the accumulation of cells with four basal bodies, whereas overexpression of active protein produces supernumary basal bodies and blocks cytokinesis. TbNRKC is located on mature and immature basal bodies and is the first T. brucei NRK to be found associated with the basal body cytokinesis pathway.

  12. T. brucei infection reduces B lymphopoiesis in bone marrow and truncates compensatory splenic lymphopoiesis through transitional B-cell apoptosis.

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    Viki Bockstal

    2011-06-01

    Full Text Available African trypanosomes of the Trypanosoma brucei species are extracellular protozoan parasites that cause the deadly disease African trypanosomiasis in humans and contribute to the animal counterpart, Nagana. Trypanosome clearance from the bloodstream is mediated by antibodies specific for their Variant Surface Glycoprotein (VSG coat antigens. However, T. brucei infection induces polyclonal B cell activation, B cell clonal exhaustion, sustained depletion of mature splenic Marginal Zone B (MZB and Follicular B (FoB cells, and destruction of the B-cell memory compartment. To determine how trypanosome infection compromises the humoral immune defense system we used a C57BL/6 T. brucei AnTat 1.1 mouse model and multicolor flow cytometry to document B cell development and maturation during infection. Our results show a more than 95% reduction in B cell precursor numbers from the CLP, pre-pro-B, pro-B, pre-B and immature B cell stages in the bone marrow. In the spleen, T. brucei induces extramedullary B lymphopoiesis as evidenced by significant increases in HSC-LMPP, CLP, pre-pro-B, pro-B and pre-B cell populations. However, final B cell maturation is abrogated by infection-induced apoptosis of transitional B cells of both the T1 and T2 populations which is not uniquely dependent on TNF-, Fas-, or prostaglandin-dependent death pathways. Results obtained from ex vivo co-cultures of living bloodstream form trypanosomes and splenocytes demonstrate that trypanosome surface coat-dependent contact with T1/2 B cells triggers their deletion. We conclude that infection-induced and possibly parasite-contact dependent deletion of transitional B cells prevents replenishment of mature B cell compartments during infection thus contributing to a loss of the host's capacity to sustain antibody responses against recurring parasitemic waves.

  13. Identification and Functional Characterisation of CRK12:CYC9, a Novel Cyclin-Dependent Kinase (CDK-Cyclin Complex in Trypanosoma brucei.

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    Séverine Monnerat

    Full Text Available The protozoan parasite, Trypanosoma brucei, is spread by the tsetse fly and causes trypanosomiasis in humans and animals. Both the life cycle and cell cycle of the parasite are complex. Trypanosomes have eleven cdc2-related kinases (CRKs and ten cyclins, an unusually large number for a single celled organism. To date, relatively little is known about the function of many of the CRKs and cyclins, and only CRK3 has previously been shown to be cyclin-dependent in vivo. Here we report the identification of a previously uncharacterised CRK:cyclin complex between CRK12 and the putative transcriptional cyclin, CYC9. CRK12:CYC9 interact to form an active protein kinase complex in procyclic and bloodstream T. brucei. Both CRK12 and CYC9 are essential for the proliferation of bloodstream trypanosomes in vitro, and we show that CRK12 is also essential for survival of T. brucei in a mouse model, providing genetic validation of CRK12:CYC9 as a novel drug target for trypanosomiasis. Further, functional characterisation of CRK12 and CYC9 using RNA interference reveals roles for these proteins in endocytosis and cytokinesis, respectively.

  14. Non-radioactive method for labelling Trypanosoma brucei brucei ...

    African Journals Online (AJOL)

    It was observed that (i) the biological activities of the T.brucei brucei like the motility, viability, and growth were not affected adversely by the biotinylation; (ii) as little as 100ug Sulfo-NHS-LC-Biotin was enough to label about 6x106 Trypanosoma Brucei Brucei; (iii) high temperature appears to have adverse effect on the ...

  15. Evaluation of some organic compounds on bloodstream forms of Trypanosoma cruzi

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    João S. Silva

    1992-09-01

    Full Text Available Accidental transmission of Chagas' disease to man by blood transfusion is a serious problem in Latin-America. This paper describes the testing of several synthetic, semi-synthetic, and natural compounds for their activity against blood trypomastigotes in vitro at 4-C. The compounds embody several types of chemical structures: benzoquinone, naphthoquinone, anthracenequinone, phenanthrenequinone, imidazole, piperazine, quinoline, xanthene, and simple benzenic and naphthalenic derivates. Some of them are for the first time tested against Trypanosoma cruzi. The toxic effect these compounds on this parasite was done by two quite distinct sets of experiments. In one set, the compounds were added to infected blood as ethanolic solution. In this situation the most active one was a furan-1, 2-naphthoquinone, in the same range as gentian violet, a new fact to be considered in the assessment of structure-activity relationships in this class of compounds. In other set, we tentatively evaluated the biological activity of water insoluble compounds by adding them in a pure form without solvent into infected blood. In this way some appear to be very active and it was postulated that the effectiveness of such compounds must result from interactions between them and specific blood components.

  16. Nitroheterocyclic drug resistance mechanisms in Trypanosoma brucei.

    Science.gov (United States)

    Wyllie, Susan; Foth, Bernardo J; Kelner, Anna; Sokolova, Antoaneta Y; Berriman, Matthew; Fairlamb, Alan H

    2016-03-01

    The objective of this study was to identify the mechanisms of resistance to nifurtimox and fexinidazole in African trypanosomes. Bloodstream-form Trypanosoma brucei were selected for resistance to nifurtimox and fexinidazole by stepwise exposure to increasing drug concentrations. Clones were subjected to WGS to identify putative resistance genes. Transgenic parasites modulating expression of genes of interest were generated and drug susceptibility phenotypes determined. Nifurtimox-resistant (NfxR) and fexinidazole-resistant (FxR) parasites shared reciprocal cross-resistance suggestive of a common mechanism of action. Previously, a type I nitroreductase (NTR) has been implicated in nitro drug activation. WGS of resistant clones revealed that NfxR parasites had lost >100 kb from one copy of chromosome 7, rendering them hemizygous for NTR as well as over 30 other genes. FxR parasites retained both copies of NTR, but lost >70 kb downstream of one NTR allele, decreasing NTR transcription by half. A single knockout line of NTR displayed 1.6- and 1.9-fold resistance to nifurtimox and fexinidazole, respectively. Since NfxR and FxR parasites are ∼6- and 20-fold resistant to nifurtimox and fexinidazole, respectively, additional factors must be involved. Overexpression and knockout studies ruled out a role for a putative oxidoreductase (Tb927.7.7410) and a hypothetical gene (Tb927.1.1050), previously identified in a genome-scale RNAi screen. NTR was confirmed as a key resistance determinant, either by loss of one gene copy or loss of gene expression. Further work is required to identify which of the many dozens of SNPs identified in the drug-resistant cell lines contribute to the overall resistance phenotype. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.

  17. Cytosolic peroxidases protect the lysosome of bloodstream African trypanosomes from iron-mediated membrane damage.

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    Corinna Hiller

    2014-04-01

    Full Text Available African trypanosomes express three virtually identical non-selenium glutathione peroxidase (Px-type enzymes which preferably detoxify lipid-derived hydroperoxides. As shown previously, bloodstream Trypanosoma brucei lacking the mitochondrial Px III display only a weak and transient proliferation defect whereas parasites that lack the cytosolic Px I and Px II undergo extremely fast lipid peroxidation and cell lysis. The phenotype can completely be rescued by supplementing the medium with the α-tocopherol derivative Trolox. The mechanism underlying the rapid cell death remained however elusive. Here we show that the lysosome is the origin of the cellular injury. Feeding the px I-II knockout parasites with Alexa Fluor-conjugated dextran or LysoTracker in the presence of Trolox yielded a discrete lysosomal staining. Yet upon withdrawal of the antioxidant, the signal became progressively spread over the whole cell body and was completely lost, respectively. T. brucei acquire iron by endocytosis of host transferrin. Supplementing the medium with iron or transferrin induced, whereas the iron chelator deferoxamine and apo-transferrin attenuated lysis of the px I-II knockout cells. Immunofluorescence microscopy with MitoTracker and antibodies against the lysosomal marker protein p67 revealed that disintegration of the lysosome precedes mitochondrial damage. In vivo experiments confirmed the negligible role of the mitochondrial peroxidase: Mice infected with px III knockout cells displayed only a slightly delayed disease development compared to wild-type parasites. Our data demonstrate that in bloodstream African trypanosomes, the lysosome, not the mitochondrion, is the primary site of oxidative damage and cytosolic trypanothione/tryparedoxin-dependent peroxidases protect the lysosome from iron-induced membrane peroxidation. This process appears to be closely linked to the high endocytic rate and distinct iron acquisition mechanisms of the infective

  18. Flux Analysis of the Trypanosoma brucei Glycolysis Based on a Multiobjective-Criteria Bioinformatic Approach

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    Amine Ghozlane

    2012-01-01

    Full Text Available Trypanosoma brucei is a protozoan parasite of major of interest in discovering new genes for drug targets. This parasite alternates its life cycle between the mammal host(s (bloodstream form and the insect vector (procyclic form, with two divergent glucose metabolism amenable to in vitro culture. While the metabolic network of the bloodstream forms has been well characterized, the flux distribution between the different branches of the glucose metabolic network in the procyclic form has not been addressed so far. We present a computational analysis (called Metaboflux that exploits the metabolic topology of the procyclic form, and allows the incorporation of multipurpose experimental data to increase the biological relevance of the model. The alternatives resulting from the structural complexity of networks are formulated as an optimization problem solved by a metaheuristic where experimental data are modeled in a multiobjective function. Our results show that the current metabolic model is in agreement with experimental data and confirms the observed high metabolic flexibility of glucose metabolism. In addition, Metaboflux offers a rational explanation for the high flexibility in the ratio between final products from glucose metabolism, thsat is, flux redistribution through the malic enzyme steps.

  19. Knockdown of asparagine synthetase A renders Trypanosoma brucei auxotrophic to asparagine.

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    Inês Loureiro

    Full Text Available Asparagine synthetase (AS catalyzes the ATP-dependent conversion of aspartate into asparagine using ammonia or glutamine as nitrogen source. There are two distinct types of AS, asparagine synthetase A (AS-A, known as strictly ammonia-dependent, and asparagine synthetase B (AS-B, which can use either ammonia or glutamine. The absence of AS-A in humans, and its presence in trypanosomes, suggested AS-A as a potential drug target that deserved further investigation. We report the presence of functional AS-A in Trypanosoma cruzi (TcAS-A and Trypanosoma brucei (TbAS-A: the purified enzymes convert L-aspartate into L-asparagine in the presence of ATP, ammonia and Mg(2+. TcAS-A and TbAS-A use preferentially ammonia as a nitrogen donor, but surprisingly, can also use glutamine, a characteristic so far never described for any AS-A. TbAS-A knockdown by RNAi didn't affect in vitro growth of bloodstream forms of the parasite. However, growth was significantly impaired when TbAS-A knockdown parasites were cultured in medium with reduced levels of asparagine. As expected, mice infections with induced and non-induced T. brucei RNAi clones were similar to those from wild-type parasites. However, when induced T. brucei RNAi clones were injected in mice undergoing asparaginase treatment, which depletes blood asparagine, the mice exhibited lower parasitemia and a prolonged survival in comparison to similarly-treated mice infected with control parasites. Our results show that TbAS-A can be important under in vivo conditions when asparagine is limiting, but is unlikely to be suitable as a drug target.

  20. Antitrypanosomal compounds from the essential oil and extracts of Keetia leucantha leaves with inhibitor activity on Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase.

    Science.gov (United States)

    Bero, J; Beaufay, C; Hannaert, V; Hérent, M-F; Michels, P A; Quetin-Leclercq, J

    2013-02-15

    Keetia leucantha is a West African tree used in traditional medicine to treat several diseases among which parasitic infections. The dichloromethane extract of leaves was previously shown to possess growth-inhibitory activities on Plasmodium falciparum, Trypanosoma brucei brucei and Leishmania mexicana mexicana with low or no cytotoxicity (>100 μg/ml on human normal fibroblasts) (Bero et al. 2009, 2011). In continuation of our investigations on the antitrypanosomal compounds from this dichloromethane extract, we analyzed by GC-FID and GC-MS the essential oil of its leaves obtained by hydrodistillation and the major triterpenic acids in this extract by LC-MS. Twenty-seven compounds were identified in the oil whose percentages were calculated using the normalization method. The essential oil, seven of its constituents and the three triterpenic acids were evaluated for their antitrypanosomal activity on Trypanosoma brucei brucei bloodstream forms (Tbb BSF) and procyclic forms (Tbb PF) to identify an activity on the glycolytic process of trypanosomes. The oil showed an IC(50) of 20.9 μg/ml on Tbb BSF and no activity was observed on Tbb PF. The best antitrypanosomal activity was observed for ursolic acid with IC(50) of 2.5 and 6.5 μg/ml respectively on Tbb BSF and Tbb PF. The inhibitory activity on a glycolytic enzyme of T. brucei, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), was also evaluated for betulinic acid, olenaolic acid, ursolic acid, phytol, α-ionone and β-ionone. The three triterpenic acids and β-ionone showed inhibitory activities on GAPDH with oleanolic acid being the most active with an inhibition of 72.63% at 20 μg/ml. This paper reports for the first time the composition and antitrypanosomal activity of the essential oil of Keetia leucantha. Several of its constituents and three triterpenic acids present in the dichloromethane leaves extract showed a higher antitrypanosomal activity on bloodstream forms of Tbb as compared to procyclic forms

  1. Trypanosoma brucei TbIF1 inhibits the essential Finf1/inf-ATPase in the infectious form of the parasite

    Czech Academy of Sciences Publication Activity Database

    Panicucci, Brian; Gahura, Ondřej; Zíková, Alena

    2017-01-01

    Roč. 11, č. 4 (2017), č. článku e0005552. ISSN 1935-2735 R&D Projects: GA MŠk(CZ) EE2.3.30.0032; GA ČR GA17-22248S Institutional support: RVO:60077344 Keywords : mt * TblF1 * Trypanosoma brucei Subject RIV: EE - Microbiology, Virology Impact factor: 3.834, year: 2016

  2. Taxonomy Icon Data: Trypanosoma brucei [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Trypanosoma brucei Trypanosoma brucei Trypanosoma_brucei_L.png Trypanosoma_brucei_NL.png Trypanosoma_bruce...i_S.png Trypanosoma_brucei_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Trypanosoma+bruce...i&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Trypanosoma+brucei&t=NL http://bioscie...ncedbc.jp/taxonomy_icon/icon.cgi?i=Trypanosoma+brucei&t=S http://biosciencedbc.jp.../taxonomy_icon/icon.cgi?i=Trypanosoma+brucei&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=121 ...

  3. [Spa types and antibiotic resistance of Staphylococcus aureus bloodstream isolates obtained form patients of the University Clinical Center in Gdańsk].

    Science.gov (United States)

    Wiśniewska, Katarzyna; Kasprzyk, Joanna; Piechowicz, Lidia; Bronk, Marek; Swieć, Krystyna

    2013-01-01

    Staphylococcus aureus is a leading cause of bloodstream infections. For epidemiological investigations of this bacteria spa genotyping is used as the method which has a high discriminatory power and gives results that can be easily compared between laboratories. In contrast to methicillin-resistant S.aureus (MRSA), relatively little is known about spa types among methicillin-susceptible strains (MSSA). We used spa typing and antibiotic resistance patterns analysis for retrospective study of S.aureus bloodstream isolates population from the University Clinical Centre (UCC) in Gdańsk. The study was performed on 53 isolates from patients of 19 different units/ departments of the UCC. The isolates were tested for the susceptibility to antimicrobial agents. Spa typing was performed on the basis of the sequence analysis of the polymorphic X region of the protein A gene (spa) amplified form the isolates. Spa types were determined by Ridom Staph Type software and were clustered into spa-CCs (clonal complexes) using the algorithm BURP-based upon repeat pattern. MLST (Multilocus Sequence Typing) clonal complexes were predicted from BURP analysis by the Ridom SpaServer database. In MRSA the staphylococcal chromosomal casette (SCC) mec was determined, Spa-typing yielded 26 types. Six spa-CC and seven singletons were identified. The most frequent was spa-CC021involving 38% of isolates. The CC021 consisted of 7 spa types and the most common was t021 corresponding with MLST-CC30. The second frequent was singleton, related to MLST-CC1, with only one type t127. There were 3 MRSA isolates in the population. The MRSA strains were identified as different spa types: t003/ SCCmecII, t008/SCCmecIV and clonally related to MSSA t032/SCCmecIV. No one MRSA strains belonged to spa-CC021. The spa clonal cluster corresponding with widely distributed among invasive S.aureus strains in Europe MLST-CC30 was found as the most frequent among S.aureus bloodstream isolates from the UCC. Occurrence of

  4. Hepatic response in Trypanosomia brucei brucei infected-rats ...

    African Journals Online (AJOL)

    Ethanol leaf extract of Tithonia diversifolia was investigated for its hepato-curative activity in Trypanosoma brucei brucei infected-rats. The phytochemical compositions of the plant extract were also evaluated. The leaf extract was administered 14 days post-infection at dose of 200 and 400 mg/kg orally once daily.

  5. In vitro investigation of Brazilian Cerrado plant extract activity against Plasmodium falciparum, Trypanosoma cruzi and T. brucei gambiense.

    Science.gov (United States)

    Charneau, Sébastien; de Mesquita, Mariana Laundry; Bastos, Izabela Marques Dourado; Santana, Jaime Martins; de Paula, José Elias; Grellier, Philippe; Espindola, Laila Salmen

    2016-06-01

    The threatened Brazilian Cerrado biome is an important biodiversity hotspot but still few explored that constitutes a potential reservoir of molecules to treat infectious diseases. We selected eight Cerrado plant species for screening against the erythrocytic stages of Plasmodium falciparum, human intracellular stages of Trypanosoma cruzi and bloodstream forms of T. brucei gambiense, and for their cytotoxicity upon the rat L6-myoblast cell line. Bioassays were performed with 37 hexane, ethyl acetate and ethanol extracts prepared from different plant organs. Activities against parasites were observed for 24 extracts: 9 with anti-P. falciparum, 4 with anti-T. cruzi and 11 with anti-T. brucei gambiense activities. High anti-protozoal activity (IC50 values < 10 μg/mL) without obvious cytotoxicity to L6 cells was observed for eight extracts from plants: Connarus suberosus, Blepharocalyx salicifolius, Psidium laruotteanum and Myrsine guianensis. Overall, studies of plant extracts will contribute to increase the biodiversity knowledge essential for Cerrado conservation and sustainable development.

  6. SUMOylation in Trypanosoma brucei

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    Cornelia Andrea Klein

    2013-10-01

    Full Text Available Small ubiquitin like modifier (SUMO proteins are involved in many processes in eukaryotes. We here show that Trypanosoma brucei SUMO (Tb927.5.3210 modifies many proteins. The levels of SUMOylation were unaffected by temperature changes but were increased by severe oxidative stress. We obtained evidence that trypanosome homologues of the SUMO conjugating enzyme Ubc9 (Tb927.2.2460 and the SUMO-specific protease SENP (Tb927.9.2220 are involved in SUMOylation and SUMO removal, respectively.

  7. Megazol and its bioisostere 4H-1,2,4-triazole: comparing the trypanocidal, cytotoxic and genotoxic activities and their in vitro and in silico interactions with the Trypanosoma brucei nitroreductase enzyme

    Directory of Open Access Journals (Sweden)

    Alcione Silva de Carvalho

    2014-06-01

    Full Text Available Megazol (7 is a 5-nitroimidazole that is highly active against Trypanosoma cruzi and Trypanosoma brucei, as well as drug-resistant forms of trypanosomiasis. Compound 7 is not used clinically due to its mutagenic and genotoxic properties, but has been largely used as a lead compound. Here, we compared the activity of 7 with its 4H-1,2,4-triazole bioisostere (8 in bloodstream forms of T. brucei and T. cruzi and evaluated their activation by T. brucei type I nitroreductase (TbNTR enzyme. We also analysed the cytotoxic and genotoxic effects of these compounds in whole human blood using Comet and fluorescein diacetate/ethidium bromide assays. Although the only difference between 7 and 8 is the substitution of sulphur (in the thiadiazole in 7 for nitrogen (in the triazole in 8, the results indicated that 8 had poorer antiparasitic activity than 7 and was not genotoxic, whereas 7 presented this effect. The determination of Vmax indicated that although 8 was metabolised more rapidly than 7, it bounds to the TbNTR with better affinity, resulting in equivalent kcat/KM values. Docking assays of 7 and 8 performed within the active site of a homology model of the TbNTR indicating that 8 had greater affinity than 7.

  8. Diverse patterns of expression of the cytochrome c oxidase subunit I gene and unassigned reading frames 4 and 5 during the life cycle of Trypanosoma brucei.

    Science.gov (United States)

    Jasmer, D P; Feagin, J E; Stuart, K

    1985-01-01

    Transcription of a maxicircle segment from Trypanosoma brucei 164 that contains nucleotide (nt) sequences corresponding to cytochrome c oxidase subunit I (COI) and unassigned reading frames (URFs) 4 and 5 of other mitochondrial systems was investigated. Two major transcripts that differ in size by ca. 200 nt map to each of the COI and URF4 genes, while a single major transcript maps to URF5. In total RNA, the larger COI transcript is more abundant in procyclic forms (PFs) than in bloodstream forms (BFs), the smaller COI and both URF4 transcripts have similar abundances in both forms, and the single URF5 transcript is more abundant in BF than PF. These patterns of expression differ in poly(A)+ RNA as a result of a higher proportion of poly(A)+ mitochondrial transcripts in PFs than in BFs. In addition, small (300- to 500-nt) RNAs that are transcribed from C-rich sequences located between putative protein-coding genes also exhibit diverse patterns of expression between life cycle stages and differences in polyadenylation in PFs compared with BFs. These observations suggest that multiple processes regulate the differential expression of mitochondrial genes in T. brucei. Images PMID:2427925

  9. Lytic antibodies elicited by Trypanosoma cruzi infection recognize epitopes present on both bloodstream trypomastigote and epimastigote forms of parasite

    Directory of Open Access Journals (Sweden)

    Harumi A. Takehara

    1988-10-01

    Full Text Available Sera of Chaga's disease patients containing anti-T. cruzi lytic antibodies were submitted to affinity chromatography using Sepharose 4B conjugated with antigen extracted from epimasiigote or trypomasiigote forms of the parasite. Epimastigotes were obtained from culture at the exponential growth phase and the trypomastigotes from blood of infected and immunosuppressed mice. Antigen of both parasite forms was obtained by sonication of the parasites followed by centrifugation. Both antigens were then conjugated to activated Sepharose 4B. Affinity chromatography was performed by passing sera from chagasic patients through an immunoadsorbent column containing either epimasiigote or trypomasiigote antigens. Antibodies bound to the column were eluted with cold 0,2 M glycine buffer pH 2,8. The eluted antibodies were analysed regarding their isotype and lytic activity. The results showed that anti-T. cruzi lytic antibodies present in sera from chagasic patients are mainly located in the IgG isotype and recognize epitopes present in both trypomasiigote and epimastigote forms. A brief report of this work has already been published12.

  10. Spliced leader trapping reveals widespread alternative splicing patterns in the highly dynamic transcriptome of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Daniel Nilsson

    2010-08-01

    Full Text Available Trans-splicing of leader sequences onto the 5'ends of mRNAs is a widespread phenomenon in protozoa, nematodes and some chordates. Using parallel sequencing we have developed a method to simultaneously map 5'splice sites and analyze the corresponding gene expression profile, that we term spliced leader trapping (SLT. The method can be applied to any organism with a sequenced genome and trans-splicing of a conserved leader sequence. We analyzed the expression profiles and splicing patterns of bloodstream and insect forms of the parasite Trypanosoma brucei. We detected the 5' splice sites of 85% of the annotated protein-coding genes and, contrary to previous reports, found up to 40% of transcripts to be differentially expressed. Furthermore, we discovered more than 2500 alternative splicing events, many of which appear to be stage-regulated. Based on our findings we hypothesize that alternatively spliced transcripts present a new means of regulating gene expression and could potentially contribute to protein diversity in the parasite. The entire dataset can be accessed online at TriTrypDB or through: http://splicer.unibe.ch/.

  11. Digital gene expression analysis of two life cycle stages of the human-infective parasite, Trypanosoma brucei gambiense reveals differentially expressed clusters of co-regulated genes

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    Wildridge David

    2010-02-01

    Full Text Available Abstract Background The evolutionarily ancient parasite, Trypanosoma brucei, is unusual in that the majority of its genes are regulated post-transcriptionally, leading to the suggestion that transcript abundance of most genes does not vary significantly between different life cycle stages despite the fact that the parasite undergoes substantial cellular remodelling and metabolic changes throughout its complex life cycle. To investigate this in the clinically relevant sub-species, Trypanosoma brucei gambiense, which is the causative agent of the fatal human disease African sleeping sickness, we have compared the transcriptome of two different life cycle stages, the potentially human-infective bloodstream forms with the non-human-infective procyclic stage using digital gene expression (DGE analysis. Results Over eleven million unique tags were generated, producing expression data for 7360 genes, covering 81% of the genes in the genome. Compared to microarray analysis of the related T. b. brucei parasite, approximately 10 times more genes with a 2.5-fold change in expression levels were detected. The transcriptome analysis revealed the existence of several differentially expressed gene clusters within the genome, indicating that contiguous genes, presumably from the same polycistronic unit, are co-regulated either at the level of transcription or transcript stability. Conclusions DGE analysis is extremely sensitive for detecting gene expression differences, revealing firstly that a far greater number of genes are stage-regulated than had previously been identified and secondly and more importantly, this analysis has revealed the existence of several differentially expressed clusters of genes present on what appears to be the same polycistronic units, a phenomenon which had not previously been observed in microarray studies. These differentially regulated clusters of genes are in addition to the previously identified RNA polymerase I polycistronic

  12. Role of cytokines in Trypanosoma brucei-induced anaemia: A ...

    African Journals Online (AJOL)

    the blood-brain barrier. The subspecies Trypanosoma brucei rhodesiense in eastern and southern Africa generally causes a more acute form of ... The persistence of anaemia beyond the initial wave of parasitaemia (after which low numbers of parasites are in circulation) indicates that anaemia may be directly induced.

  13. Spliced leader RNA silencing (SLS - a programmed cell death pathway in Trypanosoma brucei that is induced upon ER stress

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    Michaeli Shulamit

    2012-05-01

    Full Text Available Abstract Trypanosoma brucei is the causative agent of African sleeping sickness. The parasite cycles between its insect (procyclic form and mammalian hosts (bloodstream form. Trypanosomes lack conventional transcription regulation, and their genes are transcribed in polycistronic units that are processed by trans-splicing and polyadenylation. In trans-splicing, which is essential for processing of each mRNA, an exon, the spliced leader (SL is added to all mRNAs from a small RNA, the SL RNA. Trypanosomes lack the machinery for the unfolded protein response (UPR, which in other eukaryotes is induced under endoplasmic reticulum (ER stress. Trypanosomes respond to such stress by changing the stability of mRNAs, which are essential for coping with the stress. However, under severe ER stress that is induced by blocking translocation of proteins to the ER, treatment of cells with chemicals that induce misfolding in the ER, or extreme pH, trypanosomes elicit the spliced leader silencing (SLS pathway. In SLS, the transcription of the SL RNA gene is extinguished, and tSNAP42, a specific SL RNA transcription factor, fails to bind to its cognate promoter. SLS leads to complete shut-off of trans-splicing. In this review, I discuss the UPR in mammals and compare it to the ER stress response in T. brucei leading to SLS. I summarize the evidence supporting the notion that SLS is a programmed cell death (PCD pathway that is utilized by the parasites to substitute for the apoptosis observed in higher eukaryotes under prolonged ER stress. I present the hypothesis that SLS evolved to expedite the death process, and rapidly remove from the population unfit parasites that, by elimination via SLS, cause minimal damage to the parasite population.

  14. Telomeric expression sites are highly conserved in Trypanosoma brucei.

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    Christiane Hertz-Fowler

    Full Text Available Subtelomeric regions are often under-represented in genome sequences of eukaryotes. One of the best known examples of the use of telomere proximity for adaptive purposes are the bloodstream expression sites (BESs of the African trypanosome Trypanosoma brucei. To enhance our understanding of BES structure and function in host adaptation and immune evasion, the BES repertoire from the Lister 427 strain of T. brucei were independently tagged and sequenced. BESs are polymorphic in size and structure but reveal a surprisingly conserved architecture in the context of extensive recombination. Very small BESs do exist and many functioning BESs do not contain the full complement of expression site associated genes (ESAGs. The consequences of duplicated or missing ESAGs, including ESAG9, a newly named ESAG12, and additional variant surface glycoprotein genes (VSGs were evaluated by functional assays after BESs were tagged with a drug-resistance gene. Phylogenetic analysis of constituent ESAG families suggests that BESs are sequence mosaics and that extensive recombination has shaped the evolution of the BES repertoire. This work opens important perspectives in understanding the molecular mechanisms of antigenic variation, a widely used strategy for immune evasion in pathogens, and telomere biology.

  15. The Flagellar Arginine Kinase in Trypanosoma brucei Is Important for Infection in Tsetse Flies.

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    Cher-Pheng Ooi

    Full Text Available African trypanosomes are flagellated parasites that cause sleeping sickness. Parasites are transmitted from one mammalian host to another by the bite of a tsetse fly. Trypanosoma brucei possesses three different genes for arginine kinase (AK including one (AK3 that encodes a protein localised to the flagellum. AK3 is characterised by the presence of a unique amino-terminal insertion that specifies flagellar targeting. We show here a phylogenetic analysis revealing that flagellar AK arose in two independent duplication events in T. brucei and T. congolense, the two species of African trypanosomes that infect the tsetse midgut. In T. brucei, AK3 is detected in all stages of parasite development in the fly (in the midgut and in the salivary glands as well as in bloodstream cells, but with predominance at insect stages. Genetic knockout leads to a slight reduction in motility and impairs parasite infectivity towards tsetse flies in single and competition experiments, both phenotypes being reverted upon expression of an epitope-tagged version of AK3. We speculate that this flagellar arginine kinase is important for T. brucei infection of tsetse, especially in the context of mixed infections and that its flagellar targeting relies on a system equivalent to that discovered for calflagins, a family of trypanosome flagellum calcium binding proteins.

  16. The Flagellar Arginine Kinase in Trypanosoma brucei Is Important for Infection in Tsetse Flies.

    Science.gov (United States)

    Ooi, Cher-Pheng; Rotureau, Brice; Gribaldo, Simonetta; Georgikou, Christina; Julkowska, Daria; Blisnick, Thierry; Perrot, Sylvie; Subota, Ines; Bastin, Philippe

    2015-01-01

    African trypanosomes are flagellated parasites that cause sleeping sickness. Parasites are transmitted from one mammalian host to another by the bite of a tsetse fly. Trypanosoma brucei possesses three different genes for arginine kinase (AK) including one (AK3) that encodes a protein localised to the flagellum. AK3 is characterised by the presence of a unique amino-terminal insertion that specifies flagellar targeting. We show here a phylogenetic analysis revealing that flagellar AK arose in two independent duplication events in T. brucei and T. congolense, the two species of African trypanosomes that infect the tsetse midgut. In T. brucei, AK3 is detected in all stages of parasite development in the fly (in the midgut and in the salivary glands) as well as in bloodstream cells, but with predominance at insect stages. Genetic knockout leads to a slight reduction in motility and impairs parasite infectivity towards tsetse flies in single and competition experiments, both phenotypes being reverted upon expression of an epitope-tagged version of AK3. We speculate that this flagellar arginine kinase is important for T. brucei infection of tsetse, especially in the context of mixed infections and that its flagellar targeting relies on a system equivalent to that discovered for calflagins, a family of trypanosome flagellum calcium binding proteins.

  17. Malleable mitochondrion of Trypanosoma brucei.

    Science.gov (United States)

    Verner, Zdeněk; Basu, Somsuvro; Benz, Corinna; Dixit, Sameer; Dobáková, Eva; Faktorová, Drahomíra; Hashimi, Hassan; Horáková, Eva; Huang, Zhenqiu; Paris, Zdeněk; Peña-Diaz, Priscila; Ridlon, Lucie; Týč, Jiří; Wildridge, David; Zíková, Alena; Lukeš, Julius

    2015-01-01

    The importance of mitochondria for a typical aerobic eukaryotic cell is undeniable, as the list of necessary mitochondrial processes is steadily growing. Here, we summarize the current knowledge of mitochondrial biology of an early-branching parasitic protist, Trypanosoma brucei, a causative agent of serious human and cattle diseases. We present a comprehensive survey of its mitochondrial pathways including kinetoplast DNA replication and maintenance, gene expression, protein and metabolite import, major metabolic pathways, Fe-S cluster synthesis, ion homeostasis, organellar dynamics, and other processes. As we describe in this chapter, the single mitochondrion of T. brucei is everything but simple and as such rivals mitochondria of multicellular organisms. Copyright © 2015. Published by Elsevier Inc.

  18. Reduced Mitochondrial Membrane Potential Is a Late Adaptation of Trypanosoma brucei brucei to Isometamidium Preceded by Mutations in the γ Subunit of the F1Fo-ATPase.

    Directory of Open Access Journals (Sweden)

    Anthonius A Eze

    2016-08-01

    Full Text Available Isometamidium is the main prophylactic drug used to prevent the infection of livestock with trypanosomes that cause Animal African Trypanosomiasis. As well as the animal infective trypanosome species, livestock can also harbor the closely related human infective subspecies T. b. gambiense and T. b. rhodesiense. Resistance to isometamidium is a growing concern, as is cross-resistance to the diamidine drugs diminazene and pentamidine.Two isometamidium resistant Trypanosoma brucei clones were generated (ISMR1 and ISMR15, being 7270- and 16,000-fold resistant to isometamidium, respectively, which retained their ability to grow in vitro and establish an infection in mice. Considerable cross-resistance was shown to ethidium bromide and diminazene, with minor cross-resistance to pentamidine. The mitochondrial membrane potentials of both resistant cell lines were significantly reduced compared to the wild type. The net uptake rate of isometamidium was reduced 2-3-fold but isometamidium efflux was similar in wild-type and resistant lines. Fluorescence microscopy and PCR analysis revealed that ISMR1 and ISMR15 had completely lost their kinetoplast DNA (kDNA and both lines carried a mutation in the nuclearly encoded γ subunit gene of F1 ATPase, truncating the protein by 22 amino acids. The mutation compensated for the loss of the kinetoplast in bloodstream forms, allowing near-normal growth, and conferred considerable resistance to isometamidium and ethidium as well as significant resistance to diminazene and pentamidine, when expressed in wild type trypanosomes. Subsequent exposure to either isometamidium or ethidium led to rapid loss of kDNA and a further increase in isometamidium resistance.Sub-lethal exposure to isometamidium gives rise to viable but highly resistant trypanosomes that, depending on sub-species, are infective to humans and cross-resistant to at least some diamidine drugs. The crucial mutation is in the F1 ATPase γ subunit, which

  19. Steroid Alkaloids from Holarrhena africana with Strong Activity against Trypanosoma brucei rhodesiense.

    Science.gov (United States)

    Nnadi, Charles Okeke; Nwodo, Ngozi Justina; Kaiser, Marcel; Brun, Reto; Schmidt, Thomas J

    2017-07-06

    In our continued search for natural compounds with activity against Trypanosoma brucei, causative agent of human African trypanosomiasis (HAT, "sleeping sickness"), we have investigated extracts from the leaves and bark of the West African Holarrhenaafricana (syn. Holarrhena floribunda; Apocynaceae). The extracts and their alkaloid-enriched fractions displayed promising in vitro activity against bloodstream forms of T. brucei rhodesiense (Tbr; East African HAT). Bioactivity-guided chromatographic fractionation of the alkaloid-rich fractions resulted in the isolation of 17 steroid alkaloids, one nitrogen-free steroid and one alkaloid-like non-steroid. Impressive activities (IC50 in µM) against Tbr were recorded for 3β-holaphyllamine (0.40 ± 0.28), 3α-holaphyllamine (0.37 ± 0.16), 3β-dihydroholaphyllamine (0.67 ± 0.03), N-methylholaphyllamine (0.08 ± 0.01), conessimine (0.17 ± 0.08), conessine (0.42 ± 0.09), isoconessimine (0.17 ± 0.11) and holarrhesine (0.12 ± 0.08) with selectivity indices ranging from 13 to 302. Based on comparison of the structures of this congeneric series of steroid alkaloids and their activities, structure-activity relationships (SARs) could be established. It was found that a basic amino group at position C-3 of the pregnane or pregn-5-ene steroid nucleus is required for a significant anti-trypanosomal activity. The mono-methylated amino group at C-3 represents an optimum for activity. ∆(5,6) unsaturation slightly increased the activity while hydrolysis of C-12β ester derivatives led to a loss of activity. An additional amino group at C-20 engaged in a pyrrolidine ring closed towards C-18 significantly increased the selectivity index of the compounds. Our findings provide useful empirical data for further development of steroid alkaloids as a novel class of anti-trypanosomal compounds which represent a promising starting point towards new drugs to combat human African trypanosomiasis.

  20. Steroid Alkaloids from Holarrhena africana with Strong Activity against Trypanosoma brucei rhodesiense

    Directory of Open Access Journals (Sweden)

    Charles Okeke Nnadi

    2017-07-01

    Full Text Available In our continued search for natural compounds with activity against Trypanosoma brucei, causative agent of human African trypanosomiasis (HAT, “sleeping sickness”, we have investigated extracts from the leaves and bark of the West African Holarrhena africana (syn. Holarrhena floribunda; Apocynaceae. The extracts and their alkaloid-enriched fractions displayed promising in vitro activity against bloodstream forms of T. brucei rhodesiense (Tbr; East African HAT. Bioactivity-guided chromatographic fractionation of the alkaloid-rich fractions resulted in the isolation of 17 steroid alkaloids, one nitrogen-free steroid and one alkaloid-like non-steroid. Impressive activities (IC50 in µM against Tbr were recorded for 3β-holaphyllamine (0.40 ± 0.28, 3α-holaphyllamine (0.37 ± 0.16, 3β-dihydroholaphyllamine (0.67 ± 0.03, N-methylholaphyllamine (0.08 ± 0.01, conessimine (0.17 ± 0.08, conessine (0.42 ± 0.09, isoconessimine (0.17 ± 0.11 and holarrhesine (0.12 ± 0.08 with selectivity indices ranging from 13 to 302. Based on comparison of the structures of this congeneric series of steroid alkaloids and their activities, structure-activity relationships (SARs could be established. It was found that a basic amino group at position C-3 of the pregnane or pregn-5-ene steroid nucleus is required for a significant anti-trypanosomal activity. The mono-methylated amino group at C-3 represents an optimum for activity. ∆5,6 unsaturation slightly increased the activity while hydrolysis of C-12β ester derivatives led to a loss of activity. An additional amino group at C-20 engaged in a pyrrolidine ring closed towards C-18 significantly increased the selectivity index of the compounds. Our findings provide useful empirical data for further development of steroid alkaloids as a novel class of anti-trypanosomal compounds which represent a promising starting point towards new drugs to combat human African trypanosomiasis.

  1. Procyclic Trypanosoma brucei do not use Krebs cycle activity for energy generation.

    Science.gov (United States)

    van Weelden, Susanne W H; Fast, Beate; Vogt, Achim; van der Meer, Pieter; Saas, Joachim; van Hellemond, Jaap J; Tielens, Aloysius G M; Boshart, Michael

    2003-04-11

    The importance of a functional Krebs cycle for energy generation in the procyclic stage of Trypanosoma brucei was investigated under physiological conditions during logarithmic phase growth of a pleomorphic parasite strain. Wild type procyclic cells and mutants with targeted deletion of the gene coding for aconitase were derived by synchronous in vitro differentiation from wild type and mutant (Delta aco::NEO/Delta aco::HYG) bloodstream stage parasites, respectively, where aconitase is not expressed and is dispensable. No differences in intracellular levels of glycolytic and Krebs cycle intermediates were found in procyclic wild type and mutant cells, except for citrate that accumulated up to 90-fold in the mutants, confirming the absence of aconitase activity. Surprisingly, deletion of aconitase did not change differentiation nor the growth rate or the intracellular ATP/ADP ratio in those cells. Metabolic studies using radioactively labeled substrates and NMR analysis demonstrated that glucose and proline were not degraded via the Krebs cycle to CO(2). Instead, glucose was degraded to acetate, succinate, and alanine, whereas proline was degraded to succinate. Importantly, there was absolutely no difference in the metabolic products released by wild type and aconitase knockout parasites, and both were for survival strictly dependent on respiration via the mitochondrial electron transport chain. Hence, although the Krebs cycle enzymes are present, procyclic T. brucei do not use Krebs cycle activity for energy generation, but the mitochondrial respiratory chain is essential for survival and growth. We therefore propose a revised model of the energy metabolism of procyclic T. brucei.

  2. Blocking Synthesis of the Variant Surface Glycoprotein Coat in Trypanosoma brucei Leads to an Increase in Macrophage Phagocytosis Due to Reduced Clearance of Surface Coat Antibodies.

    Directory of Open Access Journals (Sweden)

    Jackie L Y Cheung

    2016-11-01

    Full Text Available The extracellular bloodstream form parasite Trypanosoma brucei is supremely adapted to escape the host innate and adaptive immune system. Evasion is mediated through an antigenically variable Variant Surface Glycoprotein (VSG coat, which is recycled at extraordinarily high rates. Blocking VSG synthesis triggers a precytokinesis arrest where stalled cells persist for days in vitro with superficially intact VSG coats, but are rapidly cleared within hours in mice. We therefore investigated the role of VSG synthesis in trypanosome phagocytosis by activated mouse macrophages. T. brucei normally effectively evades macrophages, and induction of VSG RNAi resulted in little change in phagocytosis of the arrested cells. Halting VSG synthesis resulted in stalled cells which swam directionally rather than tumbling, with a significant increase in swim velocity. This is possibly a consequence of increased rigidity of the cells due to a restricted surface coat in the absence of VSG synthesis. However if VSG RNAi was induced in the presence of anti-VSG221 antibodies, phagocytosis increased significantly. Blocking VSG synthesis resulted in reduced clearance of anti-VSG antibodies from the trypanosome surface, possibly as a consequence of the changed motility. This was particularly marked in cells in the G2/ M cell cycle stage, where the half-life of anti-VSG antibody increased from 39.3 ± 4.2 seconds to 99.2 ± 15.9 seconds after induction of VSG RNAi. The rates of internalisation of bulk surface VSG, or endocytic markers like transferrin, tomato lectin or dextran were not significantly affected by the VSG synthesis block. Efficient elimination of anti-VSG-antibody complexes from the trypanosome cell surface is therefore essential for trypanosome evasion of macrophages. These experiments highlight the essentiality of high rates of VSG recycling for the rapid removal of host opsonins from the parasite surface, and identify this process as a key parasite

  3. The role of the PI(3,5)P2 kinase TbFab1 in endo/lysosomal trafficking in Trypanosoma brucei.

    Science.gov (United States)

    Gilden, Julia K; Umaer, Khan; Kruzel, Emilia K; Hecht, Oliver; Correa, Renan O; Mansfield, John M; Bangs, James D

    2017-06-01

    Protein trafficking through endo/lysosomal compartments is critically important to the biology of the protozoan parasite Trypanosoma brucei, but the routes material may take to the lysosome, as well as the molecular factors regulating those routes, remain incompletely understood. Phosphoinositides are signaling phospholipids that regulate many trafficking events by recruiting specific effector proteins to discrete membrane subdomains. In this study, we investigate the role of one phosphoinositide, PI(3,5)P2 in T. brucei. We find a low steady state level of PI(3,5)P2 in bloodstream form parasites comparable to that of other organisms. RNAi knockdown of the putative PI(3)P-5 kinase TbFab1 decreases the PI(3,5)P2 pool leading to rapid cell death. TbFab1 and PI(3,5)P2 both localize strongly to late endo/lysosomes. While most trafficking functions were intact in TbFab1 deficient cells, including both endocytic and biosynthetic trafficking to the lysosome, lysosomal turnover of an endogenous ubiquitinylated membrane protein, ISG65, was completely blocked suggesting that TbFab1 plays a role in the ESCRT-mediated late endosomal/multivesicular body degradative pathways. Knockdown of a second component of PI(3,5)P2 metabolism, the PI(3,5)P2 phosphatase TbFig4, also resulted in delayed turnover of ISG65. Together, these results demonstrate an essential role for PI(3,5)P2 in the turnover of ubiquitinylated membrane proteins and in trypanosome endomembrane biology. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. The PARP promoter of Trypanosoma brucei is developmentally regulated in a chromosomal context

    DEFF Research Database (Denmark)

    Biebinger, S; Rettenmaier, S; Flaspohler, J

    1996-01-01

    RNA is abundant in procyclic forms and almost undetectable in blood-stream forms. Post-transcriptional mechanisms are mainly responsible for PARP mRNA regulation but results of nuclear run-on experiments suggested that transcription might also be regulated. We measured the activity of genomically-integrated PARP...... not developmentally regulated, but integration at the PARP locus reduced rRNA promoter activity in bloodstream forms. PARP promoter activity was 5-fold down-regulated in bloodstream forms when integrated at either site. Regulation was probably at the level of transcriptional initiation, but elongation through plasmid...

  5. In or out? On the tightness of glycosomal compartmentalization of metabolites and enzymes in Trypanosoma brucei

    NARCIS (Netherlands)

    Haanstra, Jurgen R.; Bakker, Barbara M.; Michels, Paul A. M.

    2014-01-01

    Trypanosomatids sequester large parts of glucose metabolism inside specialised peroxisomes, called glycosomes. Many studies have shown that correct glycosomal compartmentalization of glycolytic enzymes is essential for bloodstream-form Trypanosoma brucel. The recent finding of pore-forming

  6. Protective effect of humus extract against Trypanosoma brucei infection in mice.

    Science.gov (United States)

    Kodama, Hiroshi; Denso; Okazaki, Fumi; Ishida, Saeko

    2008-11-01

    Humic substances are formed during the decomposition of organic matter in humus, and are found in many natural environments in which organic materials and microorganisms are present. Oral administration of humus extract to mice successfully induced effective protection against experimental challenge by the two subspecies, Trypanosoma brucei brucei and T. brucei gambiense. Mortality was most reduced among mice who received a 3% humus extract for 21 days in drinking water ad libitum. Spleen cells from humus-administered mice exhibited significant non-specific cytotoxic activity against L1210 mouse leukemia target cells. Also, spleen cells produced significantly higher amounts of Interferon-gamma when stimulated in vitro with Concanavalin A than cells from normal controls. These results clearly show that administration to mice of humus extract induced effective resistance against Trypanosoma infection. Enhancement of the innate immune system may be involved in host defense against trypanosomiasis.

  7. Crassiflorone derivatives that inhibit Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase (TbGAPDH) and Trypanosoma cruzi trypanothione reductase (TcTR) and display trypanocidal activity.

    Science.gov (United States)

    Uliassi, Elisa; Fiorani, Giulia; Krauth-Siegel, R Luise; Bergamini, Christian; Fato, Romana; Bianchini, Giulia; Carlos Menéndez, J; Molina, Maria Teresa; López-Montero, Eulogio; Falchi, Federico; Cavalli, Andrea; Gul, Sheraz; Kuzikov, Maria; Ellinger, Bernhard; Witt, Gesa; Moraes, Carolina B; Freitas-Junior, Lucio H; Borsari, Chiara; Costi, Maria Paola; Bolognesi, Maria Laura

    2017-12-01

    Crassiflorone is a natural product with anti-mycobacterial and anti-gonorrhoeal properties, isolated from the stem bark of the African ebony tree Diospyros crassiflora. We noticed that its pentacyclic core possesses structural resemblance to the quinone-coumarin hybrid 3, which we reported to exhibit a dual-targeted inhibitory profile towards Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase (TbGAPDH) and Trypanosoma cruzi trypanothione reductase (TcTR). Following this basic idea, we synthesized a small library of crassiflorone derivatives 15-23 and investigated their potential as anti-trypanosomatid agents. 19 is the only compound of the series showing a balanced dual profile at 10 μM (% inhibition TbGAPDH  = 64% and % inhibition TcTR  = 65%). In phenotypic assay, the most active compounds were 18 and 21, which at 5 μM inhibited Tb bloodstream-form growth by 29% and 38%, respectively. Notably, all the newly synthesized compounds at 10 μM did not affect viability and the status of mitochondria in human A549 and 786-O cell lines, respectively. However, further optimization that addresses metabolic liabilities including solubility, as well as cytochromes P450 (CYP1A2, CYP2C9, CYP2C19, and CYP2D6) inhibition, is required before this class of natural product-derived compounds can be further progressed. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  8. What happens when Trypanosoma brucei leaves Africa.

    Science.gov (United States)

    Jensen, Robert E; Simpson, Larry; Englund, Paul T

    2008-10-01

    Julius Lukes and co-workers evaluated the evolutionary origin of Trypanosoma equiperdum and Trypanosoma evansi, parasites that cause horse and camel diseases. Although similar to T. brucei, the sleeping-sickness parasite, these trypanosomes do not cycle through the tsetse fly and have been able to spread beyond Africa. Transmission occurs sexually, or via blood-sucking flies or vampire bats. They concluded that these parasites, which resemble yeast petite mutants, are T. brucei sub-species, which have evolved recently through changes in mitochondrial DNA.

  9. Extracellular Vesicles from Trypanosoma brucei Mediate Virulence Factor Transfer and Cause Host Anemia.

    Science.gov (United States)

    Szempruch, Anthony J; Sykes, Steven E; Kieft, Rudo; Dennison, Lauren; Becker, Allison C; Gartrell, Anzio; Martin, William J; Nakayasu, Ernesto S; Almeida, Igor C; Hajduk, Stephen L; Harrington, John M

    2016-01-14

    Intercellular communication between parasites and with host cells provides mechanisms for parasite development, immune evasion, and disease pathology. Bloodstream African trypanosomes produce membranous nanotubes that originate from the flagellar membrane and disassociate into free extracellular vesicles (EVs). Trypanosome EVs contain several flagellar proteins that contribute to virulence, and Trypanosoma brucei rhodesiense EVs contain the serum resistance-associated protein (SRA) necessary for human infectivity. T. b. rhodesiense EVs transfer SRA to non-human infectious trypanosomes, allowing evasion of human innate immunity. Trypanosome EVs can also fuse with mammalian erythrocytes, resulting in rapid erythrocyte clearance and anemia. These data indicate that trypanosome EVs are organelles mediating non-hereditary virulence factor transfer and causing host erythrocyte remodeling, inducing anemia. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Functional and structural insights revealed by molecular dynamics simulations of an essential RNA editing ligase in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Rommie E Amaro

    2007-11-01

    Full Text Available RNA editing ligase 1 (TbREL1 is required for the survival of both the insect and bloodstream forms of Trypanosoma brucei, the parasite responsible for the devastating tropical disease African sleeping sickness. The type of RNA editing that TbREL1 is involved in is unique to the trypanosomes, and no close human homolog is known to exist. In addition, the high-resolution crystal structure revealed several unique features of the active site, making this enzyme a promising target for structure-based drug design. In this work, two 20 ns atomistic molecular dynamics (MD simulations are employed to investigate the dynamics of TbREL1, both with and without the ATP substrate present. The flexibility of the active site, dynamics of conserved residues and crystallized water molecules, and the interactions between TbREL1 and the ATP substrate are investigated and discussed in the context of TbREL1's function. Differences in local and global motion upon ATP binding suggest that two peripheral loops, unique to the trypanosomes, may be involved in interdomain signaling events. Notably, a significant structural rearrangement of the enzyme's active site occurs during the apo simulations, opening an additional cavity adjacent to the ATP binding site that could be exploited in the development of effective inhibitors directed against this protozoan parasite. Finally, ensemble averaged electrostatics calculations over the MD simulations reveal a novel putative RNA binding site, a discovery that has previously eluded scientists. Ultimately, we use the insights gained through the MD simulations to make several predictions and recommendations, which we anticipate will help direct future experimental studies and structure-based drug discovery efforts against this vital enzyme.

  11. Interaction between Trypanosoma brucei and Haemonchus ...

    African Journals Online (AJOL)

    In order to investigate the immunomodulatory influence of concurrent T. brucei and H. contortus infection in West African Dwarf (WAD) goats, 28 infected and 7 uninfected (control) of 8-9 months old male WAD goats were studied. The infected goats were separated into resistant (Class 1) and susceptible (Class 2) Faecal ...

  12. Haematology of experimental Trypanosoma brucei rhodesiense ...

    African Journals Online (AJOL)

    Haematological aberrations associated with human infective trypanosomes were investigated in the vervet monkey model of the Rhodesian sleeping sickness. Four monkeys were infected intravenously with 104 Trypanosoma brucei rhodesiense and monitored for changes in the blood profile using a haematological ...

  13. A Protein Complex Map of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Vahid H Gazestani

    2016-03-01

    Full Text Available The functions of the majority of trypanosomatid-specific proteins are unknown, hindering our understanding of the biology and pathogenesis of Trypanosomatida. While protein-protein interactions are highly informative about protein function, a global map of protein interactions and complexes is still lacking for these important human parasites. Here, benefiting from in-depth biochemical fractionation, we systematically interrogated the co-complex interactions of more than 3354 protein groups in procyclic life stage of Trypanosoma brucei, the protozoan parasite responsible for human African trypanosomiasis. Using a rigorous methodology, our analysis led to identification of 128 high-confidence complexes encompassing 716 protein groups, including 635 protein groups that lacked experimental annotation. These complexes correlate well with known pathways as well as for proteins co-expressed across the T. brucei life cycle, and provide potential functions for a large number of previously uncharacterized proteins. We validated the functions of several novel proteins associated with the RNA-editing machinery, identifying a candidate potentially involved in the mitochondrial post-transcriptional regulation of T. brucei. Our data provide an unprecedented view of the protein complex map of T. brucei, and serve as a reliable resource for further characterization of trypanosomatid proteins. The presented results in this study are available at: www.TrypsNetDB.org.

  14. Characterization of Trypanosoma brucei gambiense stocks isolated ...

    African Journals Online (AJOL)

    Characterization of Trypanosoma brucei gambiense stocks isolated from humans by RAPD fingerprinting in Côte d'Ivoire: another evidence for multiple infections. ... a given isoenzyme profile (zymodeme), confirming that this fingerprinting method has a higher discriminative power (faster molecular clock) than isoenzymes.

  15. Wild chimpanzees are infected by Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Milan Jirků

    2015-12-01

    Finally, we demonstrated that the mandrill serum was able to efficiently lyse T. b. brucei and T. b. rhodesiense, and to some extent T. b. gambiense, while the chimpanzee serum failed to lyse any of these subspecies.

  16. Genetic control of resistance to Trypanosoma brucei brucei infection in mice.

    Directory of Open Access Journals (Sweden)

    Matyáš Síma

    2011-06-01

    Full Text Available Trypanosoma brucei brucei infects livestock, with severe effects in horses and dogs. Mouse strains differ greatly in susceptibility to this parasite. However, no genes controlling these differences were mapped.We studied the genetic control of survival after T. b. brucei infection using recombinant congenic (RC strains, which have a high mapping power. Each RC strain of BALB/c-c-STS/A (CcS/Dem series contains a different random subset of 12.5% genes from the parental "donor" strain STS/A and 87.5% genes from the "background" strain BALB/c. Although BALB/c and STS/A mice are similarly susceptible to T. b. brucei, the RC strain CcS-11 is more susceptible than either of them. We analyzed genetics of survival in T. b. brucei-infected F(2 hybrids between BALB/c and CcS-11. CcS-11 strain carries STS-derived segments on eight chromosomes. They were genotyped in the F(2 hybrid mice and their linkage with survival was tested by analysis of variance.We mapped four Tbbr (Trypanosoma brucei brucei response loci that influence survival after T. b. brucei infection. Tbbr1 (chromosome 3 and Tbbr2 (chromosome 12 have effects on survival independent of inter-genic interactions (main effects. Tbbr3 (chromosome 7 influences survival in interaction with Tbbr4 (chromosome 19. Tbbr2 is located on a segment 2.15 Mb short that contains only 26 genes.This study presents the first identification of chromosomal loci controlling susceptibility to T. b. brucei infection. While mapping in F(2 hybrids of inbred strains usually has a precision of 40-80 Mb, in RC strains we mapped Tbbr2 to a 2.15 Mb segment containing only 26 genes, which will enable an effective search for the candidate gene. Definition of susceptibility genes will improve the understanding of pathways and genetic diversity underlying the disease and may result in new strategies to overcome the active subversion of the immune system by T. b. brucei.

  17. Biosynthesis of SUMOylated Proteins in Bacteria Using the Trypanosoma brucei Enzymatic System

    Science.gov (United States)

    Iribarren, Paula Ana; Berazategui, María Agustina; Cazzulo, Juan José; Alvarez, Vanina Eder

    2015-01-01

    Post-translational modification with the Small Ubiquitin-like Modifier (SUMO) is conserved in eukaryotic organisms and plays important regulatory roles in proteins affecting diverse cellular processes. In Trypanosoma brucei, member of one of the earliest branches in eukaryotic evolution, SUMO is essential for normal cell cycle progression and is likely to be involved in the epigenetic control of genes crucial for parasite survival, such as those encoding the variant surface glycoproteins. Molecular pathways modulated by SUMO have started to be discovered by proteomic studies; however, characterization of functional consequences is limited to a reduced number of targets. Here we present a bacterial strain engineered to produce SUMOylated proteins, by transferring SUMO from T. brucei together with the enzymes essential for its activation and conjugation. Due to the lack of background in E. coli, this system is useful to express and identify SUMOylated proteins directly in cell lysates by immunoblotting, and SUMOylated targets can be eventually purified for biochemical or structural studies. We applied this strategy to describe the ability of TbSUMO to form chains in vitro and to detect SUMOylation of a model substrate, PCNA both from Saccharomyces cerevisiae and from T. brucei. To further validate targets, we applied an in vitro deconjugation assay using the T. brucei SUMO-specific protease capable to revert the pattern of modification. This system represents a valuable tool for target validation, mutant generation and functional studies of SUMOylated proteins in trypanosomatids. PMID:26258470

  18. Maf1 is a negative regulator of transcription in Trypanosoma brucei.

    Science.gov (United States)

    Romero-Meza, Gabriela; Vélez-Ramírez, Daniel E; Florencio-Martínez, Luis E; Román-Carraro, Fiordaliso C; Manning-Cela, Rebeca; Hernández-Rivas, Rosaura; Martínez-Calvillo, Santiago

    2017-02-01

    RNA polymerase III (Pol III) produces small RNA molecules that play essential roles in mRNA processing and translation. Maf1, originally described as a negative regulator of Pol III transcription, has been studied from yeast to human. Here we characterized Maf1 in the parasitic protozoa Trypanosoma brucei (TbMaf1), representing the first report to analyse Maf1 in an early-diverged eukaryote. While Maf1 is generally encoded by a single-copy gene, the T. brucei genome contains two almost identical TbMaf1 genes. The TbMaf1 protein has the three conserved sequences and is predicted to fold into a globular structure. Unlike in yeast, TbMaf1 localizes to the nucleus in procyclic forms of T. brucei under normal growth conditions. Cell lines that either downregulate or overexpress TbMaf1 were generated, and growth curve analysis with them suggested that TbMaf1 participates in the regulation of cell growth of T. brucei. Nuclear run-on and chromatin immunoprecipitation analyses demonstrated that TbMaf1 represses Pol III transcription of tRNA and U2 snRNA genes by associating with their promoters. Interestingly, 5S rRNA levels do not change after TbMaf1 ablation or overexpression. Notably, our data also revealed that TbMaf1 regulates Pol I transcription of procyclin gene and Pol II transcription of SL RNA genes. © 2016 John Wiley & Sons Ltd.

  19. Biosynthesis of SUMOylated Proteins in Bacteria Using the Trypanosoma brucei Enzymatic System.

    Directory of Open Access Journals (Sweden)

    Paula Ana Iribarren

    Full Text Available Post-translational modification with the Small Ubiquitin-like Modifier (SUMO is conserved in eukaryotic organisms and plays important regulatory roles in proteins affecting diverse cellular processes. In Trypanosoma brucei, member of one of the earliest branches in eukaryotic evolution, SUMO is essential for normal cell cycle progression and is likely to be involved in the epigenetic control of genes crucial for parasite survival, such as those encoding the variant surface glycoproteins. Molecular pathways modulated by SUMO have started to be discovered by proteomic studies; however, characterization of functional consequences is limited to a reduced number of targets. Here we present a bacterial strain engineered to produce SUMOylated proteins, by transferring SUMO from T. brucei together with the enzymes essential for its activation and conjugation. Due to the lack of background in E. coli, this system is useful to express and identify SUMOylated proteins directly in cell lysates by immunoblotting, and SUMOylated targets can be eventually purified for biochemical or structural studies. We applied this strategy to describe the ability of TbSUMO to form chains in vitro and to detect SUMOylation of a model substrate, PCNA both from Saccharomyces cerevisiae and from T. brucei. To further validate targets, we applied an in vitro deconjugation assay using the T. brucei SUMO-specific protease capable to revert the pattern of modification. This system represents a valuable tool for target validation, mutant generation and functional studies of SUMOylated proteins in trypanosomatids.

  20. Trypanosoma brucei: two steps to spread out from Africa.

    Science.gov (United States)

    Lun, Zhao-Rong; Lai, De-Hua; Li, Feng-Jun; Lukes, Julius; Ayala, Francisco J

    2010-09-01

    Trypanosoma brucei equiperdum and Trypanosoma brucei evansi are typically considered separate species, although a recent study suggested that these organisms can be classified as subspecies of Trypanosoma brucei, which we also favor. Here we present a scenario that attempts to explain the continuing evolution of the dyskinetoplastic and akinetoplastic strains, as a consequence of loss of selective pressure(s) leading to the loss of kinetoplast DNA. Copyright 2010 Elsevier Ltd. All rights reserved.

  1. Identification of Trypanosoma evansi, Trypanosoma equiperdum and Trypanosoma brucei brucei using repetitive DNA probes.

    Science.gov (United States)

    Zhang, Z Q; Baltz, T

    1994-06-01

    The phylogenetic relatedness of 15 stocks of Trypanosoma evansi, three stocks of Trypanosoma equiperdum and one stock of Trypanosoma brucei brucei was determined using Southern blot analysis of restriction enzyme digested DNA, probed with two repetitive DNA sequences from T. b. brucei. A dendrogram derived by cluster analysis of restriction fragment length polymorphism (RFLP) revealed three groups of related stocks. Group 1 included 14 stocks of T. evansi and one stock of T. equiperdum. Group 2 included two stocks of T. equiperdum and one stock of T. evansi. Group 3 included the one stock of T. brucei brucei. Group 2 is more closely related to Group 3 than Group 1, by analysis of the banding patterns. Further analysis of the T. evansi in Group 1 revealed that the patterns of isolates from different provinces in China were identical, but differed from T. evansi isolated from Africa, South America and the Philippines. These results provide insight into the origins of T. evansi and suggest that RFLP may be a useful means of distinguishing closely related trypanosomes.

  2. Detection of Trypanosoma brucei gambiense and T. b. rhodesiense ...

    African Journals Online (AJOL)

    Detection of Trypanosoma brucei gambiense and T. b. rhodesiense in Glossina fuscipes fuscipes ( Diptera: Glossinidae ) and Stomoxys flies using the polymerase chain reaction (PCR) technique in southern Sudan.

  3. (Berenil(B)) in the Treatment of Experimental Trypanosoma brucei ...

    African Journals Online (AJOL)

    Dr Olaleye

    Animal welfare was observed in accordance with. International guidelines for the use of laboratory animals for biomedical research (EC, 1996). Trypanosomes: Trypanosoma brucei brucei (Federe strain) obtained from NITR, Vom, was used and the parasites were maintained by serial passages in rats. One millilitre of.

  4. The Effect of Garlic Extracts on Experimental Trypanosoma brucei ...

    African Journals Online (AJOL)

    The anti-trypanosomal effect of aqueous and methanolic extracts of garlic were studied in Trypanosoma brucei brucei infected rabbits. With the establishment of infection, parasitaemia, anaemia, leucopenia, neutropenia and lymphocytosis developed. There was decrease in total serum protein, albumin and increase in ...

  5. Pathogenicity of Trypanosoma brucei in African giant rats ...

    African Journals Online (AJOL)

    Pathogenicity of Trypanosoma brucei in African giant rats ( Cricetomys gambianus , Water House) ... The course of trypanosomosis was investigated over a period of two weeks in six African giant rats (Cricetomys gambianus) experimentally infected with Trypanosoma brucei. Six other rats served as uninfected control.

  6. CHARACTERIZATION AND ANTIPARASITIC ACTIVITY OF BENZOPHENONE THIOSEMICARBAZONES ON Trypanosoma brucei brucei

    Directory of Open Access Journals (Sweden)

    Georges C. Accrombessi

    2011-02-01

    Full Text Available The structure of four synthesized thiosemicarbazones, substituted or not, of benzophenone has been confirmed by spectrometrical analysis IR, NMR 1H and 13C. Their anti-trypanosomal activities were evaluated on Trypanosoma brucei brucei. Among these compounds, benzophenone 4 phenyl-3-thiosemicarbazone 4 has the highest activity with the half-inhibitory concentration (IC50 = 8.48 micromolar (µM. Benzophenone 4-methyl-3-thiosemicarbazone 3 and benzophenone thiosemicarbazone 1 showed moderate anti-trypanosomal activity with IC50 values equal to 23.27 µM and 67.17 µM respectively. Benzophenone 2 methyl-3-thiosemicarbazone 2 showed no activity up to IC50 = 371.74 µM.

  7. Surface electrical charge of bloodstream trypomastigotes of Trypanosoma cruzi strains

    Directory of Open Access Journals (Sweden)

    Maria Auxiliadora de Sousa

    1983-12-01

    Full Text Available Bloodstream trypomastigotes of some Trypanosoma cruzi strains were processed through DEAE-cellulose columns under standardized conditions. The results obtained suggest mainly that these strains present different surface charges, that there are subpopulations of bloodstream trypomastigotes as regards electrical charges and that the broad forms are less negative than the slender ones.Tripomastigotas sanguíneos de algumas cepas de Trypanosoma cruzi foram processadas em colunas de DEAE-celulose sob condições padronizadas. Os resultados obtidos sugerem principalmente que estas cepas possuem cargas superficiais diferentes, que em relação a este aspecto existem subpopulações de tripomastigotas e que as formas largas são menos negativas do que as finas.

  8. Extracellular-signal regulated kinase 8 of Trypanosoma brucei uniquely phosphorylates its proliferating cell nuclear antigen homolog and reveals exploitable properties.

    Science.gov (United States)

    Valenciano, Ana L; Knudsen, Giselle M; Mackey, Zachary B

    2016-10-17

    The Trypanosoma brucei subspecies T. brucei gambiense and T. brucei rhodesiense are vector-borne pathogens that cause sleeping sickness also known as Human African Trypanosomiasis (HAT), which is fatal if left untreated. The drugs that treat HAT are ineffective and cause toxic side effects. One strategy for identifying safer and more effective HAT drugs is to therapeutically exploit essential gene targets in T. brucei. Genes that make up a basic mitogen-activated protein kinase (MAPK) network are present in T. brucei. Tb927.10.5140 encodes an essential MAPK that is homologous to the human extracellular-signal regulated kinase 8 (HsERK8) which forms a tight complex with the replication factor proliferating cell nuclear antigen (PCNA) to stabilize intracellular PCNA levels. Here we demonstrate that (TbPCNA) is uniquely phos-phorylated on serine (S) and threonine (T) residues in T. brucei and that TbERK8 phosphorylates TbPCNA at each of these residues. The ability of an ERK8 homolog to phosphorylate a PCNA homolog is a novel biochemical property that is first demonstrated here in T. brucei and may be unique to this pathogen. We demonstrate that the potent HsERK8 inhibitor Ro318220, has an IC50 for TbERK8 that is several hundred times higher than its reported IC50 for HsERK8. This indicated that the active sites of TbERK8 and HsERK8 can be selectively inhibited, which provides a rational basis for discovering inhibitors that specifically target this essential parasite MAPK to kill the parasite.

  9. Combinations of alkaloids affecting different molecular targets with the saponin digitonin can synergistically enhance trypanocidal activity against Trypanosoma brucei brucei

    National Research Council Canada - National Science Library

    Krstin, Sonja; Peixoto, Herbenya Silva; Wink, Michael

    2015-01-01

    .... In this study, the potential synergism of mutual combinations of bioactive alkaloids and alkaloids with a membrane-active steroidal saponin, digitonin, was explored with regard to their effect on T. b. brucei...

  10. Candida Infection of the Bloodstream - Candidemia

    Science.gov (United States)

    Candida Infection of the Bloodstream– Candidemia Fungal Disease Series #4 Candida is the single most important cause of fungal infections worldwide. In the U.S., Candida is the 4th most common cause of bloodstream ...

  11. Extracellular release of acid phosphatase from blood stream forms ...

    African Journals Online (AJOL)

    Acid phosphatase (ACP) activity was demonstrated in blood stream form of Trypanosome brucei brucei harvested from infected Wister rats by Ion Exchange DEAE Cellulose 52 chromatography. Whole parasite extract (WPE) and Excretory Secretory Extract (ESE) were prepared and analyzed for acid phosphatase activity.

  12. A transcription-independent epigenetic mechanism is associated with antigenic switching in Trypanosoma brucei.

    Science.gov (United States)

    Aresta-Branco, Francisco; Pimenta, Silvia; Figueiredo, Luisa M

    2016-04-20

    Antigenic variation in Trypanosoma brucei relies on periodic switching of variant surface glycoproteins (VSGs), which are transcribed monoallelically by RNA polymerase I from one of about 15 bloodstream expression sites (BES). Chromatin of the actively transcribed BES is depleted of nucleosomes, but it is unclear if this open conformation is a mere consequence of a high rate of transcription, or whether it is maintained by a transcription-independent mechanism. Using an inducible BES-silencing reporter strain, we observed that chromatin of the active BES remains open for at least 24 hours after blocking transcription. This conformation is independent of the cell-cycle stage, but dependent upon TDP1, a high mobility group box protein. For two days after BES silencing, we detected a transient and reversible derepression of several silent BESs within the population, suggesting that cells probe other BESs before commitment to one, which is complete by 48 hours. FACS sorting and subsequent subcloning confirmed that probing cells are switching intermediates capable of returning to the original BES, switch to the probed BES or to a different BES. We propose that regulation of BES chromatin structure is an epigenetic mechanism important for successful antigenic switching. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  13. Sulfhydryl reagent susceptibility in proteins with high sequence similarity--triosephosphate isomerase from Trypanosoma brucei, Trypanosoma cruzi and Leishmania mexicana.

    Science.gov (United States)

    Garza-Ramos, G; Cabrera, N; Saavedra-Lira, E; Tuena de Gómez-Puyou, M; Ostoa-Saloma, P; Pérez-Montfort, R; Gómez-Puyou, A

    1998-05-01

    The amino acid sequence of triosephosphate isomerase from Trypanosoma brucei, Trypanosoma cruzi, and Leishmania mexicana have an identity of 68%. Using the numbering system for the T. brucei enzyme, in their aligned sequences, the T. cruzi and leishmanial enzymes have cysteine residues at positions 14, 40, 117 and 126. T. brucei triosephosphate isomerase has cysteine residues at positions 14, 40 and 126, and a valine residue at position 117. Dithionitrobenzoic acid and methylmethane thiosulfonate inhibited the three enzymes, but T. cruzi triosephosphate isomerase was more than 100-fold more sensitive. The sensitivity of wild type triosephosphate isomerase from T. cruzi and T. brucei to the reagents was equal to that of the Cys117Val and Val117Cys mutant enzymes, respectively. Triosephosphate isomerases that have cysteine residues at positions 40 and 126, but lack a cysteine residue at position 14 are insensitive to methylmethane thiosulfonate. Thus, sulfhydryl reagents act on Cys14. At stoichiometric concentrations, the reagents inhibited the three enzymes as a consequence of structural alterations as measured by binding of 8-anilino-1-napthalenesulfonic acid to previously buried hydrophobic regions. However, the times for half-maximal alterations were 10 min, 15 hours and over 30 hours for T. cruzi, T. brucei and L. mexicana triosephosphate isomerase, respectively. The effect of pH on the action of the sulfhydryl reagents and molecular modeling showed no differences in the solvent accessibility of Cys14. As Cys14 forms part of the dimer interface, the data indicate that, in the three enzymes, barriers of different magnitude hinder the interaction between the sulfhydryl reagents and Cys14. The barrier is lower in T. cruzi triosephosphate isomerase which makes its dimer interface more susceptible for perturbation.

  14. Phenolic Constituents of Medicinal Plants with Activity against Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Ya Nan Sun

    2016-04-01

    Full Text Available Neglected tropical diseases (NTDs affect over one billion people all over the world. These diseases are classified as neglected because they impact populations in areas with poor financial conditions and hence do not attract sufficient research investment. Human African Trypanosomiasis (HAT or sleeping sickness, caused by the parasite Trypanosoma brucei, is one of the NTDs. The current therapeutic interventions for T. brucei infections often have toxic side effects or require hospitalization so that they are not available in the rural environments where HAT occurs. Furthermore, parasite resistance is increasing, so that there is an urgent need to identify novel lead compounds against this infection. Recognizing the wide structural diversity of natural products, we desired to explore and identify novel antitrypanosomal chemotypes from a collection of natural products obtained from plants. In this study, 440 pure compounds from various medicinal plants were tested against T. brucei by in a screening using whole cell in vitro assays. As the result, twenty-two phenolic compounds exhibited potent activity against cultures of T. brucei. Among them, eight compounds—4, 7, 11, 14, 15, 18, 20, and 21—showed inhibitory activity against T. brucei, with IC50 values below 5 µM, ranging from 0.52 to 4.70 μM. Based on these results, we attempt to establish some general trends with respect to structure-activity relationships, which indicate that further investigation and optimization of these derivatives might enable the preparation of potentially useful compounds for treating HAT.

  15. Regulation and spatial organization of PCNA in Trypanosoma brucei

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, Doris; Gassen, Alwine [University of Munich (LMU), Department Biology I, Genetics, Grosshaderner Str. 2-4, 82152 Martinsried (Germany); Maiser, Andreas; Leonhardt, Heinrich [University of Munich (LMU), Department Biology II, Grosshaderner Str. 2-4, 82152 Martinsried (Germany); Janzen, Christian J., E-mail: christian.janzen@uni-wuerzburg.de [University of Munich (LMU), Department Biology I, Genetics, Grosshaderner Str. 2-4, 82152 Martinsried (Germany)

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer Characterization of the proliferating cell nuclear antigen in Trypanosoma brucei (TbPCNA). Black-Right-Pointing-Pointer TbPCNA is a suitable marker to detect replication in T. brucei. Black-Right-Pointing-Pointer TbPCNA distribution and regulation is different compared to closely related parasites T. cruzi and Leishmania donovani. -- Abstract: As in most eukaryotic cells, replication is regulated by a conserved group of proteins in the early-diverged parasite Trypanosoma brucei. Only a few components of the replication machinery have been described in this parasite and regulation, sub-nuclear localization and timing of replication are not well understood. We characterized the proliferating cell nuclear antigen in T. brucei (TbPCNA) to establish a spatial and temporal marker for replication. Interestingly, PCNA distribution and regulation is different compared to the closely related parasites Trypanosoma cruzi and Leishmania donovani. TbPCNA foci are clearly detectable during S phase of the cell cycle but in contrast to T. cruzi they are not preferentially located at the nuclear periphery. Furthermore, PCNA seems to be degraded when cells enter G2 phase in T. brucei suggesting different modes of replication regulation or functions of PCNA in these closely related eukaryotes.

  16. Evaluation of In Vitro Activity of Essential Oils against Trypanosoma brucei brucei and Trypanosoma evansi

    Directory of Open Access Journals (Sweden)

    Nathan Habila

    2010-01-01

    Full Text Available Essential oils (EOs from Cymbopogon citratus (CC, Eucalyptus citriodora (EC, Eucalyptus camaldulensis (ED, and Citrus sinensis (CS were obtained by hydrodistillation process. The EOs were evaluated in vitro for activity against Trypanosoma brucei brucei (Tbb and Trypanosoma evansi (T. evansi. The EOs were found to possess antitrypanosomal activity in vitro in a dose-dependent pattern in a short period of time. The drop in number of parasite over time was achieved doses of 0.4 g/ml, 0.2 g/mL, and 0.1 g/mL for all the EOs. The concentration of 0.4 g/mL CC was more potent at 3 minutes and 2 minutes for Tbb and T. evansi, respectively. The GC-MS analysis of the EOs revealed presence of Cyclobutane (96.09% in CS, 6-octenal (77.11% in EC, Eucalyptol (75% in ED, and Citral (38.32% in CC among several other organic compounds. The results are discussed in relation to trypanosome chemotherapy.

  17. Trypanosoma brucei TBRGG1, a mitochondrial oligo(U)-binding protein that co-localizes with an in vitro RNA editing activity

    NARCIS (Netherlands)

    Vanhamme, L.; Perez-Morga, D.; Marchal, C.; Speijer, D.; Lambert, L.; Geuskens, M.; Alexandre, S.; Ismaïli, N.; Göringer, U.; Benne, R.; Pays, E.

    1998-01-01

    We report the characterization of a Trypanosoma brucei 75-kDa protein of the RGG (Arg-Gly-Gly) type, termed TBRGG1. Dicistronic and monocistronic transcripts of the TBRGG1 gene were produced by both alternative splicing and polyadenylation. TBRGG1 was found in two or three forms that differ in their

  18. Mechanism of Trypanosoma brucei gambiense resistance to human serum

    DEFF Research Database (Denmark)

    Uzureau, Pierrick; Uzureau, Sophie; Lecordier, Laurence

    2013-01-01

    The African parasite Trypanosoma brucei gambiense accounts for 97% of human sleeping sickness cases. T. b. gambiense resists the specific human innate immunity acting against several other tsetse-fly-transmitted trypanosome species such as T. b. brucei, the causative agent of nagana disease......GP), which prevents APOL1 toxicity and induces stiffening of membranes upon interaction with lipids. Two additional features contribute to resistance to TLFs: reduction of sensitivity to APOL1 requiring cysteine protease activity, and TbHpHbR inactivation due to a L210S substitution. According...

  19. Nucleoside analysis of DNA from Trypanosoma brucei and Trypanosoma equiperdum.

    Science.gov (United States)

    Crozatier, M; De Brij, R J; Den Engelse, L; Johnson, P J; Borst, P

    1988-11-01

    We have digested trypanosome DNA with a combination of pancreatic DNase I, nuclease P1 and bovine alkaline phosphatase and fractionated the resulting nucleosides on a Supelcosil LC-18-S column by high pressure liquid chromatography. We find less than 0.1% unusual nucleosides, both in Trypanosoma brucei and in a Trypanosoma equiperdum stock, in contrast to a previous report of an unusual nucleoside replacing dC at 1.3% of total nucleosides in T. equiperdum. Our results agree with previous suggestions that the modification of inactive telomeric expression sites for variant-specific surface glycoprotein genes in T. brucei only affects a very small fraction of the total DNA.

  20. Effects of Morinda lucida leaf extract on Trypanosoma brucei brucei infection in mice.

    Science.gov (United States)

    Asuzu, I U; Chineme, C N

    1990-10-01

    The dried leaves of Morinda lucida were extracted with 50% methanol and the extract was recovered in a 9.7% w/w yield. Acute toxicity tests were performed in mice and the intraperitoneal LD50 of the extract was 2000 mg/kg. The extract induced purgation in mice from the first hour after oral administration and reached its peak between the third and fourth hour. The purgation was not dose-dependent. M. lucida leaf extract i.p. significantly suppressed the level of parasitemia after Trypanosoma brucei infection in mice. Suppression of existing parasitemia appeared dose-dependent with 1000 mg/kg i.p. producing the maximum effect. The best trypanocidal activity was obtained when treatment with M. lucida extract commenced simultaneously with trypanosome inoculation.

  1. Immunomodulatory activity of Buchholzia coriacea seed methanol extract on Trypanosoma brucei brucei infected mice.

    Science.gov (United States)

    Eze, James I; Ekelozie, Chioma F; Nweze, Nwakego E

    2017-12-01

    The seeds of Buchholzia coriacea Engler (Capparaceae) are used in Eastern Nigeria to treat feverish conditions, and to treat malaria and sleeping sickness that cause fever. The current study assesses the immunomodulatory activity of Buchholzia coriacea seed extract on Trypanosoma brucei brucei infected mice. Delayed hypersensitivity reaction, humoral antibody response and in-vivo leucocyte mobilization tests were assessed in three different experiments to determine the effect of the extract on immune response. Seventy-five (75) mice (25 mice per experiment) were used for the study and were each infected with 1.00 × 106 trypanosomes intra-peritoneally. Groups A, B and C were given 250, 500 and 1000 mg/kg of the extract, respectively, group D received 7.5 mg/kg body weight of levamisole and group E was the control. Sheep RBCs were used as antigen. The acute toxicity tests did not cause clinical signs or death within 24 h post treatment at all the doses tested. The extract inhibited delayed hypersensitivity reaction by 20.9 and 20.8% at 250 and 500 mg/kg, respectively, while at 1000 mg/kg, the paw size increased (-101.9%) when compared with the control. The extract elevated the antibody titre from 1.60 ± 0.40 for control to 8.00 ± 3.58 for 500 mg/kg group. The extract increased in total leucocytes counts. The extract has a very wide safety margin and was able to improve immune response. The results of the present study showed that Buchholzia coriacea seed methanol extract possesses immunostimulatory activity on trypanosome-infected mice.

  2. A Short Communication: Bloodstream infection among cancer ...

    African Journals Online (AJOL)

    A Short Communication: Bloodstream infection among cancer patients at Shafa cancer hospital- Ahwaz. ... Journal of Tropical Microbiology and Biotechnology ... We performed a prospective assessment of the current epidemiology of bacteraemia in 612 cancer patients, with patient's age (mean 30, range 1-81 years), ...

  3. ( Nigella sativa ) oil on Trypanosoma brucei -infected rats

    African Journals Online (AJOL)

    The effect of black seed oil (Nigella sativa oil) on parasitaemia, some serum and liver enzymes as well as some haematological parameters in Trypanosoma brucei-infected rats were investigated. The results show there was low parasitaemia and extension of life span of rats from 12 days of the infected untreated (control) ...

  4. The genome of the African trypanosome Trypanosoma brucei.

    Science.gov (United States)

    Berriman, Matthew; Ghedin, Elodie; Hertz-Fowler, Christiane; Blandin, Gaëlle; Renauld, Hubert; Bartholomeu, Daniella C; Lennard, Nicola J; Caler, Elisabet; Hamlin, Nancy E; Haas, Brian; Böhme, Ulrike; Hannick, Linda; Aslett, Martin A; Shallom, Joshua; Marcello, Lucio; Hou, Lihua; Wickstead, Bill; Alsmark, U Cecilia M; Arrowsmith, Claire; Atkin, Rebecca J; Barron, Andrew J; Bringaud, Frederic; Brooks, Karen; Carrington, Mark; Cherevach, Inna; Chillingworth, Tracey-Jane; Churcher, Carol; Clark, Louise N; Corton, Craig H; Cronin, Ann; Davies, Rob M; Doggett, Jonathon; Djikeng, Appolinaire; Feldblyum, Tamara; Field, Mark C; Fraser, Audrey; Goodhead, Ian; Hance, Zahra; Harper, David; Harris, Barbara R; Hauser, Heidi; Hostetler, Jessica; Ivens, Al; Jagels, Kay; Johnson, David; Johnson, Justin; Jones, Kristine; Kerhornou, Arnaud X; Koo, Hean; Larke, Natasha; Landfear, Scott; Larkin, Christopher; Leech, Vanessa; Line, Alexandra; Lord, Angela; Macleod, Annette; Mooney, Paul J; Moule, Sharon; Martin, David M A; Morgan, Gareth W; Mungall, Karen; Norbertczak, Halina; Ormond, Doug; Pai, Grace; Peacock, Chris S; Peterson, Jeremy; Quail, Michael A; Rabbinowitsch, Ester; Rajandream, Marie-Adele; Reitter, Chris; Salzberg, Steven L; Sanders, Mandy; Schobel, Seth; Sharp, Sarah; Simmonds, Mark; Simpson, Anjana J; Tallon, Luke; Turner, C Michael R; Tait, Andrew; Tivey, Adrian R; Van Aken, Susan; Walker, Danielle; Wanless, David; Wang, Shiliang; White, Brian; White, Owen; Whitehead, Sally; Woodward, John; Wortman, Jennifer; Adams, Mark D; Embley, T Martin; Gull, Keith; Ullu, Elisabetta; Barry, J David; Fairlamb, Alan H; Opperdoes, Fred; Barrell, Barclay G; Donelson, John E; Hall, Neil; Fraser, Claire M; Melville, Sara E; El-Sayed, Najib M

    2005-07-15

    African trypanosomes cause human sleeping sickness and livestock trypanosomiasis in sub-Saharan Africa. We present the sequence and analysis of the 11 megabase-sized chromosomes of Trypanosoma brucei. The 26-megabase genome contains 9068 predicted genes, including approximately 900 pseudogenes and approximately 1700 T. brucei-specific genes. Large subtelomeric arrays contain an archive of 806 variant surface glycoprotein (VSG) genes used by the parasite to evade the mammalian immune system. Most VSG genes are pseudogenes, which may be used to generate expressed mosaic genes by ectopic recombination. Comparisons of the cytoskeleton and endocytic trafficking systems with those of humans and other eukaryotic organisms reveal major differences. A comparison of metabolic pathways encoded by the genomes of T. brucei, T. cruzi, and Leishmania major reveals the least overall metabolic capability in T. brucei and the greatest in L. major. Horizontal transfer of genes of bacterial origin has contributed to some of the metabolic differences in these parasites, and a number of novel potential drug targets have been identified.

  5. Roles of triosephosphate isomerase and aerobic metabolism in Trypanosoma brucei.

    NARCIS (Netherlands)

    Helfert, S.; Estevez, A.M.; Bakker, B.M.; Michels, P.A.M.; Clayton, C.

    2001-01-01

    Kinetoplastid protozoa compartmentalize the first seven enzymes of glycolysis and two enzymes of glycerol metabolism in a microbody, the glycosome. While in its mammalian host, Trypanosoma brucei depends entirely on glucose for ATP generation. Under aerobic conditions, most of the glucose is

  6. Population genetic structure and cladistic analysis of Trypanosoma brucei isolates

    NARCIS (Netherlands)

    Agbo, E.C.; Clausen, P.H.; Buscher, P.; Majiwa, P.A.O.; Pas, te M.F.W.; Claassen, E.

    2003-01-01

    Using a novel multilocus DNA marker analysis method, we studied the population genetic structure of Trypansoma brucei stocks and derived clones isolated from animal and rhodesiense sleeping sickness patients during a national sleeping sickness control program in Mukono district, Uganda. We then

  7. Trypanosoma brucei Co-opts NK Cells to Kill Splenic B2 B Cells.

    Directory of Open Access Journals (Sweden)

    Deborah Frenkel

    2016-07-01

    Full Text Available After infection with T. brucei AnTat 1.1, C57BL/6 mice lost splenic B2 B cells and lymphoid follicles, developed poor parasite-specific antibody responses, lost weight, became anemic and died with fulminating parasitemia within 35 days. In contrast, infected C57BL/6 mice lacking the cytotoxic granule pore-forming protein perforin (Prf1-/- retained splenic B2 B cells and lymphoid follicles, developed high-titer antibody responses against many trypanosome polypeptides, rapidly suppressed parasitemia and did not develop anemia or lose weight for at least 60 days. Several lines of evidence show that T. brucei infection-induced splenic B cell depletion results from natural killer (NK cell-mediated cytotoxicity: i B2 B cells were depleted from the spleens of infected intact, T cell deficient (TCR-/- and FcγRIIIa deficient (CD16-/- C57BL/6 mice excluding a requirement for T cells, NKT cell, or antibody-dependent cell-mediated cytotoxicity; ii administration of NK1.1 specific IgG2a (mAb PK136 but not irrelevant IgG2a (myeloma M9144 prevented infection-induced B cell depletion consistent with a requirement for NK cells; iii splenic NK cells but not T cells or NKT cells degranulated in infected C57BL/6 mice co-incident with B cell depletion evidenced by increased surface expression of CD107a; iv purified NK cells from naïve C57BL/6 mice killed purified splenic B cells from T. brucei infected but not uninfected mice in vitro indicating acquisition of an NK cell activating phenotype by the post-infection B cells; v adoptively transferred C57BL/6 NK cells prevented infection-induced B cell population growth in infected Prf1-/- mice consistent with in vivo B cell killing; vi degranulated NK cells in infected mice had altered gene and differentiation antigen expression and lost cytotoxic activity consistent with functional exhaustion, but increased in number as infection progressed indicating continued generation. We conclude that NK cells in T. brucei

  8. A target-based high throughput screen yields Trypanosoma brucei hexokinase small molecule inhibitors with antiparasitic activity.

    Directory of Open Access Journals (Sweden)

    Elizabeth R Sharlow

    2010-04-01

    Full Text Available The parasitic protozoan Trypanosoma brucei utilizes glycolysis exclusively for ATP production during infection of the mammalian host. The first step in this metabolic pathway is mediated by hexokinase (TbHK, an enzyme essential to the parasite that transfers the gamma-phospho of ATP to a hexose. Here we describe the identification and confirmation of novel small molecule inhibitors of bacterially expressed TbHK1, one of two TbHKs expressed by T. brucei, using a high throughput screening assay.Exploiting optimized high throughput screening assay procedures, we interrogated 220,233 unique compounds and identified 239 active compounds from which ten small molecules were further characterized. Computation chemical cluster analyses indicated that six compounds were structurally related while the remaining four compounds were classified as unrelated or singletons. All ten compounds were approximately 20-17,000-fold more potent than lonidamine, a previously identified TbHK1 inhibitor. Seven compounds inhibited T. brucei blood stage form parasite growth (0.03brucei parasites, Leishmania promastigotes, and mammalian cell lines. Analysis of two structurally related compounds, ebselen and SID 17387000, revealed that both were mixed inhibitors of TbHK1 with respect to ATP. Additionally, both compounds inhibited parasite lysate-derived HK activity. None of the compounds displayed structural similarity to known hexokinase inhibitors or human African trypanosomiasis therapeutics.The novel chemotypes identified here could represent leads for future therapeutic development against the African trypanosome.

  9. Infection Probability Score, APACHE II and KARNOFSKY scoring systems as predictors of bloodstream infection onset in hematology-oncology patients

    Directory of Open Access Journals (Sweden)

    Terzis Konstantinos

    2010-05-01

    Full Text Available Abstract Background Bloodstream Infections (BSIs in neutropenic patients often cause considerable morbidity and mortality. Therefore, the surveillance and early identification of patients at high risk for developing BSIs might be useful for the development of preventive measures. The aim of the current study was to assess the predictive power of three scoring systems: Infection Probability Score (IPS, APACHE II and KARNOFSKY score for the onset of Bloodstream Infections in hematology-oncology patients. Methods A total of 102 patients who were hospitalized for more than 48 hours in a hematology-oncology department in Athens, Greece between April 1st and October 31st 2007 were included in the study. Data were collected by using an anonymous standardized recording form. Source materials included medical records, temperature charts, information from nursing and medical staff, and results on microbiological testing. Patients were followed daily until hospital discharge or death. Results Among the 102 patients, Bloodstream Infections occurred in 17 (16.6% patients. The incidence density of Bloodstream Infections was 7.74 per 1,000 patient-days or 21.99 per 1,000 patient-days at risk. The patients who developed a Bloodstream Infection were mainly females (p = 0.004, with twofold time mean length of hospital stay (p Conclusion Between the three different prognostic scoring systems, Infection Probability Score had the best sensitivity in predicting Bloodstream Infections.

  10. von Willebrand factor, Jedi knight of the bloodstream.

    Science.gov (United States)

    Springer, Timothy A

    2014-08-28

    When blood vessels are cut, the forces in the bloodstream increase and change character. The dark side of these forces causes hemorrhage and death. However, von Willebrand factor (VWF), with help from our circulatory system and platelets, harnesses the same forces to form a hemostatic plug. Force and VWF function are so closely intertwined that, like members of the Jedi Order in the movie Star Wars who learn to use "the Force" to do good, VWF may be considered the Jedi knight of the bloodstream. The long length of VWF enables responsiveness to flow. The shape of VWF is predicted to alter from irregularly coiled to extended thread-like in the transition from shear to elongational flow at sites of hemostasis and thrombosis. Elongational force propagated through the length of VWF in its thread-like shape exposes its monomers for multimeric binding to platelets and subendothelium and likely also increases affinity of the A1 domain for platelets. Specialized domains concatenate and compact VWF during biosynthesis. A2 domain unfolding by hydrodynamic force enables postsecretion regulation of VWF length. Mutations in VWF in von Willebrand disease contribute to and are illuminated by VWF biology. I attempt to integrate classic studies on the physiology of hemostatic plug formation into modern molecular understanding, and point out what remains to be learned. © 2014 by The American Society of Hematology.

  11. Human and animal Trypanosomes in Cote d'Ivoire form a single breeding population.

    Directory of Open Access Journals (Sweden)

    Paul Capewell

    Full Text Available BACKGROUND: Trypanosoma brucei is the causative agent of African Sleeping Sickness in humans and contributes to the related veterinary disease, Nagana. T. brucei is segregated into three subspecies based on host specificity, geography and pathology. T. b. brucei is limited to animals (excluding some primates throughout sub-Saharan Africa and is non-infective to humans due to trypanolytic factors found in human serum. T. b. gambiense and T. b. rhodesiense are human infective sub-species. T. b. gambiense is the more prevalent human, causing over 97% of human cases. Study of T. b. gambiense is complicated in that there are two distinct groups delineated by genetics and phenotype. The relationships between the two groups and local T. b. brucei are unclear and may have a bearing on the evolution of the human infectivity traits. METHODOLOGY/PRINCIPAL FINDINGS: A collection of sympatric T. brucei isolates from Côte d'Ivoire, consisting of T. b. brucei and both groups of T. b. gambiense have previously been categorized by isoenzymes, RFLPs and Blood Incubation Infectivity Tests. These samples were further characterized using the group 1 specific marker, TgSGP, and seven microsatellites. The relationships between the T. b. brucei and T. b. gambiense isolates were determined using principal components analysis, neighbor-joining phylogenetics, STRUCTURE, FST, Hardy-Weinberg equilibrium and linkage disequilibrium. CONCLUSIONS/SIGNIFICANCE: Group 1 T. b. gambiense form a clonal genetic group, distinct from group 2 and T. b. brucei, whereas group 2 T. b. gambiense are genetically indistinguishable from local T. b. brucei. There is strong evidence for mating within and between group 2 T. b. gambiense and T. b. brucei. We found no evidence to support the hypothesis that group 2 T. b. gambiense are hybrids of group 1 and T. b. brucei, suggesting that human infectivity has evolved independently in groups 1 and 2 T. b. gambiense.

  12. Crystal structure of arginine methyltransferase 6 from Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Chongyuan Wang

    Full Text Available Arginine methylation plays vital roles in the cellular functions of the protozoan Trypanosoma brucei. The T. brucei arginine methyltransferase 6 (TbPRMT6 is a type I arginine methyltransferase homologous to human PRMT6. In this study, we report the crystal structures of apo-TbPRMT6 and its complex with the reaction product S-adenosyl-homocysteine (SAH. The structure of apo-TbPRMT6 displays several features that are different from those of type I PRMTs that were structurally characterized previously, including four stretches of insertion, the absence of strand β15, and a distinct dimerization arm. The comparison of the apo-TbPRMT6 and SAH-TbPRMT6 structures revealed the fine rearrangements in the active site upon SAH binding. The isothermal titration calorimetry results demonstrated that SAH binding greatly increases the affinity of TbPRMT6 to a substrate peptide derived from bovine histone H4. The western blotting and mass spectrometry results revealed that TbPRMT6 methylates bovine histone H4 tail at arginine 3 but cannot methylate several T. brucei histone tails. In summary, our results highlight the structural differences between TbPRMT6 and other type I PRMTs and reveal that the active site rearrangement upon SAH binding is important for the substrate binding of TbPRMT6.

  13. Effect of diminazene aceturate, levamisole and vitamin C combination therapy in rats experimentally infected with Trypanosoma brucei brucei.

    Science.gov (United States)

    Chekwube, Adieme Ijeoma; Onyema, Ezeh Ikenna; Ikenna, Ugochukwu Emmanuel; Ezeokonkwo, Romanus Chukwuduruo

    2014-06-01

    To investigate the effect of diminazene aceturate (DA) alone or in combination with either levamisole and/or Vitamin C in albino rats experimentally infected with Trypanosoma brucei brucei. Thirty adult male albino rats, randomly assigned into 6 groups (A-F) of 5 rats each were used. They were either infected with 1×10(6) trypanosomes intraperitoneally (groups A-E) or uninfected (group F). The different groups were treated respectively as follows: group A-with 3.5 mg/kg DA; group B-3.5 mg/kg DA and 7.5 mg/kg levamisole; group C-3.5 mg/kg DA and 100 mg/kg vitamin C; and group D-3.5 mg/kg DA and 7.5 mg/kg levamisole and 100 mg/kg vitamin C. Group E was left untreated. Parameters assessed include: rectal temperature, body weight changes, packed cell volume (PCV), Haemoglobin concentration (Hb), total leucocyte count (TLC) differential leucocyte count (DLC), parasitaemia, clinical signs and survivability. Average pre-patent period of 5 days was recorded. Parasites in the blood were cleared in all treated groups (A-D) within 48 hours post treatment (PT). Untreated rats in group E died between 25 and 32 days post infection (PI). Relapse was not recorded in all the treated groups (A-D). The initial reduction in PCV, Hb, TLC and increases in rectal temperature following infection were reversed by the treatments. The rats that received drug combinations (groups B, C and D) showed faster and higher recovery rates than the uninfected control and group A. Levamisole and/or Vitamin C combination with DA were more effective in the treatment of rats infected with Trypanosoma brucei brucei. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  14. Sec16 determines the size and functioning of the Golgi in the protist parasite, Trypanosoma brucei.

    Science.gov (United States)

    Sealey-Cardona, Marco; Schmidt, Katy; Demmel, Lars; Hirschmugl, Tatjana; Gesell, Tanja; Dong, Gang; Warren, Graham

    2014-06-01

    The Sec16 homologue in Trypanosoma brucei has been identified and characterized. TbSec16 colocalizes with COPII components at the single endoplasmic reticulum exit site (ERES), which is next to the single Golgi stack in the insect (procyclic) form of this organism. Depletion of TbSec16 reduces the size of the ERES and the Golgi, and slows growth and transport of a secretory marker to the cell surface; conversely, overexpression of TbSec16 increases the size of the ERES and Golgi but has no effect on growth or secretion. Together these data suggest that TbSec16 regulates the size of the ERES and Golgi and this size is set for optimal growth of the organism. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Pathogenicity of bloodstream and cerebrospinal fluid forms of ...

    African Journals Online (AJOL)

    kemrilib

    carried out to compare the pathogenicity of CSF and BSF of T.b. rhodesiense parasites in Swiss white mice following ... survival of the mice was monitored daily until the experiment was terminated. Data was analyzed using general linear ... white mice before being cryopreserved. During the experiment, the cryopreserved.

  16. Characterization of Two Mitochondrial Flavin Adenine Dinucleotide-Dependent Glycerol-3-Phosphate Dehydrogenases in Trypanosoma brucei

    Czech Academy of Sciences Publication Activity Database

    Škodová, Ingrid; Verner, Zdeněk; Bringaud, F.; Fabian, P.; Lukeš, Julius; Horváth, A.

    2013-01-01

    Roč. 12, č. 12 (2013), s. 1664-1673 ISSN 1535-9778 R&D Projects: GA ČR(CZ) GAP305/11/2179; GA ČR GD206/09/H026; GA MŠk LH12104 Institutional support: RVO:60077344 Keywords : alternative NADH dehydrogenase * inducible expression system * blood-stream forms * complex-I * procyclic trypanosomes * sleeping sickness * oxidase * localization * metabolism * cycle Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.179, year: 2013

  17. Dynamin-like proteins in Trypanosoma brucei: A division of labour between two paralogs?

    Czech Academy of Sciences Publication Activity Database

    Benz, C.; Stříbrná, Eva; Hashimi, Hassan; Lukeš, Julius

    2017-01-01

    Roč. 12, č. 5 (2017), č. článku e0177200. E-ISSN 1932-6203 R&D Projects: GA ČR GA15-21974S; GA ČR GA17-24036S; GA MŠk LL1601 Institutional support: RVO:60077344 Keywords : blood-stream forms * mitochondrial fission * sequence alignment * gtpase activity * single dynamin * life-cycle * endocytosis * fis1 * expression * surface Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.806, year: 2016

  18. Rab23 is a flagellar protein in Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Field Mark C

    2011-06-01

    Full Text Available Abstract Background Rab small GTPases are important mediators of membrane transport, and orthologues frequently retain similar locations and functions, even between highly divergent taxa. In metazoan organisms Rab23 is an important negative regulator of Sonic hedgehog signaling and is crucial for correct development and differentiation of cellular lineages by virtue of an involvement in ciliary recycling. Previously, we reported that Trypanosoma brucei Rab23 localized to the nuclear envelope 1, which is clearly inconsistent with the mammalian location and function. As T. brucei is unicellular the potential that Rab23 has no role in cell signaling was possible. Here we sought to further investigate the role(s of Rab23 in T. brucei to determine if Rab23 was an example of a Rab protein with divergent function in distinct taxa. Methods/major findings The taxonomic distribution of Rab23 was examined and compared with the presence of flagella/cilia in representative taxa. Despite evidence for considerable secondary loss, we found a clear correlation between a conventional flagellar structure and the presence of a Rab23 orthologue in the genome. By epitope-tagging, Rab23 was localized and found to be present at the flagellum throughout the cell cycle. However, RNAi knockdown did not result in a flagellar defect, suggesting that Rab23 is not required for construction or maintenance of the flagellum. Conclusions The location of Rab23 at the flagellum is conserved between mammals and trypanosomes and the Rab23 gene is restricted to flagellated organisms. These data may suggest the presence of a Rab23-mediated signaling mechanism in trypanosomes.

  19. The acidocalcisome vacuolar transporter chaperone 4 catalyzes the synthesis of polyphosphate in insect-stages of Trypanosoma brucei and T. cruzi.

    Science.gov (United States)

    Ulrich, Paul N; Lander, Noelia; Kurup, Samarchith P; Reiss, Laura; Brewer, Jessica; Soares Medeiros, Lia C; Miranda, Kildare; Docampo, Roberto

    2014-01-01

    Polyphosphate is a polymer of inorganic phosphate found in both prokaryotes and eukaryotes. Polyphosphate typically accumulates in acidic, calcium-rich organelles known as acidocalcisomes, and recent research demonstrated that vacuolar transporter chaperone 4 catalyzes its synthesis in yeast. The human pathogens Trypanosoma brucei and T. cruzi possess vacuolar transporter chaperone 4 homologs. We demonstrate that T. cruzi vacuolar transporter chaperone 4 localizes to acidocalcisomes of epimastigotes by immunofluorescence and immuno-electron microscopy and that the recombinant catalytic region of the T. cruzi enzyme is a polyphosphate kinase. RNA interference of the T. brucei enzyme in procyclic form parasites reduced short chain polyphosphate levels and resulted in accumulation of pyrophosphate. These results suggest that this trypanosome enzyme is an important component of a polyphosphate synthase complex that utilizes ATP to synthesize and translocate polyphosphate to acidocalcisomes in insect stages of these parasites. © 2013 The Author(s) Journal of Eukaryotic Microbiology © 2013 International Society of Protistologists.

  20. The orthologue of Sjögren's syndrome nuclear autoantigen 1 (SSNA1 in Trypanosoma brucei is an immunogenic self-assembling molecule.

    Directory of Open Access Journals (Sweden)

    Helen P Price

    Full Text Available Primary Sjögren's Syndrome (PSS is a highly prevalent autoimmune disease, typically manifesting as lymphocytic infiltration of the exocrine glands leading to chronically impaired lacrimal and salivary secretion. Sjögren's Syndrome nuclear autoantigen 1 (SSNA1 or NA14 is a major specific target for autoantibodies in PSS but the precise function and clinical relevance of this protein are largely unknown. Orthologues of the gene are absent from many of the commonly used model organisms but are present in Chlamyodomonas reinhardtii (in which it has been termed DIP13 and most protozoa. We report the functional characterisation of the orthologue of SSNA1 in the kinetoplastid parasite, Trypanosoma brucei. Both TbDIP13 and human SSNA1 are small coiled-coil proteins which are predicted to be remote homologues of the actin-binding protein tropomyosin. We use comparative proteomic methods to identify potential interacting partners of TbDIP13. We also show evidence that TbDIP13 is able to self-assemble into fibril-like structures both in vitro and in vivo, a property which may contribute to its immunogenicity. Endogenous TbDIP13 partially co-localises with acetylated α-tubulin in the insect procyclic stage of the parasite. However, deletion of the DIP13 gene in cultured bloodstream and procyclic stages of T. brucei has little effect on parasite growth or morphology, indicating either a degree of functional redundancy or a function in an alternative stage of the parasite life cycle.

  1. Minimum Information Loss Based Multi-kernel Learning for Flagellar Protein Recognition in Trypanosoma Brucei

    KAUST Repository

    Wang, Jim Jing-Yan

    2014-12-01

    Trypanosma brucei (T. Brucei) is an important pathogen agent of African trypanosomiasis. The flagellum is an essential and multifunctional organelle of T. Brucei, thus it is very important to recognize the flagellar proteins from T. Brucei proteins for the purposes of both biological research and drug design. In this paper, we investigate computationally recognizing flagellar proteins in T. Brucei by pattern recognition methods. It is argued that an optimal decision function can be obtained as the difference of probability functions of flagella protein and the non-flagellar protein for the purpose of flagella protein recognition. We propose to learn a multi-kernel classification function to approximate this optimal decision function, by minimizing the information loss of such approximation which is measured by the Kull back-Leibler (KL) divergence. An iterative multi-kernel classifier learning algorithm is developed to minimize the KL divergence for the problem of T. Brucei flagella protein recognition, experiments show its advantage over other T. Brucei flagellar protein recognition and multi-kernel learning methods. © 2014 IEEE.

  2. Antitrypanosomal effect of methanolic extract of Zingiber officinale (ginger on Trypanosoma brucei brucei-infected Wistar mice

    Directory of Open Access Journals (Sweden)

    P. I. Kobo

    2014-10-01

    Full Text Available Aim: The study was carried out to determine the in vivo antitrypanosomal effect of methanolic extract of Zingiber officinale (ginger in Trypanosoma brucei brucei-infected mice. Materials and Methods: Twenty-five mice were randomly allocated into five groups of five animals each. Group I and II were given Tween 80 (1 ml/kg and diminazene aceturate (3.5 mg/kg to serve as untreated and treated controls, respectively. Groups III-V received the extract at 200, 400 and 800 mg/kg body weight, respectively. All treatments were given for 6 consecutive days and through the oral route. The mean body weight, mean survival period and daily level of parasitaemia were evaluated. Results: Acute toxicity showed the extract to be relatively safe. There was an insignificant increase in body weight and survival rate of mice treated with the extract. The level of parasitaemia in the extract treated groups was decreased. Conclusion: This study shows the in vivo potential of methanolic extract of Z. officinale in the treatment of trypanosomiasis.

  3. Bloodstream Infections with Mycobacterium tuberculosis among HIV patients

    Centers for Disease Control (CDC) Podcasts

    2010-09-23

    This podcast looks at bloodstream infections with Mycobacterium tuberculosis and other pathogens among outpatients infected with HIV in Southeast Asia. CDC health scientist Kimberly McCarthy discusses the study and why bloodstream infections occur in HIV-infected populations.  Created: 9/23/2010 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 9/23/2010.

  4. Pseudomonas aeruginosa Bloodstream Infection: Importance of Appropriate Initial Antimicrobial Treatment

    OpenAIRE

    Micek, Scott T; Lloyd, Ann E.; David J. Ritchie; Reichley, Richard M.; Fraser, Victoria J.; Kollef, Marin H

    2005-01-01

    Pseudomonas aeruginosa bloodstream infection is a serious infection with significant patient mortality and health-care costs. Nevertheless, the relationship between initial appropriate antimicrobial treatment and clinical outcomes is not well established. This study was a retrospective cohort analysis employing automated patient medical records and the pharmacy database at Barnes-Jewish Hospital. Three hundred five patients with P. aeruginosa bloodstream infection were identified over a 6-yea...

  5. 1H, 13C and 15N resonance assignment of Urm1 from Trypanosoma brucei.

    Science.gov (United States)

    Zhang, Wen; Ding, Husheng; Zhang, Jiahai; Tu, Xiaoming

    2008-06-01

    Urm1 (ubiquitin-related modifier), involved in diverse biological processes in yeast, is proved to be a "molecular fossil" in ubiquitin superfamily. Here we report the resonance assignment of Urm1 from Trypanosoma brucei.

  6. Proximity Interactions among Basal Body Components in Trypanosoma brucei Identify Novel Regulators of Basal Body Biogenesis and Inheritance

    Directory of Open Access Journals (Sweden)

    Hung Quang Dang

    2017-01-01

    Full Text Available The basal body shares similar architecture with centrioles in animals and is involved in nucleating flagellar axonemal microtubules in flagellated eukaryotes. The early-branching Trypanosoma brucei possesses a motile flagellum nucleated from the basal body that consists of a mature basal body and an adjacent pro-basal body. Little is known about the basal body proteome and its roles in basal body biogenesis and flagellar axoneme assembly in T. brucei. Here, we report the identification of 14 conserved centriole/basal body protein homologs and 25 trypanosome-specific basal body proteins. These proteins localize to distinct subdomains of the basal body, and several of them form a ring-like structure surrounding the basal body barrel. Functional characterization of representative basal body proteins revealed distinct roles in basal body duplication/separation and flagellar axoneme assembly. Overall, this work identified novel proteins required for basal body duplication and separation and uncovered new functions of conserved basal body proteins in basal body duplication and separation, highlighting an unusual mechanism of basal body biogenesis and inheritance in this early divergent eukaryote.

  7. A Flagellar Pocket Membrane Fraction from Trypanosoma brucei rhodesiense: Immunogold Localization and Nonvariant Immunoprotection

    Science.gov (United States)

    1988-01-01

    membrane components. specific glycoproteins from Trypanosoma equiperdum variants. Exp. Parasitol. 64:1-11. FEBS Lett. 82:93-96. 20. Melton, D. W., D. S...Fraction from Trypanosoma brucei rhodesiense: Immunogold Localization and Nonvariant Immunoprotection JOHN G. OLENICK,* RUTH WOLFF,’ ROBERT K. NAUMAN...obtained for each of three distinct variable antigenic types (VATs) of a serodeme of Trypanosoma brucei rhodesiense Wellcome strain. Products of

  8. Risk factors for nosocomial bloodstream infections.

    Science.gov (United States)

    Apostolopolou, Eleni; Katsaris, Georgios; Katostaras, Theophanis

    A retrospective study of 205 patients was performed to identify the risk factors associated with nosocomial bloodstream infection (BSI). The study occurred during a 5-month period in four medical-surgical intensive care units (ICUs) in Athens, Greece. Risk factors were determined using single and multivariate analyses. Thirty-five patients developed nosocomial BSI (17.1%). The incidence density (defined as the number of new cases of BSI divided by the total of patient-days in the population studied; Jarvis, 1997) of BSI was 14.3 per 1000 patient-days (total number of days that patients are in the ICU during the selected time period). A multivariate model showed that only three factors were significantly and independently responsible for nosocomial BSI: the length of ICU stay (adjusted odds ratios (AOR) 1.052, 95% confidence interval (CI) 1.018-1.087, P = 0.002); the presence of trauma at admission (AOR 2.622, 95% CI 1.074-6.404, P = 0.034); and nosocomial ventilator-associated pneumonia (AOR 6.153, 95% CI 2.305-16.422, P = 0.000). These results show that the factors that had most influence on the development of nosocomial BSI were those factors associated with the treatment received by patients during ICU stay.

  9. Dual functions of α-ketoglutarate dehydrogenase E2 in the Krebs cycle and mitochondrial DNA inheritance in Trypanosoma brucei.

    Science.gov (United States)

    Sykes, Steven E; Hajduk, Stephen L

    2013-01-01

    The dihydrolipoyl succinyltransferase (E2) of the multisubunit α-ketoglutarate dehydrogenase complex (α-KD) is an essential Krebs cycle enzyme commonly found in the matrices of mitochondria. African trypanosomes developmentally regulate mitochondrial carbohydrate metabolism and lack a functional Krebs cycle in the bloodstream of mammals. We found that despite the absence of a functional α-KD, bloodstream form (BF) trypanosomes express α-KDE2, which localized to the mitochondrial matrix and inner membrane. Furthermore, α-KDE2 fractionated with the mitochondrial genome, the kinetoplast DNA (kDNA), in a complex with the flagellum. A role for α-KDE2 in kDNA maintenance was revealed in α-KDE2 RNA interference (RNAi) knockdowns. Following RNAi induction, bloodstream trypanosomes showed pronounced growth reduction and often failed to equally distribute kDNA to daughter cells, resulting in accumulation of cells devoid of kDNA (dyskinetoplastic) or containing two kinetoplasts. Dyskinetoplastic trypanosomes lacked mitochondrial membrane potential and contained mitochondria of substantially reduced volume. These results indicate that α-KDE2 is bifunctional, both as a metabolic enzyme and as a mitochondrial inheritance factor necessary for the distribution of kDNA networks to daughter cells at cytokinesis.

  10. Genotypic analysis of Acinetobacter bloodstream infection isolates in a Turkish university hospital.

    NARCIS (Netherlands)

    Alp, E.; Esel, D.; Yildiz, O.; Voss, A.; Melchers, W.J.G.; Doganay, M.

    2006-01-01

    Acinetobacter baumannii is a significant pathogen of bloodstream infections in hospital patients that frequently causes single clone outbreaks. We aimed to evaluate the genetic relatedness and antimicrobial susceptibility of Acinetobacter spp. bloodstream isolates, in order to obtain insight into

  11. Dynamic modelling under uncertainty: the case of Trypanosoma brucei energy metabolism.

    Directory of Open Access Journals (Sweden)

    Fiona Achcar

    2012-01-01

    Full Text Available Kinetic models of metabolism require detailed knowledge of kinetic parameters. However, due to measurement errors or lack of data this knowledge is often uncertain. The model of glycolysis in the parasitic protozoan Trypanosoma brucei is a particularly well analysed example of a quantitative metabolic model, but so far it has been studied with a fixed set of parameters only. Here we evaluate the effect of parameter uncertainty. In order to define probability distributions for each parameter, information about the experimental sources and confidence intervals for all parameters were collected. We created a wiki-based website dedicated to the detailed documentation of this information: the SilicoTryp wiki (http://silicotryp.ibls.gla.ac.uk/wiki/Glycolysis. Using information collected in the wiki, we then assigned probability distributions to all parameters of the model. This allowed us to sample sets of alternative models, accurately representing our degree of uncertainty. Some properties of the model, such as the repartition of the glycolytic flux between the glycerol and pyruvate producing branches, are robust to these uncertainties. However, our analysis also allowed us to identify fragilities of the model leading to the accumulation of 3-phosphoglycerate and/or pyruvate. The analysis of the control coefficients revealed the importance of taking into account the uncertainties about the parameters, as the ranking of the reactions can be greatly affected. This work will now form the basis for a comprehensive Bayesian analysis and extension of the model considering alternative topologies.

  12. Mortality in enterococcal bloodstream infections increases with inappropriate antimicrobial therapy

    DEFF Research Database (Denmark)

    Suppli, M.; Aabenhus, R.; Harboe, Z.B.

    2010-01-01

    Enterococcus species are common in nosocomial bloodstream infections and their incidence is rising. Although well recognized in several serious bacterial infections, the influence of appropriate antimicrobial therapy in enterococcal bacteraemia has not been fully settled. The aim of the study.......7-10), thrombocytopenia (3.9, 1.6-9.3), chronic liver failure (3.3, 1.1-10) and age >/=60 years (2.2, 0.99-5.0). Antibiotics not appropriately covering enterococci are frequently administered empirically in suspected bloodstream infections. Inappropriate antibiotic therapy was an independent risk factor for mortality...

  13. Role of centrins 2 and 3 in organelle segregation and cytokinesis in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Angamuthu Selvapandiyan

    Full Text Available Centrins are calcium binding proteins involved in cell division in eukaryotes. Previously, we have shown that depletion of centrin1 in Trypanosoma brucei (T. brucei displayed arrested organelle segregation resulting in loss of cytokinesis. In this study we analyzed the role of T. brucei centrin2 (TbCen2 and T. brucei 3 (TbCen3 in the early events of T. brucei procyclic cell cycle. Both the immunofluorescence assay and electron microscopy showed that TbCen2 and 3-deficient cells were enlarged in size with duplicated basal bodies, multinuclei and new flagella that are detached along the length of the cell body. In both TbCen2 and TbCen3 depleted cells segregation of the organelles i.e. basal bodies, kinetoplast and nucleus was disrupted. Further analysis of the cells with defective organelle segregation identified three different sub configurations of organelle mis-segregations (Type 1-3. In addition, in majority of the TbCen2 depleted cells and in nearly half of the TbCen3 depleted cells, the kinetoplasts were enlarged and undivided. The abnormal segregations ultimately led to aborted cytokinesis and hence affected growth in these cells. Therefore, both centrin2 and 3 are involved in organelle segregation similar to centrin1 as was previously observed. In addition, we identified their role in kinetoplast division which may be also linked to overall mis-segregation.

  14. High-throughput Gene Tagging in Trypanosoma brucei.

    Science.gov (United States)

    Dyer, Philip; Dean, Samuel; Sunter, Jack

    2016-08-12

    Improvements in mass spectrometry, sequencing and bioinformatics have generated large datasets of potentially interesting genes. Tagging these proteins can give insights into their function by determining their localization within the cell and enabling interaction partner identification. We recently published a fast and scalable method to generate Trypanosoma brucei cell lines that express a tagged protein from the endogenous locus. The method was based on a plasmid we generated that, when coupled with long primer PCR, can be used to modify a gene to encode a protein tagged at either terminus. This allows the tagging of dozens of trypanosome proteins in parallel, facilitating the large-scale validation of candidate genes of interest. This system can be used to tag proteins for localization (using a fluorescent protein, epitope tag or electron microscopy tag) or biochemistry (using tags for purification, such as the TAP (tandem affinity purification) tag). Here, we describe a protocol to perform the long primer PCR and the electroporation in 96-well plates, with the recovery and selection of transgenic trypanosomes occurring in 24-well plates. With this workflow, hundreds of proteins can be tagged in parallel; this is an order of magnitude improvement to our previous protocol and genome scale tagging is now possible.

  15. 900-IJBCS-Article-Prof Georges Accrombessi

    African Journals Online (AJOL)

    DR GATSING

    Antitrypanosomal activity (LILIT,. Alamar BlueTM). The test is performed on the bloodstream form of the strain 427 of. Trypanosoma brucei brucei by the "Lilit. Alamar Blue" method (Baltz et al., 1985;. Räz et al., 1997). The stock solutions of. 1,3,4-thiadiazolines have been prepared from an initial concentration of 10 mg/ml in.

  16. Author Details

    African Journals Online (AJOL)

    Ngotho, M. Vol 13, No 3 (2006) - Articles Haematology of experimental Trypanosoma brucei rhodesiense infection in vervet monkeys. Abstract PDF · Vol 15, No 1 (2008) - Articles Pathogenicity of bloodstream and cerebrospinal fluid forms of Trypanosoma brucei rhodesiense in Swiss White Mice Abstract PDF. ISSN: 1022- ...

  17. Prevention of nosocomial bloodstream infections in preterm infants

    NARCIS (Netherlands)

    K. Helder MScN (Onno)

    2013-01-01

    textabstractProtecting patients from harm is the overarching theme of the studies presented here. More precisely, this thesis places a focus on the prevention of nosocomial or hospitalacquired bloodstream infections in preterm infants, thus saving them from further harm. A nosocomial infection is an

  18. Ligand tunnels in T. brucei and human CYP51: Insights for parasite-specific drug design.

    Science.gov (United States)

    Yu, Xiaofeng; Nandekar, Prajwal; Mustafa, Ghulam; Cojocaru, Vlad; Lepesheva, Galina I; Wade, Rebecca C

    2016-01-01

    Cytochrome P450 sterol 14α-demethylase (CYP51) is an essential enzyme for sterol biosynthesis and a target for anti-parasitic drug design. However, the design of parasite-specific drugs that inhibit parasitic CYP51 without severe side effects remains challenging. The active site of CYP51 is situated in the interior of the protein. Here, we characterize the potential ligand egress routes and mechanisms in Trypanosoma brucei and human CYP51 enzymes. We performed Random Acceleration Molecular Dynamics simulations of the egress of four different ligands from the active site of models of soluble and membrane-bound T. brucei CYP51 and of soluble human CYP51. In the simulations, tunnel 2f, which leads to the membrane, was found to be the predominant ligand egress tunnel for all the ligands studied. Tunnels S, 1 and W, which lead to the cytosol, were also used in T. brucei CYP51, whereas tunnel 1 was the only other tunnel used significantly in human CYP51. The common tunnels found previously in other CYPs were barely used. The ligand egress times were shorter for human than T. brucei CYP51, suggesting lower barriers to ligand passage. Two gating residues, F105 and M460, in T. brucei CYP51 that modulate the opening of tunnels 2f and S were identified. Although the main egress tunnel was the same, differences in the tunnel-lining residues, ligand passage and tunnel usage were found between T. brucei and human CYP51s. The results provide a basis for the design of selective anti-parasitic agents targeting the ligand tunnels. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Trypanosoma brucei gambiense group 1 is distinguished by a unique amino acid substitution in the HpHb receptor implicated in human serum resistance.

    Directory of Open Access Journals (Sweden)

    Rebecca E Symula

    Full Text Available Trypanosoma brucei rhodesiense (Tbr and T. b. gambiense (Tbg, causative agents of Human African Trypanosomiasis (sleeping sickness in Africa, have evolved alternative mechanisms of resisting the activity of trypanosome lytic factors (TLFs, components of innate immunity in human serum that protect against infection by other African trypanosomes. In Tbr, lytic activity is suppressed by the Tbr-specific serum-resistance associated (SRA protein. The mechanism in Tbg is less well understood but has been hypothesized to involve altered activity and expression of haptoglobin haemoglobin receptor (HpHbR. HpHbR has been shown to facilitate internalization of TLF-1 in T.b. brucei (Tbb, a member of the T. brucei species complex that is susceptible to human serum. By evaluating the genetic variability of HpHbR in a comprehensive geographical and taxonomic context, we show that a single substitution that replaces leucine with serine at position 210 is conserved in the most widespread form of Tbg (Tbg group 1 and not found in related taxa, which are either human serum susceptible (Tbb or known to resist lysis via an alternative mechanism (Tbr and Tbg group 2. We hypothesize that this single substitution contributes to reduced uptake of TLF and thus may play a key role in conferring serum resistance to Tbg group 1. In contrast, similarity in HpHbR sequence among isolates of Tbg group 2 and Tbb/Tbr provides further evidence that human serum resistance in Tbg group 2 is likely independent of HpHbR function.

  20. Coordinated Molecular Cross-Talk between Staphylococcus aureus, Endothelial Cells and Platelets in Bloodstream Infection

    Directory of Open Access Journals (Sweden)

    Carolina D. Garciarena

    2015-12-01

    Full Text Available Staphylococcus aureus is an opportunistic pathogen often carried asymptomatically on the human body. Upon entry to the otherwise sterile environment of the cardiovascular system, S. aureus can lead to serious complications resulting in organ failure and death. The success of S. aureus as a pathogen in the bloodstream is due to its ability to express a wide array of cell wall proteins on its surface that recognise host receptors, extracellular matrix proteins and plasma proteins. Endothelial cells and platelets are important cells in the cardiovascular system and are a major target of bloodstream infection. Endothelial cells form the inner lining of a blood vessel and provide an antithrombotic barrier between the vessel wall and blood. Platelets on the other hand travel throughout the cardiovascular system and respond by aggregating around the site of injury and initiating clot formation. Activation of either of these cells leads to functional dysregulation in the cardiovascular system. In this review, we will illustrate how S. aureus establish intimate interactions with both endothelial cells and platelets leading to cardiovascular dysregulation.

  1. Arterial blood pressure changes in acute T. brucei infection of dogs ...

    African Journals Online (AJOL)

    The aim of this study is to find out the usefulness of serial arterial blood pressure measurements in predicting severity and outcome of acute Trypanosoma brucei infection in dogs. Twenty adult dogs of mixed sexes and aged between 2 and 5 years were used for this study. The dogs were of good cardiac health and were ...

  2. Phosphatidylinositol 4-kinase III-beta is required for Golgi maintenance and cytokinesis in Trypanosoma brucei.

    Science.gov (United States)

    Rodgers, Melissa J; Albanesi, Joseph P; Phillips, Margaret A

    2007-07-01

    The parasitic protozoan Trypanosoma brucei contains two type III phosphatidylinositol 4-kinases (alpha and beta). We have cloned the gene encoding the T. brucei type III phosphatidylinositol 4-kinase beta (TbPI4KIII-beta), expressed the protein in COS-7 cells, and confirmed that the protein catalyzes the phosphorylation of phosphatidylinositol. Depletion of TbPI4KIII-beta in procyclic T. brucei by RNA interference (RNAi) resulted in inhibition of cell growth and a distorted cellular morphology. RNAi cells had a distorted Golgi apparatus, and lysosomal and flagellar pocket proteins were mislocalized. Ultrastructural analysis revealed the internal accumulation of a heterogeneous population of vesicles, abnormal positioning of organelles, and a loss of cell polarity. Scanning electron microcopy revealed a twisted phenotype, and dividing cells often exhibited a detached daughter flagellum and lacked a cleavage furrow. Cell cycle analysis confirmed that cells depleted of TbPI4KIII-beta have a postmitotic cytokinesis block that occurs after a single round of mitosis, suggestive of a specific cell cycle block. In summary, TbPI4KIII-beta is an essential protein in procyclic T. brucei, required for maintenance of Golgi structure, protein trafficking, normal cellular shape, and cytokinesis.

  3. Procyclic Trypanosoma brucei do not use Krebs cycle activity for energy generation

    NARCIS (Netherlands)

    Weelden, van S.W.H.; Fast, B.; Vogt, A.; Meer, van der P.; Saas, J.; Hellemond, van J.J.; Tielens, A.G.M.; Boshart, M.

    2003-01-01

    The importance of a functional Krebs cycle for energy generation in the procyclic stage of Trypanosoma brucei was investigated under physiological conditions during logarithmic phase growth of a pleomorphic parasite strain. Wild type procyclic cells and mutants with targeted deletion of the gene

  4. The promoter for a variant surface glycoprotein gene expression site in Trypanosoma brucei

    NARCIS (Netherlands)

    Zomerdijk, J. C.; Ouellette, M.; ten Asbroek, A. L.; Kieft, R.; Bommer, A. M.; Clayton, C. E.; Borst, P.

    1990-01-01

    The variant-specific surface glycoprotein (VSG) gene 221 of Trypanosoma brucei is transcribed as part of a 60 kb expression site (ES). We have identified the promoter controlling this multigene transcription unit by the use of 221 chromosome-enriched DNA libraries and VSG gene 221 expression site

  5. Deletion of the Trypanosoma brucei Superoxide Dismutase Gene sodb1 Increases Sensitivity to Nifurtimox and Benznidazole▿

    Science.gov (United States)

    Prathalingham, S. Radhika; Wilkinson, Shane R.; Horn, David; Kelly, John M.

    2007-01-01

    It has been more than 25 years since it was first reported that nifurtimox and benznidazole promote superoxide production in trypanosomes. However, there has been no direct evidence of an association between the drug-induced free radicals and trypanocidal activity. Here, we identify a superoxide dismutase required to protect Trypanosoma brucei from drug-generated superoxide. PMID:17145786

  6. Deletion of the Trypanosoma brucei superoxide dismutase gene sodb1 increases sensitivity to nifurtimox and benznidazole.

    Science.gov (United States)

    Prathalingham, S Radhika; Wilkinson, Shane R; Horn, David; Kelly, John M

    2007-02-01

    It has been more than 25 years since it was first reported that nifurtimox and benznidazole promote superoxide production in trypanosomes. However, there has been no direct evidence of an association between the drug-induced free radicals and trypanocidal activity. Here, we identify a superoxide dismutase required to protect Trypanosoma brucei from drug-generated superoxide.

  7. Trypanosoma brucei Infection in a herd of sedentary cattle in Danja ...

    African Journals Online (AJOL)

    Trypanosoma brucei Infection in a herd of sedentary cattle in Danja Local Government Area, Katsina State, Northern Nigeria– A possible resurgence of Tsetse flies ... resulted in advocacy for pastoralists to settle down into productive cattle production compared to the nomadic behavior which does not enhance productivity.

  8. Novel molecular mechanism for targeting the parasite Trypanosoma brucei with snake venom toxins

    DEFF Research Database (Denmark)

    Martos Esteban, Andrea; Laustsen, Andreas Hougaard; Carrington, Mark

    Trypanosoma brucei is a parasitic protozoan species capable to infecting insect vectors whose bite further produces African sleeping sickness inhuman beings. During parasites’extracellular lives in the mammalian host, its outer coat, mainly composedof Variable surface glycoproteins (VSGs)[2], und...

  9. Aquaglyceroporins Are the Entry Pathway of Boric Acid in Trypanosoma brucei.

    Science.gov (United States)

    Marsiccobetre, Sabrina; Rodríguez-Acosta, Alexis; Lang, Florian; Figarella, Katherine; Uzcátegui, Néstor L

    2017-05-01

    The boron element possesses a range of different effects on living beings. It is essential to beneficial at low concentrations, but toxic at excessive concentrations. Recently, some boron-based compounds have been identified as promising molecules against Trypanosoma brucei, the causative agent of sleeping sickness. However, until now, the boron metabolism and its access route into the parasite remained elusive. The present study addressed the permeability of T. brucei aquaglyceroporins (TbAQPs) for boric acid, the main natural boron species. To this end, the three TbAQPs were expressed in Saccharomyces cerevisiae and Xenopus laevis oocytes. Our findings in both expression systems showed that all three TbAQPs are permeable for boric acid. Especially TbAQP2 is highly permeable for this compound, displaying one of the highest conductances reported for a solute in these channels. Additionally, T. brucei aquaglyceroporin activities were sensitive to pH. Taken together, these results establish that TbAQPs are channels for boric acid and are highly efficient entry pathways for boron into the parasite. Our findings stress the importance of studying the physiological functions of boron and their derivatives in T. brucei, as well as the pharmacological implications of their uptake by trypanosome aquaglyceroporins. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. BAPTA-AM decreases cellular pH, inhibits acidocalcisome acidification and autophagy in amino acid-starved T. brucei.

    Science.gov (United States)

    Li, Feng-Jun; Tan, Kevin S W; He, Cynthia Y

    2017-04-01

    To investigate the role of Ca2+ signaling in starvation-induced autophagy in Trypanosoma brucei, the causative agent of human African trypanosomiasis, we used cell-permeant Ca2+ chelator BAPTA-AM and cell impermeant chelator EGTA, and examined the potential involvement of several intracellular Ca2+ signaling pathways in T. brucei autophagy. The results showed an unexpected effect of BAPTA-AM in decreasing cellular pH and inhibiting acidocalcisome acidification in starved cells. The implication of these results in the role of Ca2+ signaling and cellular/organellar pH in T. brucei autophagy is discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Host response to Candida albicans bloodstream infection and sepsis

    Science.gov (United States)

    Duggan, Seána; Leonhardt, Ines; Hünniger, Kerstin; Kurzai, Oliver

    2015-01-01

    Candida albicans is a major cause of bloodstream infection which may present as sepsis and septic shock - major causes of morbidity and mortality world-wide. After invasion of the pathogen, innate mechanisms govern the early response. Here, we outline the models used to study these mechanisms and summarize our current understanding of innate immune responses during Candida bloodstream infection. This includes protective immunity as well as harmful responses resulting in Candida induced sepsis. Neutrophilic granulocytes are considered principal effector cells conferring protection and recognize C. albicans mainly via complement receptor 3. They possess a range of effector mechanisms, contributing to elimination of the pathogen. Neutrophil activation is closely linked to complement and modulated by activated mononuclear cells. A thorough understanding of these mechanisms will help in creating an individualized approach to patients suffering from systemic candidiasis and aid in optimizing clinical management. PMID:25785541

  12. Histopathological evaluation of the efficacy of antifungals for experimental Trichosporon bloodstream infection.

    Science.gov (United States)

    Sasai, Daisuke; Okubo, Yoichiro; Ishiwatari, Takao; Sugita, Takashi; Kaneko, Takehiko; Murayama, Somay Yamagata; Shimamura, Tsuyoshi; Shinozaki, Minoru; Hasegawa, Chikako; Mitsuda, Aki; Tochigi, Naobumi; Wakayama, Megumi; Nemoto, Tetsuo; Shibuya, Kazutoshi

    2013-01-01

    The efficacy of polyene macrolides to treat experimental Trichosporon bloodstream infection was evaluated by histopathological examination and viable cell counts in the kidneys of infected mice. Viable cell counts on the 5th day after infection confirmed that liposomal amphotericin B (L-AMB) is a more effective treatment than fluconazole (FLC) for mice infected with an azole-resistant strain of Trichosporon. Histological examination revealed that the administration of L-AMB induced a transformation from acute purulent inflammation caused by both azole-susceptible and -resistant strain infections to a chronic and subsiding form, whereas FLC failed to convert the acute inflammation induced by the azole-resistant strain to a subsiding form. Our results demonstrate that polyene macrolides can be used as an alternative therapy for infection of azole-resistant strains of Trichosporon and that histopathological evaluation is useful for elucidating the pathophysiology of an experimental Trichosporon infection.

  13. Excess mortality in women with hospital-acquired bloodstream infection.

    Science.gov (United States)

    Leibovici, L; Paul, M; Weinberger, M; Koenigsberger, H; Drucker, M; Samra, Z; Yahav, J; Pitlik, S D

    2001-08-01

    We examined the outcomes of bloodstream infection in men and in women and whether any sex-related differences were explained by underlying disorders, severity of disease, or clinical management. Using a prospectively collected database, we compared in-hospital mortality in men and women. We used multivariable logistic regression analysis to test whether sex-related differences could be due to potential confounders. Of 4250 patients with bloodstream infections, 1750 (41%) had hospital-acquired infections. The overall case fatality was 31% (625 of 2032) in women and 29% (631 of 2218, P = 0.1) in men. However, 43% (325/758) of the women with hospital-acquired infections died, compared with 33% (327/992) of the men (P = 0.0001). In a multivariate analysis, female sex was associated with greater mortality in patients with hospital-acquired infections (odds ratio = 1.7; 95% confidence interval: 1.1 to 2.6). The excess mortality in women was mainly seen in patients with major underlying disorders (fatality rate of 45% [234 of 525] in women vs. 32% in men [234 of 743, P = 0.0001). Mortality in women with hospital-acquired bloodstream infections is substantially greater than in men. The excess mortality was concentrated in women with severe underlying disorders, suggesting that sepsis might have accentuated differences in the outcome of underlying disorders in women.

  14. Untargeted metabolomics reveals a lack of synergy between nifurtimox and eflornithine against Trypanosoma brucei.

    Science.gov (United States)

    Vincent, Isabel M; Creek, Darren J; Burgess, Karl; Woods, Debra J; Burchmore, Richard J S; Barrett, Michael P

    2012-01-01

    A non-targeted metabolomics-based approach is presented that enables the study of pathways in response to drug action with the aim of defining the mode of action of trypanocides. Eflornithine, a polyamine pathway inhibitor, and nifurtimox, whose mode of action involves its metabolic activation, are currently used in combination as first line treatment against stage 2, CNS-involved, human African trypanosomiasis (HAT). Drug action was assessed using an LC-MS based non-targeted metabolomics approach. Eflornithine revealed the expected changes to the polyamine pathway as well as several unexpected changes that point to pathways and metabolites not previously described in bloodstream form trypanosomes, including a lack of arginase activity and N-acetylated ornithine and putrescine. Nifurtimox was shown to be converted to a trinitrile metabolite indicative of metabolic activation, as well as inducing changes in levels of metabolites involved in carbohydrate and nucleotide metabolism. However, eflornithine and nifurtimox failed to synergise anti-trypanosomal activity in vitro, and the metabolomic changes associated with the combination are the sum of those found in each monotherapy with no indication of additional effects. The study reveals how untargeted metabolomics can yield rapid information on drug targets that could be adapted to any pharmacological situation.

  15. Untargeted metabolomics reveals a lack of synergy between nifurtimox and eflornithine against Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Isabel M Vincent

    Full Text Available A non-targeted metabolomics-based approach is presented that enables the study of pathways in response to drug action with the aim of defining the mode of action of trypanocides. Eflornithine, a polyamine pathway inhibitor, and nifurtimox, whose mode of action involves its metabolic activation, are currently used in combination as first line treatment against stage 2, CNS-involved, human African trypanosomiasis (HAT. Drug action was assessed using an LC-MS based non-targeted metabolomics approach. Eflornithine revealed the expected changes to the polyamine pathway as well as several unexpected changes that point to pathways and metabolites not previously described in bloodstream form trypanosomes, including a lack of arginase activity and N-acetylated ornithine and putrescine. Nifurtimox was shown to be converted to a trinitrile metabolite indicative of metabolic activation, as well as inducing changes in levels of metabolites involved in carbohydrate and nucleotide metabolism. However, eflornithine and nifurtimox failed to synergise anti-trypanosomal activity in vitro, and the metabolomic changes associated with the combination are the sum of those found in each monotherapy with no indication of additional effects. The study reveals how untargeted metabolomics can yield rapid information on drug targets that could be adapted to any pharmacological situation.

  16. Bloodstream-To-Eye Infections Are Facilitated by Outer Blood-Retinal Barrier Dysfunction.

    Directory of Open Access Journals (Sweden)

    Phillip S Coburn

    Full Text Available The blood-retinal barrier (BRB functions to maintain the immune privilege of the eye, which is necessary for normal vision. The outer BRB is formed by tightly-associated retinal pigment epithelial (RPE cells which limit transport within the retinal environment, maintaining retinal function and viability. Retinal microvascular complications and RPE dysfunction resulting from diabetes and diabetic retinopathy cause permeability changes in the BRB that compromise barrier function. Diabetes is the major predisposing condition underlying endogenous bacterial endophthalmitis (EBE, a blinding intraocular infection resulting from bacterial invasion of the eye from the bloodstream. However, significant numbers of EBE cases occur in non-diabetics. In this work, we hypothesized that dysfunction of the outer BRB may be associated with EBE development. To disrupt the RPE component of the outer BRB in vivo, sodium iodate (NaIO3 was administered to C57BL/6J mice. NaIO3-treated and untreated mice were intravenously injected with 108 colony forming units (cfu of Staphylococcus aureus or Klebsiella pneumoniae. At 4 and 6 days postinfection, EBE was observed in NaIO3-treated mice after infection with K. pneumoniae and S. aureus, although the incidence was higher following S. aureus infection. Invasion of the eye was observed in control mice following S. aureus infection, but not in control mice following K. pneumoniae infection. Immunohistochemistry and FITC-dextran conjugate transmigration assays of human RPE barriers after infection with an exoprotein-deficient agr/sar mutant of S. aureus suggested that S. aureus exoproteins may be required for the loss of the tight junction protein, ZO-1, and for permeability of this in vitro barrier. Our results support the clinical findings that for both pathogens, complications which result in BRB permeability increase the likelihood of bacterial transmigration from the bloodstream into the eye. For S. aureus, however, BRB

  17. Persistent ER stress induces the spliced leader RNA silencing pathway (SLS, leading to programmed cell death in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Hanoch Goldshmidt

    2010-01-01

    Full Text Available Trypanosomes are parasites that cycle between the insect host (procyclic form and mammalian host (bloodstream form. These parasites lack conventional transcription regulation, including factors that induce the unfolded protein response (UPR. However, they possess a stress response mechanism, the spliced leader RNA silencing (SLS pathway. SLS elicits shut-off of spliced leader RNA (SL RNA transcription by perturbing the binding of the transcription factor tSNAP42 to its cognate promoter, thus eliminating trans-splicing of all mRNAs. Induction of endoplasmic reticulum (ER stress in procyclic trypanosomes elicits changes in the transcriptome similar to those induced by conventional UPR found in other eukaryotes. The mechanism of up-regulation under ER stress is dependent on differential stabilization of mRNAs. The transcriptome changes are accompanied by ER dilation and elevation in the ER chaperone, BiP. Prolonged ER stress induces SLS pathway. RNAi silencing of SEC63, a factor that participates in protein translocation across the ER membrane, or SEC61, the translocation channel, also induces SLS. Silencing of these genes or prolonged ER stress led to programmed cell death (PCD, evident by exposure of phosphatidyl serine, DNA laddering, increase in reactive oxygen species (ROS production, increase in cytoplasmic Ca(2+, and decrease in mitochondrial membrane potential, as well as typical morphological changes observed by transmission electron microscopy (TEM. ER stress response is also induced in the bloodstream form and if the stress persists it leads to SLS. We propose that prolonged ER stress induces SLS, which serves as a unique death pathway, replacing the conventional caspase-mediated PCD observed in higher eukaryotes.

  18. Aparasitemic serological suspects in Trypanosoma brucei gambiense human African trypanosomiasis : a potential human reservoir of parasites ?

    OpenAIRE

    Koffi, Mathurin; Solano, Philippe; Denizot, M.; Courtin, D.; Garcia, André; Lejon, V.; Buscher, P.; Cuny, Gérard; Jamonneau, Vincent

    2006-01-01

    The serological and parasitological tests used for Trypanosoma brucei gambiense human African trypanosomiasis (HAT) diagnosis have low specificity and sensitivity, respectively, and in the field, control program teams are faced with subjects with positive serology but negative parasitology who remain untreated. The aim of this work was to explore, using PCR tool, the significance of these aparasitemic serological suspects. Since discordant PCR results have been observed earlier with different...

  19. Differential virulence and tsetse fly transmissibility of Trypanosoma congolense and Trypanosoma brucei strains

    Directory of Open Access Journals (Sweden)

    Purity K. Gitonga

    2017-01-01

    Full Text Available African animal trypanosomiasis causes significant economic losses in sub-Saharan African countries because of livestock mortalities and reduced productivity. Trypanosomes, the causative agents, are transmitted by tsetse flies (Glossina spp.. In the current study, we compared and contrasted the virulence characteristics of five Trypanosoma congolense and Trypanosoma brucei isolates using groups of Swiss white mice (n = 6. We further determined the vectorial capacity of Glossina pallidipes, for each of the trypanosome isolates. Results showed that the overall pre-patent (PP periods were 8.4 ± 0.9 (range, 4–11 and 4.5 ± 0.2 (range, 4–6 for T. congolense and T. brucei isolates, respectively (p < 0.01. Despite the longer mean PP, T. congolense–infected mice exhibited a significantly (p < 0.05 shorter survival time than T. brucei–infected mice, indicating greater virulence. Differences were also noted among the individual isolates with T. congolense KETRI 2909 causing the most acute infection of the entire group with a mean ± standard error survival time of 9 ± 2.1 days. Survival time of infected tsetse flies and the proportion with mature infections at 30 days post-exposure to the infective blood meals varied among isolates, with subacute infection–causing T. congolense EATRO 1829 and chronic infection–causing T. brucei EATRO 2267 isolates showing the highest mature infection rates of 38.5% and 23.1%, respectively. Therefore, our study provides further evidence of occurrence of differences in virulence and transmissibility of eastern African trypanosome strains and has identified two, T. congolense EATRO 1829 and T. brucei EATRO 2267, as suitable for tsetse infectivity and transmissibility experiments.

  20. Mapping of branch sites in trans-spliced pre-mRNAs of Trypanosoma brucei.

    Science.gov (United States)

    Patzelt, E; Perry, K L; Agabian, N

    1989-01-01

    The process of trans splicing is essential to the maturation of all mRNAs in the Trypanosomatidae, a family of protozoan parasites, and to specific mRNAs in several species of nematode. In Trypanosoma brucei, a 39-nucleotide (nt) leader sequence originating from a small, 139-nt donor RNA (the spliced leader [SL] RNA) is spliced to the 5' end of mRNAs. An intermediate in this trans-splicing process is a Y structure which contains the 3' 100 nt of the SL RNA covalently linked to the pre-mRNA via a 2'-5' phosphodiester bond at the branch point residue. We mapped the branch points in T. brucei alpha- and beta-tubulin pre-mRNAs. The primary branch acceptors for the alpha- and beta-tubulins are 44 and 56 nt upstream of the 3' splice sites, respectively, and are A residues. Minor branch acceptors were detected 42 and 49 nt upstream of the alpha-tubulin splice site and 58 nt upstream of the splice site in beta-tubulin. The regions surrounding these branch points lack homology to the consensus sequences determined for mammalian cells and yeasts; there is also no conservation among the sequences themselves. Thus, the identified sequences suggest that the mechanism of branch point recognition in T. brucei differs from the mechanism of recognition by U2 RNA that has been proposed for other eucaryotes. Images PMID:2479824

  1. Molecular variation of Trypanosoma brucei subspecies as revealed by AFLP fingerprinting.

    Science.gov (United States)

    Agbo, E E C; Majiwa, P A O; Claassen, H J H M; te Pas, M F W

    2002-04-01

    Genetic analysis of Trypanosoma spp. depends on the detection of variation between strains. We have used the amplified fragment length polymorphism (AFLP) technique to develop a convenient and reliable method for genetic characterization of Trypanosome (sub)species. AFLP accesses multiple independent sites within the genome and would allow a better definition of the relatedness of different Trypanosome (sub)species. Nine isolates (3 from each T. brucei subspecies) were tested with 40 AFLP primer combinations to identify the most appropriate pairs of restriction endonucleases and selective primers. Primers based on the recognition sequences of EcoRI and BglII were chosen and used to analyse 31 T. brucei isolates. Similarity levels calculated with the Pearson correlation coefficient ranged from 15 to 98%, and clusters were determined using the unweighted pair-group method using arithmetic averages (UPGMA). At the intraspecific level, AFLP fingerprints were grouped by numerical analysis in 2 main clusters, allowing a clear separation of T. b. gambiense (cluster I) from T. b. brucei and T. b. rhodesiense isolates (cluster II). Interspecies evaluation of this customized approach produced heterogeneous AFLP patterns, with unique genetic markers, except for T. evansi and T. equiperdum, which showed identical patterns and clustered together.

  2. A fresh look at polymicrobial bloodstream infection in cancer patients.

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    Cristina Royo-Cebrecos

    Full Text Available To assess the current incidence, clinical features, risk factors, aetiology, antimicrobial resistance and outcomes of polymicrobial bloodstream infection (PBSI in patients with cancer.All prospectively collected episodes of PBSI in hospitalised patients were compared with episodes of monomicrobial bloodstream infection (MBSI between 2006 and 2015.We identified 194 (10.2% episodes of PBSI and 1702 MBSI (89.8%. The presence of cholangitis, biliary stenting, neutropenia, corticosteroids, neutropenic enterocolitis and other abdominal infections were identified as risk factors for PBSI. Overall, Gram-negative organisms were the most frequent aetiology, but Enterococcus spp. were especially frequent causes of Gram-positive PBSI (30.8%. Multidrug-resistant (MDR organisms were more commonly found in PBSI than in MBSI (20.6% vs 12.9%; p = 0.003. Compared to patients with MBSI, those with PBSI presented with higher early (15% vs 1.4%; p = 0.04 and overall (32% vs 20.9%; p<0.001 case-fatality rates. Risk factors for overall case-fatality were a high-risk MASCC (Multinational Association of Supportive Care in Cancer index score, corticosteroid use, persistent bacteraemia and septic shock.PBSI is a frequent complication in patients with cancer and is responsible for high mortality rates. Physicians should identify patients at risk for PBSI and provide empiric antibiotic therapy that covers the most frequent pathogens involved in these infections, including MDR strains.

  3. Emerging technologies for rapid identification of bloodstream pathogens.

    Science.gov (United States)

    Kothari, Atul; Morgan, Margie; Haake, David A

    2014-07-15

    Technologies for rapid microbial identification are poised to revolutionize clinical microbiology and enable informed decision making for patients with life-threatening bloodstream infections. Species identification of microorganisms in positive blood cultures can be performed in minutes using commercial fluorescence in situ hybridization tests or mass spectroscopy. Microorganisms in positive blood cultures can also be identified within 1-2.5 hours using automated polymerase chain reaction-based systems that can also detect selected antibiotic resistance markers, such as methicillin resistance. When combined with antibiotic stewardship programs, these approaches improve clinical outcomes and reduce healthcare expenditures. Tests for direct detection in whole blood samples are highly desirable because of their potential to identify bloodstream pathogens without waiting 1-2 days for blood cultures to become positive. However, results for pathogen detection in whole blood do not overlap with those of conventional blood culture techniques and we are still learning how best to use these approaches. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  4. A Pre-clinical Animal Model of Trypanosoma brucei Infection Demonstrating Cardiac Dysfunction.

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    Charlotte S McCarroll

    2015-05-01

    Full Text Available African trypanosomiasis (AT, caused by Trypanosoma brucei species, results in both neurological and cardiac dysfunction and can be fatal if untreated. Research on the pathogenesis and treatment of the disease has centred to date on the characteristic neurological symptoms, whereas cardiac dysfunction (e.g. ventricular arrhythmias in AT remains largely unstudied. Animal models of AT demonstrating cardiac dysfunction similar to that described in field cases of AT are critically required to transform our understanding of AT-induced cardiac pathophysiology and identify future treatment strategies. We have previously shown that T. brucei can interact with heart muscle cells (cardiomyocytes to induce ventricular arrhythmias in ex vivo adult rat hearts. However, it is unknown whether the arrhythmias observed ex vivo are also present during in vivo infection in experimental animal models. Here we show for the first time the characterisation of ventricular arrhythmias in vivo in two animal models of AT infection using electrocardiographic (ECG monitoring. The first model utilised a commonly used monomorphic laboratory strain, Trypanosoma brucei brucei Lister 427, whilst the second model used a pleomorphic laboratory strain, T. b. brucei TREU 927, which demonstrates a similar chronic infection profile to clinical cases. The frequency of ventricular arrhythmias and heart rate (HR was significantly increased at the endpoint of infection in the TREU 927 infection model, but not in the Lister 427 infection model. At the end of infection, hearts from both models were isolated and Langendorff perfused ex vivo with increasing concentrations of the β-adrenergic agonist isoproterenol (ISO. Interestingly, the increased frequency of arrhythmias observed in vivo in the TREU 927 infection model was lost upon isolation of the heart ex vivo, but re-emerged with the addition of ISO. Our results demonstrate that TREU 927 infection modifies the substrate of the myocardium

  5. IL-6 is Upregulated in Late-Stage Disease in Monkeys Experimentally Infected with Trypanosoma brucei rhodesiense

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    Dawn Nyawira Maranga

    2013-01-01

    Full Text Available The management of human African trypanosomiasis (HAT is constrained by lack of simple-to-use diagnostic, staging, and treatment tools. The search for novel biomarkers is, therefore, essential in the fight against HAT. The current study aimed at investigating the potential of IL-6 as an adjunct parameter for HAT stage determination in vervet monkey model. Four adult vervet monkeys (Chlorocebus aethiops were experimentally infected with Trypanosoma brucei rhodesiense and treated subcuratively at 28 days after infection (dpi to induce late stage disease. Three noninfected monkeys formed the control group. Cerebrospinal fluid (CSF and blood samples were obtained at weekly intervals and assessed for various biological parameters. A typical HAT-like infection was observed. The late stage was characterized by significant (P<0.05 elevation of CSF IL-6, white blood cell count, and total protein starting 35 dpi with peak levels of these parameters coinciding with relapse parasitaemia. Brain immunohistochemical staining revealed an increase in brain glial fibrillary acidic protein expression indicative of reactive astrogliosis in infected animals which were euthanized in late-stage disease. The elevation of IL-6 in CSF which accompanied other HAT biomarkers indicates onset of parasite neuroinvasion and show potential for use as an adjunct late-stage disease biomarker in the Rhodesian sleeping sickness.

  6. IL-6 is Upregulated in Late-Stage Disease in Monkeys Experimentally Infected with Trypanosoma brucei rhodesiense

    Science.gov (United States)

    Nyawira Maranga, Dawn; Kagira, John Maina; Kinyanjui, Christopher Kariuki; Muturi Karanja, Simon; Wangari Maina, Naomi; Ngotho, Maina

    2013-01-01

    The management of human African trypanosomiasis (HAT) is constrained by lack of simple-to-use diagnostic, staging, and treatment tools. The search for novel biomarkers is, therefore, essential in the fight against HAT. The current study aimed at investigating the potential of IL-6 as an adjunct parameter for HAT stage determination in vervet monkey model. Four adult vervet monkeys (Chlorocebus aethiops) were experimentally infected with Trypanosoma brucei rhodesiense and treated subcuratively at 28 days after infection (dpi) to induce late stage disease. Three noninfected monkeys formed the control group. Cerebrospinal fluid (CSF) and blood samples were obtained at weekly intervals and assessed for various biological parameters. A typical HAT-like infection was observed. The late stage was characterized by significant (P < 0.05) elevation of CSF IL-6, white blood cell count, and total protein starting 35 dpi with peak levels of these parameters coinciding with relapse parasitaemia. Brain immunohistochemical staining revealed an increase in brain glial fibrillary acidic protein expression indicative of reactive astrogliosis in infected animals which were euthanized in late-stage disease. The elevation of IL-6 in CSF which accompanied other HAT biomarkers indicates onset of parasite neuroinvasion and show potential for use as an adjunct late-stage disease biomarker in the Rhodesian sleeping sickness. PMID:24194772

  7. Similarity in variable antigen type composition of Trypanosoma brucei rhodesiense populations in different sites within the mouse host.

    Science.gov (United States)

    Turner, C M; Hunter, C A; Barry, J D; Vickerman, K

    1986-01-01

    Trypanosoma brucei rhodesiense subpopulations in different sites within the body of infected mice were isolated and enumerated on day 6 of cyclically transmitted infections. Most trypanosomes were in the blood vasculature and spleen but approximately 6% occurred in lymph nodes and about 9% were extravascular. Most of the extravascular trypanosomes were in the peritoneal and pleural cavities; significant numbers also occurred in the brain and kidneys. Six major variable antigen types (VATs) were detected by immunofluorescence using specific antisera and monoclonal antibodies. The prevalence of each VAT was essentially the same in subpopulations in the blood, mesenteric and inguinal lymph nodes, brain, kidneys and peritoneal and pleural cavities. This similarity of VAT composition in different subpopulations is probably caused by high rates of dynamic interchange of trypanosomes between sites. Extravascular trypanosomes, therefore, form a significant proportion of the total population in acute infections of mice but they do not appear to play any special role in the population biology of antigenic variation at this stage of infection.

  8. The first reported catheter-related Brevibacterium casei bloodstream infection in a child with acute leukemia and review of the literature

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    Zumrut Sahbudak Bal

    Full Text Available Brevibacterium spp. are catalase-positive, non-spore-forming, non motile, aerobic Gram- positive rods that were considered apathogenic until a few reports of infections in immunocompromised patients had been published. To the best of our knowledge, this is the first report of B. casei catheter-related bloodstream infection in a child with acute leukemia. We aim to enhance the awareness of pediatric hematology and infectious disease specialists about this pathogen and review of the literature.

  9. Immunization with recombinant actin from Trypanosoma evansi induces protective immunity against T. evansi, T. equiperdum and T. b. brucei infection.

    Science.gov (United States)

    Li, San-Qiang; Yang, Wu-Biao; Lun, Zhao-Rong; Ma, Ling-Jun; Xi, Shou-Min; Chen, Qun-Li; Song, Xiao-Wei; Kang, Jian; Yang, Lan-Ze

    2009-01-01

    Actin gene of Trypanosoma evansi (STIB 806) was cloned and expressed in Escherichia coli. The predicted amino acid sequence of T. evansi actin shows 100%, 98.7%, and 93.1%, homology with Trypanosoma equiperdum, Trypanosoma brucei brucei, and Trypanosoma cruzi. Recombinant actin was expressed as inclusion bodies in E. coli. It was purified and renatured for immunological studies. Mice immunized with the renatured recombinant actin were protected from lethal challenge with T. evansi STIB 806, T. equiperdum STIB 818, and T. b. brucei STIB 940, showing 63.3%, 56.7%, and 53.3% protection, respectively. Serum collected from the rabbit immunized with recombinant actin inhibited the growth of T. evansi, T. equiperdum, and T. b. brucei in vitro cultivation. Serum from mice and rabbits immunized with recombinant actin only recognized T. evansi actin but not mouse actin. The results of this study suggest that the recombinant T. evansi actin induces protective immunity against T. evansi, T. equiperdum, and T. b. brucei infection and may be useful in the development of a vaccine with other cytoskeletal proteins to prevent animal trypanosomiasis caused by these three trypanosome species.

  10. Chemopreventive effect of methanolic extract of Azadirachta indica on experimental Trypanosoma brucei induced oxidative stress in dogs.

    Science.gov (United States)

    Omobowale, Temidayo O; Oyagbemi, Ademola A; Oyewunmi, Oyefunbi A; Adejumobi, Olumuyiwa A

    2015-01-01

    The medicinal properties of Azadirachta indica have been harnessed for many years in the treatment of many diseases in both humans and animals. Twenty-five apparently healthy dogs weighing between 3 and 8 kg were randomly divided into five groups with five dogs in each group. Ameliorative effect of A. indica on erythrocyte antioxidant status and markers of oxidative stress were assessed. Liver and kidney function tests were also performed. Pre-treatment with methanolic extract of Azadirachta indica (MEAI) at different doses did not significantly alter the values of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase activity in Trypanosoma brucei infection. Although, serum creatinine significantly (P indica, after 2 weeks of T. brucei infection. However, the reduced glutathione (GSH) content of the erythrocyte increased significantly in animals pre-treated with 50 mg/kg and 200 mg/kg of A. indica respectively. Markers of oxidative stress such as malondialdehyde and hydrogen peroxide generated were higher in animals infected with T. brucei with no significant (P >0.05) difference compared to the values obtained in pre-treated animals. Pre-treatment with 100 mg/kg and 200 mg/kg of A. indica significantly (P < 0.05) decreased serum myeloperoxidase activity at 2 weeks post-infection with T. brucei. From this study, MEAI showed significant ability to attenuate oxidative stress and inflammation during experimental T. brucei infection.

  11. The nucleotide sequence of the variable region in Trypanosoma brucei completes the sequence analysis of the maxicircle component of mitochondrial kinetoplast DNA

    NARCIS (Netherlands)

    Sloof, P.; de Haan, A.; Eier, W.; van Iersel, M.; Boel, E.; van Steeg, H.; Benne, R.

    1992-01-01

    The nucleotide sequence of two non-contiguous DNA fragments of 4.0 and 2.2 kb, respectively, of the kinetoplast maxicircle of Trypanosoma brucei brucei EATRO strain 427 has been determined, completing the sequence analysis of the so-called variable region (see also de Vries et al., 1988, Mol.

  12. PCR approach for the detection of Trypanosoma brucei and T. equiperdum and their differentiation from T. evansi based on maxicircle kinetoplast DNA.

    Science.gov (United States)

    Li, Feng-Jun; Gasser, Robin B; Lai, De-Hua; Claes, Filip; Zhu, Xing-Quan; Lun, Zhao-Rong

    2007-02-01

    The goal of this study was to develop a PCR approach based on the sequence of maxicircle kinetoplast DNA (kDNA) of Trypanosoma brucei to distinguish T. brucei/T. equiperdum from T. evansi and to evaluate its diagnostic use for their detection in blood samples. Primers derived from the sequence of the maxicircle kDNA of T. brucei, encoding the NADH dehydrogenase subunit 5 (nad5) gene, were used to test the PCR-amplification from T. brucei (including T. b. brucei and T. b. rhodesiense), T. equiperdum, T. evansi, T. vivax and T. congolense. A primer pair to a nuclear DNA region incorporated into a separate PCR was employed to control for the presence of amplifiable genomic DNA (representing the subgenus Trypanozoon) in each sample subjected to the PCR. Products of approximately 395bp were amplified from all T. brucei and T. equiperdum samples tested using the nad5-PCR, but not from T. evansi DNA samples or any of the control samples representing T. vivax, T. congolense, or host. The current PCR approach allows the rapid differentiation of T. brucei/T.equiperdum from T. evansi and can detect the equivalent of 20-25 cells of T. brucei or T. equiperdum in purified genomic DNA or infected blood samples.

  13. Minimising central line-associated bloodstream infection rate in inserting central venous catheters in the adult intensive care units.

    Science.gov (United States)

    Hina, Hedaya Rateb; McDowell, Joan R S

    2017-12-01

    To investigate the procedural aspects in inserting central venous catheters that minimise central line-associated bloodstream infection rates in adult intensive care units through a structured literature review. In adult intensive care units, central line-associated bloodstream infections are a major cause of high mortality rates and increased in costs due to the consequences of complications. Eligible articles were identified by combining indexed keywords using Boolean operator of "AND" under databases of Ovid and CINAHL. Titles and abstract of retrieved papers were screened and duplicates removed. Inclusion and exclusion criteria were applied to derive the final papers, which contained seminal studies. The quality of papers was assessed using a special data extraction form. The number of papers retrieved from all databases was 337, reduced to 302 after removing duplicates. Papers were scanned for titles and abstract to locate those relevant to the review question. After this, 250 papers were excluded for different reasons and a total of 52 papers were fully accessed to assess for eligibility. The final number of papers included was 10 articles. Many interventions can be implemented in the adult intensive care unit during the insertion of a central venous catheter to minimise central line-associated bloodstream infections rates. These include choosing the subclavian site to insert the catheters as the least infectious and decolonising patients' skin with alcoholic chlorhexidine gluconate preparation due to its broad antimicrobial effect and durability. Choosing optimal sites for central venous catheter insertion is a complex process that relies on many factors. Furthermore, the introduction of chlorhexidine gluconate preparations should be accompanied with multifaceted interventions including quality improvement initiatives to improve healthcare workers' compliance. As a quality marker in adult intensive care units, healthcare sectors should work on establishing

  14. Limitations of Murine Models for Assessment of Antibody-Mediated Therapies or Vaccine Candidates against Staphylococcus epidermidis Bloodstream Infection

    Science.gov (United States)

    Zhang, Jinrong; Kesselly, Augustus; Lam, Hubert; Kleanthous, Harry; Yethon, Jeremy A.

    2016-01-01

    Staphylococcus epidermidis is normally a commensal colonizer of human skin and mucus membranes, but, due to its ability to form biofilms on indwelling medical devices, it has emerged as a leading cause of nosocomial infections. Bacteremia or bloodstream infection is a frequent and costly complication resulting from biofilm fouling of medical devices. Our goal was to develop a murine model of S. epidermidis infection to identify potential vaccine targets for the prevention of S. epidermidis bacteremia. However, assessing the contribution of adaptive immunity to protection against S. epidermidis challenge was complicated by a highly efficacious innate immune response in mice. Naive mice rapidly cleared S. epidermidis infections from blood and solid organs, even when the animals were immunocompromised. Cyclophosphamide-mediated leukopenia reduced the size of the bacterial challenge dose required to cause lethality but did not impair clearance after a nonlethal challenge. Nonspecific innate immune stimulation, such as treatment with a Toll-like receptor 4 (TLR4) agonist, enhanced bacterial clearance. TLR2 signaling was confirmed to accelerate the clearance of S. epidermidis bacteremia, but TLR2−/− mice could still resolve a bloodstream infection. Furthermore, TLR2 signaling played no role in the clearance of bacteria from the spleen. In conclusion, these data suggest that S. epidermidis bloodstream infection is cleared in a highly efficient manner that is mediated by both TLR2-dependent and -independent innate immune mechanisms. The inability to establish a persistent infection in mice, even in immunocompromised animals, rendered these murine models unsuitable for meaningful assessment of antibody-mediated therapies or vaccine candidates. PMID:26857577

  15. Antimicrobial resistance predicts death in Tanzanian children with bloodstream infections: a prospective cohort study

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    Msangi Viola

    2007-05-01

    Full Text Available Abstract Background Bloodstream infection is a common cause of hospitalization, morbidity and death in children. The impact of antimicrobial resistance and HIV infection on outcome is not firmly established. Methods We assessed the incidence of bloodstream infection and risk factors for fatal outcome in a prospective cohort study of 1828 consecutive admissions of children aged zero to seven years with signs of systemic infection. Blood was obtained for culture, malaria microscopy, HIV antibody test and, when necessary, HIV PCR. We recorded data on clinical features, underlying diseases, antimicrobial drug use and patients' outcome. Results The incidence of laboratory-confirmed bloodstream infection was 13.9% (255/1828 of admissions, despite two thirds of the study population having received antimicrobial therapy prior to blood culture. The most frequent isolates were klebsiella, salmonellae, Escherichia coli, enterococci and Staphylococcus aureus. Furthermore, 21.6% had malaria and 16.8% HIV infection. One third (34.9% of the children with laboratory-confirmed bloodstream infection died. The mortality rate from Gram-negative bloodstream infection (43.5% was more than double that of malaria (20.2% and Gram-positive bloodstream infection (16.7%. Significant risk factors for death by logistic regression modeling were inappropriate treatment due to antimicrobial resistance, HIV infection, other underlying infectious diseases, malnutrition and bloodstream infection caused by Enterobacteriaceae, other Gram-negatives and candida. Conclusion Bloodstream infection was less common than malaria, but caused more deaths. The frequent use of antimicrobials prior to blood culture may have hampered the detection of organisms susceptible to commonly used antimicrobials, including pneumococci, and thus the study probably underestimates the incidence of bloodstream infection. The finding that antimicrobial resistance, HIV-infection and malnutrition predict fatal

  16. Diagnosis of Bacterial Bloodstream Infections: A 16S Metagenomics Approach.

    Science.gov (United States)

    Decuypere, Saskia; Meehan, Conor J; Van Puyvelde, Sandra; De Block, Tessa; Maltha, Jessica; Palpouguini, Lompo; Tahita, Marc; Tinto, Halidou; Jacobs, Jan; Deborggraeve, Stijn

    2016-02-01

    Bacterial bloodstream infection (bBSI) is one of the leading causes of death in critically ill patients and accurate diagnosis is therefore crucial. We here report a 16S metagenomics approach for diagnosing and understanding bBSI. The proof-of-concept was delivered in 75 children (median age 15 months) with severe febrile illness in Burkina Faso. Standard blood culture and malaria testing were conducted at the time of hospital admission. 16S metagenomics testing was done retrospectively and in duplicate on the blood of all patients. Total DNA was extracted from the blood and the V3-V4 regions of the bacterial 16S rRNA genes were amplified by PCR and deep sequenced on an Illumina MiSeq sequencer. Paired reads were curated, taxonomically labeled, and filtered. Blood culture diagnosed bBSI in 12 patients, but this number increased to 22 patients when combining blood culture and 16S metagenomics results. In addition to superior sensitivity compared to standard blood culture, 16S metagenomics revealed important novel insights into the nature of bBSI. Patients with acute malaria or recovering from malaria had a 7-fold higher risk of presenting polymicrobial bloodstream infections compared to patients with no recent malaria diagnosis (p-value = 0.046). Malaria is known to affect epithelial gut function and may thus facilitate bacterial translocation from the intestinal lumen to the blood. Importantly, patients with such polymicrobial blood infections showed a 9-fold higher risk factor for not surviving their febrile illness (p-value = 0.030). Our data demonstrate that 16S metagenomics is a powerful approach for the diagnosis and understanding of bBSI. This proof-of-concept study also showed that appropriate control samples are crucial to detect background signals due to environmental contamination.

  17. Diagnosis of Bacterial Bloodstream Infections: A 16S Metagenomics Approach.

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    Saskia Decuypere

    2016-02-01

    Full Text Available Bacterial bloodstream infection (bBSI is one of the leading causes of death in critically ill patients and accurate diagnosis is therefore crucial. We here report a 16S metagenomics approach for diagnosing and understanding bBSI.The proof-of-concept was delivered in 75 children (median age 15 months with severe febrile illness in Burkina Faso. Standard blood culture and malaria testing were conducted at the time of hospital admission. 16S metagenomics testing was done retrospectively and in duplicate on the blood of all patients. Total DNA was extracted from the blood and the V3-V4 regions of the bacterial 16S rRNA genes were amplified by PCR and deep sequenced on an Illumina MiSeq sequencer. Paired reads were curated, taxonomically labeled, and filtered. Blood culture diagnosed bBSI in 12 patients, but this number increased to 22 patients when combining blood culture and 16S metagenomics results. In addition to superior sensitivity compared to standard blood culture, 16S metagenomics revealed important novel insights into the nature of bBSI. Patients with acute malaria or recovering from malaria had a 7-fold higher risk of presenting polymicrobial bloodstream infections compared to patients with no recent malaria diagnosis (p-value = 0.046. Malaria is known to affect epithelial gut function and may thus facilitate bacterial translocation from the intestinal lumen to the blood. Importantly, patients with such polymicrobial blood infections showed a 9-fold higher risk factor for not surviving their febrile illness (p-value = 0.030.Our data demonstrate that 16S metagenomics is a powerful approach for the diagnosis and understanding of bBSI. This proof-of-concept study also showed that appropriate control samples are crucial to detect background signals due to environmental contamination.

  18. Genome and phylogenetic analyses of Trypanosoma evansi reveal extensive similarity to T. brucei and multiple independent origins for dyskinetoplasty.

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    Jason Carnes

    2015-01-01

    Full Text Available Two key biological features distinguish Trypanosoma evansi from the T. brucei group: independence from the tsetse fly as obligatory vector, and independence from the need for functional mitochondrial DNA (kinetoplast or kDNA. In an effort to better understand the molecular causes and consequences of these differences, we sequenced the genome of an akinetoplastic T. evansi strain from China and compared it to the T. b. brucei reference strain. The annotated T. evansi genome shows extensive similarity to the reference, with 94.9% of the predicted T. b. brucei coding sequences (CDS having an ortholog in T. evansi, and 94.6% of the non-repetitive orthologs having a nucleotide identity of 95% or greater. Interestingly, several procyclin-associated genes (PAGs were disrupted or not found in this T. evansi strain, suggesting a selective loss of function in the absence of the insect life-cycle stage. Surprisingly, orthologous sequences were found in T. evansi for all 978 nuclear CDS predicted to represent the mitochondrial proteome in T. brucei, although a small number of these may have lost functionality. Consistent with previous results, the F1FO-ATP synthase γ subunit was found to have an A281 deletion, which is involved in generation of a mitochondrial membrane potential in the absence of kDNA. Candidates for CDS that are absent from the reference genome were identified in supplementary de novo assemblies of T. evansi reads. Phylogenetic analyses show that the sequenced strain belongs to a dominant group of clonal T. evansi strains with worldwide distribution that also includes isolates classified as T. equiperdum. At least three other types of T. evansi or T. equiperdum have emerged independently. Overall, the elucidation of the T. evansi genome sequence reveals extensive similarity of T. brucei and supports the contention that T. evansi should be classified as a subspecies of T. brucei.

  19. Genome and phylogenetic analyses of Trypanosoma evansi reveal extensive similarity to T. brucei and multiple independent origins for dyskinetoplasty.

    Science.gov (United States)

    Carnes, Jason; Anupama, Atashi; Balmer, Oliver; Jackson, Andrew; Lewis, Michael; Brown, Rob; Cestari, Igor; Desquesnes, Marc; Gendrin, Claire; Hertz-Fowler, Christiane; Imamura, Hideo; Ivens, Alasdair; Kořený, Luděk; Lai, De-Hua; MacLeod, Annette; McDermott, Suzanne M; Merritt, Chris; Monnerat, Severine; Moon, Wonjong; Myler, Peter; Phan, Isabelle; Ramasamy, Gowthaman; Sivam, Dhileep; Lun, Zhao-Rong; Lukeš, Julius; Stuart, Ken; Schnaufer, Achim

    2015-01-01

    Two key biological features distinguish Trypanosoma evansi from the T. brucei group: independence from the tsetse fly as obligatory vector, and independence from the need for functional mitochondrial DNA (kinetoplast or kDNA). In an effort to better understand the molecular causes and consequences of these differences, we sequenced the genome of an akinetoplastic T. evansi strain from China and compared it to the T. b. brucei reference strain. The annotated T. evansi genome shows extensive similarity to the reference, with 94.9% of the predicted T. b. brucei coding sequences (CDS) having an ortholog in T. evansi, and 94.6% of the non-repetitive orthologs having a nucleotide identity of 95% or greater. Interestingly, several procyclin-associated genes (PAGs) were disrupted or not found in this T. evansi strain, suggesting a selective loss of function in the absence of the insect life-cycle stage. Surprisingly, orthologous sequences were found in T. evansi for all 978 nuclear CDS predicted to represent the mitochondrial proteome in T. brucei, although a small number of these may have lost functionality. Consistent with previous results, the F1FO-ATP synthase γ subunit was found to have an A281 deletion, which is involved in generation of a mitochondrial membrane potential in the absence of kDNA. Candidates for CDS that are absent from the reference genome were identified in supplementary de novo assemblies of T. evansi reads. Phylogenetic analyses show that the sequenced strain belongs to a dominant group of clonal T. evansi strains with worldwide distribution that also includes isolates classified as T. equiperdum. At least three other types of T. evansi or T. equiperdum have emerged independently. Overall, the elucidation of the T. evansi genome sequence reveals extensive similarity of T. brucei and supports the contention that T. evansi should be classified as a subspecies of T. brucei.

  20. Genome-wide analysis of chromatin structures in Trypanosoma brucei using high-resolution MNase-ChIP-seq.

    Science.gov (United States)

    Wedel, Carolin; Siegel, T Nicolai

    2017-09-01

    Specific DNA-protein interactions are the basis for many important cellular mechanisms like the regulation of gene expression or replication. Knowledge about the precise genomic locations of DNA-protein interactions is important because it provides insight into the regulation of these processes. Recently, we have adapted an approach that combines micrococcal nuclease (MNase) digestion of chromatin with chromatin immunoprecipitation in Trypanosoma brucei. Here, we describe in detail how this method can be used to map the genome-wide distribution of nucleosomes or other DNA-binding proteins at high resolution in T. brucei. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Pyrimidine Salvage Enzymes Are Essential for De Novo Biosynthesis of Deoxypyrimidine Nucleotides in Trypanosoma brucei.

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    Christopher Leija

    2016-11-01

    Full Text Available The human pathogenic parasite Trypanosoma brucei possess both de novo and salvage routes for the biosynthesis of pyrimidine nucleotides. Consequently, they do not require salvageable pyrimidines for growth. Thymidine kinase (TK catalyzes the formation of dTMP and dUMP and is one of several salvage enzymes that appear redundant to the de novo pathway. Surprisingly, we show through analysis of TK conditional null and RNAi cells that TK is essential for growth and for infectivity in a mouse model, and that a catalytically active enzyme is required for its function. Unlike humans, T. brucei and all other kinetoplastids lack dCMP deaminase (DCTD, which provides an alternative route to dUMP formation. Ectopic expression of human DCTD resulted in full rescue of the RNAi growth phenotype and allowed for selection of viable TK null cells. Metabolite profiling by LC-MS/MS revealed a buildup of deoxypyrimidine nucleosides in TK depleted cells. Knockout of cytidine deaminase (CDA, which converts deoxycytidine to deoxyuridine led to thymidine/deoxyuridine auxotrophy. These unexpected results suggested that T. brucei encodes an unidentified 5'-nucleotidase that converts deoxypyrimidine nucleotides to their corresponding nucleosides, leading to their dead-end buildup in TK depleted cells at the expense of dTTP pools. Bioinformatics analysis identified several potential candidate genes that could encode 5'-nucleotidase activity including an HD-domain protein that we show catalyzes dephosphorylation of deoxyribonucleotide 5'-monophosphates. We conclude that TK is essential for synthesis of thymine nucleotides regardless of whether the nucleoside precursors originate from the de novo pathway or through salvage. Reliance on TK in the absence of DCTD may be a shared vulnerability among trypanosomatids and may provide a unique opportunity to selectively target a diverse group of pathogenic single-celled eukaryotes with a single drug.

  2. Chemical characterisation of Nigerian red propolis and its biological activity against Trypanosoma Brucei.

    Science.gov (United States)

    Omar, Ruwida M K; Igoli, John; Gray, Alexander I; Ebiloma, Godwin Unekwuojo; Clements, Carol; Fearnley, James; Ebel, Ru Angeli Edrada; Zhang, Tong; De Koning, Harry P; Watson, David G

    2016-01-01

    A previous study showed the unique character of Nigerian red propolis from Rivers State, Nigeria (RSN), with regards to chemical composition and activity against Trypanosoma brucei in comparison with other African propolis. To carry out fractionation and biological testing of Nigerian propolis in order to isolate compounds with anti-trypanosomal activity. To compare the composition of the RSN propolis with the composition of Brazilian red propolis. Profiling was carried out using HPLC-UV-ELSD and HPLC-Orbitrap-FTMS on extracts of two samples collected from RSN with data extraction using MZmine software. Isolation was carried out by normal phase and reversed phase MPLC. Elucidation of the compounds with a purity > 95% was performed by 1D/2D NMR HRMS and HRLC-MS(n) . Ten phenolic compounds were isolated or in the case of liquiritigenin partially purified. Data for nine of these correlated with literature reports of known compounds i.e. one isoflavanone, calycosin (1); two flavanones, liquiritigenin (2) and pinocembrin (5); an isoflavan, vestitol (3); a pterocarpan, medicarpin (4); two prenylflavanones, 8-prenylnaringenin (7) and 6-prenylnaringenin (8); and two geranyl flavonoids, propolin D (9) and macarangin (10). The tenth was elucidated as a previously undescribed dihydrobenzofuran (6). The isolated compounds were tested against Trypanosoma brucei and displayed moderate to high activity. Some of the compounds tested had similar activity against wild type T. brucei and two strains displaying pentamidine resistance. Nigerian propolis from RSN has some similarities with Brazilian red propolis. The propolis displayed anti-trypanosomal activity at a potentially useful level. Copyright © 2015 John Wiley & Sons, Ltd.

  3. The transcriptome of the human pathogen Trypanosoma brucei at single-nucleotide resolution.

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    Nikolay G Kolev

    2010-09-01

    Full Text Available The genome of Trypanosoma brucei, the causative agent of African trypanosomiasis, was published five years ago, yet identification of all genes and their transcripts remains to be accomplished. Annotation is challenged by the organization of genes transcribed by RNA polymerase II (Pol II into long unidirectional gene clusters with no knowledge of how transcription is initiated. Here we report a single-nucleotide resolution genomic map of the T. brucei transcriptome, adding 1,114 new transcripts, including 103 non-coding RNAs, confirming and correcting many of the annotated features and revealing an extensive heterogeneity of 5' and 3' ends. Some of the new transcripts encode polypeptides that are either conserved in T. cruzi and Leishmania major or were previously detected in mass spectrometry analyses. High-throughput RNA sequencing (RNA-Seq was sensitive enough to detect transcripts at putative Pol II transcription initiation sites. Our results, as well as recent data from the literature, indicate that transcription initiation is not solely restricted to regions at the beginning of gene clusters, but may occur at internal sites. We also provide evidence that transcription at all putative initiation sites in T. brucei is bidirectional, a recently recognized fundamental property of eukaryotic promoters. Our results have implications for gene expression patterns in other important human pathogens with similar genome organization (Trypanosoma cruzi, Leishmania sp. and revealed heterogeneity in pre-mRNA processing that could potentially contribute to the survival and success of the parasite population in the insect vector and the mammalian host.

  4. Variation of G-rich mitochondrial transcripts among stocks of Trypanosoma brucei.

    Science.gov (United States)

    Jasmer, D P; Feagin, J E; Payne, M; Stuart, K

    1987-01-15

    We have compared maxicircle transcripts from eight stocks of subspecies of Trypanosoma brucei. Transcripts from the rRNA and protein genes have a constant size among stocks and exhibit only minor variation in abundance. In contrast, four of the G+C rich sequences encode multiple transcripts that very markedly in size or abundance. Maxicircle nucleotide sequence comparison of three stocks shows very limited sequence divergence suggesting that sequence divergence may not explain the transcript variability. These results suggest that the G-rich transcripts do not encode proteins and that their variability among stocks may result from posttranscriptional processing events.

  5. Secular Trends in Nosocomial Bloodstream Infections : Antibiotic-Resistant Bacteria Increase the Total Burden of Infection

    NARCIS (Netherlands)

    Ammerlaan, H. S. M.; Harbarth, S.; Buiting, A. G. M.; Crook, D. W.; Fitzpatrick, F.; Hanberger, H.; Herwaldt, L. A.; van Keulen, P. H. J.; Kluytmans, J. A. J. W.; Kola, A.; Kuchenbecker, R. S.; Lingaas, E.; Meessen, N.; Morris-Downes, M. M.; Pottinger, J. M.; Rohner, P.; dos Santos, R. P.; Seifert, H.; Wisplinghoff, H.; Ziesing, S.; Walker, A. S.; Bonten, M. J. M.

    2013-01-01

    Background. It is unknown whether rising incidence rates of nosocomial bloodstream infections (BSIs) caused by antibiotic-resistant bacteria (ARB) replace antibiotic-susceptible bacteria (ASB), leaving the total BSI rate unaffected. Methods. We investigated temporal trends in annual incidence

  6. Catheter Removal versus Retention in the Management of Catheter-Associated Enterococcal Bloodstream Infections

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    Jonas Marschall

    2013-01-01

    Full Text Available BACKGROUND: Enterococci are an important cause of central venous catheter (CVC-associated bloodstream infections (CA-BSI. It is unclear whether CVC removal is necessary to successfully manage enterococcal CA-BSI.

  7. Impact estimates of nosocomial bloodstream infection: looking from a different angle.

    Science.gov (United States)

    Vogelaers, Dirk; Lambert, Marie-Laurence; Blot, Stijn

    2011-01-01

    Mortality associated with nosocomial bloodstream infection is multifactorial. Source of infection, etiology, age, underlying disease, acute illness, and appropriateness of antimicrobial therapy all contribute to the final outcome. As such, estimates of mortality attributable to bloodstream infection may differ largely according to the presence or absence of risk factors in distinct patient populations. The adverse effect of nosocomial bloodstream infection for the individual patient is substantial, with about a doubling of the risk of death. Yet, in settings with a high standard of care in terms of infection prevention and control, the occurrence rate of bloodstream infection is relatively low and therefore its impact on overall ICU mortality rather limited. As a consequence, untargeted interventional studies focused on infection prevention should use occurrence rate of infection rather than mortality as outcome variable.

  8. Rate, risk factors, and outcomes of nosocomial primary bloodstream infection in pediatric intensive care unit patients.

    Science.gov (United States)

    Yogaraj, Jeya S; Elward, Alexis M; Fraser, Victoria J

    2002-09-01

    The objective of this study was to determine the rate, risk factors, and outcomes of nosocomial primary bloodstream infection in pediatric intensive care unit (PICU) patients. Prospective cohort study. This study was performed at St Louis Children's Hospital, a 235-bed academic tertiary care center with a combined 22-bed medical and surgical PICU. Subjects for this study were patients admitted to the PICU between September 1, 1999, and May 31, 2000. None. Patients were monitored for the development of nosocomial bloodstream infections from the day of PICU admission until 48 hours after PICU discharge. Of 911 patients, 526 (58%) were male and 674 (74%) were white. Congenital heart disease (29%), lung disease (25%), and genetic syndrome (18%) were common. There were 65 episodes of primary bloodstream infection in 57 patients; 5 were polymicrobial and 7 patients had multiple bloodstream infections. Coagulase-negative Staphylococcus was the leading cause of bloodstream infection (n = 28), followed by Enterobacter cloacae (n = 8). The rate of bloodstream infection was 13.8 per 1000 central venous catheter days. In multiple logistic regression analysis, patients with bloodstream infection were more likely to have multiple central venous catheters (adjusted odds ratio [aOR]: 5.7; 95% confidence interval [CI]: 2.9-10.9), arterial catheters (aOR: 5.5; 95% CI: 1.8-16.3), invasive procedures performed in the PICU (aOR: 4.0; 95%CI: 2.0-7.8), and be transported out of the PICU (aOR: 3.4; 95% CI: 1.8-6.7) to the radiology or operating room suites. Severity of illness as measured by admission Pediatric Risk of Mortality score, underlying illnesses, and medications were not associated with increased risk of nosocomial bloodstream infection. Conclusions This study identified a high rate of bloodstream infection among St Louis Children's Hospital PICU patients. Risk factors for bloodstream infection were related more to process of care than to severity of illness. Additional

  9. Understanding chromatin dynamics during antigenic variation in trypanosoma brucei

    OpenAIRE

    Branco, Francisco Maria dos Santos e Silva Aresta, 1985-

    2016-01-01

    Tese de doutoramento, Ciências Biomédicas (Microbiologia e Parasitologia), Universidade de Lisboa, Faculdade de Medicina, 2016 African trypanosomiasis is a disease restricted to sub-Saharian Africa and it assumes two forms: Human African trypanosomiasis (HAT or sleeping sickness) or Animal African trypanosomiasis (AAT or n’gana), both being fatal if untreated. While HAT causes an estimated number of 15000 new cases each year and 70 million people are at risk, AAT causes an enormous economi...

  10. Central Line-Associated Bloodstream Infections in Pediatric Intensive Care Unit

    OpenAIRE

    Tanıl Kendirli; Ayhan Yaman; Çağlar Ödek; Halil Özdemir; Adem Karbuz; Bilge Aldemir; Haluk Güriz; Can Ateş; Gamze Özsoy; Derya Aysev; Ergin Çiftçi; Erdal İnce

    2017-01-01

    Introduction: The aim of this study was to determine the frequency of central line-associated bloodstream infections, risk factors, their relationship with catheter insertion location, and the effect of central line-associated bloodstream infections on mortality and pediatric intensive care unit (PICU) length of stay. Methods: This was a prospective, observational and cohort study, carried out between November 2009 and February 2011. During this period, all the patients who had central-lin...

  11. Central Line-Associated Bloodstream Infections in Pediatric Intensive Care Unit

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    Tanıl Kendirli

    2017-08-01

    Full Text Available Introduction: The aim of this study was to determine the frequency of central line-associated bloodstream infections, risk factors, their relationship with catheter insertion location, and the effect of central line-associated bloodstream infections on mortality and pediatric intensive care unit (PICU length of stay. Methods: This was a prospective, observational and cohort study, carried out between November 2009 and February 2011. During this period, all the patients who had central-line were monitored for central line-associated bloodstream infection. Results: In the study period, 275 patients were admitted to our PICU. The frequency of invasive device usage was 38.9% (107 for central venous catheter, 38.2% (105 for mechanical ventilation, 53.3% (147 for urinary catheter, and 11.3% (32 for artery line. Central line-associated bloodstream infection was detected in 16 (14.8% of the patients and 23 central line-associated bloodstream infection attacks were observed. There were 14 central line-associated bloodstream infection attacks in 1.000 central venous catheter usage days. There were 168 patients without central venous catheter and 4 (2.4% of them had blood stream infection. Thirty-six patients died and the mortality rate was 13%. Five of these patients (13.8% died due to central line-associated bloodstream infection, 27 (25% of them had central venous catheter and 9 (6% of them did not (p=0.001. Conclusion: In conclusion, central line-associated bloodstream infection is one of the serious healthcare-associated infections, and it is an important cause of morbidity and mortality in PICUs.

  12. Procalcitonin Levels in Gram-Positive, Gram-Negative, and Fungal Bloodstream Infections

    OpenAIRE

    Christian Leli; Marta Ferranti; Amedeo Moretti; Zainab Salim Al Dhahab; Elio Cenci; Antonella Mencacci

    2015-01-01

    Procalcitonin (PCT) can discriminate bacterial from viral systemic infections and true bacteremia from contaminated blood cultures. The aim of this study was to evaluate PCT diagnostic accuracy in discriminating Gram-positive, Gram-negative, and fungal bloodstream infections. A total of 1,949 samples from patients with suspected bloodstream infections were included in the study. Median PCT value in Gram-negative (13.8?ng/mL, interquartile range (IQR) 3.4?44.1) bacteremias was significantly hi...

  13. Structural and functional insight into ADF/cofilin from Trypanosoma brucei.

    Science.gov (United States)

    Dai, Kun; Liao, Shanhui; Zhang, Jiahai; Zhang, Xuecheng; Tu, Xiaoming

    2013-01-01

    The ADF/cofilin family has been characterized as a group of actin-binding proteins critical for controlling the assembly of actin within the cells. In this study, the solution structure of the ADF/cofilin from Trypanosoma brucei (TbCof) was determined by NMR spectroscopy. TbCof adopts the conserved ADF/cofilin fold with a central β-sheet composed of six β-strands surrounded by five α-helices. Isothermal titration calorimetry experiments denoted a submicromolar affinity between TbCof and G-actin, and the affinity between TbCof and ADP-G-actin was five times higher than that between TbCof and ATP-G-actin at low ionic strength. The results obtained from electron microscopy and actin filament sedimentation assays showed that TbCof depolymerized but did not co-sediment with actin filaments and its ability of F-actin depolymerization was pH independent. Similar to actin, TbCof was distributed throughout the cytoplasm. All our data indicate a structurally and functionally conserved ADF/cofilin from Trypanosoma brucei.

  14. Structural and Functional Association of Trypanosoma brucei MIX Protein with Cytochrome c Oxidase Complex ▿ †

    Science.gov (United States)

    Zíková, Alena; Panigrahi, Aswini K.; Uboldi, Alessandro D.; Dalley, Rachel A.; Handman, Emanuela; Stuart, Kenneth

    2008-01-01

    A mitochondrial inner membrane protein, designated MIX, seems to be essential for cell viability. The deletion of both alleles was not possible, and the deletion of a single allele led to a loss of virulence and aberrant mitochondrial segregation and cell division in Leishmania major. However, the mechanism by which MIX exerts its effect has not been determined. We show here that MIX is also expressed in the mitochondrion of Trypanosoma brucei, and using RNA interference, we found that its loss leads to a phenotype that is similar to that described for Leishmania. The loss of MIX also had a major effect on cytochrome c oxidase activity, on the mitochondrial membrane potential, and on the production of mitochondrial ATP by oxidative phosphorylation. Using a tandem affinity purification tag, we found that MIX is associated with a multiprotein complex that contains subunits of the mitochondrial cytochrome c oxidase complex (respiratory complex IV), the composition of which was characterized in detail. The specific function of MIX is unknown, but it appears to be important for the function of complex IV and for mitochondrial segregation and cell division in T. brucei. PMID:18776036

  15. Base J and H3.V Regulate Transcriptional Termination in Trypanosoma brucei.

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    Danae Schulz

    2016-01-01

    Full Text Available Trypanosoma brucei is a protozoan parasite that lacks many transcription factors found in other eukaryotes, such as those whose binding demarcates enhancers. T. brucei retains histone variants and modifications, however, and it is hypothesized that it relies on epigenetic marks to define transcription-related boundaries. The histone H3 variant (H3.V and an alternate nucleotide, base J (ß-D-glucosyl-hydroxymethyluracil, are two chromatin marks found at both transcription termination sites (TTSs and telomeres. Here, we report that the absence of both base J and H3.V result in transcription readthrough and the appearance of antisense transcripts near TTSs. Additionally, we find that maintaining the transcriptional silencing of pol I-transcribed telomeric Variant Surface Glycoprotein (VSG genes appears to be dependent on deposition of H3.V alone. Our study reveals that gene expression depends on different epigenetic cues depending on chromosomal location and on the transcribing polymerase. This work provides insight into how these signals may have evolved into the more nuanced and fine-tuned gene regulatory mechanisms observed in other model systems.

  16. Tail characteristics of Trypanosoma brucei mitochondrial transcripts are developmentally altered in a transcript-specific manner.

    Science.gov (United States)

    Gazestani, Vahid H; Hampton, Marshall; Shaw, Aubie K; Salavati, Reza; Zimmer, Sara L

    2018-02-01

    The intricate life cycle of Trypanosoma brucei requires extensive regulation of gene expression levels of the mtRNAs for adaptation. Post-transcriptional gene regulatory programs, including unencoded mtRNA 3' tail additions, potentially play major roles in this adaptation process. Intriguingly, T. brucei mitochondrial transcripts possess two distinct unencoded 3' tails, each with a differing functional role; i.e., while one type is implicated in RNA stability (in-tails), the other type appears associated with translation (ex-tails). We examined the degree to which tail characteristics differ among cytochrome c oxidase subunits I and III (CO1 and CO3), and NADH dehydrogenase subunit 1 (ND1) transcripts, and to what extent these characteristics differ developmentally. We found that CO1, CO3 and ND1 transcripts possess longer in-tails in the mammalian life stage. By mathematically modelling states of in-tail and ex-tail addition, we determined that the typical length at which an in-tail is extended to become an ex-tail differs by transcript and, in the case of ND1, by life stage. To the best of our knowledge, we provide the first evidence that developmental differences exist in tail length distributions of mtRNAs, underscoring the potential involvement of in-tail and ex-tail populations in mitochondrial post-transcriptional regulation mechanisms. Copyright © 2017 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.

  17. Investigating the Chaperone Properties of a Novel Heat Shock Protein, Hsp70.c, from Trypanosoma brucei

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    Adélle Burger

    2014-01-01

    Full Text Available The neglected tropical disease, African Trypanosomiasis, is fatal and has a crippling impact on economic development. Heat shock protein 70 (Hsp70 is an important molecular chaperone that is expressed in response to stress and Hsp40 acts as its co-chaperone. These proteins play a wide range of roles in the cell and they are required to assist the parasite as it moves from a cold blooded insect vector to a warm blooded mammalian host. A novel cytosolic Hsp70, from Trypanosoma brucei, TbHsp70.c, contains an acidic substrate binding domain and lacks the C-terminal EEVD motif. The ability of a cytosolic Hsp40 from Trypanosoma brucei J protein 2, Tbj2, to function as a co-chaperone of TbHsp70.c was investigated. The main objective was to functionally characterize TbHsp70.c to further expand our knowledge of parasite biology. TbHsp70.c and Tbj2 were heterologously expressed and purified and both proteins displayed the ability to suppress aggregation of thermolabile MDH and chemically denatured rhodanese. ATPase assays revealed a 2.8-fold stimulation of the ATPase activity of TbHsp70.c by Tbj2. TbHsp70.c and Tbj2 both demonstrated chaperone activity and Tbj2 functions as a co-chaperone of TbHsp70.c. In vivo heat stress experiments indicated upregulation of the expression levels of TbHsp70.c.

  18. Secondary metabolites from Vietnamese marine invertebrates with activity against Trypanosoma brucei and T. cruzi.

    Science.gov (United States)

    Thao, Nguyen Phuong; No, Joo Hwan; Luyen, Bui Thi Thuy; Yang, Gyongseon; Byun, Soo Young; Goo, Junghyun; Kim, Kyung Tae; Cuong, Nguyen Xuan; Nam, Nguyen Hoai; Van Minh, Chau; Schmidt, Thomas J; Kang, Jong Seong; Kim, Young Ho

    2014-06-11

    Marine-derived natural products from invertebrates comprise an extremely diverse and promising source of the compounds from a wide variety of structural classes. This study describes the discovery of five marine natural products with activity against Trypanosoma species by natural product library screening using whole cell in vitro assays. We investigated the anti-trypanosomal activity of the extracts from the soft corals and echinoderms living in Vietnamese seas. Of the samples screened, the methanolic extracts of several marine organisms exhibited potent activities against cultures of Trypanosoma brucei and T. cruzi (EC50 activity against T. brucei with EC50 values ranging from 1.57 ± 0.14 to 14.6 ± 1.36 μM, relative to the positive control, pentamidine (EC50 = 0.015 ± 0.003 μM). Laevigatol B (1) and 5α-cholest-8(14)-ene-3β,7α-diol (5) exhibited also significant inhibitory effects on T. cruzi. The cytotoxic activity of the pure compounds on mammalian cells was also assessed and found to be insignificant in all cases. This is the first report on the inhibitory effects of marine organisms collected in Vietnamese seas against Trypanosoma species responsible for neglected tropical diseases.

  19. 1H, 13C and 15N resonance assignments for a putative ADF/Cofilin from Trypanosoma brucei.

    Science.gov (United States)

    Dai, Kun; Yuan, Guangfa; Liao, Shanhui; Zhang, Jiahai; Tu, Xiaoming

    2011-10-01

    Actin-depolymerizing factor (ADF)/cofilin proteins are a family of actin-binding proteins expressed in almost all eukaryotic cells, and play a significant role in regulating actin-filament dynamics. Here we report the resonance assignments of a putative ADF/cofilin from Trypanosoma brucei for further understanding of the relationship between its structure and function.

  20. Variations in maxi-circle and mini-circle sequences in kinetoplast DNAs from different Trypanosoma brucei strains.

    NARCIS (Netherlands)

    P. Borst (Piet); F. Fase-Fowler; J.H.J. Hoeijmakers (Jan); A.C.C. Frasch

    1980-01-01

    textabstractWe have compared a total of 30 recognition sites for eight restriction endonucleases on the 20-kilobase-pair maxi-circle of kinetoplast DNAs from five different Trypanosoma brucei strains. In addition to three polymorphic sites were have found a 5 kilobase-pair region that is not cleaved

  1. THE CYTOSOLIC AND GLYCOSOMAL GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE FROM TRYPANOSOMA-BRUCEI - KINETIC-PROPERTIES AND COMPARISON WITH HOMOLOGOUS ENZYMES

    NARCIS (Netherlands)

    LAMBEIR, AM; LOISEAU, AM; KUNTZ, DA; VELLIEUX, FM; MICHELS, PAM; OPPERDOES, FR

    1991-01-01

    The protozoan haemoflagellate Trypanosoma brucei has two NAD-dependent glyceraldehyde-3-phosphate dehydrogenase isoenzymes, each with a different localization within the cell. One isoenzyme is found in the cytosol, as in other eukaryotes, while the other is found in the glycosome, a microbody-like

  2. A tropical tale: how Naja nigricollis venom beats Trypanosoma brucei

    DEFF Research Database (Denmark)

    Martos Esteban, Andrea; Laustsen, Andreas Hougaard; Carrington, Mark

    Trypanosoma brucei is a parasitic protozoan species capable to infecting insect vectors whose bite further produces African sleeping sickness inhuman beings [1]. During the parasite’s extracellular life in the mammalian host,its outer coat, mainly composed of Variable Surface Glycoproteins (VSGs...

  3. Haematological indices in Trypanosoma brucei brucei (Federe isolate infected Nigerian donkeys (Equus asinus treated with homidium and isometamidium chloride of ciprofloxacin in broiler chickens after single intravenous and intraingluvial administration

    Directory of Open Access Journals (Sweden)

    Queen Nneka Oparah

    2017-03-01

    Full Text Available The efficacy of intramuscular administration of Homidium chloride (Novidium® and Isometamidium chloride (Sécuridium® in Nigerian donkeys (Equus asinus experimentally infected with T. b. brucei (Federe isolate was investigated. Changes in haematological and serum biochemical indices were evaluated using clinical haematology and biochemistry methods. Red blood cell (RBC count for the negative control group was significantly higher than for the positive control, Novidium® and Sécuridium®-treatment groups. Haemoglobin (Hb concentration significantly reduced in the infected untreated group compared with other groups. Packed cell volume (PCV was significantly different between negative and positive controls, and also between the infected untreated and treatment groups. There was significant reduction in platelet counts post-infection and post-treatment. Mean corpuscular volume (MCV increased significantly in the treatment groups while mean corpuscular haemoglobin concentration (MCHC significantly reduced only in the Sécuridium®-treatment group. Lymphocyte count for infected untreated was non-significantly higher than for the uninfected controls, but treatment with both trypanocides recorded further increases, which were higher compared with that of the uninfected group. Post infection and treatment, aspartate aminotransferase (AST levels increased significantly. There were non-significant differences in electrolyte ion concentrations across the groups except for chloride ion which recorded a significant reduction in the Novidium®-treatment group. This experiment revealed that Nigerian donkeys infected with T. brucei brucei (Federe isolate developed symptoms of trypanosomosis; anaemia, lymphocytosis and thrombocytopenia. Treatment with the trypanocides ameliorated effects of the infection, and results suggest that immunosuppression may not be a substantial clinical manifestation of T. brucei brucei (Federe isolate trypanosomosis in Nigerian

  4. The changing epidemiology of Staphylococcus aureus bloodstream infection

    DEFF Research Database (Denmark)

    Laupland, K.B.; Lyytikäinen, O.; Søgaard, Mette

    2013-01-01

    Clin Microbiol Infect ABSTRACT: Although the epidemiology of Staphylococcus aureus bloodstream infection (BSI) has been changing, international comparisons are lacking. We sought to determine the incidence of S. aureus BSI and assess trends over time and by region. Population-based surveillance...... episodes of S. aureus BSI were identified. The overall annual incidence rate for S. aureus BSI was 26.1 per 100 000 population, and those for methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) were 24.2 and 1.9 per 100 000, respectively. Although the overall incidence...... of community-onset MSSA BSI (15.0 per 100 000) was relatively similar across regions, the incidence rates of hospital-onset MSSA (9.2 per 100 000), community-onset MRSA (1.0 per 100 000) and hospital-onset MRSA (0.8 per 100 000) BSI varied substantially. Whereas the overall incidence of S. aureus BSI did...

  5. Bloodstream Infections in a Neonatal Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    Mehmet Sah Ižpek

    2016-09-01

    Full Text Available Aim: To determine the pattern of bloodstream infections (BSIs and antimicrobial susceptibility of pathogens in a neonatal intensive care unit (NICU.Material and Method: Positive hemoculture of neonates diagnosed with nosocomial sepsis from March 2011 to March 2014 in the NICU of Diyarbakir Maternity and Children%u2019s Hospital, in the southeastern region of Anatolia, Turkey, were retrospectively reviewed. Results: A total of 148 pathogens were isolated in 142 neonates. The most common microorganisms isolated were Klebsiella pneumoniae (40.5% and Acinetobacter baumannii (29.7% which was a result of a hospital outbreak. Multi-drug resistant (MDR strains accounted for 20.0% of K. pneumoniae isolates and 93.2% of A. baumannii isolates. The sepsis-attributable mortality rate was higher in cases infected with MDR strains than in cases infected without MDR strains or Candida spp (24% vs. 9.7%, p=0.032. Discussion: In our unit, BSIs were more often caused by Gram negative bacteria. BSIs caused by MDR strains were associated with a higher rate of sepsis-attributable mortality.

  6. Antibiogram for Haemodialysis Catheter-Related Bloodstream Infections

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    Abdul Halim Abdul Gafor

    2014-01-01

    Full Text Available Background. Haemodialysis (HD catheter-related bloodstream infections (CRBSIs are a major complication of long-term catheter use in HD. This study identified the epidemiology of HD CRBSIs and to aid in the choice of empiric antibiotics therapy given to patients with HD CRBSIs. Methods. Patients with HD CRBSIs were identified. Their blood cultures were performed according to standard sterile technique. Specimens were sent to the microbiology lab for culture and sensitivity testing. Results were tabulated in antibiograms. Results. 18 patients with a median age of 61.0 years (IQR: 51.5–73.25 were confirmed to have HD CRBSIs based on our study criteria. Eight (44.4% patients had gram-negative infections, 7 (38.9% patients gram-positive infections, and 3 (16.7% patients had polymicrobial infections. We noted that most of the gram-negative bacteria were sensitive to ceftazidime. Unfortunately, cloxacillin resistance was high among gram-positive organisms. Coagulase-negative Staphylococcus and Bacillus sp. were the most common gram-positive organisms and they were sensitive to vancomycin. Conclusion. Our study revealed the increased incidence of gram-negative organism in HD CRBSIs. Antibiogram is an important tool in deciding empirical antibiotics for HD CRBSIs. Tailoring your antibiotics accordingly to the antibiogram can increase the chance of successful treatment and prevent the emergence of bacterial resistance.

  7. Vaccine Protection of Leukopenic Mice against Staphylococcus aureus Bloodstream Infection

    Science.gov (United States)

    Rauch, Sabine; Gough, Portia; Kim, Hwan Keun; Schneewind, Olaf

    2014-01-01

    The risk for Staphylococcus aureus bloodstream infection (BSI) is increased in immunocompromised individuals, including patients with hematologic malignancy and/or chemotherapy. Due to the emergence of antibiotic-resistant strains, designated methicillin-resistant S. aureus (MRSA), staphylococcal BSI in cancer patients is associated with high mortality; however, neither a protective vaccine nor pathogen-specific immunotherapy is currently available. Here, we modeled staphylococcal BSI in leukopenic CD-1 mice that had been treated with cyclophosphamide, a drug for leukemia and lymphoma patients. Cyclophosphamide-treated mice were highly sensitive to S. aureus BSI and developed infectious lesions lacking immune cell infiltrates. Virulence factors of S. aureus that are key for disease establishment in immunocompetent hosts—α-hemolysin (Hla), iron-regulated surface determinants (IsdA and IsdB), coagulase (Coa), and von Willebrand factor binding protein (vWbp)—are dispensable for the pathogenesis of BSI in leukopenic mice. In contrast, sortase A mutants, which cannot assemble surface proteins, display delayed time to death and increased survival in this model. A vaccine with four surface antigens (ClfA, FnBPB, SdrD, and SpAKKAA), which was identified by genetic vaccinology using sortase A mutants, raised antigen-specific immune responses that protected leukopenic mice against staphylococcal BSI. PMID:25183728

  8. Molecular profiles of Trypanosoma brucei, T. evansi and T. equiperdum stocks revealed by the random amplified polymorphic DNA method.

    Science.gov (United States)

    Lun, Zhao-Rong; Li, An-Xing; Chen, Xiao-Guang; Lu, Li-Xin; Zhu, Xing-Quan

    2004-03-01

    A total of 20 random primers (10-mers) were used to amplify RAPD markers from the genomic DNA of four Trypanosoma brucei stocks from East and West Africa, four T. evansi stocks from Africa, Asia and South America and one T. equiperdum stock from Asia. Between 65 and 88 reproducible fragments ranging from 0.25 to 2.15 kb were generated from these stocks depending on the stock/primer combination. The similarity coefficient (SC) among the stocks of T. brucei from Kenya, Nigeria, Tanzania and Zambia ranged from 62.9% to 74.0% (average: 67.6%). The SC among the stocks of T. evansi from Kenya, China and Brazil was 76.4%-95.5% (average: 86.4%), while the SC between T. evansi stock from China and Brazil was 95.5%. For T. evansi and T. equiperdum, the SC among the stocks ranged from 81.2% to 94.4% (average: 87.6%). As for the SC among the stocks of T. brucei and T. evansi, it was found to be from 54.7% to 80.3% (average: 68.0%) and the SC among stocks of T. brucei and T. equiperdum was from 59.4% to 76.9% (average: 68.1%). Our results indicate that the stocks of T. evansi from China and from Brazil are more closely related to the stock of T. equiperdum from China than to the stocks of T. evansi isolated from Kenya and to the stocks of T. brucei. In addition, our results further support the hypothesis that T. evansi stocks from China and Brazil could have arisen from a single lineage. The possible evolution of T. evansi and T. equiperdum is also discussed.

  9. ATG24 Represses Autophagy and Differentiation and Is Essential for Homeostasy of the Flagellar Pocket in Trypanosoma brucei.

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    Ana Brennand

    Full Text Available We have previously identified homologs for nearly half of the approximately 30 known yeast Atg's in the genome database of the human sleeping sickness parasite Trypanosoma brucei. So far, only a few of these homologs have their role in autophagy experimentally confirmed. Among the candidates was the ortholog of Atg24 that is involved in pexophagy in yeast. In T. brucei, the peroxisome-like organelles named glycosomes harbor core metabolic processes, especially glycolysis. In the autotrophic yeast, autophagy is essential for adaptation to different nutritional environments by participating in the renewal of the peroxisome population. We hypothesized that autophagic turnover of the parasite's glycosomes plays a role in differentiation during its life cycle, which demands adaptation to different host environments and associated dramatic changes in nutritional conditions. We therefore characterized T. brucei ATG24, the T. brucei ortholog of yeast Atg24 and mammalian SNX4, and found it to have a regulatory role in autophagy and differentiation as well as endocytic trafficking. ATG24 partially localized on endocytic membranes where it was recruited via PI3-kinase III/VPS34. ATG24 silencing severely impaired receptor-mediated endocytosis of transferrin, but not adsorptive uptake of a lectin, and caused a major enlargement of the flagellar pocket. ATG24 silencing approximately doubled the number of autophagosomes, suggesting a role in repressing autophagy, and strongly accelerated differentiation, in accordance with a role of autophagy in parasite differentiation. Overexpression of the two isoforms of T. brucei ATG8 fused to GFP slowed down differentiation, possibly by a dominant-negative effect. This was overcome by ATG24 depletion, further supporting its regulatory role.

  10. Central venous catheter-related bloodstream infection caused by Staphylococcus aureus: microbiology and risk factors

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    Geraldo Sadoyma

    Full Text Available Although central vascular catheters (CVC are indispensable in modern medicine, they are an important risk factor for primary bacteremias. We examined the incidence and risk factors associated with catheter-related bloodstream infection (CR-BSI caused by Staphylococcus aureus in surgical patients. A prospective study was carried out in the Hospital das Clínicas da Universidade Federal de Uberlândia (HC-UFU from September 2000 to December 2002. The skin insertion site, catheter tip, and blood were microbiologically analyzed. Demographics and risk factors were recorded for each patient, and cultures were identified phenotypically. Staphylococcus aureus was the most frequent pathogen, with an incidence rate of 4.9 episodes of CR-BSIs per 1,000 catheter/days. Based on logistic regression, the independent risk factors were: colonization on the insertion site =200 colony forming units (CFU/20 cm² (p=0.03; odds ratio (OR =6.89 and catheter tip (p=0.01; OR=7.95. The CR-BSI rate was high; it was mainly associated with S. aureus, and skin colonization at the insertion site and on the catheter tip were important risk factors for CR-BSI.

  11. Pathogenicity of Candida albicans isolates from bloodstream and mucosal candidiasis assessed in mice and Galleria mellonella.

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    Frenkel, M; Mandelblat, M; Alastruey-Izquierdo, A; Mendlovic, S; Semis, R; Segal, E

    2016-03-01

    The working hypothesis of this study was to elucidate a possible association between the pathogenic potential of Candida albicans strains with a clinical entity, systemic versus superficial candidiasis. Specifically, we assessed the pathogenicity of two groups of clinical C. albicans isolates: isolates from bloodstream infection (S) versus isolates from vaginitis patients (M), in two experimental in vivo systems - mice and Galleria melonella, in comparison to a control strain (CBS 562). Mice and G. mellonella larvae were inoculated with CBS 562 and the different S and M isolates, and followed up for survival rate and survival time during 30 and 7 days, respectively. Candida kidney colonization of mice was assessed by histopathology and colony-forming units' enumeration. The results revealed: (1) S and M isolates had different behavior patterns in the two models and varied in different parameters; (2) no statistically significant difference in pathogenicity between S and M isolates as whole groups was noted; (3) S14 was the most virulent isolate and close to the standard strain CBS 562 in both models. This study is distinctive in its outline combining two different groups of C. albicans clinical isolates originating from two different clinical entities that were assessed in vivo concurrently in two models. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  12. Susceptibility to chlorhexidine amongst multidrug-resistant clinical isolates of Staphylococcus epidermidis from bloodstream infections.

    Science.gov (United States)

    Hijazi, Karolin; Mukhopadhya, Indrani; Abbott, Felicity; Milne, Kathleen; Al-Jabri, Zaaima J; Oggioni, Marco R; Gould, Ian M

    2016-07-01

    The emergence of Staphylococcus isolates with reduced susceptibility to chlorhexidine is being increasingly reported. We present an update to a previous report showing the continuing efficacy of chlorhexidine-based infection control measures against Staphylococcus aureus over 6 years. In this study, qacA/B genes were screened in Staphylococcus isolates collected over another 6 years in the same intensive care unit in Scotland where chlorhexidine baths form an essential component of long-term control of nosocomial infections. Consistent with our previous study, we report minimal presence of qacA/B in S. aureus strains from screening samples and bacteraemia patients but the new finding of a high proportion of qacA/B carriage in Staphylococcus epidermidis associated with reduced susceptibility to chlorhexidine. S. epidermidis isolates positive for qacA/B were clonally diverse, although 65% of isolates belonged to the multidrug-resistant (MDR) clone ST2. These findings raise concerns in relation to the selection of MDR strains by chlorhexidine and are important in the context of recent evidence emphasising the benefits of targeting bloodstream infections associated with coagulase-negative staphylococci. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  13. Chimerization at the AQP2–AQP3 locus is the genetic basis of melarsoprol–pentamidine cross-resistance in clinical Trypanosoma brucei gambiense isolates

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    Fabrice E. Graf

    2015-08-01

    Full Text Available Aquaglyceroporin-2 is a known determinant of melarsoprol–pentamidine cross-resistance in Trypanosoma brucei brucei laboratory strains. Recently, chimerization at the AQP2–AQP3 tandem locus was described from melarsoprol–pentamidine cross-resistant Trypanosoma brucei gambiense isolates from sleeping sickness patients in the Democratic Republic of the Congo. Here, we demonstrate that reintroduction of wild-type AQP2 into one of these isolates fully restores drug susceptibility while expression of the chimeric AQP2/3 gene in aqp2–aqp3 null T. b. brucei does not. This proves that AQP2–AQP3 chimerization is the cause of melarsoprol–pentamidine cross-resistance in the T. b. gambiense isolates.

  14. Further evidence from SSCP and ITS DNA sequencing support Trypanosoma evansi and Trypanosoma equiperdum as subspecies or even strains of Trypanosoma brucei

    OpenAIRE

    Wen, Y; Lun, Z; Zhu, X; Hide, G; Lai, D

    2016-01-01

    The subgenus Trypanozoon includes three species Trypanosoma brucei, Trypanosoma evansi and Trypanosoma equiperdum, which are morphologically identical and indistinguishable even using some molecular methods. In this study, PCR-based single strand conformation polymorphism (PCR-SSCP) was used to analyze the ribosomal DNA of the Trypanozoon species. Data indicate different patterns of ITS2 fragments between T. brucei, T. evansi and T. equiperdum by SSCP. Furthermore, analysis of total ITS seque...

  15. Epidemiology of Bloodstream Infections at a Cancer Center

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    Eduardo Velasco

    2000-09-01

    Full Text Available CONTEXT: Cancer patients are at unusually high risk for developing bloodstream infections (BSI, which are a major cause of in-hospital morbidity and mortality. OBJECTIVE: To describe the epidemiological characteristics and the etiology of BSI in cancer patients. DESIGN: Descriptive study. SETTING: Terciary Oncology Care Center. PARTICIPANTS: During a 24-month period all hospitalized patients with clinically significant BSI were evaluated in relation to several clinical and demographic factors. RESULTS: The study enrolled 435 episodes of BSI (349 patients. The majority of the episodes occurred among non-neutropenic patients (58.6% and in those younger than 40 years (58.2%. There was a higher occurrence of unimicrobial infections (74.9%, nosocomial episodes (68.3% and of those of undetermined origin (52.8%. Central venous catheters (CVC were present in 63.2% of the episodes. Overall, the commonest isolates from blood in patients with hematology diseases and solid tumors were staphylococci (32% and 34.7%, respectively. There were 70 episodes of fungemia with a predominance of Candida albicans organisms (50.6%. Fungi were identified in 52.5% of persistent BSI and in 91.4% of patients with CVC. Gram-negative bacilli prompted the CVC removal in 45.5% of the episodes. Oxacillin resistance was detected in 26.3% of Staphylococcus aureus isolates and in 61.8% of coagulase-negative Staphylococcus. Vancomycin-resistant enterococci were not observed. Initial empirical antimicrobial therapy was considered appropriate in 60.5% of the cases. CONCLUSION: The identification of the microbiology profile of BSI and the recognition of possible risk factors in high-risk cancer patients may help in planning and conducting more effective infection control and preventive measures, and may also allow further analytical studies for reducing severe infectious complications in such groups of patients.

  16. Enhanced succinic acid production in Aspergillus saccharolyticus by heterologous expression of fumarate reductase from Trypanosoma brucei

    DEFF Research Database (Denmark)

    Yang, Lei; Lübeck, Mette; Ahring, Birgitte K.

    2015-01-01

    production medium as well as the complete medium, but the measured enzyme activities were different depending on the media. Furthermore, a soluble NADH-dependent fumarate reductase gene (frd) from Trypanosoma brucei was inserted and expressed in A. saccharolyticus. The expression of the frd gene led......Aspergillus saccharolyticus exhibits great potential as a cell factory for industrial production of dicarboxylic acids. In the analysis of the organic acid profile, A. saccharolyticus was cultivated in an acid production medium using two different pH conditions. The specific activities...... on the pattern and the amount of organic acids produced by A. saccharolyticus. The wild-type strain produced higher amount of malic acid and succinic acid in the pH buffered condition (pH 6.5) compared with the pH non-buffered condition. The enzyme assays showed that the rTCA branch was active in the acid...

  17. Compositional compartmentalization of the nuclear genomes of Trypanosoma brucei and Trypanosoma equiperdum.

    Science.gov (United States)

    Isacchi, A; Bernardi, G; Bernardi, G

    1993-12-06

    High molecular weight DNA preparations from Trypanosoma brucei and Trypanosoma equiperdum were fractionated by preparative centrifugation in a Cs2SO4 density gradient in the presence of BAMD, bis(acetatomercurimethyl)dioxane, a sequence-specific DNA ligand. Analytical centrifugation in CsCl of the DNA fractions so obtained showed that both DNAs had a bimodal distribution with two major peaks banding at 1.702-1.703 and 1.708 g/cm3 and representing 1/3 and 2/3 of total DNA, respectively. Several minor components were also detected. These results indicate that a compositional compartmentalization is not only found in the genome of vertebrates and plants, as already described, but also in those of protozoa such as Trypanosomes.

  18. Population genetics of Trypanosoma brucei rhodesiense: clonality and diversity within and between foci.

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    Craig W Duffy

    2013-11-01

    Full Text Available African trypanosomes are unusual among pathogenic protozoa in that they can undergo their complete morphological life cycle in the tsetse fly vector with mating as a non-obligatory part of this development. Trypanosoma brucei rhodesiense, which infects humans and livestock in East and Southern Africa, has classically been described as a host-range variant of the non-human infective Trypanosoma brucei that occurs as stable clonal lineages. We have examined T. b. rhodesiense populations from East (Uganda and Southern (Malawi Africa using a panel of microsatellite markers, incorporating both spatial and temporal analyses. Our data demonstrate that Ugandan T. b. rhodesiense existed as clonal populations, with a small number of highly related genotypes and substantial linkage disequilibrium between pairs of loci. However, these populations were not stable as the dominant genotypes changed and the genetic diversity also reduced over time. Thus these populations do not conform to one of the criteria for strict clonality, namely stability of predominant genotypes over time, and our results show that, in a period in the mid 1990s, the previously predominant genotypes were not detected but were replaced by a novel clonal population with limited genetic relationship to the original population present between 1970 and 1990. In contrast, the Malawi T. b. rhodesiense population demonstrated significantly greater diversity and evidence for frequent genetic exchange. Therefore, the population genetics of T. b. rhodesiense is more complex than previously described. This has important implications for the spread of the single copy T. b. rhodesiense gene that allows human infectivity, and therefore the epidemiology of the human disease, as well as suggesting that these parasites represent an important organism to study the influence of optional recombination upon population genetic dynamics.

  19. Secondary Metabolites from Vietnamese Marine Invertebrates with Activity against Trypanosoma brucei and T. cruzi

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    Nguyen Phuong Thao

    2014-06-01

    Full Text Available Marine-derived natural products from invertebrates comprise an extremely diverse and promising source of the compounds from a wide variety of structural classes. This study describes the discovery of five marine natural products with activity against Trypanosoma species by natural product library screening using whole cell in vitro assays. We investigated the anti-trypanosomal activity of the extracts from the soft corals and echinoderms living in Vietnamese seas. Of the samples screened, the methanolic extracts of several marine organisms exhibited potent activities against cultures of Trypanosoma brucei and T. cruzi (EC50 < 5.0 μg/mL. Among the compounds isolated from these extracts, laevigatol B (1 from Lobophytum crassum and L. laevigatum, (24S-ergost-4-ene-3-one (2 from Sinularia dissecta, astropectenol A (3 from Astropecten polyacanthus, and cholest-8-ene-3β,5α,6β,7α-tetraol (4 from Diadema savignyi showed inhibitory activity against T. brucei with EC50 values ranging from 1.57 ± 0.14 to 14.6 ± 1.36 μM, relative to the positive control, pentamidine (EC50 = 0.015 ± 0.003 μM. Laevigatol B (1 and 5α-cholest-8(14-ene-3β,7α-diol (5 exhibited also significant inhibitory effects on T. cruzi. The cytotoxic activity of the pure compounds on mammalian cells was also assessed and found to be insignificant in all cases. This is the first report on the inhibitory effects of marine organisms collected in Vietnamese seas against Trypanosoma species responsible for neglected tropical diseases.

  20. Protein functional links in Trypanosoma brucei, identified by gene fusion analysis

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    Trimpalis Philip

    2011-07-01

    Full Text Available Abstract Background Domain or gene fusion analysis is a bioinformatics method for detecting gene fusions in one organism by comparing its genome to that of other organisms. The occurrence of gene fusions suggests that the two original genes that participated in the fusion are functionally linked, i.e. their gene products interact either as part of a multi-subunit protein complex, or in a metabolic pathway. Gene fusion analysis has been used to identify protein functional links in prokaryotes as well as in eukaryotic model organisms, such as yeast and Drosophila. Results In this study we have extended this approach to include a number of recently sequenced protists, four of which are pathogenic, to identify fusion linked proteins in Trypanosoma brucei, the causative agent of African sleeping sickness. We have also examined the evolution of the gene fusion events identified, to determine whether they can be attributed to fusion or fission, by looking at the conservation of the fused genes and of the individual component genes across the major eukaryotic and prokaryotic lineages. We find relatively limited occurrence of gene fusions/fissions within the protist lineages examined. Our results point to two trypanosome-specific gene fissions, which have recently been experimentally confirmed, one fusion involving proteins involved in the same metabolic pathway, as well as two novel putative functional links between fusion-linked protein pairs. Conclusions This is the first study of protein functional links in T. brucei identified by gene fusion analysis. We have used strict thresholds and only discuss results which are highly likely to be genuine and which either have already been or can be experimentally verified. We discuss the possible impact of the identification of these novel putative protein-protein interactions, to the development of new trypanosome therapeutic drugs.

  1. The changing pattern of bloodstream infections associated with the rise in HIV prevalence in northeastern Thailand.

    Science.gov (United States)

    Chierakul, W; Rajanuwong, A; Wuthiekanun, V; Teerawattanasook, N; Gasiprong, M; Simpson, A; Chaowagul, W; White, N J

    2004-11-01

    A survey of bloodstream infections was conducted in the large regional hospital in Ubon Ratchatani, northeastern Thailand between 1989 and 1998, during the onset of the HIV epidemic. The incidence of Staphylococcus aureus, Escherichia coli, Klebsiella/Enterobacter and Pseudomonas aeruginosa bacteraemias remained constant whereas infections caused by Burkholderia pseudomallei, non-typhoid Salmonellae, Cryptococcus neoformans, Penicillum marneffei and to a lesser extent Streptococcus pneumoniae all rose. Burkholderia pseudomallei infections were unrelated to HIV, whereas the other infections were associated directly with HIV. Group D non-typhoid Salmonellae bloodstream infections (mainly Salmonella enteritidis) rose coincident with the increase in HIV seroprevalence, and preceded the increase in the other HIV-associated infections. Other non-typhoid Salmonella bacteraemias increased two years after the rise in group D infections, and invasive yeast infections increased four years later, coincident with the increase in AIDS. Increasing Group D non-typhoid Salmonella bloodstream infections are an early warning signal of an impending rise in AIDS.

  2. The first reported catheter-related Brevibacterium casei bloodstream infection in a child with acute leukemia and review of the literature.

    Science.gov (United States)

    Bal, Zumrut Sahbudak; Sen, Semra; Karapinar, Deniz Yilmaz; Aydemir, Sohret; Vardar, Fadil

    2015-01-01

    Brevibacterium spp. are catalase-positive, non-spore-forming, non motile, aerobic Gram-positive rods that were considered apathogenic until a few reports of infections in immunocompromised patients had been published. To the best of our knowledge, this is the first report of B. casei catheter-related bloodstream infection in a child with acute leukemia. We aim to enhance the awareness of pediatric hematology and infectious disease specialists about this pathogen and review of the literature. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.

  3. Nosocomial bloodstream infections in ICU and non-ICU patients.

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    Suljagić, Vesna; Cobeljić, Miloje; Janković, Slavenka; Mirović, Veljko; Marković-Denić, Ljiljana; Romić, Predrag; Mikić, Dragan

    2005-08-01

    Nosocomial bloodstream infections (BSI) create a serious health problem in hospitals all over the world. The objectives of our study were to explore putative disease markers and potential risk factors with nosocomial BSI in patients in intensive care units (ICU) and non-ICU patients and to determine risk factors associated with increased 28-day mortality rate in patients with nosocomial BSI acquired in combined medical-surgical ICU. However, the major purposes of this report were to identify epidemiologic differences between nosocomial BSI acquired in ICU and non-ICU, as well as analyses outcomes for patients with nosocomial BSI acquired in ICU. A 1-year prospective cohort study was performed to determine the incidence of nosocomial BSI in hospitalized patients. Patient characteristics, risk factors related to health care, and source of infection of patients with BSI acquired in non-ICU were compared with those patient with BSI acquired in ICU. Also, nested case-control study of patients to nosocomial BSI acquired in ICU was performed to evaluate outcome. Patients were identified by active surveillance and positive blood culture during the study period. The incidence of nosocomial BSI was 2.2 per 1000 admission in non-ICU patients and 17.4 per 1000 admission in ICU patients. The 28-day crude mortality rate was 69% in ICU patients. A multivariate model showed that nasogastric tube (RR, 25.1; 95% CI: 3.845-163.85; P=.001), mechanical ventilation (RR, 13.04; 95% CI: 1.974-96.136; P=.008), and H2 blockers (RR, 12.16; 95% CI: 1.748-84.623; P=.012) were more prevalent among patients with BSI acquired in ICU, and aggressive procedures (RR, 8.65; 95% CI: 1.70-44.00; P=.009) were more prevalent among patients with BSI acquired in non-ICU patients. Risk factors independently associated with increased 28-day mortality rate in ICU patients were mechanical ventilation (OR, 8.63; 95% CI: 1.5-49.8; P=.016) and SAPS II >40 (OR, 6.0; 95% CI: 1.0-35.7; P=.049). The most common

  4. No gold standard estimation of the sensitivity and specificity of two molecular diagnostic protocols for Trypanosoma brucei spp. in Western Kenya.

    Directory of Open Access Journals (Sweden)

    Barend Mark de Clare Bronsvoort

    2010-01-01

    Full Text Available African animal trypanosomiasis is caused by a range of tsetse transmitted protozoan parasites includingTrypanosoma vivax, Trypanosoma congolense and Trypansoma brucei. In Western Kenya and other parts of East Africa two subspecies of T. brucei, T.b. brucei and the zoonoticT.b. rhodesiense, co-circulate in livestock. A range of polymerase chain reactions (PCR have been developed as important molecular diagnostic tools for epidemiological investigations of T. brucei s.l. in the animal reservoir and of its zoonotic potential. Quantification of the relative performance of different diagnostic PCRs is essential to ensure comparability of studies. This paper describes an evaluation of two diagnostic test systems for T. brucei using a T. brucei s.l. specific PCR [1] and a single nested PCR targeting the Internal Transcribed Spacer (ITS regions of trypanosome ribosomal DNA [2]. A Bayesian formulation of the Hui-Walter latent class model was employed to estimate their test performance in the absence of a gold standard test for detecting T.brucei s.l. infections in ear-vein blood samples from cattle, pig, sheep and goat populations in Western Kenya, stored on Whatman FTA cards. The results indicate that the system employing the T. brucei s.l. specific PCR (Se1=0.760 had a higher sensitivity than the ITS-PCR (Se2=0.640; both have high specificity (Sp1=0.998; Sp2=0.997. The true prevalences for livestock populations were estimated (pcattle=0.091, ppigs=0.066, pgoats=0.005, psheep=0.006, taking into account the uncertainties in the specificity and sensitivity of the two test systems. Implications of test performance include the required survey sample size; due to its higher sensitivity and specificity, the T. brucei s.l. specific PCR requires a consistently smaller sample size than the ITS-PCR for the detection of T. brucei s.l. However the ITS-PCR is able to simultaneously screen samples for other pathogenic trypanosomes and may thus be, overall, a better

  5. Diagnosis of human trypanosomiasis, due to Trypanosoma brucei gambiense in central Africa, by the polymerase chain reaction

    OpenAIRE

    Penchenier, Laurent; Simo, G.; Grébaut, Pascal; Nkinin, S.; Laveissière, Claude; Herder, Stéphane

    2000-01-01

    During a mass screening of sleeping sickness conducted in 1998 and 1999, and involving 27,932 persons in Cameroon and the Central African Republic, we tested the polymerase chain reaction (PCR) on whole blood for the diagnosis of human African trypanosomiasis due to #Trypanosoma brucei gambiense$. The 1858 samples obtained were from 4 groups : 155 infected patients, 1432 serological suspects detected by the card agglutination test for trypanosomiasis (CATT), 222 negative controls living in th...

  6. Reducing catheter-associated bloodstream infections in the pediatric intensive care unit: Business case for quality improvement.

    Science.gov (United States)

    Nowak, Jeffrey E; Brilli, Richard J; Lake, Michael R; Sparling, Karen W; Butcher, John; Schulte, Marion; Wheeler, Derek S

    2010-09-01

    To determine whether catheter-associated bloodstream infections were associated with increased lengths of stay in pediatric intensive care units and hospitals and increased healthcare costs in critically ill children. Previous studies have shown that hospital-acquired bloodstream infections are associated with longer stays in pediatric intensive care units, increased hospital costs, and increased hospital mortality. Catheter-associated bloodstream infections comprise the vast majority of hospital-acquired bloodstream infections. Retrospective, case-matched, cohort study and financial analysis. University-affiliated children's medical center. Twenty-two critically ill children with catheter-associated bloodstream infections and their matched controls. None. We compared the length of stay, mortality, and hospital costs in critically ill children with catheter-associated bloodstream infections and matched controls. The presence of catheter-associated bloodstream infections extended the entire hospital length of stay by 9 days (6.5 days while in the pediatric intensive care unit) and increased hospital costs by $33,039, primarily driven by the increase in length of stay days. Quality improvement efforts directed at reducing the prevalence of catheter-associated bloodstream infections during the period of study decreased total hospital days by 354, reduced total hospital costs by $1,298,271, and reduced total costs to payers by $1,415,676. The potential cost savings from reducing or eliminating catheter-associated bloodstream infections in the pediatric intensive care unit are significant. Elimination of catheter-associated bloodstream infections will directly reduce hospital costs, improve asset utilization, and most importantly, improve clinical care.

  7. Routine Surveillance for Bloodstream Infections in a Pediatric Hematopoietic Stem Cell Transplant Cohort: Do Patients Benefit?

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    Heather Rigby

    2007-01-01

    Full Text Available BACKGROUND: Hematopoietic stem cell transplant (HSCT recipients are at a high risk for late bloodstream infection (BSI. Controversy exists regarding the benefit of surveillance blood cultures in this immunosuppressed population. Despite the common use of this practice, the practical value is not well established in non-neutropenic children following HSCT.

  8. Characterization of third-generation cephalosporin-resistant Escherichia coli from bloodstream infections in Denmark

    DEFF Research Database (Denmark)

    Hansen, Frank; Olsen, Stefan S; Heltberg, Ole

    2014-01-01

    The aim of the study was to investigate the molecular epidemiology of 87 third-generation cephalosporin-resistant Escherichia coli (3GC-R Ec) from bloodstream infections in Denmark from 2009. Sixty-eight of the 87 isolates were extended-spectrum beta-lactamase (ESBL) producers, whereas 17 isolates...

  9. Early removal versus expectant management of central venous catheters in neonates with bloodstream infection.

    Science.gov (United States)

    Vasudevan, Chakrapani; Oddie, Sam J; McGuire, William

    2016-04-20

    Uncertainty exists regarding the management of newborn infants with a bloodstream infection and a central venous catheter in place. The central venous catheter may act as a nidus for infecting organisms and observational studies have suggested that early removal of the catheter is associated with a lower incidence of persistent or complicated infection. However, since central venous catheters provide secure vascular access to deliver nutrition and medications, the possible harms of early removal versus expectant management also need to be considered. To determine the effect of early removal versus expectant management of central venous catheters on morbidity and mortality in newborn infants with bloodstream infections. We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 11), MEDLINE (1966 to October 2015), EMBASE (1980 to October 2015), CINAHL (1982 to October 2015), conference proceedings and previous reviews. Randomised and quasi-randomised controlled trials that compared early removal versus expectant management of central venous catheters in neonates with bloodstream infections. We used the standard methods of the Cochrane Neonatal Review Group. We did not identify any eligible randomised controlled trials. There are no trial data to guide practice regarding early removal versus expectant management of central venous catheters in newborn infants with bloodstream infections. A simple and pragmatic randomised controlled trial is needed to resolve the uncertainty about optimal management in this common and important clinical scenario.

  10. Epidemiological investigation of Candida species causing bloodstream infection in paediatric small bowel transplant recipients.

    Science.gov (United States)

    Suhr, Mallory J; Gomes-Neto, João Carlos; Banjara, Nabaraj; Florescu, Diana F; Mercer, David F; Iwen, Peter C; Hallen-Adams, Heather E

    2017-06-01

    Small bowel transplantation (SBT) can be a life-saving medical procedure. However, these recipients experience high risk of bloodstream infections caused by Candida. This research aims to characterise the SBT recipient gut microbiota over time following transplantation and investigate the epidemiology of candidaemia in seven paediatric patients. Candida species from the recipients' ileum and bloodstream were identified by internal transcribed spacer sequence and distinguished to strain by multilocus sequence typing and randomly amplified polymorphic DNA. Antifungal susceptibility of bloodstream isolates was determined against nine antifungals. Twenty-two ileostomy samples harboured at least one Candida species. Fungaemia were caused by Candida parapsilosis, Candida albicans, Candida glabrata, Candida orthopsilosis and Candida pelliculosa. All but three bloodstream isolates showed susceptibility to all the antifungals tested. One C. glabrata isolate showed multidrug resistance to itraconazole, amphotericin B and posaconazole and intermediate resistance to caspofungin. Results are congruent with both endogenous (C. albicans, C. glabrata) and exogenous (C. parapsilosis) infections; results also suggest two patients were infected by the same strain of C. parapsilosis. Continuing to work towards a better understanding of sources of infection-particularly the exogenous sources-would lead to targeted prevention strategies. © 2017 Blackwell Verlag GmbH.

  11. Severe Community-Acquired Bloodstream Infection with Acinetobacter ursingii in Person who Injects Drugs.

    Science.gov (United States)

    Salzer, Helmut J F; Rolling, Thierry; Schmiedel, Stefan; Klupp, Eva-Maria; Lange, Christoph; Seifert, Harald

    2016-01-01

    We report a community-acquired bloodstream infection with Acinteobacter ursingii in an HIV-negative woman who injected drugs. The infection was successfully treated with meropenem. Species identification was performed by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Improved identification of Acinetobacter spp. by using this method will help identify clinical effects of this underdiagnosed pathogen.

  12. Virulence and antimicrobial resistance of Staphylococcus aureus isolated from bloodstream infections and pneumonia in Southern Poland

    NARCIS (Netherlands)

    Pomorska-Wesolowska, Monika; Chmielarczyk, Agnieszka; Chlebowicz, Monika; Ziolkowski, Grzegorz; Szczypta, Anna; Natkaniec, Joanna; Romaniszyn, Dorota; Pobiega, Monika; Dzikowska, Miroslawa; Krawczyk, Lech; Koziol, Joanna; Wojkowska-Mach, Jadwiga

    2017-01-01

    Objectives: Staphylococcus aureus remains the most important cause of infections in hospitals and long-term care facilities. The aim of this study was to analyse the resistance, virulence, and epidemiological and genetic relationships of S. aureus from bloodstream infections (BSIs) and pneumonia

  13. Weather parameters and nosocomial bloodstream infection: a case-referent study.

    Science.gov (United States)

    Caldeira, Silvia Maria; Cunha, Antonio Ribeiro da; Akazawa, Renata Tamie; Moreira, Rayana Gonçalves; Souza, Lenice do Rosário de; Fortaleza, Carlos Magno Castelo Branco

    2015-01-01

    OBJECTIVE To evaluate if temperature and humidity influenced the etiology of bloodstream infections in a hospital from 2005 to 2010. METHODS The study had a case-referent design. Individual cases of bloodstream infections caused by specific groups or pathogens were compared with several references. In the first analysis, average temperature and humidity values for the seven days preceding collection of blood cultures were compared with an overall "seven-days moving average" for the study period. The second analysis included only patients with bloodstream infections. Several logistic regression models were used to compare different pathogens and groups with respect to the immediate weather parameters, adjusting for demographics, time, and unit of admission. RESULTS Higher temperatures and humidity were related to the recovery of bacteria as a whole (versus fungi) and of gram-negative bacilli. In the multivariable models, temperature was positively associated with the recovery of gram-negative bacilli (OR = 1.14; 95%CI 1.10;1.19) or Acinetobacter baumannii (OR = 1.26; 95%CI 1.16;1.37), even after adjustment for demographic and admission data. An inverse association was identified for humidity. CONCLUSIONS The study documented the impact of temperature and humidity on the incidence and etiology of bloodstream infections. The results correspond with those from ecological studies, indicating a higher incidence of gram-negative bacilli during warm seasons. These findings should guide policies directed at preventing and controlling healthcare-associated infections.

  14. Community-acquired bloodstream infection caused by Pseudomonas paucimobilis: case report and review of the literature.

    OpenAIRE

    Morrison, A J; Shulman, J. A

    1986-01-01

    Various sources of Pseudomonas paucimobilis bacterial infections have been documented. We report the third human case of bloodstream infection due to P. paucimobilis and review the literature in English regarding community-acquired and nosocomial infection due to this bacterium. Biochemical and genetic characteristics supporting the pathogenic potential of P. paucimobilis are presented, and the antibiotic susceptibility profile of the organism is summarized.

  15. Patients with Central Lines - What You Need to Know to Avoid a Bloodstream Infection PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    2011-03-01

    This 60 second PSA is based on the March, 2011 CDC Vital Signs report which indicates bloodstream infections in patients with central lines are largely preventable when healthcare providers use CDC-recommended infection control steps.  Created: 3/1/2011 by Centers for Disease Control and Prevention (CDC).   Date Released: 3/1/2011.

  16. Identification of a bacterial-like HslVU protease in the mitochondria of Trypanosoma brucei and its role in mitochondrial DNA replication.

    Directory of Open Access Journals (Sweden)

    Ziyin Li

    2008-04-01

    Full Text Available ATP-dependent protease complexes are present in all living organisms, including the 26S proteasome in eukaryotes, Archaea, and Actinomycetales, and the HslVU protease in eubacteria. The structure of HslVU protease resembles that of the 26S proteasome, and the simultaneous presence of both proteases in one organism was deemed unlikely. However, HslVU homologs have been identified recently in some primordial eukaryotes, though their potential function remains elusive. We characterized the HslVU homolog from Trypanosoma brucei, a eukaryotic protozoan parasite and the causative agent of human sleeping sickness. TbHslVU has ATP-dependent peptidase activity and, like its bacterial counterpart, has essential lysine and N-terminal threonines in the catalytic subunit. By epitope tagging, TbHslVU localizes to mitochondria and is associated with the mitochondrial genome, kinetoplast DNA (kDNA. RNAi of TbHslVU dramatically affects the kDNA by causing over-replication of the minicircle DNA. This leads to defects in kDNA segregation and, subsequently, to continuous network growth to an enormous size. Multiple discrete foci of nicked/gapped minicircles are formed on the periphery of kDNA disc, suggesting a failure in repairing the gaps in the minicircles for kDNA segregation. TbHslVU is a eubacterial protease identified in the mitochondria of a eukaryote. It has a novel function in regulating mitochondrial DNA replication that has never been observed in other organisms.

  17. Proteins and lipids of glycosomal membranes from Leishmania tarentolae and Trypanosoma brucei [v1; ref status: indexed, http://f1000r.es/x1

    Directory of Open Access Journals (Sweden)

    Claudia Colasante

    2013-01-01

    Full Text Available In kinetoplastid protists, several metabolic pathways, including glycolysis and purine salvage, are located in glycosomes, which are microbodies that are evolutionarily related to peroxisomes. With the exception of some potential transporters for fatty acids, and one member of the mitochondrial carrier protein family, proteins that transport metabolites across the glycosomal membrane have yet to be identified. We show here that the phosphatidylcholine species composition of Trypanosoma brucei glycosomal membranes resembles that of other cellular membranes, which means that glycosomal membranes are expected to be impermeable to small hydrophilic molecules unless transport is facilitated by specialized membrane proteins. Further, we identified 464 proteins in a glycosomal membrane preparation from Leishmania tarentolae. The proteins included approximately 40 glycosomal matrix proteins, and homologues of peroxisomal membrane proteins - PEX11, GIM5A and GIM5B; PXMP4, PEX2 and PEX16 - as well as the transporters GAT1 and GAT3. There were 27 other proteins that could not be unambiguously assigned to other compartments, and that had predicted trans-membrane domains. However, no clear candidates for transport of the major substrates and intermediates of energy metabolism were found. We suggest that, instead, these metabolites are transported via pores formed by the known glycosomal membrane proteins.

  18. [Clinical features of invasive candidiasis and risk factors for Candida bloodstream infection in children: a multicenter study in Urumqi, China].

    Science.gov (United States)

    Ai Er Ken, Ai Bi Bai; Ma, Zhi-Hua; Xiong, Dai-Qin; Xu, Pei-Ru

    2017-04-01

    To investigate the clinical features of invasive candidiasis in children and the risk factors for Candida bloodstream infection. A retrospective study was performed on 134 children with invasive candidiasis and hospitalized in 5 tertiary hospitals in Urumqi, China, between January 2010 and December 2015. The Candida species distribution was investigated. The clinical data were compared between the patients with and without Candida bloodstream infection. The risk factors for Candida bloodstream infection were investigated using multivariate logistic regression analysis. A total of 134 Candida strains were isolated from 134 children with invasive candidiasis, and non-albicans Candida (NAC) accounted for 53.0%. The incidence of invasive candidiasis in the PICU and other pediatric wards were 41.8% and 48.5% respectively. Sixty-eight patients (50.7%) had Candida bloodstream infection, and 45 patients (33.6%) had Candida urinary tract infection. There were significant differences in age, rate of use of broad-spectrum antibiotics, and incidence rates of chronic renal insufficiency, heart failure, urinary catheterization, and NAC infection between the patients with and without Candida bloodstream infection (Pcandidiasis is similar between the PICU and other pediatric wards. NAC is the most common species of invasive candidiasis. Candida bloodstream infection is the most common invasive infection. Younger age (1-24 months) and NAC infection are the risk factors for Candida bloodstream infection.

  19. Nosocomial bloodstream infection in a neonatal intensive care unit of a medical center: a three-year review.

    Science.gov (United States)

    Tseng, Ya-Chun; Chiu, Yu-Chiao; Wang, Jen-Hsien; Lin, Hsiao-Chuan; Lin, Hung-Chih; Su, Bai-Horng; Chiu, Hsiu-Hui

    2002-09-01

    Bloodstream infections are the most frequent nosocomial infections in neonatal intensive care units. This retrospective study surveyed the epidemiologic characteristics of nosocomial bloodstream infections which occurred in the neonatal intensive care unit from January 1, 1997 to December 31, 1999. The overall infection patient rate was 5.5% in the 3-year period, and the overall infection patient-day rate was 4.4 per 1000 patient-days. Low birth weight was a risk factor for bloodstream infections. The rate of infection for neonates with birth weight below 1000 g ranged from 36.6% to 45.8% (1997: 36.6%; 1998: 45.8% and 1999: 38.9%). The most common pathogens causing nosocomial bloodstream infection were: Staphylococcus aureus (18.5%) (with 92% oxacillin-resistant), Acinectobacter baumannii (16.3%), Klebsiella pneumoniae (11.9%), Escherichia coli (9.6%), and Pseudomonas aeruginosa (8.1%). The mortality due to nosocomial bloodstream infection was highest among gram-negative bacteria, especially with P. aeruginosa (45.5%). Therefore, surveillance of nosocomial bloodstream infection and successful strategies to decrease nosocomial bloodstream infection, such as infection control and optimal antibiotic use, are warranted.

  20. Prevention of bloodstream infections by photodynamic inactivation of multiresistant Pseudomonas aeruginosa in burn wounds

    Science.gov (United States)

    Hashimoto, M. C. E.; Prates, R. A.; Toffoli, D. J.; Courrol, L. C.; Ribeiro, M. S.

    2010-02-01

    Bloodstream infections are potentially life-threatening diseases. They can cause serious secondary infections, and may result in endocarditis, severe sepsis or toxic-shock syndrome. Pseudomonas aeruginosa is an opportunistic pathogen and one of the most important etiological factors responsible for nosocomial infections, mainly in immuno-compromissed hosts, characteristic of patients with severe burns. Its multiresistance to antibiotics produces many therapeutic problems, and for this reason, the development of an alternative method to antibiotic therapy is needed. Photodynamic inactivation (PDI) may be an effective and alternative therapeutic option to prevent bloodstream infections in patients with severe burns. In this study we report the use of PDI to prevent bloodstream infections in mice with third-degree burns. Burns were produced on the back of the animals and they were infected with 109 cfu/mL of multi-resistant (MR) P. aeruginosa. Fifteen animals were divided into 3 groups: control, PDT blue and PDT red. PDT was performed thirty minutes after bacterial inoculation using 10μM HB:La+3 and a light-emitting diode (LED) emitting at λ=460nm+/-20nm and a LED emitting at λ=645 nm+/-10nm for 120s. Blood of mice were colected at 7h, 10h, 15h, 18h and 22h pos-infection (p.i.) for bacterial counting. Control group presented 1×104 cfu/mL in bloodstream at 7h p.i. increasing to 1×106 at 22h, while mice PDT-treated did not present any bacteria at 7h; only at 22h p.i. they presented 1×104cfu/mL. These results suggest that HB:La+3 associated to blue LED or red LED is effective to delay and diminish MR P.aeruginosa bloodstream invasion in third-degree-burned mice.

  1. Hyperglycemia at the Time of Acquiring Central Catheter-Associated Bloodstream Infections Is Associated With Mortality in Critically Ill Children.

    Science.gov (United States)

    Marsillio, Lauren E; Ginsburg, Sarah L; Rosenbaum, Cecilia H; Coffin, Susan E; Naim, Maryam Y; Priestley, Margaret A; Srinivasan, Vijay

    2015-09-01

    Hyperglycemia is common and may be a risk factor for nosocomial infections, including central catheter-associated bloodstream infections in critically ill children. It is unknown whether hyperglycemia at the time of acquiring central catheter-associated bloodstream infections in pediatric critical illness is associated with worse outcomes. We hypothesized that hyperglycemia (blood glucose concentration > 126 mg/dL [> 7 mmol/L]) at the time of acquiring central catheter-associated bloodstream infections (from 4 d prior to the day of first positive blood culture, i.e., central catheter-associated bloodstream infections) in critically ill children is common and associated with ICU mortality. Retrospective observational cohort study. Fifty-five-bed PICU and 26-bed cardiac ICU at an academic freestanding children's hospital. One hundred sixteen consecutively admitted critically ill children from January 1, 2008, to June 30, 2012, who were 0-21 years with central catheter-associated bloodstream infections were included. We excluded children with diabetes mellitus, metabolic disorders, and those with a "do not attempt resuscitation" order. None. The study cohort had an overall ICU mortality of 23%, with 48% of subjects developing hyperglycemia at the time of acquiring central catheter-associated bloodstream infections. Compared with survivors, nonsurvivors experienced more hyperglycemia both at the time of acquiring central catheter-associated bloodstream infections and subsequently. Median blood glucose at the time of acquiring central catheter-associated bloodstream infections was higher in nonsurvivors compared with survivors (139.5 mg/dL [7.7 mmol/L] vs 111 mg/dL [6.2 mmol/L]; p 7 mmol/L) during the 7 days following central catheter-associated bloodstream infections (in comparison to 45% of survivors; p = 0.03). After controlling for severity of illness and interventions, hyperglycemia at the time of acquiring central catheter-associated bloodstream infections

  2. Polysomes of Trypanosoma brucei: Association with Initiation Factors and RNA-Binding Proteins.

    Directory of Open Access Journals (Sweden)

    Cornelia Klein

    Full Text Available We report here the results of experiments designed to identify RNA-binding proteins that might be associated with Trypanosoma brucei polysomes. After some preliminary mass spectrometry of polysomal fractions, we investigated the distributions of selected tagged proteins using sucrose gradients and immunofluorescence. As expected, the polysomal fractions contained nearly all annotated ribosomal proteins, the translation-associated protein folding complex, and many translation factors, but also many other abundant proteins. Results suggested that cap-binding proteins EIF4E3 and EIF4E4 were associated with both free and membrane-bound polysomes. The EIF4E binding partners EIF4G4 and EIF4G3 were present but the other EIF4E and EIF4G paralogues were not detected. The dominant EIF4E in the polysomal fraction is EIF4E4 and very few polysomal mRNAs are associated with EIF4G. Thirteen potential mRNA-binding proteins were detected in the polysomes, including the known polysome-associated protein RBP42. The locations of two of the other proteins were tested after epitope tagging: RBP29 was in the nucleus and ZC3H29 was in the cytoplasm. Quantitative analyses showed that specific association of an RNA-binding protein with the polysome fraction in sucrose gradients will not be detected if the protein is in more than 25-fold molar excess over its target binding sites.

  3. Functional analysis of TOEFAZ1 uncovers protein domains essential for cytokinesis in Trypanosoma brucei.

    Science.gov (United States)

    Sinclair-Davis, Amy N; McAllaster, Michael R; de Graffenried, Christopher L

    2017-10-09

    The parasite Trypanosoma brucei is highly polarized, including a flagellum that is attached along the cell surface by the flagellum attachment zone (FAZ). During cell division, the new FAZ positions the cleavage furrow, which ingresses from the anterior tip of the cell towards the posterior. We recently identified Tip Of the Extending FAZ protein 1 (TOEFAZ1) as an essential protein in trypanosome cytokinesis. We analyzed the localization and function of TOEFAZ1 domains using overexpression and RNAi complementation. TOEFAZ1 comprises three domains with separable functions: an N-terminal α-helical domain that may be involved in FAZ recruitment, a central intrinsically disordered domain that retains the morphogenic kinase TbPLK at the new FAZ tip, and a C-terminal zinc finger domain necessary for TOEFAZ1 oligomerization. Both the N-terminal and C-terminal domains are essential for TOEFAZ1 function, but TbPLK retention at the FAZ is not necessary for cytokinesis. The feasibility of alternate cytokinetic pathways that do not employ TOEFAZ1 are also assessed. Our results show that TOEFAZ1 is a multimeric scaffold for recruiting proteins that control the timing and location of cleavage furrow ingression. © 2017. Published by The Company of Biologists Ltd.

  4. Isothermal microcalorimetry, a new tool to monitor drug action against Trypanosoma brucei and Plasmodium falciparum.

    Directory of Open Access Journals (Sweden)

    Tanja Wenzler

    Full Text Available Isothermal microcalorimetry is an established tool to measure heat flow of physical, chemical or biological processes. The metabolism of viable cells produces heat, and if sufficient cells are present, their heat production can be assessed by this method. In this study, we investigated the heat flow of two medically important protozoans, Trypanosoma brucei rhodesiense and Plasmodium falciparum. Heat flow signals obtained for these pathogens allowed us to monitor parasite growth on a real-time basis as the signals correlated with the number of viable cells. To showcase the potential of microcalorimetry for measuring drug action on pathogenic organisms, we tested the method with three antitrypanosomal drugs, melarsoprol, suramin and pentamidine and three antiplasmodial drugs, chloroquine, artemether and dihydroartemisinin, each at two concentrations on the respective parasite. With the real time measurement, inhibition was observed immediately by a reduced heat flow compared to that in untreated control samples. The onset of drug action, the degree of inhibition and the time to death of the parasite culture could conveniently be monitored over several days. Microcalorimetry is a valuable element to be added to the toolbox for drug discovery for protozoal diseases such as human African trypanosomiasis and malaria. The method could probably be adapted to other protozoan parasites, especially those growing extracellularly.

  5. Duplicated paralogous genes subject to positive selection in the genome of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Richard D Emes

    2008-05-01

    Full Text Available Whole genome studies have highlighted duplicated genes as important substrates for adaptive evolution. We have investigated adaptive evolution in this class of genes in the human parasite Trypanosoma brucei, as indicated by the ratio of non-synonymous (amino-acid changing to synonymous (amino acid retaining nucleotide substitution rates.We have identified duplicated genes that are most rapidly evolving in this important human parasite. This is the first attempt to investigate adaptive evolution in this species at the codon level. We identify 109 genes within 23 clusters of paralogous gene expansions to be subject to positive selection.Genes identified include surface antigens in both the mammalian and insect host life cycle stage suggesting that competitive interaction is not solely with the adaptive immune system of the mammalian host. Also surface transporters related to drug resistance and genes related to developmental progression are detected. We discuss how adaptive evolution of these genes may highlight lineage specific processes essential for parasite survival. We also discuss the implications of adaptive evolution of these targets for parasite biology and control.

  6. Further evidence from SSCP and ITS DNA sequencing support Trypanosoma evansi and Trypanosoma equiperdum as subspecies or even strains of Trypanosoma brucei.

    Science.gov (United States)

    Wen, Yan-Zi; Lun, Zhao-Rong; Zhu, Xing-Quan; Hide, Geoff; Lai, De-Hua

    2016-07-01

    The subgenus Trypanozoon includes three species Trypanosoma brucei, Trypanosoma evansi and Trypanosoma equiperdum, which are morphologically identical and indistinguishable even using some molecular methods. In this study, PCR-based single strand conformation polymorphism (PCR-SSCP) was used to analyze the ribosomal DNA of the Trypanozoon species. Data indicate different patterns of ITS2 fragments between T. brucei, T. evansi and T. equiperdum by SSCP. Furthermore, analysis of total ITS sequences within these three members of the subgenus Trypanozoon showed a high degree of homology using phylogenetic analysis but were polyphyletic in haplotype networks. These data provide novel nuclear evidence to further support the notion that T. evansi and T. equiperdum should be subspecies or even strains of T. brucei. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Detection of tumour cells in the bloodstream of patients with uveal melanoma: influence of surgical manipulation on the dissemination of tumour cells in the bloodstream.

    Science.gov (United States)

    Charitoudis, Georgios; Schuster, Ronny; Joussen, Antonia M; Keilholz, Ulrich; Bechrakis, Nikolaos E

    2016-04-01

    The detection of circulating tumour cells in the bloodstream before and after surgical manipulation, and the qualitative detection of potential shedding of tumour cells during surgical manipulation of patients with uveal melanoma. 202 patients treated for a newly diagnosed uveal melanoma were included in the study. Blood samples were acquired 24 h before and 30 min after the basic surgical steps. Detection of potential circulating melanoma cells was extrapolated from the presence of tyrosinase and MelanA/Mart1 transcripts by reverse transcription PCR. Based on the measurement of tyrosinase transcripts, as a result of the first and second surgical manipulation there were three and zero transitions from negative to positive respectively, while there were two and one transitions from positive to negative, respectively. According to MelanA/Mart1 transcripts, there were 19 and 5 transitions from negative to positive respectively, and 15 and 2 transitions from positive to negative, respectively. No statistically significant differences were documented, concerning the presence of circulating tumour cells in the blood samples acquired before and after the first surgical manipulation or the second one. The change in the percentage of patients with detected tumour cells in their bloodstream was not statistically significant. The frequent shifts from negative to positive samples as well as from positive to negative samples comparing preoperative to postoperative samples indicates discontinuous shedding or variation due to measurements close to the threshold of detection. As a conclusion, the surgical manipulation does not seem to have a measurable contribution to the spread of melanoma cells in the bloodstream. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  8. Author Details

    African Journals Online (AJOL)

    Guya, S. Vol 15, No 1 (2008) - Articles Pathogenicity of bloodstream and cerebrospinal fluid forms of Trypanosoma brucei rhodesiense in Swiss White Mice Abstract PDF. ISSN: 1022-9272. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

  9. African Journal of Health Sciences - Vol 15, No 1 (2008)

    African Journals Online (AJOL)

    Pathogenicity of bloodstream and cerebrospinal fluid forms of Trypanosoma brucei rhodesiense in Swiss White Mice · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. K Ndung'u, M Ngotho, J Kinyua, J Kagira, S Guya, J Ndung'u, G Murilla, 34-41.

  10. Bacterial bloodstream infections in a tertiary infectious diseases hospital in Northern Vietnam: aetiology, drug resistance, and treatment outcome

    NARCIS (Netherlands)

    Dat, V.Q.; Vu, H.N.; The, H. de; Nguyen, H.T.; Hoang, L.B.; Viet, D. Vu Tien; Bui, C.L.; Nguyen, K. Van; Nguyen, T.V.; Trinh, D.T.; Torre, A.; Doorn, H.R. van; Nadjm, B.; Wertheim, H.F.L.

    2017-01-01

    BACKGROUND: Bloodstream infections (BSIs) are associated with high morbidity and mortality worldwide. However their aetiology, antimicrobial susceptibilities and associated outcomes differ between developed and developing countries. Systematic data from Vietnam are scarce. Here we present aetiologic

  11. Antiseptic barrier cap effective in reducing central line-associated bloodstream infections : A systematic review and meta-analysis

    NARCIS (Netherlands)

    Voor In 't Holt, Anne F; Helder, Onno K; Vos, Margreet C; Schafthuizen, Laura; Sülz, Sandra; van den Hoogen, Agnes|info:eu-repo/dai/nl/343075156; Ista, Erwin

    2017-01-01

    BACKGROUND: Microorganisms can intraluminally access a central venous catheter via the catheter hub. The catheter hub should be appropriately disinfected to prevent central line-associated bloodstream infections (CLABSIs). However, compliance with the time-consuming manual disinfection process is

  12. Early oral switch therapy in low-risk Staphylococcus aureus bloodstream infection (SABATO) : Study protocol for a randomized controlled trial

    NARCIS (Netherlands)

    Kaasch, Achim J.; Fätkenheuer, Gerd; Prinz-Langenohl, Reinhild; Paulus, Ursula; Hellmich, Martin; Weiß, Verena; Jung, Norma; Rieg, Siegbert; Kern, Winfried V.; Seifert, Harald; Lewalter, Karl; Lemmen, Sebastian; Stijnis, Cornelis; Van der Meer, Jan; Soriano, Alex; Ruiz, Laura Morata; Arastéh, Keikawus; Stocker, Hartmut; Kluytmans, Jan; Veenemans, Jacobien; Brodt, Hans Reinhard; Stephan, Christoph; Wolf, Timo; Kessel, Johanna; Joost, Insa; Sinha, Bhanu; van Assen, Sander; Wilting, Kasper; Tobias Welte, Welte; Christiane Mölgen, Mölgen; Julia Freise, Freise; Brunkhorst, Frank; Pletz, Mathias; Hagel, Stefan; Becker, Christian; Frieling, Thomas; Kösters, Katrin; Reuter, Stefan; Hsiao, Mikai; Rupp, Jan; Dalhoff, Klaus; Turner, David; Snape, Susan; Crusz, Shanika; Venkatesan, Pradhib; Salzberger, Bernd; Hanses, Frank; Rodriguez-Baño, Jesùs; Méndez, Adoración Valiente; López-Cortés, Luis Eduardo; Cisneros, José Miguel; Navarro-Amuedo, Maria Dolores; Bonten, Marc; Oosterheert, Jan Jelrik; Ekkelenkamp, Miquel

    2015-01-01

    Background: Current guidelines recommend that patients with Staphylococcus aureus bloodstream infection (SAB) are treated with long courses of intravenous antimicrobial therapy. This serves to avoid SAB-related complications such as relapses, local extension and distant metastatic foci. However, in

  13. Diagnostic accuracy of loopamp Trypanosoma brucei detection kit for diagnosis of human African trypanosomiasis in clinical samples.

    Directory of Open Access Journals (Sweden)

    Patrick Mitashi

    Full Text Available BACKGROUND: Molecular methods have great potential for sensitive parasite detection in the diagnosis of human African trypanosomiasis (HAT, but the requirements in terms of laboratory infrastructure limit their use to reference centres. A recently developed assay detects the Trypanozoon repetitive insertion mobile element (RIME DNA under isothermal amplification conditions and has been transformed into a ready-to-use kit format, the Loopamp Trypanosoma brucei. In this study, we have evaluated the diagnostic performance of the Loopamp Trypanosoma brucei assay (hereafter called LAMP in confirmed T.b. gambiense HAT patients, HAT suspects and healthy endemic controls from the Democratic Republic of the Congo (DRC. METHODOLOGY/PRINCIPAL FINDINGS: 142 T.b. gambiense HAT patients, 111 healthy endemic controls and 97 HAT suspects with unconfirmed status were included in this retrospective evaluation. Reference standard tests were parasite detection in blood, lymph or cerebrospinal fluid. Archived DNA from blood of all study participants was analysed in duplicate with LAMP. Sensitivity of LAMP in parasitologically confirmed cases was 87.3% (95% CI 80.9-91.8% in the first run and 93.0% (95% CI 87.5-96.1% in the second run. Specificity in healthy controls was 92.8% (95% CI 86.4-96.3% in the first run and 96.4% (95% CI 91.1-98.6% in the second run. Reproducibility was excellent with a kappa value of 0.81. CONCLUSIONS/SIGNIFICANCE: In this laboratory-based study, the Loopamp Trypanosoma brucei Detection Kit showed good diagnostic accuracy and excellent reproducibility. Further studies are needed to assess the feasibility of its routine use for diagnosis of HAT under field conditions.

  14. New functions for parts of the Krebs cycle in procyclic Trypanosoma brucei, a cycle not operating as a cycle.

    Science.gov (United States)

    van Weelden, Susanne W H; van Hellemond, Jaap J; Opperdoes, Fred R; Tielens, Aloysius G M

    2005-04-01

    We investigated whether substrate availability influences the type of energy metabolism in procyclic Trypanosoma brucei. We show that absence of glycolytic substrates (glucose and glycerol) does not induce a shift from a fermentative metabolism to complete oxidation of substrates. We also show that glucose (and even glycolysis) is not essential for normal functioning and proliferation of pleomorphic procyclic T. brucei cells. Furthermore, absence of glucose did not result in increased degradation of amino acids. Variations in availability of glucose and glycerol did result, however, in adaptations in metabolism in such a way that the glycosome was always in redox balance. We argue that it is likely that, in procyclic cells, phosphoglycerate kinase is located not only in the cytosol, but also inside glycosomes, as otherwise an ATP deficit would occur in this organelle. We demonstrate that procyclic T. brucei uses parts of the Krebs cycle for purposes other than complete degradation of mitochondrial substrates. We suggest that citrate synthase plus pyruvate dehydrogenase and malate dehydrogenase are used to transport acetyl-CoA units from the mitochondrion to the cytosol for the biosynthesis of fatty acids, a process we show to occur in proliferating procyclic cells. The part of the Krebs cycle consisting of alpha-ketoglutarate dehydrogenase and succinyl-CoA synthetase was used for the degradation of proline and glutamate to succinate. We also demonstrate that the subsequent enzymes of the Krebs cycle, succinate dehydrogenase and fumarase, are most likely used for conversion of succinate into malate, which can then be used in gluconeogenesis.

  15. Trypanosoma brucei RAP1 maintains telomere and subtelomere integrity by suppressing TERRA and telomeric RNA:DNA hybrids.

    Science.gov (United States)

    Nanavaty, Vishal; Sandhu, Ranjodh; Jehi, Sanaa E; Pandya, Unnati M; Li, Bibo

    2017-06-02

    Trypanosoma brucei causes human African trypanosomiasis and regularly switches its major surface antigen, VSG, thereby evading the host's immune response. VSGs are monoallelically expressed from subtelomeric expression sites (ESs), and VSG switching exploits subtelomere plasticity. However, subtelomere integrity is essential for T. brucei viability. The telomeric transcript, TERRA, was detected in T. brucei previously. We now show that the active ES-adjacent telomere is transcribed. We find that TbRAP1, a telomere protein essential for VSG silencing, suppresses VSG gene conversion-mediated switching. Importantly, TbRAP1 depletion increases the TERRA level, which appears to result from longer read-through into the telomere downstream of the active ES. Depletion of TbRAP1 also results in more telomeric RNA:DNA hybrids and more double strand breaks (DSBs) at telomeres and subtelomeres. In TbRAP1-depleted cells, expression of excessive TbRNaseH1, which cleaves the RNA strand of the RNA:DNA hybrid, brought telomeric RNA:DNA hybrids, telomeric/subtelomeric DSBs and VSG switching frequency back to WT levels. Therefore, TbRAP1-regulated appropriate levels of TERRA and telomeric RNA:DNA hybrid are fundamental to subtelomere/telomere integrity. Our study revealed for the first time an important role of a long, non-coding RNA in antigenic variation and demonstrated a link between telomeric silencing and subtelomere/telomere integrity through TbRAP1-regulated telomere transcription. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  16. Current strategies for the prevention and management of central line-associated bloodstream infections

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    Zhuolin Han

    2010-11-01

    Full Text Available Zhuolin Han, Stephen Y Liang, Jonas MarschallDivision of Infectious Diseases, Washington University School of Medicine in St Louis, St Louis, MO, USAAbstract: Central venous catheters are an invaluable tool for diagnostic and therapeutic purposes in today’s medicine, but their use can be complicated by bloodstream infections (BSIs. While evidence-based preventive measures are disseminated by infection control associations, the optimal management of established central line-associated BSIs has been summarized in infectious diseases guidelines. We prepared an overview of the state-of-the-art of prevention and management of central line-associated BSIs and included topics such as the role of antibiotic-coated catheters, the role of catheter removal in the management, and a review of currently used antibiotic compounds and the duration of treatment.Keywords: central venous catheters, bloodstream infections, guidelines, prevention

  17. Cluster of Candida parapsilosis primary bloodstream infection in a neonatal intensive care unit

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    Carmem Lúcia P. da Silva

    Full Text Available Candida parapsilosis is an increasingly important bloodstream pathogen in neonatal intensive care units (NICU. We investigated a cluster of bloodstream infections in a NICU to determine whether nosocomial transmission occurred. During a 3-day period, 3 premature infants hospitalized in the same unit presented with sepsis caused by C. parapsilosis. Electrophoretic karyotype of the organisms was performed by using pulsed field gel electrophoresis in a countour-clamped homogeneous electric field system. The isolate from 1 newborn could not be typed, and the isolates from the remaining 2 infants had identical patterns. All 3 cases are described. We conclude that nosocomial transmission of C. parapsilosis occurred and that neonates under intensive care may represent a risk group for this pathogen.

  18. Cluster of Candida parapsilosis primary bloodstream infection in a neonatal intensive care unit

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    Silva Carmem Lúcia P. da

    2001-01-01

    Full Text Available Candida parapsilosis is an increasingly important bloodstream pathogen in neonatal intensive care units (NICU. We investigated a cluster of bloodstream infections in a NICU to determine whether nosocomial transmission occurred. During a 3-day period, 3 premature infants hospitalized in the same unit presented with sepsis caused by C. parapsilosis. Electrophoretic karyotype of the organisms was performed by using pulsed field gel electrophoresis in a countour-clamped homogeneous electric field system. The isolate from 1 newborn could not be typed, and the isolates from the remaining 2 infants had identical patterns. All 3 cases are described. We conclude that nosocomial transmission of C. parapsilosis occurred and that neonates under intensive care may represent a risk group for this pathogen.

  19. [Risk factors for bloodstream infections in liver or kidney transplantation recipients].

    Science.gov (United States)

    Wan, Qiquan; Xiao, Xuefei; Ye, Qifa; Zhou, Jiandang

    2012-09-01

    To investigate the possible risk factors for death among liver or kidney recipients with bloodstream infections (BSIs). A retrospective study of 138 episodes of bloodstream infections documented in 103 patients was conducted to assess potential risk factors for mortality. The risk factors were identified by logistic regression analysis. The mean age of the patients was 12-66 (42.3±12.7) years. The majority of infections were nosocomial (78.6%). The BSIs-related mortality rate was 39.8% (41/103). The following variables were identified as risk factors for BSIs-related mortality by univariate analysis: intraabdominal/ biliary focus (P=0.003), polymicrobial infection (Prisk factors for increased

  20. Prevention of catheter-related bloodstream infections in patients on hemodialysis: challenges and management strategies

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    Soi V

    2016-04-01

    Full Text Available Vivek Soi, Carol L Moore, Lalathakasha Kumbar, Jerry Yee Division of Nephrology and Hypertension, Henry Ford Health System, Detroit, MI, USA Abstract: Catheter-related bloodstream infections are a significant source of morbidity and mortality in the end-stage renal disease population. Although alternative accesses to undergoing renal replacement therapy exist, many patients begin hemodialysis with a dialysis catheter due to logistic and physiologic factors involved in arteriovenous fistula creation and maturation. Colonization of catheters via skin flora leads to the production of biofilm, which acts as a reservoir for virulent bacteria. Preventative therapies center on appropriate catheter maintenance, infection control measures, and early removal of devices as patients transition to other access. Despite best efforts, when conservative measures fail to prevent infections in a high-risk population, antimicrobial lock therapy should be considered as an option to combat catheter-related bloodstream infections. Keywords: hemodialysis, CRBSI, catheter, end-stage renal disease, ESRD

  1. Is an increased dwell time of a peripherally inserted catheter associated with an increased risk of bloodstream infection in infants?

    Science.gov (United States)

    Smith, P Brian; Benjamin, Daniel K; Cotten, C Michael; Schultz, Eric; Guo, Rose; Nowell, Lisa; Smithwick, Mary Laura; Thornburg, Courtney D

    2008-08-01

    To estimate the risk of bloodstream infection associated with catheter dwell time in infants. Retrospective study. Duke University Medical Center neonatal intensive care unit, an academic, level 3 nursery in Durham, North Carolina. A case of catheter-associated bloodstream infection was defined as one that occurred in an infant whose culture-positive blood sample was collected more than 24 hours after catheter insertion or within 72 hours after catheter removal. We used multivariable logistic regression to control for the catheter's position and dwell time as well as the infant's sex, gestational age, age at time of catheter insertion, birth weight, and weight at time of catheter insertion. We identified 135 cases of catheter-associated bloodstream infection. The mean catheter dwell time was 12.2 days (range, 0-113 days), and the mean time to bloodstream infection was 10.8 days (range, 1-57 days). An increase in catheter dwell time was associated with a lower risk of bloodstream infection (odds ratio, 0.975 [95% confidence interval, 0.954-0.996]; P = .02). No increased risk of catheter-associated bloodstream infection was observed with increased catheter dwell time. This may have been due to the infant's improved nutrition, decreased need for other invasive devices, and maturing skin and immune system as catheter dwell time increased.

  2. 3D Architecture of the Trypanosoma brucei Flagella Connector, a Mobile Transmembrane Junction.

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    Johanna L Höög

    2016-01-01

    Full Text Available Cellular junctions are crucial for the formation of multicellular organisms, where they anchor cells to each other and/or supportive tissue and enable cell-to-cell communication. Some unicellular organisms, such as the parasitic protist Trypanosoma brucei, also have complex cellular junctions. The flagella connector (FC is a three-layered transmembrane junction that moves with the growing tip of a new flagellum and attaches it to the side of the old flagellum. The FC moves via an unknown molecular mechanism, independent of new flagellum growth. Here we describe the detailed 3D architecture of the FC suggesting explanations for how it functions and its mechanism of motility.We have used a combination of electron tomography and cryo-electron tomography to reveal the 3D architecture of the FC. Cryo-electron tomography revealed layers of repetitive filamentous electron densities between the two flagella in the interstitial zone. Though the FC does not change in length and width during the growth of the new flagellum, the interstitial zone thickness decreases as the FC matures. This investigation also shows interactions between the FC layers and the axonemes of the new and old flagellum, sufficiently strong to displace the axoneme in the old flagellum. We describe a novel filament, the flagella connector fibre, found between the FC and the axoneme in the old flagellum.The FC is similar to other cellular junctions in that filamentous proteins bridge the extracellular space and are anchored to underlying cytoskeletal structures; however, it is built between different portions of the same cell and is unique because of its intrinsic motility. The detailed description of its structure will be an important tool to use in attributing structure / function relationships as its molecular components are discovered in the future. The FC is involved in the inheritance of cell shape, which is important for the life cycle of this human parasite.

  3. 3D Architecture of the Trypanosoma brucei Flagella Connector, a Mobile Transmembrane Junction

    Science.gov (United States)

    Höög, Johanna L.; Lacomble, Sylvain; Bouchet-Marquis, Cedric; Briggs, Laura; Park, Kristin; Hoenger, Andreas; Gull, Keith

    2016-01-01

    Background Cellular junctions are crucial for the formation of multicellular organisms, where they anchor cells to each other and/or supportive tissue and enable cell-to-cell communication. Some unicellular organisms, such as the parasitic protist Trypanosoma brucei, also have complex cellular junctions. The flagella connector (FC) is a three-layered transmembrane junction that moves with the growing tip of a new flagellum and attaches it to the side of the old flagellum. The FC moves via an unknown molecular mechanism, independent of new flagellum growth. Here we describe the detailed 3D architecture of the FC suggesting explanations for how it functions and its mechanism of motility. Methodology/Principal Findings We have used a combination of electron tomography and cryo-electron tomography to reveal the 3D architecture of the FC. Cryo-electron tomography revealed layers of repetitive filamentous electron densities between the two flagella in the interstitial zone. Though the FC does not change in length and width during the growth of the new flagellum, the interstitial zone thickness decreases as the FC matures. This investigation also shows interactions between the FC layers and the axonemes of the new and old flagellum, sufficiently strong to displace the axoneme in the old flagellum. We describe a novel filament, the flagella connector fibre, found between the FC and the axoneme in the old flagellum. Conclusions/Significance The FC is similar to other cellular junctions in that filamentous proteins bridge the extracellular space and are anchored to underlying cytoskeletal structures; however, it is built between different portions of the same cell and is unique because of its intrinsic motility. The detailed description of its structure will be an important tool to use in attributing structure / function relationships as its molecular components are discovered in the future. The FC is involved in the inheritance of cell shape, which is important for the life

  4. Virulence and pathogenicity of three Trypanosoma brucei rhodesiense stabilates in a Swiss white mouse model

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    Christopher Kariuki

    2015-05-01

    Full Text Available Background: A key objective in basic research on human African trypanosomiasis (HAT is developing a cheap and reliable experimental model of the disease for use in pathogenesis and drug studies.Objective: With a view to improving current models, a study was undertaken to characterise the virulence and pathogenicity of three Trypanosoma brucei rhodesiense stabilates, labelled as International Livestock Research Institute (ILRI-2918, ILRI-3953, and Institute of Primate Research (IPR-001, infected into Swiss white mice.Methods: Swiss white mice were infected intraperitoneally with trypanosomes and observedfor parasitaemia using wet blood smears obtained by tail snipping. Induction of late-stagedisease was undertaken using diminazene aceturate (40 mg/kg, Berenil with curativetreatment done using melarsoprol (3.6 mg/kg, Arsobal.Results: The prepatent period for the stabilates ranged from three to four days with mean peak parasitaemia ranging from Log10 6.40 to 8.36. First peak parasitaemia for all stabilates varied between six and seven days post infection (DPI followed by secondary latency in ILRI-2918 (15–17 DPI and IPR-001 (17–19 DPI. Survival times ranged from six DPI (ILRI-3953 to 86 DPI (IPR-001. Hindleg paresis was observed in both ILRI-3953 (at peak parasitaemia and ILRI-2918 (after relapse parasitaemia. Mice infected with IPR-001 survived until 54 DPI when curative treatment was undertaken.Conclusions: This study demonstrated that the stabilates ILRI-2918 and ILRI-3953 were unsuitable for modelling late-stage HAT in mice. The stabilate IPR-001 demonstrated the potential to induce chronic trypanosomiasis in Swiss white mice for use in development of a late-stage model of HAT.

  5. Bacterial bloodstream infections in the allogeneic hematopoietic cell transplant patient: new considerations for a persistent nemesis.

    Science.gov (United States)

    Dandoy, C E; Ardura, M I; Papanicolaou, G A; Auletta, J J

    2017-08-01

    Bacterial bloodstream infections (BSI) cause significant transplant-related morbidity and mortality following allogeneic hematopoietic cell transplantation (allo-HCT). This manuscript reviews the risk factors for and the bacterial pathogens causing BSIs in allo-HCT recipients in the contemporary transplant period. In addition, it offers insight into emerging resistant pathogens and reviews clinical management considerations to treat and strategies to prevent BSIs in allo-HCT patients.

  6. INTERVENTIONS TO DECREASE CATHETER-ASSOCIATED BLOODSTREAM INFECTIONS IN NEWBORNS: AN INTEGRATIVE REVIEW

    OpenAIRE

    Curan, Gabriela Ramos Ferreira; Rossetto, Edilaine Giovanini

    2017-01-01

    ABSTRACT Objective: to perform an integrative review of strategies presented in care bundles to decrease central catheter-associated bloodstream infection among newborns. . Method a search was conducted of the Cochrane Library, IBECS, PubMed, Lilacs, Medline and Scielo catalogues, using the terms "bundle", "catheter-related infection", "infection control", "prevention", "evidence-based nursing"," evidence-based medicine" and" central venous catheter". Inclusion criteria were: papers publish...

  7. Tsukamurella catheter-related bloodstream infection in a pediatric patient with pulmonary hypertension

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    Kristen A. Wendorf

    2010-03-01

    Full Text Available Catheter-related bloodstream infections (CR-BSI are important complications in patients with long-term indwelling central venous catheters. In this report, we present the case of a 14-year-old male with pulmonary hypertension treated with continuous treprostinil infusion, who presented with a CR-BSI caused by a Tsukamurella species. This case highlights the potential for this unusual organism to cause infection in immunocompetent patients.

  8. Efficacy of an infection control programme in reducing nosocomial bloodstream infections in a Senegalese neonatal unit.

    Science.gov (United States)

    Landre-Peigne, C; Ka, A S; Peigne, V; Bougere, J; Seye, M N; Imbert, P

    2011-10-01

    Neonatal nosocomial infections are public health threats in the developing world, and successful interventions are rarely reported. A before-and-after study was conducted in the neonatal unit of the Hôpital Principal de Dakar, Senegal to assess the efficacy of a multi-faceted hospital infection control programme implemented from March to May 2005. The interventions included clustering of nursing care, a simple algorithm for empirical therapy of suspected early-onset sepsis, minimal invasive care and promotion of early discharge of neonates. Data on nosocomial bloodstream infections, mortality, bacterial resistance and antibiotic use were collected before and after implementation of the infection control programme. One hundred and twenty-five infants were admitted immediately before the programme (Period 1, January-February 2005) and 148 infants were admitted immediately after the programme (Period 2, June-July 2005). The two groups of infants were comparable in terms of reason for admission and birth weight. After implementation of the infection control programme, the overall rate of nosocomial bloodstream infections decreased from 8.8% to 2.0% (P=0.01), and the rate of nosocomial bloodstream infections/patient-day decreased from 10.9 to 2.9/1000 patient-days (P=0.03). Overall mortality rates did not differ significantly. The proportion of neonates who received antimicrobial therapy for suspected early-onset sepsis decreased significantly from 100% to 51% of at-risk infants (Pnosocomial bloodstream infections, and the efficacy of these interventions was long-lasting. Such interventions could be extended to other low-income countries. Copyright © 2011 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  9. Risk factors of nosocomial bloodstream infections in surgical intensive care unit.

    Science.gov (United States)

    Zhang, Xing; Tong, Meng-Meng; Zhang, Miao-Zun; Zhu, Hui-Peng

    2015-01-01

    Many studies have examined risk factors of nosocomial bloodstream infections. However risk factors of nosocomial bloodstream infections in surgical intensive care unit have never been reported. The aim of this study was to investigate this topic. Retrospective surgical intensive care unit patients' data were collected in a tertiary hospital from January 2010 to August 2014. Infected and non-infected patients were compared with univariate analysis of categorical variables to obtain statistical significance risk factors. Then multivariate logistic regression analysis was performed to acquire the final risk factors. 98 patients were diagnosed with nosocomial bloodstream infections in total. Mortality rate was 29.6% (n=29). The data indicated gram-positive cocci were the main pathogens (64.3%; n=63). Multivariate logistic analysis indicated that age (>65 years old) (OR, 2.297; CI95, 0.870 to 6.062), acute physiology and chronic health evaluation II score (>18) (OR, 6.981; CI95, 2.330 to 15.865), multiple organ dysfunction score (>8) (OR, 9.857; CI95, 6.395 to 19.505), mechanical ventilation (OR, 4.583; CI95, 2.134 to 10.956), central venous catheter (OR, 5.875; CI95, 2.212 to 13.456) and selective surgery (OR, 3.455; CI95, 3.442-9.235) were risk factors of nosocomial BSI. Patients with nosocomial bloodstream infections in surgical intensive care unit setting often have a poor prognosis. Age (>65 years old), chronic health evaluation II score (>18), multiple organ dysfunction score (>8), usage of mechanical ventilation, central venous catheter and selective surgery can be regarded as risk factors.

  10. Protein A Suppresses Immune Responses during Staphylococcus aureus Bloodstream Infection in Guinea Pigs

    Science.gov (United States)

    Kim, Hwan Keun; Falugi, Fabiana; Thomer, Lena; Missiakas, Dominique M.

    2015-01-01

    ABSTRACT   Staphylococcus aureus infection is not associated with the development of protective immunity, and disease relapses occur frequently. We hypothesize that protein A, a factor that binds immunoglobulin Fcγ and cross-links VH3 clan B cell receptors (IgM), is the staphylococcal determinant for host immune suppression. To test this, vertebrate IgM was examined for protein A cross-linking. High VH3 binding activity occurred with human and guinea immunoglobulin, whereas mouse and rabbit immunoglobulins displayed little and no binding, respectively. Establishing a guinea pig model of S. aureus bloodstream infection, we show that protein A functions as a virulence determinant and suppresses host B cell responses. Immunization with SpAKKAA, which cannot bind immunoglobulin, elicits neutralizing antibodies that enable guinea pigs to develop protective immunity. Importance  Staphylococcus aureus is the leading cause of soft tissue and bloodstream infections; however, a vaccine with clinical efficacy is not available. Using mice to model staphylococcal infection, earlier work identified protective antigens; however, corresponding human clinical trials did not reach their endpoints. We show that B cell receptor (IgM) cross-linking by protein A is an important immune evasion strategy of S. aureus that can be monitored in a guinea pig model of bloodstream infection. Further, immunization with nontoxigenic protein A enables infected guinea pigs to elicit antibody responses that are protective against S. aureus. Thus, the guinea pig model may support preclinical development of staphylococcal vaccines. PMID:25564466

  11. Second-Generation central venous catheter in the prevention of bloodstream infection: a systematic review

    Directory of Open Access Journals (Sweden)

    Janislei Gislei Dorociaki Stocco

    Full Text Available Abstract Objective: to evaluate the effectiveness and safety in the use of second-generation central venous catheters impregnated in clorhexidine and silver sulfadiazine when compared with other catheters, being them impregnated or not, in order to prevent the bloodstream infection prevention. Method: systematic review with meta-analysis. Databases searched: MEDLINE, EMBASE, CINAHL, LILACS/SciELO, Cochrane CENTRAL; search in Congress Proceedings and records from Clinical Trials. Results: 1.235 studies were identified, 97 were pre-selected and 4 were included. In catheter-related bloodstream infection, there was no statistical significance between second-generation impregnated catheter compared with the non-impregnated ones, absolute relative risk 1,5% confidence interval 95% (3%-1%, relative risk 0,68 (confidence interval 95%, 0,40-1,15 and number needed to treat 66. In the sensitivity analysis, there was less bloodstream infection in impregnated catheters (relative risk 0,50, confidence interval 95%, 0,26-0,96. Lower colonization, absolute relative risk 9,6% (confidence interval 95%, 10% to 4%, relative risk 0,51 (confidence interval 95% from 0,38-0,85 and number needed to treat 5. Conclusion: the use of second-generation catheters was effective in reducing the catheter colonization and infection when a sensitivity analysis is performed. Future clinical trials are suggested to evaluate sepsis rates, mortality and adverse effects.

  12. [Nosocomial bloodstream infections caused by gram-negative bacilli: epidemiology and risk factors for mortality].

    Science.gov (United States)

    Lizaso, Diego; Aguilera C, Karina; Correa, Malena; Yantorno, María Laura; Cuitiño, Mario; Pérez, Lorena; Lares, Mónica; Parra, Gloria de la; Esposto, Amadeo

    2008-10-01

    Nosocomial bacteremia is a major cause of hospital infection, associated with high rate of morbidity and mortality, prolonged hospital stay and higher costs. However, few prospective studies analyse the prognostic factors associated with mortality of gramnegative rods bloodstream infections in hospital wards outside of intensive care units. A prospective/descriptive study was conducted from March to December 2006. All patients with nosocomial-acquired bloodstream infection due to gramnegative rods were included. Epidemiology and clinical features were analysed as potential prognostic factors for mortality. During the study period, 84 cases were detected, being A. baumannii, Burkholderia sp and E. coli the most frequent isolates, with a mortality of 48%>. Bacteremia derived from a high-mortality associated septic focus (RR 4.9, IC95%> 1.3 - 18.8) and admission to intensive care unit (RR 4.78, IC95%> 1.7- 13.1) were independent variables associated with mortality. Inappropriate empirical antibiotic treatment was not associated with greater risk of mortality. Nosocomial gramnegative bloodstream infections in our series were mainly due to non-fermentative bacilli and were associated with high mortality rates when their origin was a high risk septic focus or the patient was admitted to intensive care unit.

  13. Procalcitonin levels in gram-positive, gram-negative, and fungal bloodstream infections.

    Science.gov (United States)

    Leli, Christian; Ferranti, Marta; Moretti, Amedeo; Al Dhahab, Zainab Salim; Cenci, Elio; Mencacci, Antonella

    2015-01-01

    Procalcitonin (PCT) can discriminate bacterial from viral systemic infections and true bacteremia from contaminated blood cultures. The aim of this study was to evaluate PCT diagnostic accuracy in discriminating Gram-positive, Gram-negative, and fungal bloodstream infections. A total of 1,949 samples from patients with suspected bloodstream infections were included in the study. Median PCT value in Gram-negative (13.8 ng/mL, interquartile range (IQR) 3.4-44.1) bacteremias was significantly higher than in Gram-positive (2.1 ng/mL, IQR 0.6-7.6) or fungal (0.5 ng/mL, IQR 0.4-1) infections (P Gram-negatives from Gram-positives at the best cut-off value of 10.8 ng/mL and an AUC of 0.944 (95% CI 0.919-0.969, P Gram-negatives from fungi at the best cut-off of 1.6 ng/mL. Additional results showed a significant difference in median PCT values between Enterobacteriaceae and nonfermentative Gram-negative bacteria (17.1 ng/mL, IQR 5.9-48.5 versus 3.5 ng/mL, IQR 0.8-21.5; P Gram-negative from Gram-positive and fungal bloodstream infections. Nevertheless, its utility to predict different microorganisms needs to be assessed in further studies.

  14. In Silico Identification and in Vitro Activity of Novel Natural Inhibitors of Trypanosoma brucei Glyceraldehyde-3-phosphate-dehydrogenase

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    Fabian C. Herrmann

    2015-09-01

    Full Text Available As part of our ongoing efforts to identify natural products with activity against pathogens causing neglected tropical diseases, we are currently performing an extensive screening of natural product (NP databases against a multitude of protozoan parasite proteins. Within this project, we screened a database of NPs from a commercial supplier, AnalytiCon Discovery (Potsdam, Germany, against Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase (TbGAPDH, a glycolytic enzyme whose inhibition deprives the parasite of energy supply. NPs acting as potential inhibitors of the mentioned enzyme were identified using a pharmacophore-based virtual screening and subsequent docking of the identified hits into the active site of interest. In a set of 700 structures chosen for the screening, 13 (1.9% were predicted to possess significant affinity towards the enzyme and were therefore tested in an in vitro enzyme assay using recombinant TbGAPDH. Nine of these in silico hits (69% showed significant inhibitory activity at 50 µM, of which two geranylated benzophenone derivatives proved to be particularly active with IC50 values below 10 µM. These compounds also showed moderate in vitro activity against T. brucei rhodesiense and may thus represent interesting starting points for further optimization.

  15. In Silico Prediction and Experimental Evaluation of Furanoheliangolide Sesquiterpene Lactones as Potent Agents against Trypanosoma brucei rhodesiense

    Science.gov (United States)

    Da Costa, Fernando B.; Lopes, Norberto P.; Kaiser, Marcel; Brun, Reto

    2014-01-01

    As a continuation of our earlier study on the in vitro antiprotozoal activity of 40 natural sesquiterpene lactones (STLs), we extended the set of tested compounds from our laboratories to 59. On the basis of this extended data set, further enriched by literature data for 10 compounds tested under the same conditions, our quantitative structure-activity relationship (QSAR) analyses for activity against T. brucei rhodesiense (etiologic agent of human African trypanosomiasis, or sleeping sickness) were continued, and the QSAR model thus obtained with 69 structures was used to predict the activity of a virtual library of 1,750 STL structures. As a major result from these calculations, furanoheliangolide-type compounds, a subclass of STLs hitherto untested against T. brucei rhodesiense, were predicted to have an exceptionally high level of in vitro activity. Four representative compounds of this type, goyazensolide, 4,5-dihydro-2′,3′-epoxy-15-deoxygoyazensolide, budlein A, and 4,15-isoatriplicolide tiglate, were therefore tested. They displayed 50% inhibitory concentrations (IC50s) of 0.07, 0.20, 0.07, and 0.015 μM, respectively, so that the in silico prediction was experimentally confirmed. 4,15-Isoatriplicolide tiglate is the most potent STL against T. b. rhodesiense found. Furanoheliangolide STLs were thus identified as interesting leads against this parasite which deserve more detailed investigations. PMID:24165182

  16. Analysis of cosmid clones of nuclear DNA from Trypanosome brucei shows that the genes for variant surface glycoproteins are clustered in the genome.

    NARCIS (Netherlands)

    D. Valerio (Dinko); T. de Lange; P. Borst (Piet); F.G. Grosveld (Frank); L.H.T. van der Ploeg

    1982-01-01

    textabstractTrypanosoma brucei contains more than a hundred genes coding for the different variant surface glycoproteins (VSGs). Activation of some of these genes involves the duplication of the gene (the basic copy or BC) and transposition of the duplicate to an expression site (yielding the

  17. The mitochondrial FAD-dependent glycerol-3-phosphate dehydrogenase of Trypanosomatidae and the glycocomal redox balance of insect stages of Trypanosoma brucei and Leishmania spp.

    NARCIS (Netherlands)

    Guerra, D.G.; Decottignies, A.; Bakker, B.M.; Michels, P.A.M.

    2006-01-01

    The genes for the mitochondrial FAD-dependent glycerol-3-phosphate dehydrogenase were identified in Trypanosoma brucei and Leishmania major genomes. We have expressed the L. major gene in Saccharomyces cerevisiae and confirmed the subcellular localization and activity of the produced enzyme. Using

  18. Discovery of novel Trypanosoma brucei phosphodiesterase B1 inhibitors by virtual screening against the unliganded TbrPDEB1 crystal structure

    NARCIS (Netherlands)

    Jansen, C.; Wang, H.; Kooistra, A.J.; de Graaf, C.; Orrling, K.M.; Tenor, H.; Seebeck, T.; de Esch, I.J.P.; Ke, H.; Leurs, R.

    2013-01-01

    Trypanosoma brucei cyclic nucleotide phosphodiesterase B1 (TbrPDEB1) and TbrPDEB2 have recently been validated as new therapeutic targets for human African trypanosomiasis by both genetic and pharmacological means. In this study we report the crystal structure of the catalytic domain of the

  19. Trypanosoma brucei Plimmer & Bradford, 1899 is a synonym of T. evansi (Steel, 1885) according to current knowledge and by application of nomenclature rules.

    Science.gov (United States)

    Molinari, Jesús; Moreno, S Andrea

    2018-02-06

    Proper application of the principles of biological nomenclature is fundamental for scientific and technical communication about organisms. As other scientific disciplines, taxonomy inherently is open to change, thus species names cannot be final and immutable. Nevertheless, altering the names of organisms of high economical, medical, or veterinary importance can become a complex challenge between the scientific need to have correct classifications, and the practical ideal of having fixed classifications. Trypanosoma evansi (Steel, 1885), T. brucei Plimmer & Bradford, 1899 and T. equiperdum Doflein, 1901 are important parasites of mammals. According to current knowledge, the three names are synonyms of a single trypanosome species, the valid name of which should be T. evansi by the mandatory application of the Principle of Priority of zoological nomenclature. Subspecies known as T. brucei brucei Plimmer & Bradford, 1899, T. b. gambiense Dutton, 1902 and T. b. rhodesiense Stephens & Fantham, 1910 should be referred to respectively as T. evansi evansi (Steel, 1885), T. e. gambiense and T. e. rhodesiense. The polyphyletic groupings so far known as T. evansi and T. equiperdum should be referred respectively to as surra- and dourine-causing strains of T. e. evansi. Likewise, trypanosomes so far known as T. b. brucei should be referred to as nagana-causing strains of T. e. evansi. Though it modifies the scientific names of flagship human and animal parasites, the amended nomenclature proposed herein should be adopted because it reflects phylogenetic and biological advancements, fixes errors, and is simpler than the existing classificatory system.

  20. Immunospecific immunoglobulins and IL-10 as markers for Trypanosoma brucei rhodesiense late stage disease in experimentally infected vervet monkeys

    DEFF Research Database (Denmark)

    Ngotho, Maina; Kagira, J.M.; Jensen, Henrik Michael Elvang

    2009-01-01

    OBJECTIVE: To determine the usefulness of IL-10 and immunoglobulin M (IgM) as biomarkers for staging HAT in vervet monkeys, a useful pathogenesis model for humans. METHODS: Vervet monkeys were infected with Trypanosoma brucei rhodesiense and subsequently given sub-curative and curative treatment 28...

  1. The use of yellow fluorescent hybrids to indicate mating in Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Ferris Vanessa

    2008-02-01

    Full Text Available Abstract Background Trypanosoma brucei undergoes genetic exchange in its insect vector, the tsetse fly, by an unknown mechanism. The difficulties of working with this experimental system of genetic exchange have hampered investigation, particularly because the trypanosome life cycle stages involved cannot be cultured in vitro and therefore must be examined in the insect. Searching for small numbers of hybrid trypanosomes directly in the fly has become possible through the incorporation of fluorescent reporter genes, and we have previously carried out a successful cross using a reporter-repressor strategy. However, we could not be certain that all fluorescent trypanosomes observed in that cross were hybrids, due to mutations of the repressor leading to spontaneous fluorescence, and we have therefore developed an alternative strategy. Results To visualize the production of hybrids in the fly, parental trypanosome clones were transfected with a gene encoding Green Fluorescent Protein (GFP or Red Fluorescent Protein (RFP. Co-infection of flies with red and green fluorescent parental trypanosomes produced yellow fluorescent hybrids, which were easily visualized in the fly salivary glands. Yellow trypanosomes were not seen in midgut or proventricular samples and first appeared in the glands as epimastigotes as early as 13 days after fly infection. Cloned progeny originating from individual salivary glands had yellow, red, green or no fluorescence and were confirmed as hybrids by microsatellite, molecular karyotype and kinetoplast (mitochondrial DNA analyses. Hybrid clones showed biparental inheritance of both nuclear and kinetoplast genomes. While segregation and reassortment of the reporter genes and microsatellite alleles were consistent with Mendelian inheritance, flow cytometry measurement of DNA content revealed both diploid and polyploid trypanosomes among the hybrid progeny clones. Conclusion The strategy of using production of yellow hybrids

  2. Teaching Form as Form

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2012-01-01

    , this book offers both inspiration to teaching form and a systematic framework for pedagogical and didactical reflection on this topic. In this sense, it shapes and professionalizes design teaching, and contributes to the development of the double-professionalism, which is so essential for teachers in modern...... means that form serves both as the connective value and as the concept for reflection. In other words, form is observed as form, not anything else. The didactical challenge of teaching form as form is accentuated by students’ everyday-based pre-orientation towards function at the expense of form...... in this book that they are highly interested in both the declarative and formative dimension of making form. Methodologically, the courses described in the contributions have a strong focus on student-centered experiential activities, thereby implicitly claiming that students must learn to make form...

  3. Bacterial bloodstream infections in pediatric allogeneic hematopoietic stem cell recipients before and after implementation of a central line-associated bloodstream infection protocol: A single-center experience.

    Science.gov (United States)

    Chang, Alicia K; Foca, Marc D; Jin, Zhezhen; Vasudev, Rahul; Laird, Mary; Schwartz, Sharon; Qureshi, Mahvish; Kolb, Michelle; Levinson, Anya; Bhatia, Monica; Kung, Andrew; Garvin, James; George, Diane; Della-Latta, Phyllis; Whittier, Susan; Saiman, Lisa; Satwani, Prakash

    2016-12-01

    There are only few reports describing the influence of central line-associated bloodstream infection (CLABSI) prevention strategies on the incidence of bacterial bloodstream infections (BBSIs). We performed a retrospective cohort study among pediatric recipients of allogeneic hematopoietic stem cell transplantation (allo-HCT) to assess potential changes in BBSI rates during 3 time periods: pre-CLABSI prevention era (era 1, 2004-2005), CLABSI prevention implementation era (era 2, 2006-2009), and maintenance of CLABSI prevention era (era 3, 2010-2012). BBSI from day 0-365 following allo-HCT were studied. The comparison of person-years incidence rates among different periods was carried out by Poisson regression analysis. The mean age of patients was 10.0 years. During the study period, 126 (65%) of 190 patients had at least a single BBSI. From day 0-30, day 31-100, day 101-180, and day 181-365, 20%, 28%, 30%, and 17% of patients, respectively, experienced BBSIs. The rate of Staphylococcus epidermidis and gram-negative pathogens significantly declined from 3.16-0.93 and 6.32-2.21 per 100 person-months during era 1 and era 3, respectively (P = .001). Patients undergoing allo-HCT during era 3 were associated with decreased risk of BBSI (P = .012). Maintenance of CLABSI protocols by nursing staff and appropriate education of other care providers is essential to lower incidence of BBSI in this high-risk population, and further strategies to decrease infection burden should be studied. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  4. Sepsis from the gut: the enteric habitat of bacteria that cause late-onset neonatal bloodstream infections.

    Science.gov (United States)

    Carl, Mike A; Ndao, I Malick; Springman, A Cody; Manning, Shannon D; Johnson, James R; Johnston, Brian D; Burnham, Carey-Ann D; Weinstock, Erica Sodergren; Weinstock, George M; Wylie, Todd N; Mitreva, Makedonka; Abubucker, Sahar; Zhou, Yanjiao; Stevens, Harold J; Hall-Moore, Carla; Julian, Samuel; Shaikh, Nurmohammad; Warner, Barbara B; Tarr, Phillip I

    2014-05-01

    Late-onset sepsis is a major problem in neonatology, but the habitat of the pathogens before bloodstream invasion occurs is not well established. We examined prospectively collected stools from premature infants with sepsis to find pathogens that subsequently invaded their bloodstreams, and sought the same organisms in stools of infants without sepsis. Culture-based techniques were used to isolate stool bacteria that provisionally matched the bloodstream organisms, which were then genome sequenced to confirm or refute commonality. Of 11 children with late-onset neonatal bloodstream infections, 7 produced at least 1 stool that contained group B Streptococcus (GBS), Serratia marcescens, or Escherichia coli before their sepsis episode with provisionally matching organisms. Of 96 overlap comparison subjects without sepsis temporally associated with these cases, 4 were colonized with provisionally matching GBS or S. marcescens. Of 175 comparisons of stools from randomly selected infants without sepsis, 1 contained a GBS (this infant had also served as an overlap comparison subject and both specimens contained provisionally matching GBS). Genome sequencing confirmed common origin of provisionally matching fecal and blood isolates. The invasive E. coli were present in all presepticemic stools since birth, but gut colonization with GBS and S. marcescens occurred closer to time of bloodstream infection. The neonatal gut harbors sepsis-causing pathogens, but such organisms are not inevitable members of the normal microbiota. Surveillance microbiology, decolonization, and augmented hygiene might prevent dissemination of invasive bacteria between and within premature infants.

  5. Aquaporin 2 mutations in Trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol.

    Directory of Open Access Journals (Sweden)

    Fabrice E Graf

    Full Text Available The predominant mechanism of drug resistance in African trypanosomes is decreased drug uptake due to loss-of-function mutations in the genes for the transporters that mediate drug import. The role of transporters as determinants of drug susceptibility is well documented from laboratory-selected Trypanosoma brucei mutants. But clinical isolates, especially of T. b. gambiense, are less amenable to experimental investigation since they do not readily grow in culture without prior adaptation. Here we analyze a selected panel of 16 T. brucei ssp. field isolates that (i have been adapted to axenic in vitro cultivation and (ii mostly stem from treatment-refractory cases. For each isolate, we quantify the sensitivity to melarsoprol, pentamidine, and diminazene, and sequence the genomic loci of the transporter genes TbAT1 and TbAQP2. The former encodes the well-characterized aminopurine permease P2 which transports several trypanocides including melarsoprol, pentamidine, and diminazene. We find that diminazene-resistant field isolates of T. b. brucei and T. b. rhodesiense carry the same set of point mutations in TbAT1 that was previously described from lab mutants. Aquaglyceroporin 2 has only recently been identified as a second transporter involved in melarsoprol/pentamidine cross-resistance. Here we describe two different kinds of TbAQP2 mutations found in T. b. gambiense field isolates: simple loss of TbAQP2, or loss of wild-type TbAQP2 allele combined with the formation of a novel type of TbAQP2/3 chimera. The identified mutant T. b. gambiense are 40- to 50-fold less sensitive to pentamidine and 3- to 5-times less sensitive to melarsoprol than the reference isolates. We thus demonstrate for the first time that rearrangements of the TbAQP2/TbAQP3 locus accompanied by TbAQP2 gene loss also occur in the field, and that the T. b. gambiense carrying such mutations correlate with a significantly reduced susceptibility to pentamidine and melarsoprol.

  6. Risk factors for imipenem-nonsusceptible Acinetobacter nosocomialis bloodstream infection.

    Science.gov (United States)

    Huang, Lei; Chen, Te-Li; Lee, Yi-Tzu; Lee, Mei-Hui; Kuo, Shu-Chen; Yu, Kwok-Woon; Dou, Horng-Yunn; Fung, Chang-Phone

    2014-08-01

    The emergence of imipenem-nonsusceptible (INS) Acinetobacter baumannii complex has had a great impact on healthcare systems worldwide. Understanding the risk factors related to INS infection is useful for infection control. The risk factors for INS A. baumannii have been well documented; however, the risk factors related to INS Acinetobacter nosocomialis infection lack documentation. The purpose of this study was to identify the risk factors associated with INS A. nosocomialis bacteremia. This retrospective 9-year study included 329 adults with A. nosocomialis bacteremia in a tertiary medical center in Taiwan. Acinetobacter nosocomialis was identified using a multiplex polymerase chain reaction method and sequence analysis of a 16S-23S intergenic spacer. Among 329 patients with A. nosocomialis bacteremia, 67 had INS isolates (20.4%). Patients with INS isolates tended to have a more severe form of the diseases [with ICU admission and a higher APACHE (Acute Physiology and Chronic Health Evaluation) II score], specific underlying diseases (associated with chronic lung diseases and end-stage renal diseases, but less commonly alcoholism and chemotherapy), multiple invasive procedures, pneumonia as a primary focus of infection, and prior antimicrobial use (sulbactam, antipseudomonal penicillins, aminoglycosides, and carbapenems). Multivariable analysis showed that ICU admission, chronic lung diseases, arterial line catheterization, total parenteral nutrition, and prior use of carbapenems were independent risk factors; prior use of carbapenems was found to be the most influential (odds ratio 6.36, 95% confidence interval 2.00-20.21; p = 0.002). To our knowledge, this is the first study describing the risk factors associated with INS A. nosocomialis bacteremia. Regulated antibiotic control policy, especially for carbapenem, and infection control measures targeting patients hospitalized in ICU, with chronic lung diseases and multiple invasive procedures, may be helpful in

  7. Epidemic increase in Salmonella bloodstream infection in children, Bwamanda, the Democratic Republic of Congo.

    Science.gov (United States)

    Phoba, M-F; De Boeck, H; Ifeka, B B; Dawili, J; Lunguya, O; Vanhoof, R; Muyembe, J-J; Van Geet, C; Bertrand, S; Jacobs, J

    2014-01-01

    Salmonella enterica is the leading cause of bloodstream infection in children in sub-Saharan Africa, but few data are available from Central-Africa. We documented during the period November 2011 to May 2012 an epidemic increase in invasive Salmonella bloodstream infections in HGR Bwamanda, a referral hospital in Equateur Province, DR Congo. Salmonella spp. represented 90.4 % (103 out of 114) of clinically significant blood culture isolates and comprised Salmonella Typhimurium (54.4 %, 56 out of 103), Salmonella Enteritidis (28.2 %, 29 out of 103) and Salmonella Typhi (17.5 %, 18 out of 103), with Salmonella Enteritidis accounting for most of the increase. Most (82 out of 103, 79.6 %) isolates were obtained from children Salmonella Typhimurium and Salmonella Enteritidis were 14 months (14 days to 64 years) and 19 months (3 months to 8 years) respectively. Clinical presentation was non-specific; the in-hospital case fatality rate was 11.1 %. More than two thirds (69.7 %, 53 out of 76) of children Salmonella isolates as well as 6/18 (33.3 %) Salmonella Typhi isolates were multidrug resistant (i.e. resistant to the first-line oral antibiotics amoxicillin, trimethoprim-sulfamethoxazole and chloramphenicol), one (1.0 %) Salmonella Typhimurium had decreased ciprofloxacin susceptibility owing to a point mutation in the gyrA gene (Gly81Cys). Multilocus variable-number tandem-repeat (MLVA) analysis of the Salmonella Enteritidis isolates revealed closely related patterns comprising three major and four minor profiles, with differences limited to one out of five loci. These data show an epidemic increase in clonally related multidrug-resistant Salmonella bloodstream infection in children in DR Congo.

  8. Population-based assessment of the incidence, risk factors, and outcomes of anaerobic bloodstream infections.

    Science.gov (United States)

    Ngo, J T; Parkins, M D; Gregson, D B; Pitout, J D D; Ross, T; Church, D L; Laupland, K B

    2013-02-01

    Anaerobes are a relatively uncommon but important cause of bloodstream infection. However, their epidemiology has not been well defined in non-selected populations. We sought to describe the incidence of, risk factors for, and outcomes associated with anaerobic bacteremia. Population-based surveillance for bacteremia with anaerobic microorganisms was conducted in the Calgary area (population 1.2 million) during the period from 2000 to 2008. A total of 904 incident cases were identified, for an overall population incidence of 8.7 per 100,000 per year; 231 (26 %) were nosocomial, 300 (33 %) were healthcare-associated community-onset, and 373 (41 %) were community-acquired. Elderly males were at the greatest risk. The most common pathogens identified were: Bacteroides fragilis group (3.6 per 100,000), Clostridium (non-perfringens) spp. (1.1 per 100,000), Peptostreptococcus spp. (0.9 per 100,000), and Clostridium perfringens (0.7 per 100,000). Non-susceptibility to metronidazole was 2 %, to clindamycin 17 %, and to penicillin 42 %. Relative to the general population, risk factors for anaerobic bloodstream infection included: male sex, increasing age, a prior diagnosis of cancer, chronic liver disease, heart disease, diabetes mellitus, stroke, inflammatory bowel disease, human immunodeficiency virus (HIV) infection, chronic obstructive pulmonary disease (COPD), and/or hemodialysis-dependent chronic renal failure (HDCRF). The 30-day mortality was 20 %. Increasing age, nosocomial acquisition, presence of malignancy, and several other co-morbid illnesses were independently associated with an increased risk of death. Anaerobic bloodstream infection is responsible for a significant burden of disease in general populations. The data herein establish the extent to which anaerobes contribute to morbidity and subsequent mortality. This information is key in developing preventative, empiric treatment and research priorities.

  9. suPAR remains uninfluenced by surgery in septic patients with bloodstream infection

    Directory of Open Access Journals (Sweden)

    Rabensteiner, Jasmin

    2016-07-01

    Full Text Available Surgical trauma induces activation of the immune system and may cause an increase of inflammatory biomarkers tested postoperatively in septic patients treated for bloodstream infection. The aim of this study was to determine the impact of surgical interventions on the novel sepsis biomarker soluble urokinase plasminogen activator receptor (suPAR and to compare results with those of routine laboratory parameters CRP, PCT, and IL-6 in patients with culture-proven bloodstream infection. Forty-six adult patients with positive blood culture undergoing minor or major surgical intervention were investigated, 12 blood culture positive patients served as control group. Blood was collected 24 hours before and after surgical intervention for determination of the sepsis biomarkers suPAR, CRP, PCT, and IL-6. Within the surgical study cohort, a non-significant increase of suPAR, CRP, and PCT was observed postoperatively ( 0.642; 0.773; 0.087. In contrast, a slight decrease of IL-6 ( 0.599 was observed. A significant correlation was calculated for the pre- and postoperative difference of CRP ( 0.028 and PCT and type of surgical intervention received: after minor surgical intervention only PCT decreased significantly (<0.001, while after major surgical interventions no significant differences were observed for all biomarkers evaluated. In the control group, a significant decrease of CRP ( 0.005 and PCT ( 0.005 was observed. In patients treated adequately for bloodstream infections, postoperative suPAR levels remained uninfluenced of the surgical trauma and might therefore be a reliable parameter for postoperative infectious monitoring. After minor surgical intervention, PCT seems to be the most reliable parameter.

  10. Clinical analysis of bloodstream infections caused by Escherichia coli in elderly patients with hepatobiliary disease

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    WANG Qian

    2015-05-01

    Full Text Available ObjectiveTo investigate the clinical characteristics and drug resistance in elderly patients with hepatobiliary disease and bloodstream infections caused by Escherichia coli, and to provide a basis for clinical therapy. MethodsA retrospective analysis was performed on the clinical characteristics and drug susceptibility of 57 elderly inpatients with hepatobiliary disease and bloodstream infections caused by Escherichia coli in our hospital from 2009 to 2012. Comparison of continuous data between the two groups was made by t test, and comparison of categorical data was made by chi-square test. ResultsThe majority of patients had liver cirrhosis, and spontaneous bacterial peritonitis was the major infection source. A total of 57 strains of Escherichia coli were isolated from elderly patients with hepatobiliary disease, and 24 (421% out of them were positive for extended-spectrum β-lactamase (ESBL. ESBL-positive strains had a significantly higher level of drug resistance than ESBL-negative strains (P<0.05, except for imipenem/cilastatin, meropenem, cefoperazone/sulbactum, ticarcillin/clavulanate, and minocycline. However, there were no significant differences in age, gender, basic disease, infection source, peak body temperature, white blood cell count, and the percentage of neutrophils between the ESBL-positive group and the ESBL-negative group (P>0.05. The case-fatality rate in patients with septic shock, hepatic encephalopathy, or acute kidney injury was significantly higher than that in patients with no complications (χ2=9541,7622,9733,respectively, P<0.05. ConclusionElderly patients with hepatobiliary disease and bloodstream infections caused by ESBL-positive Escherichia coli had a high level of drug resistance and a poor prognosis for severe complications. Antibiotic therapy combined with prevention and control of severe complications should be taken as early as possible to reduce the case-fatality rate.

  11. Resistant patterns of bacteria isolated from bloodstream infections at a university hospital in Delhi

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    M S Alam

    2011-01-01

    Full Text Available Background : The choice of antimicrobial therapy for bloodstream infections is often empirical and based on the knowledge of local antimicrobial activity profiles of the most common bacteria causing such infections. Aims : The present study was aimed to investigate frequency of bacterial pathogens causing septicemia and their antimicrobial resistant pattern in hospital admitted patients. Settings and Design : It was a prospective study, conducted at Majeedia Hospital, Hamdard University, New Delhi, India. Material and Methods : We examined prospectively, 168 bacterial strains isolated from 186 clinically diagnosed septicemia cases admitted at a University Hospital in New Delhi, over a period of six months from July 2009 to December 2009. Antimicrobial susceptibility was performed according to Clinical and Laboratory Standards Institute (CLSI, USA guidelines. Results : The most frequently identified Gram-positive bacteria were coagulase-negative staphylococci 63.5%, Staphylococcus aureus 23.1%, enterococci 5.8% and alpha-haemolytic streptococci 5.8%. The most frequently Gram-negative bacteria identified were Acinetobacter species 31%, Salmonella typhi 24.1%, Escherichia coli 23.3% and Pseudomonas aeruginosa 13.8%. Coagulase-negative staphylococci showed maximum resistance to cefaclor 57.1% and ampicillin 46.9%. Staphylococcus aureus showed maximum resistance to amoxicillin 100% and ampicillin 91.7%. Acinetobacter species showed maximum resistance to amoxicillin 89.7%, amoxiclav 87.1% and ampicillin 85.7%. Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae showed maximum resistance to ampicillin, 46.4%, 92%, 93.8% and 100%, respectively. Conclusions : Gram-negative pathogens predominated in bloodstream infections. Resistance to most of the antimicrobial agents for a number of pathogens implicated in bloodstream infections, especially in Gram-negative bacteria, has reached worrisome levels and continues to increase.

  12. Procalcitonin Levels in Gram-Positive, Gram-Negative, and Fungal Bloodstream Infections

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    Christian Leli

    2015-01-01

    Full Text Available Procalcitonin (PCT can discriminate bacterial from viral systemic infections and true bacteremia from contaminated blood cultures. The aim of this study was to evaluate PCT diagnostic accuracy in discriminating Gram-positive, Gram-negative, and fungal bloodstream infections. A total of 1,949 samples from patients with suspected bloodstream infections were included in the study. Median PCT value in Gram-negative (13.8 ng/mL, interquartile range (IQR 3.4–44.1 bacteremias was significantly higher than in Gram-positive (2.1 ng/mL, IQR 0.6–7.6 or fungal (0.5 ng/mL, IQR 0.4–1 infections (P<0.0001. Receiver operating characteristic analysis showed an area under the curve (AUC for PCT of 0.765 (95% CI 0.725–0.805, P<0.0001 in discriminating Gram-negatives from Gram-positives at the best cut-off value of 10.8 ng/mL and an AUC of 0.944 (95% CI 0.919–0.969, P<0.0001 in discriminating Gram-negatives from fungi at the best cut-off of 1.6 ng/mL. Additional results showed a significant difference in median PCT values between Enterobacteriaceae and nonfermentative Gram-negative bacteria (17.1 ng/mL, IQR 5.9–48.5 versus 3.5 ng/mL, IQR 0.8–21.5; P<0.0001. This study suggests that PCT may be of value to distinguish Gram-negative from Gram-positive and fungal bloodstream infections. Nevertheless, its utility to predict different microorganisms needs to be assessed in further studies.

  13. Clinical and molecular epidemiology of Acinetobacter baumannii bloodstream infections in an endemic setting.

    Science.gov (United States)

    Marchaim, Dror; Levit, Dana; Zigron, Roy; Gordon, Michal; Lazarovitch, Tsillia; Carrico, Joao A; Chalifa-Caspi, Vered; Moran-Gilad, Jacob

    2017-03-01

    The transmission dynamics of Acinetobacter baumannii in endemic settings, and the relation between microbial properties and patients' clinical outcomes, are yet obscure and hampered by insufficient metadata. Of 20 consecutive patients with A. baumannii bloodstream infection that were thoroughly analyzed at a single center, at least one transmission opportunity was evident for 85% of patients. This implies that patient-to-patient transmission is the major mode of A. baumannii acquisitions in health facilities. Moreover, all patients who died immediately (baumannii ST457 lineage compared with other strains.

  14. Fatal Cases of Bloodstream Infection by Fusarium solani and Review of Published Literature.

    Science.gov (United States)

    Dabas, Yubhisha; Bakhshi, Sameer; Xess, Immaculata

    2016-04-01

    Fusarium species are ubiquitously present in environment and are well known as human pathogens with high mortality rate in immunocompromised patients. We report here two cases where immunocompromised patients developed fatal bloodstream infections by this organism. Isolates were further identified by ITS1 region sequencing which confirmed them as Fusarium solani. Antifungal susceptibility testing was done following CLSI M38-A2 guidelines to amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, caspofungin, and micafungin. Both patients had a fatal outcome and expired of septic shock. Therefore, identification up to species level is of utmost importance as that helps in directing the management of the patient thereby leading to a favourable outcome.

  15. Trends and outcome of nosocomial and community-acquired bloodstream infections due to Staphylococcus aureus in Finland, 1995-2001.

    Science.gov (United States)

    Lyytikäinen, O; Ruotsalainen, E; Järvinen, A; Valtonen, V; Ruutu, P

    2005-06-01

    In Finland, Staphylococcus aureus bloodstream infections are caused predominantly (>99%) by methicillin-sensitive strains. In this study, laboratory-based surveillance data on Staphylococcus aureus bloodstream infections occurring in Finland from 1995 to 2001 were analyzed. Preceding hospitalizations for all persons with Staphylococcus aureus bloodstream infections were obtained from the national hospital discharge registry, and data on outcome was obtained from the national population registry. An infection was defined as nosocomial when a positive blood culture was obtained more than 2 days after hospital admission or within 2 days of admission if there was a preceding hospital discharge within 7 days. A total of 5,045 cases were identified. The annual incidence of Staphylococcus aureus bloodstream infection rose by 55%, from 11 per 100,000 population in 1995 to 17 in 2001. The increase was detected in all adult age groups, though it was most distinct in patients >74 years of age. Nosocomial infections accounted for 51% of cases, a proportion that remained unchanged. The 28-day death-to-case ratio ranged from 1% in the age group 1-14 years to 33% in patients >74 years of age. The 28-day death-to-case ratios for nosocomial and community-acquired infections were 22% and 13%, respectively, and did not change over time. The increase in incidence among elderly persons resulted in an increase in the annual rate of mortality associated with Staphylococcus aureus bloodstream infections, from 2.6 to 4.2 deaths per 100,000 population per year. Staphylococcus aureus bloodstream infections are increasing in Finland, a country with a very low prevalence of methicillin resistance. While the increase may be due in part to increased reporting, it also reflects a growing population at risk, affected by such factors as high age and/or severe comorbidity.

  16. Crystal Structures of TbCatB and rhodesain, potential chemotherapeutic targets and major cysteine proteases of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Iain D Kerr

    2010-06-01

    Full Text Available Trypanosoma brucei is the etiological agent of Human African Trypanosomiasis, an endemic parasitic disease of sub-Saharan Africa. TbCatB and rhodesain are the sole Clan CA papain-like cysteine proteases produced by the parasite during infection of the mammalian host and are implicated in the progression of disease. Of considerable interest is the exploration of these two enzymes as targets for cysteine protease inhibitors that are effective against T. brucei.We have determined, by X-ray crystallography, the first reported structure of TbCatB in complex with the cathepsin B selective inhibitor CA074. In addition we report the structure of rhodesain in complex with the vinyl-sulfone K11002.The mature domain of our TbCat*CA074 structure contains unique features for a cathepsin B-like enzyme including an elongated N-terminus extending 16 residues past the predicted maturation cleavage site. N-terminal Edman sequencing reveals an even longer extension than is observed amongst the ordered portions of the crystal structure. The TbCat*CA074 structure confirms that the occluding loop, which is an essential part of the substrate-binding site, creates a larger prime side pocket in the active site cleft than is found in mammalian cathepsin B-small molecule structures. Our data further highlight enhanced flexibility in the occluding loop main chain and structural deviations from mammalian cathepsin B enzymes that may affect activity and inhibitor design. Comparisons with the rhodesain*K11002 structure highlight key differences that may impact the design of cysteine protease inhibitors as anti-trypanosomal drugs.

  17. Structural Characterization of CYP51 from Trypanosoma cruzi and Trypanosoma brucei Bound to the Antifungal Drugs Posaconazole and Fluconazole

    Science.gov (United States)

    Chen, Chiung-Kuang; Leung, Siegfried S. F.; Guilbert, Christophe; Jacobson, Matthew P.; McKerrow, James H.; Podust, Larissa M.

    2010-01-01

    Background Chagas Disease is the leading cause of heart failure in Latin America. Current drug therapy is limited by issues of both efficacy and severe side effects. Trypansoma cruzi, the protozoan agent of Chagas Disease, is closely related to two other major global pathogens, Leishmania spp., responsible for leishmaniasis, and Trypansoma brucei, the causative agent of African Sleeping Sickness. Both T. cruzi and Leishmania parasites have an essential requirement for ergosterol, and are thus vulnerable to inhibitors of sterol 14α-demethylase (CYP51), which catalyzes the conversion of lanosterol to ergosterol. Clinically employed anti-fungal azoles inhibit ergosterol biosynthesis in fungi, and specific azoles are also effective against both Trypanosoma and Leishmania parasites. However, modification of azoles to enhance efficacy and circumvent potential drug resistance has been problematic for both parasitic and fungal infections due to the lack of structural insights into drug binding. Methodology/Principal Findings We have determined the crystal structures for CYP51 from T. cruzi (resolutions of 2.35 Å and 2.27 Å), and from the related pathogen T. brucei (resolutions of 2.7 Å and 2.6 Å), co-crystallized with the antifungal drugs fluconazole and posaconazole. Remarkably, both drugs adopt multiple conformations when binding the target. The fluconazole 2,4-difluorophenyl ring flips 180° depending on the H-bonding interactions with the BC-loop. The terminus of the long functional tail group of posaconazole is bound loosely in the mouth of the hydrophobic substrate binding tunnel, suggesting that the major contribution of the tail to drug efficacy is for pharmacokinetics rather than in interactions with the target. Conclusions/Significance The structures provide new insights into binding of azoles to CYP51 and mechanisms of potential drug resistance. Our studies define in structural detail the CYP51 therapeutic target in T. cruzi, and offer a starting point for

  18. Diagnostic and predictive values of procalcitonin in bloodstream infections for nosocomial pneumonia.

    Science.gov (United States)

    Yan, Sheng Tao; Sun, Li Chao; Lian, Rui; Tao, Yong Kang; Zhang, Hong Bo; Zhang, Guoqiang

    2018-01-11

    We evaluated the diagnostic accuracy of PCT to distinguish between gram-negative (GN) and gram-positive (GP) bloodstream infections nosocomial pneumonia (NP) patients and compared PCT levels with the pneumonia severity index (PSI) for predicting mortality. Data were collected retrospectively for blood culture-positive NP patients between January 2014 and August 2016. PCT levels were compared between patients with GN versus GP infections. Outcome variables included 28- and 60-day mortality. PCT level was higher in GN infections than in GP infections. PCT could differentiate between GN and GP infections with an AUC value of 0.706. At a PCT cutoff of 5.4 ng/mL, the specificity for GN infections were 80.3%. The AUCs for 28- and 60-day mortality were 0.758 and 0.759 for PSI, and 0.620 and 0.634 for PCT. Serum PCT level was less predictive of mortality in GN NP patients compared with that for GP NP patients. There was a significantly positive correlation between PCT and PSI, and the correlation in GP NP patients was better than that in GN NP patients. PCT could differentiate between GN and GP bloodstream infections in patients with NP. However, PCT levels were less predictive of mortality compared with the PSI. Copyright © 2017. Published by Elsevier Inc.

  19. Muscle Releases Alpha-Sarcoglycan Positive Extracellular Vesicles Carrying miRNAs in the Bloodstream.

    Directory of Open Access Journals (Sweden)

    Michele Guescini

    Full Text Available In the past few years, skeletal muscle has emerged as an important secretory organ producing soluble factors, called myokines, that exert either autocrine, paracrine or endocrine effects. Moreover, recent studies have shown that muscle releases microRNAs into the bloodstream in response to physical exercise. These microRNAs affect target cells, such as hormones and cytokines. The mechanisms underlying microRNA secretion are poorly characterized at present. Here, we investigated whether muscle tissue releases extracellular vesicles (EVs, which carry microRNAs in the bloodstream under physiological conditions such as physical exercise. Using density gradient separation of plasma from sedentary and physically fit young men we found EVs positive for TSG101 and alpha-sarcoglycan (SGCA, and enriched for miR-206. Cytometric analysis showed that the SGCA+ EVs account for 1-5% of the total and that 60-65% of these EVs were also positive for the exosomal marker CD81. Furthermore, the SGCA-immuno captured sub-population of EVs exhibited higher levels of the miR-206/miR16 ratio compared to total plasma EVs. Finally, a significant positive correlation was found between the aerobic fitness and muscle-specific miRNAs and EV miR-133b and -181a-5p were significantly up-regulated after acute exercise. Thus, our study proposes EVs as a novel means of muscle communication potentially involved in muscle remodeling and homeostasis.

  20. Species distribution and antifungal susceptibility profile of Candida isolates from bloodstream infections in Lima, Peru.

    Science.gov (United States)

    Bustamante, B; Martins, M A; Bonfietti, L X; Szeszs, M W; Jacobs, J; Garcia, C; Melhem, M S C

    2014-06-01

    Yeast identification and in vitro susceptibility testing provide helpful information for appropriate administration of antifungal treatments; however, few reports from the Latin American region have been published. The aim of this study was to identify the species present in isolates from bloodstream infections diagnosed in nine hospitals in Lima, Peru and to determine their in vitro susceptibility to four antifungal drugs. We tested and identified 153 isolates collected between October 2009 and August 2011 using standard methods. PCR and PCR-RFLP assays were performed to distinguish Candida albicans from Candida dubliniensis and to identify species of the Candida parapsilosis and Candida glabrata complexes. Antifungal susceptibility testing for fluconazole, anidulafungin and voriconazole was performed using the CSLI M27-A3 method, and amphotericin B susceptibility was determined using the Etest method. The most frequently isolated species were: C. albicans (61; 39.9 %), C. parapsilosis (43; 28.1 %), C. tropicalis (36; 23.5%) and C. glabrata (8; 5.2 %). The overall susceptibility rates were 98.0 %, 98.7 %, 98.0 % and 97.4 % for amphotericin B, fluconazole, voriconazole and anidulafungin, respectively. No isolate was resistant to more than one drug. These results showed that the rate of resistance to four antifungal drugs was low among Candida bloodstream isolates in Lima, Peru. © 2014 The Authors.

  1. Risk factors for nosocomial bloodstream infection caused by multidrug resistant gram-negative bacilli in pediatrics

    Directory of Open Access Journals (Sweden)

    Mariana V. Arnoni

    Full Text Available The aim of this study was to identify the risk factors for nosocomial bloodstream infections by multidrug resistant Gram-negative bacilli. From November 2001 to December 2003, in the Pediatric Department of the Santa Casa de São Paulo, a retrospective case-control study was developed concerning patients who had nosocomial bloodstream infection caused by Gram-negative bacilli. Patients with multidrug resistant infections were designated as case patients, and control patients were those with an infection that did not meet the criteria for multidrug resistance. Previous use of central venous catheter and previous use of vancomycin plus third generation cephalosporins were associated to a higher chance of infections by multidrug resistant Gram-negative bacilli (Odds ratio - 5.8 and 5.2, respectively. Regarding sensitivity of the isolated agents, 47.8% were multidrug resistant, 54.2% were Klebsiella spp. ESBL producers and 36.4% were imipenem resistant Pseudomonas aeruginosa. The lethality rate was 36.9% in the studied cases and this rate was significantly higher in the group of patients with multidrug resistant infections (p=0.013. Risk factor identification as well as the knowledge of the susceptibility of the nosocomial infectious agents gave us the possibility to perform preventive and control strategies to reduce the costs and mortality related to these infections.

  2. Risk factors for nosocomial bloodstream infection caused by multidrug resistant gram-negative bacilli in pediatrics.

    Science.gov (United States)

    Arnoni, Mariana V; Berezin, Eitan N; Martino, Marinês D V

    2007-04-01

    The aim of this study was to identify the risk factors for nosocomial bloodstream infections by multidrug resistant Gram-negative bacilli. From November 2001 to December 2003, in the Pediatric Department of the Santa Casa de São Paulo, a retrospective case-control study was developed concerning patients who had nosocomial bloodstream infection caused by Gram-negative bacilli. Patients with multidrug resistant infections were designated as case patients, and control patients were those with an infection that did not meet the criteria for multidrug resistance. Previous use of central venous catheter and previous use of vancomycin plus third generation cephalosporins were associated to a higher chance of infections by multidrug resistant Gram-negative bacilli (Odds ratio--5.8 and 5.2, respectively). Regarding sensitivity of the isolated agents, 47.8% were multidrug resistant, 54.2% were Klebsiella spp. ESBL producers and 36.4% were imipenem resistant Pseudomonas aeruginosa. The lethality rate was 36.9% in the studied cases and this rate was significantly higher in the group of patients with multidrug resistant infections (p=0.013). Risk factor identification as well as the knowledge of the susceptibility of the nosocomial infectious agents gave us the possibility to perform preventive and control strategies to reduce the costs and mortality related to these infections.

  3. Determination of germ tube, phospholipase, and proteinase production by bloodstream isolates of Candida albicans

    Directory of Open Access Journals (Sweden)

    Antonella Souza Mattei

    2013-06-01

    Full Text Available Introduction Candida albicans is a commensal and opportunistic agent that causes infection in immunocompromised individuals. Several attributes contribute to the virulence and pathogenicity of this yeast, including the production of germ tubes (GTs and extracellular hydrolytic enzymes, particularly phospholipase and proteinase. This study aimed to investigate GT production and phospholipase and proteinase activities in bloodstream isolates of C. albicans. Methods One hundred fifty-three C. albicans isolates were obtained from blood samples and analyzed for GT, phospholipase, and proteinase production. The assays were performed in duplicate in egg yolk medium containing bovine serum albumin and human serum. Results Detectable amounts of proteinase were produced by 97% of the isolates, and 78% of the isolates produced phospholipase. GTs were produced by 95% of the isolates. A majority of the isolates exhibited low levels of phospholipase production and high levels of proteinase production. Conclusions Bloodstream isolates of C. albicans produce virulence factors such as GT and hydrolytic enzymes that enable them to cause infection under favorable conditions.

  4. Factors associated with suitability of empiric antibiotic therapy in hospitalized patients with bloodstream infections.

    Science.gov (United States)

    Grossman, Chagai; Keller, Nathan; Bornstein, Gil; Ben-Zvi, Ilan; Koren-Morag, Nira; Rahav, Galia

    2017-06-01

    Bacteremia is associated with high morbidity and mortality rates. Initiation of inadequate empiric antibiotic therapy is associated with a worse outcome. The aim of this study was to establish the prevalence and the factors associated with inappropriate empiric antibiotic therapy in patients hospitalized with bacteremia. A cross-sectional study was conducted during January 2010-December 2011 at the medical wards of the Chaim Sheba Medical Center, Israel. The records of all patients with bacteremia were reviewed. Clinical and laboratory characteristics, bacteremic pathogens and antimicrobial agents were retrieved from the medical records. Factors associated with appropriateness of empiric antibiotic therapy were assessed. A total of 681 eligible adults were included in the study. Antibiotic therapy was found to be inappropriate in 138 (20.2%) patients (95% C.I. 17.2-23.2). The rate of appropriateness was not related to the type of antibiotic regimen and the type of bacteria. Patients with healthcare-associated infections were more likely to be administrated inappropriate antibiotic therapy. Patients with primary bloodstream infections were also more likely to be administrated inappropriate antibiotic therapy. Empiric combination therapy was more likely to be appropriate than monotherapy, except for an aminoglycosides-based combination. Combination empiric antibiotic therapy should be considered in patients with healthcare-associated infections and in those with primary bloodstream infections.

  5. Outbreak of Serratia marcescens postsurgical bloodstream infection due to contaminated intravenous pain control fluids.

    Science.gov (United States)

    Chiang, Ping-Cherng; Wu, Tsu-Lan; Kuo, An-Jing; Huang, Yhu-Chering; Chung, Ting-Ying; Lin, Chun-Sui; Leu, Hsieh-Shong; Su, Lin-Hui

    2013-09-01

    Serratia marcescens is an important nosocomial pathogen causing significant outbreaks. Here we report an outbreak of bloodstream infection caused by S. marcescens at a 3500-bed hospital in Taiwan. The effective cooperative efforts of both laboratory personnel and infection control practitioners (ICPs) jointly contributed to the total control of the outbreak. A sudden increase in the isolation of S. marcescens from blood cultures was noted in the Clinical Microbiology Laboratory. The information was passed to the ICPs and an investigation was initiated. Pulsed-field gel electrophoresis was used to study the relationships among the isolates. Pulsotype A was identified in 43 (82.7%) of the 52 blood isolates studied. They were isolated from 52 patients distributed across 22 wards that were surveyed by seven ICPs. All patients had undergone surgery before the infection, and fentanyl-containing intravenous fluids were used for pain control in 43 of them. Isolates from 42 belonged to pulsotype A. Three S. marcescens isolates, all from fentanyl-containing fluids and demonstrating pulsotype A, were identified from 251 environmental cultures. All fentanyl-containing fluids that were in use were withdrawn and the outbreak was stopped. The outbreak of S. marcescens bloodstream infection apparently occurred through the use of fentanyl-containing fluids contaminated by a pulsotype A S. marcescens. Copyright © 2013 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  6. Propofol Sedation Exacerbates Kidney Pathology and Dissemination of Bacteria during Staphylococcus aureus Bloodstream Infections.

    Science.gov (United States)

    Visvabharathy, Lavanya; Freitag, Nancy E

    2017-07-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for large numbers of postsurgical nosocomial infections across the United States and worldwide. Propofol anesthesia is widely used in surgery and in intensive care units, and recent evidence indicates that even brief exposure to propofol can substantially increase host susceptibility to microbial infection. Here, we delineate the impact of propofol sedation on MRSA bloodstream infections in mice in the presence and absence of prophylactic antibiotic treatment. Consistent with previous reports, brief periods of anesthesia with propofol were sufficient to significantly increase bacterial burdens and kidney pathology in mice infected with MRSA. Propofol exposure increased neutrophilic infiltrates into the kidney and enhanced bacterial dissemination throughout kidney tissue. Propofol sedation reduced populations of effector phagocytes and mature dendritic cells within the kidney and led to the apparent expansion of myeloid-derived suppressor cell-like populations. When propofol was coadministered with vancomycin prophylaxis, it dramatically increased kidney abscess formation and bacterial dissemination throughout kidney tissue at early times post-S. aureus infection compared to antibiotic-treated but nonsedated animals. Taken together, our data indicate that short-term sedation with propofol significantly increases the severity of bloodstream MRSA infection, even when administered in conjunction with vancomycin prophylaxis. Copyright © 2017 American Society for Microbiology.

  7. Bloodstream infection after elective liver transplantation is associated with increased mortality in patients with cirrhosis.

    Science.gov (United States)

    Karvellas, Constantine J; McPhail, Mark; Pink, Fred; Asthana, Sonal; Muiesan, Paolo; Heaton, Nigel; Auzinger, Georg; Bernal, William; Eltringham, Ian; Wendon, Julia A

    2011-10-01

    This study aims to investigate what factors predict the development of postoperative bloodstream infection (BSI) in patients transplanted electively for chronic liver disease and compare outcomes in infected transplant recipients (BCLD) with noninfected patients (CLD). A retrospective cohort study of 218 patients who had elective liver transplantation (LT) between January 2003 and July 2005 and admitted to a specialist intensive care unit (ICU) was done. Fifteen patients had BSI post-LT (BCLD, 29 isolates) while in the ICU, and 203 patients did not (CLD). Thirty-eight percent of isolates were gram negatives; 55%, gram positives; and 7%, fungemia. Median time to first BSI post-LT was 11 days (range, 3-16 days). On admission post-LT to the ICU, patients with BCLD had higher Acute Physiology and Chronic Health Evaluation II scores (23 vs 10, P infection (hazards ratio, 8.7) was independently associated with mortality. Bloodstream infection post-LT was associated with increased severity of illness on admission, greater requirements for organ support, and increased mortality. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Strict infection control leads to low incidence of methicillin-resistant Staphylococcus aureus bloodstream infection over 20 years.

    Science.gov (United States)

    Widmer, Andreas F; Lakatos, Botond; Frei, Reno

    2015-06-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a worldwide issue associated with significant morbidity and mortality. Multiple infection control (IC) approaches have been tested to control its spread; however, the success of the majority of trials has been short-lived and many efforts have failed. We report the long-term success of MRSA control from a prospective observational study over 20 years. University Hospital Basel is a large tertiary care center with a median bed capacity of 855 and 5 intensive care units (ICUs); currently, the facility has >32,000 admissions per year. The IC program at the University Hospital Basel was created in 1993, after 2 MRSA outbreaks. The program has included strict contact precautions with single rooms for MRSA-colonized or -infected patients, targeted admission screening of high-risk patients and healthcare workers at risk for carriage, molecular typing of all MRSA strains and routine decolonization of MRSA carriers including healthcare workers. We used the incidence of MRSA bloodstream infections (BSIs) to assess the effectiveness of this program. All MRSA cases were prospectively classified using a standardized case report form in nosocomial and nonnosocomial cases, based on CDC definitions. Between 1993 and 2012, 540,669 blood samples were cultured. The number of blood cultures increased from 865 per 10,000 patient days in 1993 to 1,568 per 10,000 patient days in 2012 (P<.001). We identified 1,268 episodes of S. aureus BSI from 1,204 patients. MRSA accounted for 34 episodes (2.7%) and 24 of these (1.9%) were nosocomial. MRSA BSI incidence varied between 0 and 0.27 per 10,000 patient days and remained stable with no significant variation throughout the study period (P=.882). Long-term control of MRSA is feasible when a bundle of IC precautions is strictly enforced over time.

  9. The Correlation Between Biofilm Production and Catheter-Related Bloodstream Infections Sustained by Candida. A Case Control Study.

    Science.gov (United States)

    Brunetti, Grazia; Visconti, Valeria; Ghezzi, Maria Cristina; Giordano, Alessandra; Raponi, Giammarco

    2017-01-01

    Biofilm forming capacity of yeasts colonizing the intravenous devices is considered a key factor involved in the pathogenesis of Candida catheter-related bloodstream infections (CCRBSI). The biofilm production of strains of Candida spp. isolated both from the CVC and from the blood of patients with CCRBSI was compared to that of strains isolated from patients not having CCRBSI. Results, expressed in terms of Biofilm Index (BI), revealed that biofilm-producing strains were isolated in the CCRBSI group with a frequency significantly higher than in the non-CCRBSI group (χ(2) = 4.25, p = 0.03). The species more frequently cultured was C. parapsilosis complex (including C. parapsilosis sensu stricto, C. orthopsilosis and C. metapsilosis). When this species was isolated from the CVC tip cultures of the CCRBSI group it showed BIs significantly (p = 0.05) higher than those found in the non-CCRBSI group. All the strains of C. tropicalis isolated from the CCRBSI group produced biofilm. Instead most of the isolates of C. glabrata were non-producers. The cumulative BI of non-albicans Candida strains isolated from CCRBSI patients was significantly higher than that of non-albicans strains cultured from patients non-CCRBSI (χ(2) = 6.91; p = 0.008). C. albicans was a biofilm producer both in the CCRBSI and in the non-CCRBSI group. When isolated from the blood it showed enhanced biofilm production in the CCRBSI group only, while when colonizing the CVC it displayed high BIs both in the CCRBSI group and in non-CCRBSI group. Our data seem to indicate that the biofilm production capacity should be considered in the clinical management of CCRBSI.

  10. Nosocomial bloodstream infection in human immunodeficiency virus-infected patients in Taiwan: descriptive epidemiology and risk factors for mortality.

    Science.gov (United States)

    Wang, Jann-Tay; Sheng, Wang-Huei; Chen, Mao-Yuan; Fang, Chi-Tai; Hsieh, Szu-Min; Hsueh, Po-Ren; Hung, Chien-Ching; Chang, Shan-Chwen

    2004-10-01

    Nosocomial bloodstream infection (NBSI) is common in patients with human immunodeficiency virus (HIV) infection. This study evaluated the incidence, causative pathogens, and outcome of NBSIs in hospitalized HIV-infected patients at a university hospital in Taiwan. The medical records of all HIV-infected patients who developed NBSIs from June 1994 to June 2003 were retrospectively reviewed. A standardized case record form was used to collect demographic, clinical, laboratory, and microbiologic data. During the study period, 57 episodes of NBSIs occurred in 51 HIV-infected patients whose median age was 37 years (range, 23 to 60 years). All of the patients were at HIV infection stage C. The incidence of NBSIs was 2.3 per 1000 person-days of hospitalization (41.4 per 1000 discharges). More than three-fourths of the 57 episodes (77.2%) were classified as primary NBSIs. Other infection foci included respiratory tract (6 episodes), urinary tract (3), surgical site (2), and skin (2). Staphylococcus species were the leading pathogens (42.1%). The crude and attributable mortality rates in patients with NBSIs during the study period were 38.6% and 26.1%, respectively. Multivariate analysis using a logistic regression model revealed that shock and hypoalbuminemia at the onset of NBSIs were the 2 factors predictive of mortality. NBSIs in hospitalized patients in the late stage of HIV infection were associated with a high attributable mortality rate. Staphylococcus species were the leading pathogen responsible for NBSIs. Presentations of shock and hypoalbuminemia were predictive of mortality.

  11. Central line-associated bloodstream infections in neonates with gastrointestinal conditions: developing a candidate definition for mucosal barrier injury bloodstream infections.

    Science.gov (United States)

    Coffin, Susan E; Klieger, Sarah B; Duggan, Christopher; Huskins, W Charles; Milstone, Aaron M; Potter-Bynoe, Gail; Raphael, Bram; Sandora, Thomas J; Song, Xiaoyan; Zerr, Danielle M; Lee, Grace M

    2014-11-01

    To develop a candidate definition for central line-associated bloodstream infection (CLABSI) in neonates with presumed mucosal barrier injury due to gastrointestinal (MBI-GI) conditions and to evaluate epidemiology and microbiology of MBI-GI CLABSI in infants. Multicenter retrospective cohort study. Neonatal intensive care units from 14 US children's hospitals and pediatric facilities. A multidisciplinary focus group developed a candidate MBI-GI CLABSI definition based on presence of an MBI-GI condition, parenteral nutrition (PN) exposure, and an eligible enteric organism. CLABSI surveillance data from participating hospitals were supplemented by chart review to identify MBI-GI conditions and PN exposure. During 2009-2012, 410 CLABSIs occurred in 376 infants. MBI-GI conditions and PN exposure occurred in 149 (40%) and 324 (86%) of these 376 neonates, respectively. The distribution of pathogens was similar among neonates with versus without MBI-GI conditions and PN exposure. Fifty-nine (16%) of the 376 initial CLABSI episodes met the candidate MBI-GI CLABSI definition. Subsequent versus initial CLABSIs were more likely to be caused by an enteric organism (22 of 34 [65%] vs 151 of 376 [40%]; P = .009) and to meet the candidate MBI-GI CLABSI definition (19 of 34 [56%] vs 59 of 376 [16%]; P definition of MBI-GI CLABSI. The high proportion of MBI-GI CLABSIs among subsequent infections suggests that infants with MBI-GI CLABSI should be a population targeted for further surveillance and interventional research.

  12. Trypanosoma brucei aquaglyceroporin 2 is a high-affinity transporter for pentamidine and melaminophenyl arsenic drugs and the main genetic determinant of resistance to these drugs

    Science.gov (United States)

    Munday, Jane C.; Eze, Anthonius A.; Baker, Nicola; Glover, Lucy; Clucas, Caroline; Aguinaga Andrés, David; Natto, Manal J.; Teka, Ibrahim A.; McDonald, Jennifer; Lee, Rebecca S.; Graf, Fabrice E.; Ludin, Philipp; Burchmore, Richard J. S.; Turner, C. Michael R.; Tait, Andy; MacLeod, Annette; Mäser, Pascal; Barrett, Michael P.; Horn, David; De Koning, Harry P.

    2014-01-01

    Objectives Trypanosoma brucei drug transporters include the TbAT1/P2 aminopurine transporter and the high-affinity pentamidine transporter (HAPT1), but the genetic identity of HAPT1 is unknown. We recently reported that loss of T. brucei aquaglyceroporin 2 (TbAQP2) caused melarsoprol/pentamidine cross-resistance (MPXR) in these parasites and the current study aims to delineate the mechanism by which this occurs. Methods The TbAQP2 loci of isogenic pairs of drug-susceptible and MPXR strains of T. brucei subspecies were sequenced. Drug susceptibility profiles of trypanosome strains were correlated with expression of mutated TbAQP2 alleles. Pentamidine transport was studied in T. brucei subspecies expressing TbAQP2 variants. Results All MPXR strains examined contained TbAQP2 deletions or rearrangements, regardless of whether the strains were originally adapted in vitro or in vivo to arsenicals or to pentamidine. The MPXR strains and AQP2 knockout strains had lost HAPT1 activity. Reintroduction of TbAQP2 in MPXR trypanosomes restored susceptibility to the drugs and reinstated HAPT1 activity, but did not change the activity of TbAT1/P2. Expression of TbAQP2 sensitized Leishmania mexicana promastigotes 40-fold to pentamidine and >1000-fold to melaminophenyl arsenicals and induced a high-affinity pentamidine transport activity indistinguishable from HAPT1 by Km and inhibitor profile. Grafting the TbAQP2 selectivity filter amino acid residues onto a chimeric allele of AQP2 and AQP3 partly restored susceptibility to pentamidine and an arsenical. Conclusions TbAQP2 mediates high-affinity uptake of pentamidine and melaminophenyl arsenicals in trypanosomes and TbAQP2 encodes the previously reported HAPT1 activity. This finding establishes TbAQP2 as an important drug transporter. PMID:24235095

  13. Molecular characterization of Staphylococcus aureus bloodstream isolates collected in a Dutch University Hospital between 1999 and 2006

    NARCIS (Netherlands)

    Nulens, Eric; Stobberingh, Ellen E; van Dessel, Helke; Sebastian, Silvie; van Tiel, Frank H; Beisser, Patrick S; Deurenberg, Ruud H

    We observed that, between 1999 and 2006, up to 50% of the methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream isolates in our hospital had a genetic background common to endemic methicillin-resistant S. aureus clones (clonal complex 5 [CC5], CC8, CC22, CC30, and CC45). Furthermore,

  14. Multiresistant extended-spectrum beta-lactamase-producing Klebsiella pneumoniae causing an outbreak of nosocomial bloodstream infection.

    Science.gov (United States)

    Gonzalez-Vertiz, A; Alcantar-Curiel, D; Cuauhtli, M; Daza, C; Gayosso, C; Solache, G; Horta, C; Mejia, F; Santos, J I; Alpuche-Aranda, C

    2001-11-01

    This article describes an outbreak of bloodstream infection due to clonal dissemination of multiresistant Klebsiella pneumoniae in a neonatal area, during August 1999, in Mexico City General Hospital. The intestinal tract was the likely reservoir, and intensification of Contact Precaution measures contained the outbreak.

  15. Patients with Central Lines — What You Need to Know to Avoid a Bloodstream Infection

    Centers for Disease Control (CDC) Podcasts

    2011-03-01

    This podcast is based on the March, 2011 CDC Vital Signs report which indicates bloodstream infections in patients with central lines are largely preventable when healthcare providers use CDC-recommended infection control steps.  Created: 3/1/2011 by Centers for Disease Control and Prevention (CDC).   Date Released: 3/1/2011.

  16. Algorithm for pre-emptive glycopeptide treatment in patients with haematologic malignancies and an Enterococcus faecium bloodstream infection

    NARCIS (Netherlands)

    Zhou, Xuewei; Arends, Jan P; Span, Lambert Fr; Friedrich, Alexander W

    2013-01-01

    INTRODUCTION: Nowadays Enterococcus faecium has become one of the most emerging and challenging nosocomial pathogens. The aim of this study was to determine risk factors in haematology patients who are at risk of an Enterococcus faecium bloodstream infection (BSI) and should be considered for

  17. Identification of Ochrobactrum oryzae in Bloodstream Primary Infection in a Dialysis Patient: Can it be an Emerging Pathogen?

    Directory of Open Access Journals (Sweden)

    Luciana S Borges, Jussimara N Monteiro, Lisia Miglioli

    2016-09-01

    Full Text Available Ochrobactrum spp is a gram-negative bacillus currently considered an emerging and opportunistic infection, rare in humans, and generally associated with indwelling foreign bodies. We report a case of primary bloodstream infection related to a dialysis catheter, caused by Ochrobactrum oryzae misidentified as Ochrobactrum anthropi. J Microbiol Infect Dis 2016; 6(3: 128-131

  18. Detection of Trypanosoma brucei in field-captured tsetse flies and identification of host species fed on by the infected flies.

    Science.gov (United States)

    Konnai, Satoru; Mekata, Hirohisa; Odbileg, Raadan; Simuunza, Martin; Chembensof, Mwelwa; Witola, William Harold; Tembo, Mwase Enala; Chitambo, Harrison; Inoue, Noboru; Onuma, Misao; Ohashi, Kazuhiko

    2008-08-01

    The prevalence of trypanosome infections in tsetse flies in the Chiawa area of Lower Zambezi in Zambia, with endemic trypanosomosis, was determined by a polymerase chain reaction (PCR) method that allowed the detection of trypanosome DNA and determination of the type of animal host fed on by the tsetse fly Glossina pallidipes, using tsetse-derived DNA extracts as templates. Ninety G. pallidipes (82 females and 8 males; 18.3%) of the 492 flies captured by baited biconical traps tested positive for the presence of Trypanosoma brucei species genomic DNA. Of the 90 T. brucei-positive flies, 47 (52.2%) also tested positive for vertebrate mitochondrial DNA. Sequence analysis of the vertebrate mitochondrial DNA amplicons established that they originated from 8 different vertebrate species, namely, human (Homo sapiens), African elephant (Loxodonta cyclotis), African buffalo (Syncerus caffer), waterbuck (Kobus ellipsiprymnus), roan antelope (Hippotragus equinus), greater kudu (Tragelaphus strepsiceros), warthog (Phacochoerus africanus), and goat (Capra hircus). Furthermore, to investigate the prevalence of trypanosome infections in domestic goats in the same area where trypanosomes had been detected in tsetse files, a total of 86 goats were randomly selected from 6 different herds. Among the selected goats, 36 (41.9%) were found to be positive for T. brucei species. This combined detection method would be an ideal approach not only for mass screening for infection prevalence in tsetse populations, but also for the prediction of natural reservoirs in areas endemic for trypanosomosis.

  19. Immunization with recombinant beta-tubulin from Trypanosoma evansi induced protection against T. evansi, T. equiperdum and T. b. brucei infection in mice.

    Science.gov (United States)

    Li, S-Q; Fung, M-C; Reid, S A; Inoue, N; Lun, Z-R

    2007-04-01

    The beta-tubulin gene of Trypanosoma evansi (STIB 806) was cloned and expressed in Escherichia coli. The predicted amino acid sequence of T. evansi beta-tubulin shows 100%, 99.8%, 99.1%, and 98.6% homology with T. equiperdum, T. b. brucei, T. cruzi and T. danilewskyi, respectively, but is diverse from that of T. cyclops, showing only 51.6% of homology. Recombinant beta-tubulin was expressed as inclusion bodies in E. coli. It was purified and renatured for immunological studies. Mice immunized with the renatured recombinant beta-tubulin were protected from lethal challenge with T. evansi STIB 806, T. equiperdum STIB 818 and T. b. brucei STIB 940, showing 83.3%, 70% and 76.7% protection, respectively. Serum collected from the rabbit immunized with recombinant beta-tubulin inhibited the growth of T. evansi, T. equiperdum and T. b. brucei in vitro. Serum from mice and rabbits immunized with recombinant beta-tubulin recognized only T. evansi beta-tubulin and not mouse beta-tubulin. The results of this study demonstrated that the recombinant T. evansi beta-tubulin is a potential candidate for the development of a vaccine to prevent animal trypanosomiasis caused by these three trypanosome species.

  20. Bacterial etiology of bloodstream infections and antimicrobial resistance in Dhaka, Bangladesh, 2005–2014

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    Dilruba Ahmed

    2017-01-01

    Full Text Available Abstract Background Bloodstream infections due to bacterial pathogens are a major cause of morbidity and mortality in Bangladesh and other developing countries. In these countries, most patients are treated empirically based on their clinical symptoms. Therefore, up to date etiological data for major pathogens causing bloodstream infections may play a positive role in better healthcare management. The aim of this study was to identify the bacterial pathogens causing major bloodstream infections in Dhaka, Bangladesh and determine their antibiotic susceptibility pattern. Methods From January 2005 to December 2014, a total of 103,679 single bottle blood samples were collected from both hospitalized and domiciliary patients attending Dhaka hospital, icddrb, Bangladesh All the blood samples were processed for culture using a BACT/Alert blood culture machine. Further identification of bacterial pathogens and their antimicrobial susceptibility test were performed using standard microbiological procedures. Results Overall, 13.6% of the cultured blood samples were positive and Gram-negative (72.1% bacteria were predominant throughout the study period. Salmonella Typhi was the most frequently isolated organism (36.9% of samples in this study and a high percentage of those strains were multidrug-resistant (MDR. However, a decreasing trend in the S. Typhi isolation rate was observed and, noticeably, the percentage of MDR S. Typhi isolated declined sharply over the study period. An overall increase in the presence of Gram-positive bacteria was observed, but most significantly we observed the percentage of MDR Gram-positive bacteria to double over the study period. Overall, Gram positive bacteria were more resistant to most of the commonly used antibiotics than Gram-negative bacteria, but the MDR level was high in both groups. Conclusions This study identified the major bacterial pathogens involved with BSI in Dhaka, Bangladesh and also revealed their

  1. Time-dependent regulation analysis dissects shifts between metabolic and gen-expression regulation during differentiation of bloodstream forms.

    NARCIS (Netherlands)

    van Eunen, K.; Bouwman, J.; Lindenbergh, P.A.; Westerhoff, H.V.; Bakker, B.M.

    2009-01-01

    Time-dependent regulation analysis is a new methodology that allows us to unravel, both quantitatively and dynamically, how and when functional changes in the cell are brought about by the interplay of gene expression and metabolism. In this first experimental implementation, we dissect the initial

  2. Taurolidine lock is superior to heparin lock in the prevention of catheter related bloodstream infections and occlusions.

    Directory of Open Access Journals (Sweden)

    Evelyn D Olthof

    Full Text Available BACKGROUND AND AIMS: Patients on home parenteral nutrition (HPN are at risk for catheter-related complications; mainly infections and occlusions. We have previously shown in HPN patients presenting with catheter sepsis that catheter locking with taurolidine dramatically reduced re-infections when compared with heparin. Our HPN population therefore switched from heparin to taurolidine in 2008. The aim of the present study was to compare long-term effects of this catheter lock strategy on the occurrence of catheter-related bloodstream infections and occlusions in HPN patients. METHODS: Data of catheter-related complications were retrospectively collected from 212 patients who received HPN between January 2000 and November 2011, comprising 545 and 200 catheters during catheter lock therapy with heparin and taurolidine, respectively. We evaluated catheter-related bloodstream infection and occlusion incidence rates using Poisson-normal regression analysis. Incidence rate ratios were calculated by dividing incidence rates of heparin by those of taurolidine, adjusting for underlying disease, use of anticoagulants or immune suppressives, frequency of HPN/fluid administration, composition of infusion fluids, and duration of HPN/fluid use before catheter creation. RESULTS: Bloodstream infection incidence rates were 1.1/year for heparin and 0.2/year for taurolidine locked catheters. Occlusion incidence rates were 0.2/year for heparin and 0.1/year for taurolidine locked catheters. Adjusted incidence ratios of heparin compared to taurolidine were 5.9 (95% confidence interval, 3.9-8.7 for bloodstream infections and 1.9 (95% confidence interval, 1.1-3.1 for occlusions. CONCLUSIONS: Given that no other procedural changes than the catheter lock strategy were implemented during the observation period, these data strongly suggest that taurolidine decreases catheter-related bloodstream infections and occlusions in HPN patients compared with heparin.

  3. Central Venous Catheters and Bloodstream Infection During Induction Therapy in Children With Acute Lymphoblastic Leukemia

    DEFF Research Database (Denmark)

    Bergmann, Kristin; Hasle, Henrik; Asdahl, Peter

    2016-01-01

    treated at 3 pediatric centers in Denmark between 2008 and 2014. A total of 136 patients were followed from initial CVC placement until first BSI, CVC removal, death, or day 28, whichever occurred first. Thirty-nine BSIs were detected, of which 67% were gram-positive infections, and 59% met the criteria......The purpose of the study was to assess the risk of firsttime bloodstream infection (BSI) according to type of central venous catheter (CVC) during induction therapy in children with acute lymphoblastic leukemia (ALL). Patients eligible for our analysis were all newly diagnosed children with ALL...... for being CVC associated. The 28-day cumulative incidence of BSI was similar in 77 patients with a nontunneled CVC (28%; 95% confidence interval, 19%-40%) and in 59 patients with a tunneled CVC with external lines (TE) (33%; 95% confidence interval, 23%-47%). Subgroup analyses showed that gram...

  4. Risk for Health Care-Associated Bloodstream Infections in Pediatric Oncology Patients With Various Malignancies.

    Science.gov (United States)

    Thurman, Cara B; Abbott, Maura; Liu, Jinfang; Larson, Elaine

    This was a retrospective cohort study to identify the rates, predictors, and outcomes of health care-associated bloodstream infections (HA-BSI) among children with solid tumors, lymphoma, lymphoid leukemia, and myeloid leukemia. The study population included 4500 children ≤18 years old at a pediatric hospital in New York City from 2006 to 2014. A total of 147 HA-BSI cases were identified; using multivariable logistic regression modeling, children with a hematologic diagnosis (lymphoma, lymphoid leukemia, myeloid leukemia) were at greater risk for HA-BSI than those with a solid tumor diagnosis (all P values risk factor for HA-BSI, there was no significant difference in overall mortality from HA-BSI by tumor type ( P = .51).

  5. Positive deviance as a strategy to prevent and control bloodstream infections in intensive care

    Directory of Open Access Journals (Sweden)

    Francimar Tinoco de Oliveira

    Full Text Available Abstract OBJECTIVE To describe the application of positive deviance as a strategy to prevent and control bloodstream infections. METHOD An intervention study with nursing and medical team members working in an intensive care unit in a university hospital, between June and December 2014. The four steps of the positive defiance methodology were applied: to define, to determine, to discover and to design. RESULTS In 90 days, 188 actions were observed, of these, 36.70% (n=69 were related to catheter dressing. In 81.15% (n=56 of these dressings, the professionals most adhered to the use of flexible sterile cotton-tipped swabs to perform antisepsis at catheter entry sites and fixation dressing. CONCLUSION Positive deviance contributed to the implementation of proposals to improve work processes and team development related to problems identified in central venous catheter care.

  6. JVG9, a benzimidazole derivative, alters the surface and cytoskeleton of Trypanosoma cruzi bloodstream trypomastigotes.

    Science.gov (United States)

    Díaz-Chiguer, Dylan L; Hernández-Luis, Francisco; Nogueda-Torres, Benjamín; Castillo, Rafael; Reynoso-Ducoing, Olivia; Hernández-Campos, Alicia; Ambrosio, Javier R

    2014-09-01

    Trypanosoma cruzi has a particular cytoskeleton that consists of a subpellicular network of microtubules and actin microfilaments. Therefore, it is an excellent target for the development of new anti-parasitic drugs. Benzimidazole 2-carbamates, a class of well-known broad-spectrum anthelmintics, have been shown to inhibit the in vitro growth of many protozoa. Therefore, to find efficient anti-trypanosomal (trypanocidal) drugs, our group has designed and synthesised several benzimidazole derivatives. One, named JVG9 (5-chloro-1H-benzimidazole-2-thiol), has been found to be effective against T. cruzi bloodstream trypomastigotes under both in vitro and in vivo conditions. Here, we present the in vitro effects observed by laser scanning confocal and scanning electron microscopy on T. cruzi trypomastigotes. Changes in the surface and the distribution of the cytoskeletal proteins are consistent with the hypothesis that the trypanocidal activity of JVG9 involves the cytoskeleton as a target.

  7. JVG9, a benzimidazole derivative, alters the surface and cytoskeleton of Trypanosoma cruzi bloodstream trypomastigotes

    Directory of Open Access Journals (Sweden)

    Dylan L Díaz-Chiguer

    2014-09-01

    Full Text Available Trypanosoma cruzi has a particular cytoskeleton that consists of a subpellicular network of microtubules and actin microfilaments. Therefore, it is an excellent target for the development of new anti-parasitic drugs. Benzimidazole 2-carbamates, a class of well-known broad-spectrum anthelmintics, have been shown to inhibit the in vitro growth of many protozoa. Therefore, to find efficient anti-trypanosomal (trypanocidal drugs, our group has designed and synthesised several benzimidazole derivatives. One, named JVG9 (5-chloro-1H-benzimidazole-2-thiol, has been found to be effective against T. cruzi bloodstream trypomastigotes under both in vitro and in vivo conditions. Here, we present the in vitro effects observed by laser scanning confocal and scanning electron microscopy on T. cruzi trypomastigotes. Changes in the surface and the distribution of the cytoskeletal proteins are consistent with the hypothesis that the trypanocidal activity of JVG9 involves the cytoskeleton as a target.

  8. Clinical Characteristics of Nosocomial Bloodstream Infections in Neonates in Two Hospitals, China.

    Science.gov (United States)

    Wang, Shanmei; Chen, Sheng; Feng, Wei; Sun, Fengjun; Wang, Qian; Zhu, Ke; Song, Jie

    2017-07-21

    The improvement of medical condition requires prolonged hospital stays, which increase the risk of nosocomial bloodstream infections (BSIs). All nosocomial BSI newborns in two hospitals were included, and the demographic and clinical characteristics of bacteremia patients were obtained from the information systems. Isolates were identified by biochemical assays. Antimicrobial susceptibility was determined using disk diffusion method. Except for three same risk factors, intubation with mechanical ventilation was a risk factor in Chongqing, while low birth weight was a risk factor in Henan. Klebsiella pneumoniae was the predominant strain in Chongqing, and Escherichia coli was the most prevalent strain in Henan. The resistance rate of gram-negative bacteria in Henan was higher than that of strains in Chongqing. The risk factors and resistance rate of pathogens were different in different areas. Therefore, treatment protocols should be established based on the trends of drug resistance and bacterial spectrum.

  9. Bloodstream infections among solid organ transplant recipients: epidemiology, microbiology, associated risk factors for morbility and mortality.

    Science.gov (United States)

    Shao, Mingjie; Wan, Qiquan; Xie, Wenzhao; Ye, Qifa

    2014-10-01

    Bloodstream infections (BSIs) remain important causes of morbidity and mortality among solid organ transplant (SOT) recipients and still threaten the success of SOT. In general, among SOT recipients, risk factors for BSIs are associated with prior ICU admission, catheterization, older recipient or donor age…etc. Pulmonary focus, nosocomial source of BSIs, lack of appropriate antibiotic therapy and other variables have significant impacts on BSIs-related mortality in SOT. Most of BSIs in SOT are caused by gram-negative bacteria. However, all aspects including microbiological spectrum, morbidity and mortality rates, risk factors of BSIs and BSIs-related death depend on the type of transplantation. The purpose of this review is to summarize the epidemiology, microbiologic features including antimicrobial resistance of organisms, and associated risk factors for morbidity and mortality of BSIs according to different type of transplantation to better understand the characteristics of BSIs and improve the outcomes after SOT. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Causative agents of nosocomial bloodstream infections and their antimicrobial susceptibility patterns.

    Science.gov (United States)

    Demirturk, Nese; Demiturk, Nese; Demirdal, Tuna

    2013-11-01

    The aim of this study was to retrospectively investigate nosocomial bloodstream infections (NBI) and their antimicrobial susceptibility patterns at Afyon Kocatepe University (AKU) Hospital, Turkey, from January 2006 to December 2011 and to determine the risk factors for nosocomial BSI. Subjects were aged > or = 18 years. The data were obtained from patient files. Five hundred seventy-nine nosocomial infections in 461 patients were included in the study. Eighty-four point six percent was primary and 15.4% were secondary infections. Gram-positive cocci were the most common organisms. When compared year by year there was an increasing trend in antibacterial resistant gram-negative bacilli. The most common infection risk factors were H2 histamine receptor blocker use and blood transfusions. Regular surveillance of BSI is important to monitor changes in the types of microorganisms and their resistance patterns.

  11. JVG9, a benzimidazole derivative, alters the surface and cytoskeleton of Trypanosoma cruzi bloodstream trypomastigotes

    Science.gov (United States)

    Díaz-Chiguer, Dylan L; Hernández-Luis, Francisco; Nogueda-Torres, Benjamín; Castillo, Rafael; Reynoso-Ducoing, Olivia; Hernández-Campos, Alicia; Ambrosio, Javier R

    2014-01-01

    Trypanosoma cruzi has a particular cytoskeleton that consists of a subpellicular network of microtubules and actin microfilaments. Therefore, it is an excellent target for the development of new anti-parasitic drugs. Benzimidazole 2-carbamates, a class of well-known broad-spectrum anthelmintics, have been shown to inhibit the in vitro growth of many protozoa. Therefore, to find efficient anti-trypanosomal (trypanocidal) drugs, our group has designed and synthesised several benzimidazole derivatives. One, named JVG9 (5-chloro-1H-benzimidazole-2-thiol), has been found to be effective against T. cruzi bloodstream trypomastigotes under both in vitro and in vivo conditions. Here, we present the in vitro effects observed by laser scanning confocal and scanning electron microscopy on T. cruzi trypomastigotes. Changes in the surface and the distribution of the cytoskeletal proteins are consistent with the hypothesis that the trypanocidal activity of JVG9 involves the cytoskeleton as a target. PMID:25317703

  12. Epidemiology of bloodstream infections after myeloablative and non-myeloablative allogeneic hematopoietic stem cell transplantation

    DEFF Research Database (Denmark)

    Gjaerde, Lars I; Moser, Claus; Sengeløv, Henrik

    2017-01-01

    (GPB), 23% gram-negative bacteria (GNB), and 9% fungi. The GPB/GNB ratio declined from 2008 to 2014 (P for trend ...BACKGROUND: Patients who undergo allogeneic hematopoietic stem cell transplantation (allo-HSCT) often develop bloodstream infections (BSI). We aimed to describe the etiologies and antibiotic resistance patterns of BSI after allo-HSCT, and, as knowledge about the impact of conditioning regimen...... in a historical cohort. BSI were registered from initiation of conditioning to day 360 after transplantation. RESULTS: BSI occurred in 34% (95% confidence interval [CI]: 28%, 41%) of MA-conditioned patients and in 17% (95% CI: 12%, 22%) of NMA-conditioned patients. Of all isolates, 68% were gram-positive bacteria...

  13. Nosocomial bloodstream infections in Brazilian pediatric patients: microbiology, epidemiology, and clinical features.

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Pires Pereira

    Full Text Available BACKGROUND: Nosocomial bloodstream infections (nBSIs are an important cause of morbidity and mortality and are the most frequent type of nosocomial infection in pediatric patients. METHODS: We identified the predominant pathogens and antimicrobial susceptibilities of nosocomial bloodstream isolates in pediatric patients (≤16 years of age in the Brazilian Prospective Surveillance for nBSIs at 16 hospitals from 12 June 2007 to 31 March 2010 (Br SCOPE project. RESULTS: In our study a total of 2,563 cases of nBSI were reported by hospitals participating in the Br SCOPE project. Among these, 342 clinically significant episodes of BSI were identified in pediatric patients (≤16 years of age. Ninety-six percent of BSIs were monomicrobial. Gram-negative organisms caused 49.0% of these BSIs, Gram-positive organisms caused 42.6%, and fungi caused 8.4%. The most common pathogens were Coagulase-negative staphylococci (CoNS (21.3%, Klebsiella spp. (15.7%, Staphylococcus aureus (10.6%, and Acinetobacter spp. (9.2%. The crude mortality was 21.6% (74 of 342. Forty-five percent of nBSIs occurred in a pediatric or neonatal intensive-care unit (ICU. The most frequent underlying conditions were malignancy, in 95 patients (27.8%. Among the potential factors predisposing patients to BSI, central venous catheters were the most frequent (66.4%. Methicillin resistance was detected in 37 S. aureus isolates (27.1%. Of the Klebsiella spp. isolates, 43.2% were resistant to ceftriaxone. Of the Acinetobacter spp. and Pseudomonas aeruginosa isolates, 42.9% and 21.4%, respectively, were resistant to imipenem. CONCLUSIONS: In our multicenter study, we found a high mortality and a large proportion of gram-negative bacilli with elevated levels of resistance in pediatric patients.

  14. Clinical features and complications of viridans streptococci bloodstream infection in pediatric hemato-oncology patients.

    Science.gov (United States)

    Huang, Wan-Ting; Chang, Luan-Yin; Hsueh, Po-Ren; Lu, Chun-Yi; Shao, Pei-Lan; Huang, Fu-Yuan; Lee, Ping-Ing; Chen, Chun-Ming; Lee, Chin-Yun; Huang, Li-Min

    2007-08-01

    Viridans streptococci (VS) are part of the normal flora of humans, but are fast emerging as pathogens causing bacteremia in neutropenic patients. The clinical features, outcomes, and antibiotic susceptibilities of VS bloodstream infections in children with hemato-oncological diseases are reported in this study. A retrospective chart review of pediatric patients (pediatric patients, the incidence rate of VS bacteremia was found to be significantly higher in pediatric patients with acute myeloid leukemia compared with other hemato-oncological conditions. Most of the patients had profound neutropenia related to chemotherapy for a median of 5 days on the day of positive blood culture. Eight of the 25 patients had undergone stem cell transplantations. Streptococcus mitis was the most common bloodstream isolate and only 12 (44%) of the 27 isolated strains of VS were penicillin-susceptible. Empirical antibiotic treatments were not effective in half of the episodes, but did not affect overall mortality. Isolated bacteremia (63%) and pneumonia (22%) were the two leading clinical presentations. Complications were recognized more frequently in patients with pneumonia. Hypotension and mechanical ventilation each developed in 8 patients (31%). The overall mortality rate was 23%. Penicillin non-susceptible VS infection has emerged as a threat in children with hemato-oncological diseases, especially those with acute myeloid leukemia. S. mitis is the most common spp. of VS causing bacteremia in children and is associated with serious complications. The development of pneumonia resulted in clinical complications and higher mortality. Empirical antibiotic treatments with activity against the infecting strains did not reduce the overall mortality rate in this study.

  15. Should we use closed or open infusion containers for prevention of bloodstream infections?

    Science.gov (United States)

    Rangel-Frausto, Manuel S; Higuera-Ramirez, Francisco; Martinez-Soto, Jose; Rosenthal, Victor D

    2010-02-02

    Hospitalized patients in critical care settings are at risk for bloodstream infections (BSI). Most BSIs originate from a central line (CL), and they increase length of stay, cost, and mortality. Open infusion containers may increase the risk of contamination and administration-related (CLAB) because they allow the entry of air into the system, thereby also providing an opportunity for microbial entry. Closed infusion containers were designed to overcome this flaw. However, open infusion containers are still widely used throughout the world.The objective of the study was to determine the effect of switching from open (glass, burettes, and semi-rigid) infusion containers to closed, fully collapsible, plastic infusion containers (Viaflex) on the rate and time to onset of central line-associated bloodstream infections CLABs. An open label, prospective cohort, active healthcare-associated infection surveillance, sequential study was conducted in four ICUs in Mexico. Centers for Disease Control National Nosocomial Infections Surveillance Systems definitions were used to define device-associated infections. A total of 1,096 adult patients who had a central line in place for >24 hours were enrolled. The CLAB rate was significantly higher during the open versus the closed container period (16.1 versus 3.2 CLAB/1000 central line days; RR = 0.20, 95% CI = 0.11-0.36, P container period (1.4% Days 2-4 to 0.5% Days 8-10), but increased in the open container period (4.9% Days 2-4 to 5.4% Days 8-10). The chance of acquiring a CLAB was significantly decreased (81%) in the closed container period (Cox proportional hazard ratio 0.19, P container period (23.4% versus 16.1%; RR = 0.69, 95% CI = 0.54-0.88, P containers significantly reduced CLAB rate, the probability of acquiring CLAB, and mortality.

  16. Bloodstream infections in intensive care unit patients: distribution and antibiotic resistance of bacteria

    Directory of Open Access Journals (Sweden)

    Russotto V

    2015-08-01

    Full Text Available Vincenzo Russotto,1 Andrea Cortegiani,1 Giorgio Graziano,2 Laura Saporito,2 Santi Maurizio Raineri,1 Caterina Mammina,2 Antonino Giarratano1 1Department of Biopathology and Medical Biotechnologies (DIBIMED, Section of Anaesthesia, Analgesia, Intensive Care and Emergency, Paolo Giaccone University Hospital, University of Palermo, Palermo, Italy; 2Department of Sciences for Health Promotion and Mother-Child Care, University of Palermo, Palermo, Italy Abstract: Bloodstream infections (BSIs are among the leading infections in critically ill patients. The case-fatality rate associated with BSIs in patients admitted to intensive care units (ICUs reaches 35%–50%. The emergence and diffusion of bacteria with resistance to antibiotics is a global health problem. Multidrug-resistant bacteria were detected in 50.7% of patients with BSIs in a recently published international observational study, with methicillin resistance detected in 48% of Staphylococcus aureus strains, carbapenem resistance detected in 69% of Acinetobacter spp., in 38% of Klebsiella pneumoniae, and in 37% of Pseudomonas spp. Prior hospitalization and antibiotic exposure have been identified as risk factors for infections caused by resistant bacteria in different studies. Patients with BSIs caused by resistant strains showed an increased risk of mortality, which may be explained by a higher incidence of inappropriate empirical therapy in different studies. The molecular genetic characterization of resistant bacteria allows the understanding of the most common mechanisms underlying their resistance and the adoption of surveillance measures. Knowledge of epidemiology, risk factors, mechanisms of resistance, and outcomes of BSIs caused by resistant bacteria may have a major influence on global management of ICU patients. The aim of this review is to provide the clinician an update on BSIs caused by resistant bacteria in ICU patients. Keywords: bloodstream infections, multidrug resistant

  17. Evaluation of bloodstream infections, Clostridium difficile infections, and gut microbiota in pediatric oncology patients.

    Science.gov (United States)

    Nycz, Bryan T; Dominguez, Samuel R; Friedman, Deborah; Hilden, Joanne M; Ir, Diana; Robertson, Charles E; Frank, Daniel N

    2018-01-01

    Bloodstream infections (BSI) and Clostridium difficile infections (CDI) in pediatric oncology/hematology/bone marrow transplant (BMT) populations are associated with significant morbidity and mortality. The objective of this study was to explore possible associations between altered microbiome composition and the occurrence of BSI and CDI in a cohort of pediatric oncology patients. Stool samples were collected from all patients admitted to the pediatric oncology floor from Oct.-Dec. 2012. Bacterial profiles from patient stools were determined by bacterial 16S rRNA gene profiling. Differences in overall microbiome composition were assessed by a permutation-based multivariate analysis of variance test, while differences in the relative abundances of specific taxa were assessed by Kruskal-Wallis tests. At admission, 9 of 42 patients (21%) were colonized with C. difficile, while 6 of 42 (14%) subsequently developed a CDI. Furthermore, 3 patients (7%) previously had a BSI and 6 patients (14%) subsequently developed a BSI. Differences in overall microbiome composition were significantly associated with disease type (p = 0.0086), chemotherapy treatment (p = 0.018), BSI following admission from any cause (p < 0.0001) or suspected gastrointestinal organisms (p = 0.00043). No differences in baseline microbiota were observed between individuals who did or did not subsequently develop C. difficile infection. Additionally, multiple bacterial groups varied significantly between subjects with post-admission BSI compared with no BSI. Our results suggest that differences in gut microbiota not only are associated with type of cancer and chemotherapy, but may also be predictive of subsequent bloodstream infection.

  18. Evaluation of bloodstream infections, Clostridium difficile infections, and gut microbiota in pediatric oncology patients.

    Directory of Open Access Journals (Sweden)

    Bryan T Nycz

    Full Text Available Bloodstream infections (BSI and Clostridium difficile infections (CDI in pediatric oncology/hematology/bone marrow transplant (BMT populations are associated with significant morbidity and mortality. The objective of this study was to explore possible associations between altered microbiome composition and the occurrence of BSI and CDI in a cohort of pediatric oncology patients. Stool samples were collected from all patients admitted to the pediatric oncology floor from Oct.-Dec. 2012. Bacterial profiles from patient stools were determined by bacterial 16S rRNA gene profiling. Differences in overall microbiome composition were assessed by a permutation-based multivariate analysis of variance test, while differences in the relative abundances of specific taxa were assessed by Kruskal-Wallis tests. At admission, 9 of 42 patients (21% were colonized with C. difficile, while 6 of 42 (14% subsequently developed a CDI. Furthermore, 3 patients (7% previously had a BSI and 6 patients (14% subsequently developed a BSI. Differences in overall microbiome composition were significantly associated with disease type (p = 0.0086, chemotherapy treatment (p = 0.018, BSI following admission from any cause (p < 0.0001 or suspected gastrointestinal organisms (p = 0.00043. No differences in baseline microbiota were observed between individuals who did or did not subsequently develop C. difficile infection. Additionally, multiple bacterial groups varied significantly between subjects with post-admission BSI compared with no BSI. Our results suggest that differences in gut microbiota not only are associated with type of cancer and chemotherapy, but may also be predictive of subsequent bloodstream infection.

  19. Preventing central line-associated bloodstream infections: a qualitative study of management practices.

    Science.gov (United States)

    Scheck McAlearney, Ann; Hefner, Jennifer L; Robbins, Julie; Harrison, Michael I; Garman, Andrew

    2015-05-01

    To identify factors that may explain hospital-level differences in outcomes of programs to prevent central line-associated bloodstream infections. Extensive qualitative case study comparing higher- and lower-performing hospitals on the basis of reduction in the rate of central line-associated bloodstream infections. In-depth interviews were transcribed verbatim and analyzed to determine whether emergent themes differentiated higher- from lower-performing hospitals. Eight US hospitals that had participated in the federally funded On the CUSP-Stop BSI initiative. One hundred ninety-four interviewees including administrative leaders, clinical leaders, professional staff, and frontline physicians and nurses. A main theme that differentiated higher- from lower-performing hospitals was a distinctive framing of the goal of "getting to zero" infections. Although all sites reported this goal, at the higher-performing sites the goal was explicitly stated, widely embraced, and aggressively pursued; in contrast, at the lower-performing hospitals the goal was more of an aspiration and not embraced as part of the strategy to prevent infections. Five additional management practices were nearly exclusively present in the higher-performing hospitals: (1) top-level commitment, (2) physician-nurse alignment, (3) systematic education, (4) meaningful use of data, and (5) rewards and recognition. We present these strategies for prevention of healthcare-associated infection as a management "bundle" with corresponding suggestions for implementation. Some of the variance associated with CLABSI prevention program outcomes may relate to specific management practices. Adding a management practice bundle may provide critical guidance to physicians, clinical managers, and hospital leaders as they work to prevent healthcare-associated infections.

  20. A functionalized surface modification with vanadium nanoparticles of various valences against implant-associated bloodstream infection.

    Science.gov (United States)

    Wang, Jiaxing; Zhou, Huaijuan; Guo, Geyong; Cheng, Tao; Peng, Xiaochun; Mao, Xin; Li, Jinhua; Zhang, Xianlong

    2017-01-01

    Bloodstream infection, especially with implants involved, is an often life-threatening condition with high mortality rates, imposing a heavy burden on patients and medical systems. Herein, we firstly deposited homogeneous vanadium metal, V2O3, VO2, and V2O5 nanofilms on quartz glass by magnetron sputtering. Using these platforms, we further investigated the potential antimicrobial efficiency of these nano-VOx films and the interactions of human erythrocytes and bacteria (methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa) with our samples in a novel cell-bacteria coculture model. It was demonstrated that these nano-VOx precipitated favorable antibacterial activity on both bacteria, especially on S. aureus, and this effect increased with higher vanadium valence. A possible mechanism accountable for these results might be elevated levels of vanadium-induced intracellular reactive oxygen species. More importantly, based on hemolysis assays, our nano-VOx films were found to be able to kill prokaryotic cells but were not toxic to mammalian cells, holding the potential for the prevention of implant-related hematogenous infections. As far as we know, this is the first report wherein such nano-VOx films have assisted human erythrocytes to combat bacteria in a valence-dependent manner. Additionally, vanadium ions were released from these nano-VOx films in a sustained manner, and low-valence films possessed better biocompatibility with human fibroblasts. This work may provide new insights for biomedical applications of inorganic vanadium compounds and attract growing attention in this field. From the perspective of surface modification and functionalization, this study holds promise to avail the prophylaxis of bloodstream infections involving implantable biomedical devices.

  1. National surveillance of Staphylococcus epidermidis recovered from bloodstream infections in Belgian hospitals.

    Science.gov (United States)

    Deplano, Ariane; Vandendriessche, Stien; Nonhoff, Claire; Dodémont, Magali; Roisin, Sandrine; Denis, Olivier

    2016-07-01

    The objectives of this study were: (i) to determine the species diversity of CoNS isolated from bloodstream infections collected during a national surveillance study; and (ii) to examine the antimicrobial resistance and genomic diversity among Staphylococcus epidermidis isolates. Eighty CoNS were identified by MALDI-TOF. Antimicrobial resistance determination, molecular characterization of resistance and virulence genes, and molecular typing were performed for S. epidermidis isolates. The majority (76%) of CoNS were identified as S. epidermidis. Among these S. epidermidis, 77% were resistant to methicillin [methicillin-resistant S. epidermidis (MRSE)] and showed multiresistance to other antimicrobials. Genes implicated in resistance were erm(C), erm(A) and msr(A) for erythromycin, aacA-aphD and aadC for aminoglycosides, tet(K) for tetracycline and mupA for high-level resistance to mupirocin. Molecular typing showed that 34/40 MRSE isolates (85%) belonged to clonal complex (CC) 2 that could be subdivided into CC2-I (ST2) and CC2-II (ST5, ST59 and ST88). In contrast, methicillin-susceptible S. epidermidis displayed high genomic diversity. The majority (70%) of S. epidermidis isolates contained an icaA or arcA gene. The icaA gene was found in the CC2-I subgroup, whereas arcA was more common in methicillin-susceptible S. epidermidis. S. epidermidis was frequently recovered among CoNS isolated from bloodstream infections with a high proportion of MRSE being multiresistant. A large number of S. epidermidis belonged to CC2, a clone that is disseminated worldwide. More studies are needed to understand its clonal evolutionary success. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  2. Collaborative form(s)

    DEFF Research Database (Denmark)

    Gunn, Wendy

    Gunn asks us to consider beauty as collaborative forms of action generated by moving between design by means of anthropology and anthropology by means of design. Specifically, she gives focus to play-like reflexions on practices of designing energy products, systems and infrastructure. Design...... anthropology engages groups of people within collaborative, interdisciplinary, inter-organizational design processes and co-analytic activities vs. the individual anthropologist conducting studies of people. In doing anthropology by means of design as Gatt and Ingold (2013) have shown, design is considered...

  3. Flagellar adhesion in Trypanosoma brucei relies on interactions between different skeletal structures in the flagellum and cell body.

    Science.gov (United States)

    Rotureau, Brice; Blisnick, Thierry; Subota, Ines; Julkowska, Daria; Cayet, Nadège; Perrot, Sylvie; Bastin, Philippe

    2014-01-01

    The Trypanosoma brucei flagellum is an essential organelle anchored along the surface of the cell body through a specialized structure called the flagellum attachment zone (FAZ). Adhesion relies on the interaction of the extracellular portion of two transmembrane proteins, FLA1 and FLA1BP. Here, we identify FLAM3 as a novel large protein associated with the flagellum skeleton whose ablation inhibits flagellum attachment. FLAM3 does not contain transmembrane domains and its flagellar localization matches closely, but not exactly, that of the paraflagellar rod, an extra-axonemal structure present in the flagellum. Knockdown of FLA1 or FLAM3 triggers similar defects in motility and morphogenesis, characterized by the assembly of a drastically reduced FAZ filament. FLAM3 remains associated with the flagellum skeleton even in the absence of adhesion or a normal paraflagellar rod. However, the protein is dispersed in the cytoplasm when flagellum formation is inhibited. By contrast, FLA1 remains tightly associated with the FAZ filament even in the absence of a flagellum. In these conditions, the extracellular domain of FLA1 points to the cell surface. FLAM3 is essential for proper distribution of FLA1BP, which is restricted to the most proximal portion of the flagellum upon knockdown of FLAM3. We propose that FLAM3 is a key component of the FAZ connectors that link the axoneme to the adhesion zone, hence it acts in an equivalent manner to the FAZ filament complex, but on the side of the flagellum.

  4. A global comparison of the human and T. brucei degradomes gives insights about possible parasite drug targets.

    Directory of Open Access Journals (Sweden)

    Susan T Mashiyama

    Full Text Available We performed a genome-level computational study of sequence and structure similarity, the latter using crystal structures and models, of the proteases of Homo sapiens and the human parasite Trypanosoma brucei. Using sequence and structure similarity networks to summarize the results, we constructed global views that show visually the relative abundance and variety of proteases in the degradome landscapes of these two species, and provide insights into evolutionary relationships between proteases. The results also indicate how broadly these sequence sets are covered by three-dimensional structures. These views facilitate cross-species comparisons and offer clues for drug design from knowledge about the sequences and structures of potential drug targets and their homologs. Two protease groups ("M32" and "C51" that are very different in sequence from human proteases are examined in structural detail, illustrating the application of this global approach in mining new pathogen genomes for potential drug targets. Based on our analyses, a human ACE2 inhibitor was selected for experimental testing on one of these parasite proteases, TbM32, and was shown to inhibit it. These sequence and structure data, along with interactive versions of the protein similarity networks generated in this study, are available at http://babbittlab.ucsf.edu/resources.html.

  5. Loop Mediated Isothermal Amplification for Detection of Trypanosoma brucei gambiense in Urine and Saliva Samples in Nonhuman Primate Model

    Directory of Open Access Journals (Sweden)

    Maina Ngotho

    2015-01-01

    Full Text Available Human African trypanosomiasis (HAT is a vector-borne parasitic zoonotic disease. The disease caused by Trypanosoma brucei gambiense is the most prevalent in Africa. Early diagnosis is hampered by lack of sensitive diagnostic techniques. This study explored the potential of loop mediated isothermal amplification (LAMP and polymerase chain reaction (PCR in the detection of T. b. gambiense infection in a vervet monkey HAT model. Six vervet monkeys were experimentally infected with T. b. gambiense IL3253 and monitored for 180 days after infection. Parasitaemia was scored daily. Blood, cerebrospinal fluid (CSF, saliva, and urine samples were collected weekly. PCR and LAMP were performed on serum, CSF, saliva, and urine samples. The detection by LAMP was significantly higher than that of parasitological methods and PCR in all the samples. The performance of LAMP varied between the samples and was better in serum followed by saliva and then urine samples. In the saliva samples, LAMP had 100% detection between 21 and 77 dpi, whereas in urine the detection it was slightly lower, but there was over 80% detection between 28 and 91 dpi. However, LAMP could not detect trypanosomes in either saliva or urine after 140 and 126 dpi, respectively. The findings of this study emphasize the importance of LAMP in diagnosis of HAT using saliva and urine samples.

  6. Loop Mediated Isothermal Amplification for Detection of Trypanosoma brucei gambiense in Urine and Saliva Samples in Nonhuman Primate Model.

    Science.gov (United States)

    Ngotho, Maina; Kagira, John Maina; Gachie, Beatrice Muthoni; Karanja, Simon Muturi; Waema, Maxwell Wambua; Maranga, Dawn Nyawira; Maina, Naomi Wangari

    2015-01-01

    Human African trypanosomiasis (HAT) is a vector-borne parasitic zoonotic disease. The disease caused by Trypanosoma brucei gambiense is the most prevalent in Africa. Early diagnosis is hampered by lack of sensitive diagnostic techniques. This study explored the potential of loop mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR) in the detection of T. b. gambiense infection in a vervet monkey HAT model. Six vervet monkeys were experimentally infected with T. b. gambiense IL3253 and monitored for 180 days after infection. Parasitaemia was scored daily. Blood, cerebrospinal fluid (CSF), saliva, and urine samples were collected weekly. PCR and LAMP were performed on serum, CSF, saliva, and urine samples. The detection by LAMP was significantly higher than that of parasitological methods and PCR in all the samples. The performance of LAMP varied between the samples and was better in serum followed by saliva and then urine samples. In the saliva samples, LAMP had 100% detection between 21 and 77 dpi, whereas in urine the detection it was slightly lower, but there was over 80% detection between 28 and 91 dpi. However, LAMP could not detect trypanosomes in either saliva or urine after 140 and 126 dpi, respectively. The findings of this study emphasize the importance of LAMP in diagnosis of HAT using saliva and urine samples.

  7. Molecular Evidence of a Trypanosoma brucei gambiense Sylvatic Cycle in the Human African Trypanosomiasis Foci of Equatorial Guinea

    Directory of Open Access Journals (Sweden)

    Carlos eCordon-Obras

    2015-07-01

    Full Text Available Gambiense trypanosomiasis is considered an anthroponotic disease. Consequently, control programs are generally aimed at stopping transmission of Trypanosoma brucei gambiense (T. b. gambiense by detecting and treating human cases. However, the persistence of numerous foci despite efforts to eliminate this disease questions this strategy as unique tool to pursue the eradication. The role of animals as a reservoir of T. b. gambiense is still controversial, but could partly explain maintenance of the infection at hypo-endemic levels. In the present study, we evaluated the presence of T. b. gambiense in wild animals in Equatorial Guinea. The infection rate ranged from 0.8% in the insular focus of Luba to more than 12% in Mbini, a focus with a constant trickle of human cases. The parasite was detected in a wide range of animal species including four species never described previously as putative reservoirs. Our study comes to reinforce the hypothesis that animals may play a role in the persistence of T. b. gambiense transmission, being particularly relevant in low transmission settings. Under these conditions the integration of sustained vector control and medical interventions should be considered to achieve the elimination of Gambiense trypanosomiasis.

  8. A single amino acid substitution in the group 1 Trypanosoma brucei gambiense haptoglobin-hemoglobin receptor abolishes TLF-1 binding.

    Directory of Open Access Journals (Sweden)

    E DeJesus

    Full Text Available Critical to human innate immunity against African trypanosomes is a minor subclass of human high-density lipoproteins, termed Trypanosome Lytic Factor-1 (TLF-1. This primate-specific molecule binds to a haptoglobin-hemoglobin receptor (HpHbR on the surface of susceptible trypanosomes, initiating a lytic pathway. Group 1 Trypanosoma brucei gambiense causes human African Trypanosomiasis (HAT, escaping TLF-1 killing due to reduced uptake. Previously, we found that group 1 T. b. gambiense HpHbR (TbgHpHbR mRNA levels were greatly reduced and the gene contained substitutions within the open reading frame. Here we show that a single, highly conserved amino acid in the TbgHpHbR ablates high affinity TLF-1 binding and subsequent endocytosis, thus evading TLF-1 killing. In addition, we show that over-expression of TbgHpHbR failed to rescue TLF-1 susceptibility. These findings suggest that the single substitution present in the TbgHpHbR directly contributes to the reduced uptake and resistance to TLF-1 seen in these important human pathogens.

  9. Genetic relatedness and risk factor analysis of ampicillin-resistant and high-level gentamicin-resistant enterococci causing bloodstream infections in Tanzanian children

    NARCIS (Netherlands)

    Aamodt, Håvard; Mohn, Stein Christian; Maselle, Samuel; Manji, Karim P; Willems, Rob; Jureen, Roland; Langeland, Nina; Blomberg, Bjørn

    2015-01-01

    BACKGROUND: While enterococci resistant to multiple antimicrobials are spreading in hospitals worldwide, causing urinary tract, wound and bloodstream infections, there is little published data on these infections from Africa. METHODS: We assessed the prevalence, susceptibility patterns, clinical

  10. Delay in the administration of appropriate antimicrobial therapy in Staphylococcus aureus bloodstream infection : A prospective multicenter hospital-based cohort study

    NARCIS (Netherlands)

    Kaasch, A. J.; Rieg, S.; Kuetscher, J.; Brodt, H. -R.; Widmann, T.; Herrmann, M.; Meyer, C.; Welte, T.; Kern, P.; Haars, U.; Reuter, S.; Huebner, I.; Strauss, R.; Sinha, B.; Brunkhorst, F. M.; Hellmich, M.; Faetkenheuer, G.; Kern, W. V.; Seifert, H.

    2013-01-01

    Early broad-spectrum antimicrobial treatment reduces mortality in patients with septic shock. In a multicenter, prospective observational study, we explored whether delayed appropriate antimicrobial therapy (AAT) influences outcome in Staphylococcus aureus bloodstream infection (SAB). Two hundred

  11. Antimicrobial resistance in nosocomial bloodstream infection associated with pneumonia and the value of systematic surveillance cultures in an adult intensive care unit.

    Science.gov (United States)

    Depuydt, Pieter O; Blot, Stijn I; Benoit, Dominique D; Claeys, Geert W; Verschraegen, Gerda L; Vandewoude, Koenraad H; Vogelaers, Dirk P; Decruyenaere, Johan M; Colardyn, Francis A

    2006-03-01

    To study the occurrence of multiple-drug-resistant pathogens in nosocomial bloodstream infection associated with pneumonia. To evaluate prediction of multiple drug resistance by systematic surveillance cultures. A retrospective study of a prospectively gathered cohort. Fifty-four-bed adult medical-surgical intensive care unit of a tertiary hospital. One hundred twelve intensive care unit patients with nosocomial bloodstream infection associated with pneumonia from 1992 through 2001. None. Concordance of blood cultures with prior surveillance culture was assessed. Surveillance cultures were taken routinely as thrice weekly urinary cultures and oral swabs, once weekly anal swabs, and thrice weekly tracheal aspirates in intubated patients. Tracheal surveillance cultures from 48 to 96 hrs before bloodstream infection and surveillance cultures from any site during the same intensive care unit episode but >or=48 hrs before bloodstream infection were evaluated separately. Forty-four bloodstream infections (39%) were caused by a multiple-drug-resistant pathogen. Multiple-drug-resistant pathogens were predicted by tracheal surveillance culture in 70% (concordant); in 15%, tracheal surveillance culture grew a multiple-drug-resistant pathogen not found in blood cultures (discordant). Multiple-drug-resistant pathogens were predicted by any surveillance culture in 88%, but these surveillance cultures grew additional multiple-drug-resistant pathogens not causing bloodstream infection in up to 46% of patients. In 86% of bloodstream infections, early (i.e., within 48 hrs) antibiotic therapy was appropriate. Patients were divided into four risk categories for multiple-drug-resistant bloodstream infection based on length of prior intensive care unit stay and prior antibiotic exposure. In patients with two risk factors, knowledge of surveillance cultures increased appropriateness of early antibiotic therapy from 75-79% to 90% (pbloodstream infection associated with pneumonia in 70

  12. Bloodstream infections caused by carbapenemase-producing Klebsiella pneumoniae among intensive care unit patients after orthotopic liver transplantation: risk factors for infection and impact of resistance on outcomes.

    Science.gov (United States)

    Mouloudi, E; Massa, E; Papadopoulos, S; Iosifidis, E; Roilides, I; Theodoridou, T; Piperidou, M; Orphanou, A; Passakiotou, M; Imvrios, G; Fouzas, I; Papanikolaou, V; Gritsi-Gerogianni, N

    2014-11-01

    Carbapenem-resistant Klebsiella pneumoniae (CRKP) has emerged as an important cause of bloodstream infections in intensive care units (ICUs). The aim of this study was to determine risk factors for bloodstream infections caused by CRKP as well as risk factors for CRKP-associated mortality among ICU patients after orthotopic liver transplantation (LT). The study cohort of this observational study comprised 17 ICU patients after LT with CRKP bloodstream infections. The data from these patients were matched with 34 ICU patients (1:2) after LT without CRKP infections. The 2 groups were compared to identify risk factors for development of CRKP infection and risk factors for mortality. Seventeen CRKP bloodstream infections occurred in ICU patients after LT from January 1, 2008, to December 31, 2011. In univariate analysis, primary liver disease and especially hepatitis C virus infection or hepatocellular cancer were significant factors for development of CRKP. Acute Physiology and Chronic Health Evaluation (APACHE II) score and Sequential Organ Failure Assessment (SOFA) score as well as CRKP bloodstream infection were predictors for ICU death (P infections affect immunocompromised post-transplantation patients more. Bloodstream infections with CRKP along with APACHE and SOFA scores were predictors of death in ICU patients after LT.

  13. Searching PubMed for studies on bacteremia, bloodstream infection, septicemia, or whatever the best term is: a note of caution.

    Science.gov (United States)

    Søgaard, Mette; Andersen, Jens P; Schønheyder, Henrik C

    2012-04-01

    There is inconsistency in the terminology used to describe bacteremia. To demonstrate the impact on information retrieval, we compared the yield of articles from PubMed MEDLINE using the terms "bacteremia," "bloodstream infection," and "septicemia." We searched for articles published between 1966 and 2009, and depicted the relationships among queries graphically. To examine the content of the retrieved articles, we extracted all Medical Subject Headings (MeSH) terms and compared topic similarity using a cosine measure. The recovered articles differed greatly by term, and only 53 articles were captured by all terms. Of the articles retrieved by the "bacteremia" query, 21,438 (84.1%) were not captured when searching for "bloodstream infection" or "septicemia." Likewise, only 2,243 of the 11,796 articles recovered by free-text query for "bloodstream infection" were retrieved by the "bacteremia" query (19%). Entering "bloodstream infection" as a phrase, 46.1% of the records overlapped with the "bacteremia" query. Similarity measures ranged from 0.52 to 0.78 and were lowest for "bloodstream infection" as a phrase compared with "septicemia." Inconsistent terminology has a major impact on the yield of queries. Agreement on terminology should be sought and promoted by scientific journals. An immediate solution is to add "bloodstream infection" as entry term for bacteremia in the MeSH vocabulary. Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  14. Antimicrobial-impregnated central venous catheters for prevention of catheter-related bloodstream infection in newborn infants.

    Science.gov (United States)

    Balain, Munisha; Oddie, Sam J; McGuire, William

    2015-09-27

    Central venous catheter-related bloodstream infection is an important cause of mortality and morbidity in newborn infants cared for in neonatal units. Potential strategies to prevent these infections include the use of central venous catheters impregnated with antimicrobial agents. To determine the effect of antimicrobial-impregnated central venous catheters in preventing catheter-related bloodstream infection in newborn infants. We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 8), MEDLINE (1966 to September 2015), EMBASE (1980 to September 2015), CINAHL (1982 to September 2015), conference proceedings and previous reviews. Randomised or quasi-randomised controlled trials comparing central venous catheters impregnated or coated with any antibiotic or antiseptic versus central venous catheters without antibiotic or antiseptic coating or impregnation in newborn infants. We extracted data using the standard methods of the Cochrane Neonatal Group, with independent evaluation of risk of bias and data extraction by two review authors. We found only one small trial (N = 98). This trial found that silver zeolite-impregnated umbilical venous catheters reduced the incidence of bloodstream infection in very preterm infants (risk ratio 0.11, 95% confidence interval 0.01 to 0.87; risk difference -0.17, 95% CI -0.30 to -0.04; number needed to treat for benefit 6, 95% CI 3 to 25]. Although the data from one small trial indicates that antimicrobial-impregnated central venous catheters might prevent catheter-related bloodstream infection in newborn infants, the available evidence is insufficient to guide clinical practice. A large, simple and pragmatic randomised controlled trial is needed to resolve on-going uncertainty.

  15. Identification and Whole Genome Sequencing of the First Case of Kosakonia radicincitans Causing a Human Bloodstream Infection

    OpenAIRE

    Bhatti, Micah D.; Kalia, Awdhesh; Sahasrabhojane, Pranoti; Kim, Jiwoong; Greenberg, David E.; Shelburne, Samuel A.

    2017-01-01

    The taxonomy of Enterobacter species is rapidly changing. Herein we report a bloodstream infection isolate originally identified as Enterobacter cloacae by Vitek2 methodology that we found to be Kosakonia radicincitans using genetic means. Comparative whole genome sequencing of our isolate and other published Kosakonia genomes revealed these organisms lack the AmpC β-lactamase present on the chromosome of Enterobacter sp. A fimbriae operon primarily found in Escherichia coli O157:H7 isolates ...

  16. A Critical Appraisal of the Role of the Clinical Microbiology Laboratory in the Diagnosis of Bloodstream Infections

    OpenAIRE

    Weinstein, Melvin P.; Doern, Gary V.

    2011-01-01

    The detection of bloodstream infections is one of the most important functions of clinical microbiology laboratories. Despite advances in blood culture technology and clinical studies that have focused on the detection of bacteremia and fungemia, perfection has not been achieved and uncertainties persist. This review provides perspectives on a number of areas, including the recommended number of blood cultures, duration of incubation of blood cultures, use of anaerobic, in addition to aerobic...

  17. Bloodstream Amyloid-beta (1-40) Peptide, Cognition, and Outcomes in Heart Failure.

    Science.gov (United States)

    Bayes-Genis, Antoni; Barallat, Jaume; de Antonio, Marta; Domingo, Mar; Zamora, Elisabet; Vila, Joan; Subirana, Isaac; Gastelurrutia, Paloma; Pastor, M Cruz; Januzzi, James L; Lupón, Josep

    2017-11-01

    In the brain, amyloid-beta generation participates in the pathophysiology of cognitive disorders; in the bloodstream, the role of amyloid-beta is uncertain but may be linked to sterile inflammation and senescence. We explored the relationship between blood levels of amyloid-beta 1-40 peptide (Aβ40), cognition, and mortality (all-cause, cardiovascular, and heart failure [HF]-related) in ambulatory patients with HF. Bloodstream Aβ40 was measured in 939 consecutive patients with HF. Cognition was evaluated with the Pfeiffer questionnaire (adjusted for educational level) at baseline and during follow-up. Multivariate Cox regression analyses and measurements of performance (discrimination, calibration, and reclassification) were used, with competing risk for specific causes of death. Over 5.1 ± 2.9 years, 471 patients died (all-cause): 250 from cardiovascular causes and 131 HF-related. The median Aβ40 concentration was 519.1 pg/mL [Q1-Q3: 361.8-749.9 pg/mL]. The Aβ40 concentration correlated with age, body mass index, renal dysfunction, and New York Heart Association functional class (all P < .001). There were no differences in Aβ40 in patients with and without cognitive impairment at baseline (P = .97) or during follow-up (P = .20). In multivariable analysis, including relevant clinical predictors and N-terminal pro-B-type natriuretic peptide, Aβ40 remained significantly associated with all-cause death (HR, 1.22; 95%CI, 1.10-1.35; P < .001) and cardiovascular death (HR, 1.18; 95%CI, 1.03-1.36; P = .02), but not with HF-related death (HR, 1.13; 95%CI, 0.93-1.37; P = .22). Circulating Aβ40 improved calibration and patient reclassification. Blood levels of Aβ40 are not associated with cognitive decline in HF. Circulating Aβ40 was predictive of mortality and may indicate systemic aging. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  18. Prediction of Fluoroquinolone Resistance in Gram-Negative Bacteria Causing Bloodstream Infections.

    Science.gov (United States)

    Dan, Seejil; Shah, Ansal; Justo, Julie Ann; Bookstaver, P Brandon; Kohn, Joseph; Albrecht, Helmut; Al-Hasan, Majdi N

    2016-04-01

    Increasing rates of fluoroquinolone resistance (FQ-R) have limited empirical treatment options for Gram-negative infections, particularly in patients with severe beta-lactam allergy. This case-control study aims to develop a clinical risk score to predict the probability of FQ-R in Gram-negative bloodstream isolates. Adult patients with Gram-negative bloodstream infections (BSI) hospitalized at Palmetto Health System in Columbia, South Carolina, from 2010 to 2013 were identified. Multivariate logistic regression was used to identify independent risk factors for FQ-R. Point allocation in the fluoroquinolone resistance score (FQRS) was based on regression coefficients. Model discrimination was assessed by the area under receiver operating characteristic curve (AUC). Among 824 patients with Gram-negative BSI, 143 (17%) had BSI due to fluoroquinolone-nonsusceptible Gram-negative bacilli. Independent risk factors for FQ-R and point allocation in FQRS included male sex (adjusted odds ratio [aOR], 1.97; 95% confidence intervals [CI], 1.36 to 2.98; 1 point), diabetes mellitus (aOR, 1.54; 95% CI, 1.03 to 2.28; 1 point), residence at a skilled nursing facility (aOR, 2.28; 95% CI, 1.42 to 3.63; 2 points), outpatient procedure within 30 days (aOR, 3.68; 95% CI, 1.96 to 6.78; 3 points), prior fluoroquinolone use within 90 days (aOR, 7.87; 95% CI, 4.53 to 13.74; 5 points), or prior fluoroquinolone use within 91 to 180 days of BSI (aOR, 2.77; 95% CI, 1.17 to 6.16; 3 points). The AUC for both final logistic regression and FQRS models was 0.73. Patients with an FQRS of 0, 3, 5, or 8 had predicted probabilities of FQ-R of 6%, 22%, 39%, or 69%, respectively. The estimation of patient-specific risk of antimicrobial resistance using FQRS may improve empirical antimicrobial therapy and fluoroquinolone utilization in Gram-negative BSI. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  19. Bloodstream infection in paediatric cancer centres--leukaemia and relapsed malignancies are independent risk factors.

    Science.gov (United States)

    Ammann, R A; Laws, H J; Schrey, D; Ehlert, K; Moser, O; Dilloo, D; Bode, U; Wawer, A; Schrauder, A; Cario, G; Laengler, A; Graf, N; Furtwängler, R; Simon, A

    2015-05-01

    In a prospective multicentre study of bloodstream infection (BSI) from November 01, 2007 to July 31, 2010, seven paediatric cancer centres (PCC) from Germany and one from Switzerland included 770 paediatric cancer patients (58% males; median age 8.3 years, interquartile range (IQR) 3.8-14.8 years) comprising 153,193 individual days of surveillance (in- and outpatient days during intensive treatment). Broviac catheters were used in 63% of all patients and Ports in 20%. One hundred forty-two patients (18%; 95% CI 16 to 21%) experienced at least one BSI (179 BSIs in total; bacteraemia 70%, bacterial sepsis 27%, candidaemia 2%). In 57%, the BSI occurred in inpatients, in 79% after conventional chemotherapy. Only 56 % of the patients showed neutropenia at BSI onset. Eventually, patients with acute lymphoblastic leukaemia (ALL) or acute myeloblastic leukaemia (AML), relapsed malignancy and patients with a Broviac faced an increased risk of BSI in the multivariate analysis. Relapsed malignancy (16%) was an independent risk factor for all BSI and for Gram-positive BSI. This study confirms relapsed malignancy as an independent risk factor for BSIs in paediatric cancer patients. On a unit level, data on BSIs in this high-risk population derived from prospective surveillance are not only mandatory to decide on empiric antimicrobial treatment but also beneficial in planning and evaluating preventive bundles. • Paediatric cancer patients face an increased risk of nosocomial bloodstream infections (BSIs). • In most cases, these BSIs are associated with the use of a long-term central venous catheter (Broviac, Port), severe and prolonged immunosuppression (e.g. neutropenia) and other chemotherapy-induced alterations of host defence mechanisms (e.g. mucositis). What is New: • This study is the first multicentre study confirming relapsed malignancy as an independent risk factor for BSIs in paediatric cancer patients. • It describes the epidemiology of nosocomial BSI in

  20. Polymorphisms in Fibronectin Binding Proteins A and B among Staphylococcus aureus Bloodstream Isolates Are Not Associated with Arthroplasty Infection.

    Directory of Open Access Journals (Sweden)

    Emily M Eichenberger

    Full Text Available Nonsynonymous single nucleotide polymorphisms (SNPs in fibronectin binding protein A (fnbA of Staphylococcus aureus are associated with cardiac device infections. However, the role of fnbA SNPs in S. aureus arthroplasty infection is unknown.Bloodstream S. aureus isolates from a derivation cohort of patients at a single U.S. medical center with S. aureus bacteremia (SAB and prosthetic hip or knee arthroplasties that were infected (PJI, n = 27 or uninfected (PJU, n = 43 underwent sequencing of fnbA and fnbB. A validation cohort of S. aureus bloodstream PJI (n = 12 and PJU (n = 58 isolates from Germany also underwent fnbA and fnbB sequencing.Overall, none of the individual fnbA or fnbB SNPs were significantly associated with the PJI or PJU clinical groups within the derivation cohort. Similarly, none of the individual fnbA or fnbB SNPs were associated with PJI or PJU when the analysis was restricted to patients with either early SAB (i.e., bacteremia occurring 1 year after placement or manipulation of prostheses.In contrast to cardiac device infections, there is no association between nonsynonymous SNPs in fnbA or fnbB of bloodstream S. aureus isolates and arthroplasty infection. These results suggest that initial steps leading to S. aureus infection of cardiovascular and orthopedic prostheses may arise by distinct processes.

  1. Trypanosoma brucei Invasion and T-Cell Infiltration of the Brain Parenchyma in Experimental Sleeping Sickness: Timing and Correlation with Functional Changes.

    Directory of Open Access Journals (Sweden)

    Claudia Laperchia

    2016-12-01

    Full Text Available The timing of Trypanosoma brucei entry into the brain parenchyma to initiate the second, meningoencephalitic stage of human African trypanosomiasis or sleeping sickness is currently debated and even parasite invasion of the neuropil has been recently questioned. Furthermore, the relationship between neurological features and disease stage are unclear, despite the important diagnostic and therapeutic implications.Using a rat model of chronic Trypanosoma brucei brucei infection we determined the timing of parasite and T-cell neuropil infiltration and its correlation with functional changes. Parasite DNA was detected using trypanosome-specific PCR. Body weight and sleep structure alterations represented by sleep-onset rapid eye movement (SOREM periods, reported in human and experimental African trypanosomiasis, were monitored. The presence of parasites, as well as CD4+ and CD8+ T-cells in the neuropil was assessed over time in the brain of the same animals by immunocytochemistry and quantitative analyses.Trypanosome DNA was present in the brain at day 6 post-infection and increased more than 15-fold by day 21. Parasites and T-cells were observed in the parenchyma from day 9 onwards. Parasites traversing blood vessel walls were observed in the hypothalamus and other brain regions. Body weight gain was reduced from day 7 onwards. SOREM episodes started in most cases early after infection, with an increase in number and duration after parasite neuroinvasion.These findings demonstrate invasion of the neuropil over time, after an initial interval, by parasites and lymphocytes crossing the blood-brain barrier, and show that neurological features can precede this event. The data thus challenge the current clinical and cerebrospinal fluid criteria of disease staging.

  2. Comparative biochemical and pathological changes in some laboratory animals experimentally infected with Trypanosoma brucei and their responses to diminazene diaceturate (Veriben® therapy

    Directory of Open Access Journals (Sweden)

    Amina Ibrahim

    2015-12-01

    Full Text Available Objective: To compare the biochemical and pathological changes of Trypanosoma brucei brucei infected mice, rats and rabbits, and study the chemotherapeutic effects according to standard criteria. Methods: A total of 20 Balb/c Albino mice, 20 Wister Albino rats and 20 New Zealand rabbits, all adults and of both sexes were used in the study. Each rodent group was divided into four groups (A, B, C and D of five animals each. Animals in Groups A and C were individually infected with 0.5 mL of blood from donor rats containing 1.5 ××106 Trypanasoma brucei brucei, while Groups B and D remained uninfected. The animals were later treated like this: Group A (infected and untreated control, Group B (uninfected and untreated control, Group C (infected and treated and Group D (uninfected and treated. The treatment was administered on Day 12 after infection. Results: The prepatent period for mice and rats was 4 days while that for rabbits was 8 days. There was a significant (P < 0.05 increase in levels of liver enzymes and serum metabolites which were more marked among the mice and rats than rabbits. These changes were modulated to their preinfection values in the infected treated animals. At necropsy, all animals showed splenomegaly, hepatomegaly and nephritis. However, cardiomegaly was exclusive to the rabbits. Histopathologically, degenerative changes were observed in both the liver and kidneys which were more severe among mice and rats and moderate in rabbits. Spleen of mice showed giant macrophages, while that of the rats showed epithelioid giant cells. However, spleen of rabbits showed haemosiderosis and eosinophilic infiltrations. Hydrophobic degeneration, necrosis and mononuclear cell infiltrations in the myocardium were observed only among rabbits. Conclusions: Diminazene diaceturate was able to ameliorate the various biochemical and pathological changes which were suggestive of severe liver and kidney dysfunctions with greater intensity occurring

  3. Outbreak of Mycobacterium mucogenicum bloodstream infections among patients with sickle cell disease in an outpatient setting.

    Science.gov (United States)

    Ashraf, Muhammad Salman; Swinker, Marian; Augustino, Kerri L; Nobles, Delores; Knupp, Charles; Liles, Darla; Christie, John; Ramsey, Keith M

    2012-11-01

    To study an outbreak of Mycobacterium mucogenicum bloodstream infections in an outpatient setting. Outbreak investigation and retrospective chart review. University outpatient clinic. Patients. Patients whose blood cultures tested positive for M. mucogenicum in May or June 2008. An outbreak investigation and a review of infection control practices were conducted. During the process, environmental culture samples were obtained. Isolates from patients and the environment were genotyped with the DiversiLab typing system to identify the source. Chart reviews were conducted to study the management and outcomes of the patients. Four patients with sickle cell disease and implanted ports followed in the same hematology outpatient clinic developed blood cultures positive for M. mucogenicum. A nurse in the clinic had prepared intravenous port flushes on the sink counter, using a saline bag that was hanging over the sink throughout the shift. None of the environmental cultures grew M. mucogenicum except for the tap water from 2 rooms, 1 of which had a faucet aerator. The 4 patient isolates and the tap water isolate from the room with the aerator were found to have greater than 98.5% similarity. The subcutaneous ports were removed, and patients cleared their infections after a course of antibiotic therapy. The source of the M. mucogenicum bacteremia outbreak was identified by genotyping analysis as the clinic tap water supply. The preparation of intravenous medications near the sink was likely an important factor in transmission, along with the presence of a faucet aerator.

  4. [Blood-stream catheter related infection in inpatient children receiving parenteral nutrition].

    Science.gov (United States)

    Vaquero Sosa, E; Izquierdo García, E; Arrizabalaga Asenjo, M; Gómez Peñalba, C; Moreno Villares, J M

    2011-01-01

    Blood-stream catheter related infection is the most severe complication in patients carrying a central venous catheter. Parenteral nutrition (PN) use seems to be a risk factor for developing a catheter-related infection (CRI). In order to know the incidence of CRI in children to further implement policies to reduce nosocomial infection, we review all charts of children (1 month to 17 years) who received parenteral nutrition while in hospital. All episodes of fever + positive blood culture were recorded. Infection rate was defined as number of episodes/1000 Parenteral nutrition days. 48 positive blood cultures was obtained from 120 patients. Infection rate was 37.8/1000 days. Incidence was significantly higher in infants and toddlers (52% vs 29.8%, p = 0.016). Most frequent organisms were coagulase negative Staph. (56.8%), Gram negative bacilli (20.8%), Staph aureus (12.5%) and fungus (12.5%). No difference in incidence were found according to the underlying disease or the length of PN use. Infection rate in our PN inpatient patients was significantly higher. PN may represent a risk factor for developing a CRI. Specific measurements and policies need to be implemented to overcome present situation.

  5. [Bacterial and fungal bloodstream infections in patients at the University Hospital of Cracow].

    Science.gov (United States)

    Kedzierska, Jolanta; Wegrzyn, Joanna; Kedzierska, Anna; Pietrzyk, Agata

    2003-01-01

    In presented material evaluation of changes in sepsis and types of bloodstream infections of hospitalized patients in Wards of the University Hospital in Cracow were examined. Results of 9,138 blood cultures studied in years 1989-1999 were analysed. All of the blood samples were recovered from 4,656 infected adults at Clinics of the University Hospital in Cracow. Microbiological blood examinations were held in system of constant monitoring of isolated cultures applying BacT/Alert--colorimetric system (Organon Teknika). Cultured micro--organisms were identified using commercial biochemical tests (bio-Merieux). During period of research changes of profile of isolated microorganisms was observed. Percentage of blood infections of Enterococcus spp. etiology increased from 2.2% in 1989 to 9.8% in 1997-98 (p = 0.014). Dynamic growth of non-fermentative S. maltophilia bacilli to 5.5% (p = 0.036) and Serratia marcescens to 13.8% (p = 0.042) in 1999 was revealed. Designed according to our research review of fungal flora in years 1989-1999 revealed tendency of systematic growth of invasive candidemia frequency, from 1.1% to 10.4%. Diagnostic and therapeutic profile of Departments was in a strict connection with increase of the number and meaning of the politiological bacteremias (p = 0.036) in total number of systemic infections cases.

  6. [Exposition to total parenteral nutrition increases the risk of catheter-related bloodstream infection].

    Science.gov (United States)

    Vergara, Teresa; Véliz, Elena; Fica, Alberto

    2016-12-01

    Infectious complications associated to central venous catheter (CVC) increase morbidity, mortality and costs. Total parenteral nutrition (TPN) is one of the risk factors described for catheter-related bloodstream infection (CR-BSI). The aim of this study was explore if TPN and time of exposition, are risk factors for CR-BSI among patient exposed to this therapy. Cohort study of patients with CVC exposed and not exposed to TPN with calculation of the relative risk (RR) for CR-BSI and percentage of CR-BSI according to different times of exposition to TPN. Study encompassed years 2010-2015 and only adult patients were included. During the study period 51 events of CR-BSI were identified, with 27 occurring among those exposed to TPN and 24 among those not exposed. CR-BSI incidence rate was 6.3 in the group with TPN and 1.2 in those without this therapy (RR 5.4; IC 95 3.6-8.2). The percentage of patients with CR-BSI increased in parallel to exposition time (Pearson coefficient +0.91) and the OR increased for expositions ≥ 7 days (OR 2.8; IC 95 1.047.4; p < 0.05). Exposition to TPN increases the risk to CR-BSI in adult patients with CVC and this risk raise with exposition time.

  7. Real-time PCR TaqMan assay for rapid screening of bloodstream infection

    Science.gov (United States)

    2014-01-01

    Background Sepsis is one of the main causes of mortality and morbidity. The rapid detection of pathogens in blood of septic patients is essential for adequate antimicrobial therapy and better prognosis. This study aimed to accelerate the detection and discrimination of Gram-positive (GP) and Gram-negative (GN) bacteria and Candida species in blood culture samples by molecular methods. Methods The Real-GP®, -GN®, and -CAN® real-time PCR kit (M&D, Wonju, Republic of Korea) assays use the TaqMan probes for detecting pan-GP, pan-GN, and pan-Candida species, respectively. The diagnostic performances of the real-time PCR kits were evaluated with 115 clinical isolates, 256 positive and 200 negative blood culture bottle samples, and the data were compared to results obtained from conventional blood culture. Results Eighty-seven reference strains and 115 clinical isolates were correctly identified with specific probes corresponding to GP-bacteria, GN-bacteria and Candida, respectively. The overall sensitivity and specificity of the real-time PCR kit with blood culture samples were 99.6% and 89.5%, respectively. Conclusions The Real-GP®, -GN®, and -CAN® real-time PCR kits could be useful tools for the rapid and accurate screening of bloodstream infections (BSIs). PMID:24393579

  8. Emergence of Livestock-Associated Methicillin-Resistant Staphylococcus aureus Bloodstream Infections in Denmark

    DEFF Research Database (Denmark)

    Larsen, Jesper; Petersen, Andreas; Larsen, Anders R.

    2017-01-01

    Background: Livestock-associated methicillin-resistant Staphylococcus aureus clonal complex 398 (LA-MRSA CC398) is causing an increasing number of skin and soft tissue infections (SSTIs) in Denmark and other European countries with industrial pig production. Yet, its impact on MRSA bloodstream...... infections (BSIs) has not been well studied. Methods: We investigated the clinical epidemiology of all human cases of LA-MRSA CC398 BSI during 2010-2015. Cases of LA-MRSA CC398 BSI were compared to cases of BSI caused by other types of MRSA and cases of SSTI caused by LA-MRSA CC398. Whole-genome sequence...... analysis was used to assess the phylogenetic relationship among LA-MRSA CC398 isolates from Danish pigs and cases of BSI and SSTI. Results: The number of LA-MRSA CC398 BSIs and SSTIs increased over the years, peaking in 2014, when LA-MRSA CC398 accounted for 16% (7/44) and 21% (211/985) of all MRSA BSIs...

  9. Review of streptococcal bloodstream infections at a comprehensive cancer care center, 2000-2011.

    Science.gov (United States)

    Shelburne, Samuel A; Tarrand, Jeffrey; Rolston, Kenneth V

    2013-02-01

    To determine the comparative rates, clinical characteristics, and outcomes of invasive infections due to specific streptococcal types in patients with cancer. Review of electronic medical records of patients with non-viridans group streptococcal bloodstream infection (BSI) at the MD Anderson Cancer Center from 2000 to 2011. 550 streptococcal BSI were identified. The largest number of cases were caused by Streptococcus pneumoniae (251), group B Streptococcus (147), and gamma-hemolytic streptococci (55). Risk factors for developing a severe streptococcal infection included older age, being neutropenic at onset of BSI, and having a respiratory source of infection. Between 2000-2001 and 2010-2011, the rates of S. pneumoniae BSI and penicillin non-susceptibility decreased by 55% and 100%. In contrast the rate of group B streptococcal (GBS) BSI increased 34% over the same time period. GBS accounted for >80% of the recurrent infections following streptococcal BSI. Patients with breast cancer and those with soft-tissue/bone BSI sources were at increased risk for recurrent GBS infection but had lower rates of severe GBS disease. From 2000 to 2011, our comprehensive cancer center observed a significant decrease in the rates of S. pneumoniae BSI and a significant increase in the rates of GBS BSI. Copyright © 2012 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  10. Probing the bioinorganic chemistry of toxic metals in the mammalian bloodstream to advance human health.

    Science.gov (United States)

    Gailer, Jürgen

    2012-03-01

    The etiology of numerous grievous human diseases, including Alzheimer's and Parkinson's Disease is not well understood. Conversely, the concentration toxic metals and metalloids, such as As, Cd, Hg and Pb in human blood of the average population is well established, yet we know strikingly little about the role that they might play in the etiology of disease processes. Establishing functional connections between the chronic exposure of humans to these and other inorganic pollutants and the etiology of certain human diseases is therefore viewed by many as one of the greatest challenges in the post-genomic era. Conceptually, this task requires us to uncover hitherto unknown biomolecular mechanisms which must explain how small doses of a toxic metal/metalloid compound (low μg per day) - or mixtures thereof - may eventually result in a particular human disease. The biological complexity that is inherently associated with mammals, however, makes the discovery of these mechanisms a truly monumental task. Recent findings suggest that a better understanding of the bioinorganic chemistry of inorganic pollutants in the mammalian bloodstream represents a fruitful strategy to unravel relevant biomolecular mechanisms. The adverse effect(s) that toxic metals/metalloid compounds exert on the transport of essential ultratrace elements to internal organs appear particularly pertinent. A brief overview of the effect that arsenite and Hg(2+) exert on the mammalian metabolism of selenium is presented. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Incidence of nosocomial hemodialysis-associated bloodstream infections at a county teaching hospital.

    Science.gov (United States)

    Gnass, Matías; Gielish, Caren; Acosta-Gnass, Silvia

    2014-02-01

    Infections are an important cause of morbidity and mortality in patients undergoing hemodialysis. Limited information is to be found regarding nosocomial hemodialysis-associated bloodstream infections (HABSI). We sought to determine the rate of nosocomial HABSI and its associated risk factors at Riverside County Regional Medical Center. Inpatients who received hemodialysis during 2011 and 2012 were included, and outcomes were recorded along with risk factors. Data was analyzed with SPSS Inc software. A total of 619 patients was included. Fourteen HABSI were detected, with a rate of 3.33/1,000 hemodialysis sessions and 1.03/1,000 patient-days. An association was detected between HABSI and vascular access type (highest risk with nontunneled catheters), length of hospital stay, number of hemodialysis sessions, and hemoglobin A1c level. A correlation was also noted between HABSI because of MRSA and colonization of nares with MRSA. A predominance of staphylococci infections was detected. The rate of HABSI observed at Riverside County Regional Medical Center was lower than similar studies (2.5 per 1,000 patient-days and 3.95 per 1,000 hemodialysis sessions). The most important risk factors were determined to be nontunneled catheters, hemoglobin A1c greater than 7%, and nares colonization for HABSI because of MRSA. Infection prevention efforts in the inpatient hemodialysis population should focus on control of hyperglycemia and decolonization of nares from MRSA. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  12. The risk factors for mortality in deceased donor liver transplant recipients with bloodstream infections.

    Science.gov (United States)

    Wan, Q Q; Ye, Q F; Ming, Y Z; Ma, Y; Zhou, J D; Qiao, B B

    2013-01-01

    Information on risk factors for mortality among deceased donor liver transplant recipients with bloodstream infections (BSIs) was sought using a retrospective analysis from January 2002 to January 2012. We performed deceased donor liver transplantations in 135 subjects who experienced 77 episodes of BSIs. We assessed risk factors for mortality among 43 of them using univariate and multivariate logistic regression analysis. The 43 recipients (31.9%) who developed BSI showed a mean age of 45.1 (45.1 ± 14.1 years). The majority of infections were nosocomial in origin (97.7%), with more than half being polymicrobial (53.5%). There were 24 deaths among these recipients (55.8%). The univariate analysis identified the following variables as risk factors for BSI-related mortality: polymicrobial (P = .029), platelet count 1.5 mg/dL (P = .008), and septic shock (P risk factors for mortality to be a serum creatinine > 1.5 mg/dL and septic shock. The risk factors significantly associated with increased mortality in deceased donor liver transplant recipients with BSIs are higher serum creatinine levels and septic shock. Despite appropriate antimicrobial treatment, BSIs accompanied by septic shock or higher serum creatinine levels were associated with high mortality rates. It is therefore essential to protect renal function to reduce the incidence of BSIs. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Reducing neonatal nosocomial bloodstream infections through participation in a national surveillance system.

    Science.gov (United States)

    Schwab, F; Geffers, C; Bärwolff, S; Rüden, H; Gastmeier, P

    2007-04-01

    A national nosocomial surveillance system for neonatal intensive care patients with a very low birthweight was set up in Germany in 2000 (NEO-KISS). Forty-eight neonatal intensive care units (NICUs) participated in the programme, which focused upon nosocomial bloodstream infections (BSIs) and pneumonia. Only data from NICUs participating for at least three years were included and the years compared. The relative risks and their 95% confidence intervals (CIs) were calculated and a multiple logistic regression analysis performed to identify significant risk factors. Twenty-four units that met the selection criteria accumulated data for 3856 patients and 152 437 patient-days in their first three years of participation. The incidence density of BSIs decreased significantly by 24% from 8.3 BSIs per 1000 patient-days in the first year to 6.4 in the third year. In the multiple logistic regression analysis, BSI in the third year of participation was significantly lower than in the first year of participation (odds ratio=0.73, 95% CI 0.60-0.89). The year of participation was an independent risk factor for BSI but not for pneumonia. Our data suggest that participation in ongoing surveillance of nosocomial infections in NICUs, requiring individual units to feedback data, may lead to a reduction in BSI rates.

  14. Nosocomial bloodstream infections: organisms, risk factors and resistant phenotypes in the Brazilian University Hospital.

    Science.gov (United States)

    Ribas, Rosineide M; Freitas, Claudete; Gontijo Filho, Paulo P

    2007-06-01

    Bacteremia is one of the most frequent and challenging hospital-acquired infection and it is associated with high attributable morbidity and mortality and additional use of healthcare resources. The objective of this work was to determine the frequencies of its occurrence, organisms and resistance phenotypes associated to nosocomial acquired bloodstream infections. A total number of 51 nosocomial bacteremia by Gram-negative and 99 by Gram-positive were evaluated and compared during a 15-month period. The risk factors associated with these bacteremias were analyzed and antibiotic use and surgery were associated with bacteremia by Gram-negative and > 2 invasive devices with Gram-positive. The resistance phenotypes ESBL (extended-spectrum beta-lactamases) (23.5%) and AmpC/others (17.6%) correspond to 41.2 % with predominance of E. agglomerans among AmpC (44.4%) and K. pneumoniae among ESBLs (38.5%). Among S. aureus bacteremia, approximately 40% were associated to MRSA (methicillin-resistant Staphylococcus aureus).

  15. Risk Factors and Outcomes for Bloodstream Infections Secondary to Clostridium difficile Infection.

    Science.gov (United States)

    Falcone, Marco; Russo, Alessandro; Iraci, Federica; Carfagna, Paolo; Goldoni, Paola; Vullo, Vincenzo; Venditti, Mario

    2015-10-19

    We determined the incidence, risk factors, and outcomes of bloodstream infections (BSI) subsequent to Clostridium difficile infection (CDI). We performed a retrospective study of all patients with definite diagnosis of CDI admitted from January 2014 to December 2014 in two large hospitals in Rome. Two groups of patients were analyzed: those with CDI and subsequent BSI (CDI/BSI(+)) and those with CDI and no evidence of primary BSI (CDI/BSI(-)). Data about clinical features, microbiology, treatments, and mortality were obtained. Overall, 393 cases of CDI were included in the final analysis: 72 developed a primary nosocomial BSI, while 321 had CDI without microbiological and clinical evidence of BSI. Etiologic agents of BSI were Candida species (47.3%), Enterobacteriaceae (19.4%), enterococci (13.9%), and mixed infections (19.4%). In multivariate analysis, ribotype 027 status (odds ratio [OR], 6.5), CDI recurrence (OR, 5.5), severe CDI infection (OR, 8.3), and oral vancomycin at >500 mg/day (OR, 3.1) were recognized as factors independently associated with the development of nosocomial BSI. Thirty-day mortality from CDI diagnosis was higher for patients of the CDI/BSI(+) group than for the controls (38.9 versus 13.1%; P nosocomial BSI. Candida species and enteric bacteria appear to be the leading causative pathogens and are associated with poor outcomes. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  16. [Risk factors for nosocomial bloodstream infections in a neonatal intensive care unit].

    Science.gov (United States)

    Tian, Luan-Ying; Hamvas, Aaron

    2010-08-01

    To assess the risk factors for nosocomial blood-stream infection (BSI) in a neonatal intensive care unit (NICU). Clinical data from the neonates admitted to the NICU in the St. Louis Children's Hospital in Washington University School of Medicine between January 2005 and December 2006 were retrospectively studied. A total of 1 290 neonates were included. Overall, 175 nosocomial BSIs occurred. Catheter-related BSIs accounted for 62.3% (109 cases). The incidence of nosocomial BSI was 4.22 per 1 000 patient-days. Logistic regression analysis revealed that low gestational age, low Apgar scores at 5 minutes, use of central venous catheter (CVC), and longer CVC use were risk factors for the development of nosocomial BSI. In the subgroup of neonates with CVC, mechanical ventilation was an additional independent risk factor for BSI. Catheter-related BSI is the major source of nosocomial BSI in the NICU. Prematurity, low Apgar scores at birth and prolonged CVC use are risk factors for the development of BSI.

  17. Nosocomial bloodstream infections: organisms, risk factors and resistant phenotypes in the Brazilian University Hospital

    Directory of Open Access Journals (Sweden)

    Rosineide M. Ribas

    Full Text Available Bacteremia is one of the most frequent and challenging hospital-acquired infection and it is associated with high attributable morbidity and mortality and additional use of healthcare resources. The objective of this work was to determine the frequencies of its occurrence, organisms and resistance phenotypes associated to nosocomial acquired bloodstream infections. A total number of 51 nosocomial bacteremia by Gram-negative and 99 by Gram-positive were evaluated and compared during a 15-month period. The risk factors associated with these bacteremias were analyzed and antibiotic use and surgery were associated with bacteremia by Gram-negative and > 2 invasive devices with Gram-positive. The resistance phenotypes ESBL (extended-spectrum beta-lactamases (23.5% and AmpC/others (17.6% correspond to 41.2 % with predominance of E. agglomerans among AmpC (44.4% and K. pneumoniae among ESBLs (38.5%. Among S. aureus bacteremia, approximately 40% were associated to MRSA (methicillin-resistant Staphylococcus aureus.

  18. Risk Factors for Health Care-Associated Bloodstream Infections in a Neonatal Intensive Care Unit.

    Science.gov (United States)

    Ertugrul, Sabahattin; Aktar, Fesih; Yolbas, Ilyas; Yilmaz, Ahmet; Elbey, Bilal; Yildirim, Ahmet; Yilmaz, Kamil; Tekin, Recep

    2016-10-01

    Healthcare-associated bloodstream infections (HCA-BSI) are a major cause of morbidity and mortality in neonatal intensive care units (NICUs). We aimed to determine the causative organisms and risk factors of HCA-BSIs in NICUs. This study was performed between January 2011 and December 2014 in the neonatal intensive care unit of Dicle university, Turkey. The study consisted of 126 patients (infected group) with positive blood culture and 126 randomly selected patients (uninfected control group) with negative blood culture after four days of hospitalization. We found that the most common causative agents isolated from nosocomial infections (NIs) were 20.7% Staphylococcus epidermidis, 26.7% Klebsiella spp., and 13.3% Acinetobacter spp. Incidences of low gestational age, low birth weight, vaginal birth type, and long length of hospitalization were higher in the infected neonates than in the uninfected neonates. In the univariate analysis, surgical operation, ventriculoperitoneal shunt, use of umbilical catheter, nasogastric or orogastric tube, urinary catheter, mechanical ventilation, surfactant treatment, erythrocyte transfusion, plasma transfusion, thrombocyte transfusion, total parenteral nutrition infusion, intracranial hemorrhage, length of hospital stay, fifth-minute Apgar score, and total parenteral nutrition time were significantly associated with NIs. In the multiple logistic regression analysis, fifth-minute Apgar, use of erythrocyte transfusion and surgical operation were found as the independent risk factors for HCA-BSI. This study determined the causative organisms and risk factors of HCA-BSIs in NICUs.

  19. Assessment of bloodstream infections and risk factors in an intensive care unit.

    Science.gov (United States)

    Süner, Aynur; Karaoğlan, Ilkay; Mete, Ayşe Ozlem; Namiduru, Mustafa; Boşnak, Vuslat; Baydar, Ibrahim

    2015-01-01

    Nosocomial bloodstream infection (BSI) increases mortality rates, duration of stay in hospital, and treatment costs. This study was conducted to determine the rate and the risk factors of BSIs among intensive care unit patients. Sixty-four patients with BSIs (patient group) and 79 patients without a nosocomial infection (control group) were enrolled in the study. Centers for Disease Control and Prevention criteria were used for diagnosing BSIs. Potential risk factors were evaluated by multivariate logistic regression model. The BSI development rate was 15.7% (64/407), with an incidence rate of 18.2/1000 patient days. Distribution of pathogens among BSI patients were as follows: gram-positive cocci, 42.18% (27/64); gram-negative cocci, 34.3% (22/64); and Candida spp., 23.4% (15/64). Risk factors were determined as intubation, arterial catheter, tracheostomy, duration of intubation, duration of catheter use, duration of nasogastric catheter, underlying diseases of chronic renal failure and diabetes mellitus, implemented treatments of sedation and enteral nutrition, and APACHE II score. : BSIs are the leading cause of mortality and morbidity in intensive care unit patients. Determination of the local risk factors is important and necessary for decreasing the rate of BSIs and the mortality rates.

  20. A polyclonal outbreak of bloodstream infections by Enterococcus faecium in patients with hematologic malignancies.

    Science.gov (United States)

    Alatorre-Fernández, Pamela; Mayoral-Terán, Claudia; Velázquez-Acosta, Consuelo; Franco-Rodríguez, Cecilia; Flores-Moreno, Karen; Cevallos, Miguel Ángel; López-Vidal, Yolanda; Volkow-Fernández, Patricia

    2017-03-01

    Enterococcus faecium causes bloodstream infection (BSI) in patients with hematologic malignancies (HMs). We studied the clinical features and outcomes of patients with HM with vancomycin-sensitive E faecium (VSE) and vancomycin-resistant E faecium (VRE) BSI and determined the genetic relatedness of isolates and circumstances associated with the upsurge of E faecium BSI. Case-control study of patients with HM and E faecium-positive blood culture from January 2008-December 2012; cases were patients with VRE and controls were VSE isolates. The strains were tested for Van genes by polymerase chain reaction amplification and we performed pulsed-field gel electrophoresis to determine genetic relatedness. Fifty-eight episodes of E faecium BSI occurred: 35 sensitive and 23 resistant to vancomycin. Mortality was 46% and 57%, attributable 17% and 40%, respectively. Early stage HM was associated with VSE (P = .044), whereas an episode of BSI within the 3 months before the event (P = .039), prophylactic antibiotics (P = .013), and vancomycin therapy during the previous 3 months (P = .001) was associated with VRE. The VanA gene was identified in 97% of isolates studied. E faecium isolates were not clonal. E faecium BSI was associated with high mortality. This outbreak of VRE was not clonal; it was associated with antibiotic-use pressure and highly myelosuppressive chemotherapy. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  1. Daptomycin nonsusceptible vancomycin resistant Enterococcus bloodstream infections in patients with hematological malignancies: risk factors and outcomes.

    Science.gov (United States)

    Herc, Erica S; Kauffman, Carol A; Marini, Bernard L; Perissinotti, Anthony J; Miceli, Marisa H

    2017-12-01

    Daptomycin is typically the treatment of choice for vancomycin resistant Enterococcus (VRE) bloodstream infections (BSI) in patients with hematological malignancies, but increasingly daptomycin nonsusceptible VRE are being reported. We reviewed our experience with daptomycin nonsusceptible VRE BSI among patients with hematological malignancies. We compared risk factors and outcomes of 20 patients with daptomycin nonsusceptible VRE BSI (case patients) with 40 matched control patients with daptomycin susceptible VRE BSI. Case patients had more complications (6/20 vs. 2/40, p = .013); all-cause mortality was similar in both groups. By multivariable analysis, only prior daptomycin exposure within 90 days was significantly associated with daptomycin nonsusceptible VRE BSI (odds ratio 26.71; p < .0001). In 25% of case patients, all of whose VRE isolates had an initial minimum inhibitory concentration (MIC) of 4 μg/mL, nonsusceptibility developed during treatment, raising the question of whether higher doses of daptomycin should be used for VRE BSI in hematology patients.

  2. Survival Benefit of Empirical Therapy for Staphylococcus aureus Bloodstream Infections in Infants.

    Science.gov (United States)

    Thaden, Joshua T; Ericson, Jessica E; Cross, Heather; Bergin, Stephen P; Messina, Julia A; Fowler, Vance G; Benjamin, Daniel K; Clark, Reese H; Hornik, Christoph P; Smith, P Brian

    2015-11-01

    The impact of early adequate empirical antibiotic therapy on outcomes of infants in the neonatal intensive care unit (NICU) who develop Staphylococcus aureus bloodstream infections (BSI) is unknown. Infants with S. aureus BSI discharged in 1997-2012 from 348 NICUs managed by the Pediatrix Medical Group were identified. Early adequate empirical antibiotic therapy was defined as exposure to ≥1 antibiotic with anti-staphylococcal activity on the day the first positive blood culture was obtained. All other cases were defined as inadequate empirical antibiotic therapy. We evaluated the association between inadequate empirical antibiotic therapy on outcomes controlling for gestational age, small for gestational age status, gender, discharge year, mechanical ventilation, inotropic support and use of supplemental oxygen. The primary outcome was 30-day mortality. Secondary outcomes were 7-day mortality, death before hospital discharge and length of bacteremia. Of the 3339 infants with S. aureus BSI, 2492 (75%) had methicillin-susceptible S. aureus (MSSA) BSI and 847 (25%) had methicillin-resistant S. aureus (MRSA) BSI. Inadequate empirical antibiotic therapy was administered in 725 (22%) cases. Inadequate empirical antibiotic therapy was associated with increased 30-day mortality (odds ratio: 2.03; 95% confidence interval: 1.08-3.82) among infants with MRSA BSI. Inadequate empirical antibiotic therapy was not associated with increases in mortality among infants with MSSA BSI. After controlling for confounders, inadequate empirical antibiotic therapy was associated with a modestly increased mortality at 30 days for infants with MRSA BSI.

  3. Health care failure mode and effect analysis to reduce NICU line-associated bloodstream infections.

    Science.gov (United States)

    Chandonnet, Celeste J; Kahlon, Prerna S; Rachh, Pratik; Degrazia, Michele; Dewitt, Eileen C; Flaherty, Kathleen A; Spigel, Nadine; Packard, Stephanie; Casey, Denise; Rachwal, Christine; Agrawal, Pankaj B

    2013-06-01

    Central line-associated bloodstream infections (CLABSIs) in NICU result in increased mortality, morbidity, and length of stay. Our NICU experienced an increase in the number of CLABSIs over a 2-year period. We sought to reduce risks for CLABSIs using health care failure mode and effect analysis (HFMEA) by analyzing central line insertion, maintenance, and removal practices. A multidisciplinary team was assembled that included clinicians from nursing, neonatology, surgery, infection prevention, pharmacy, and quality management. Between March and October 2011, the team completed the HFMEA process and implemented action plans that included reeducation, practice changes, auditing, and outcome measures. The HFMEA identified 5 common failure modes that contribute to the development of CLABSIs. These included contamination, suboptimal environment of care, improper documentation and evaluation of central venous catheter dressing integrity, issues with equipment and suppliers, and lack of knowledge. Since implementing the appropriate action plans, the NICU has experienced a significant decrease in CLABSIs from 2.6 to 0.8 CLABSIs per 1000 line days. The process of HFMEA helped reduce the CLABSI rate and reinforce the culture of continuous quality improvement and safety in the NICU.

  4. Risk factors and outcomes of imipenem-resistant Acinetobacter bloodstream infection in North-eastern Malaysia

    Science.gov (United States)

    Deris, Zakuan Zainy; Shafei, Mohd Nazri; Harun, Azian

    2011-01-01

    Objective To determine the risk factors and outcomes of imipenem-resistant Acinetobacter baumannii (IRAB) bloodstream infection (BSI) cases, since there is very little publication on Acinetobacter baumannii infections from Malaysia. Methods A cross sectional study of 41 cases (73.2%) of imipenem-sensitive Acinetobacter baumanii (ISAB) and 15 cases (26.8%) of IRAB was conducted in a teaching hospital which was located at North-Eastern state of Malaysia. Results There was no independent risk factor for IRAB BSI identified but IRAB BSI was significantly associated with longer bacteraemic days [OR 1.23 (95% CI 1.01, 1.50)]. Although prior use of carbepenems and cephalosporin were higher among IRAB than ISAB group, statistically they were not significant. There was no significant difference in term of outcomes between the two groups. Conclusions Although statistically not significant, this analysis compliments previous publication highlighting the importance of appropriate empiric antibiotic usage in hospital especially carbepenems and need further evaluation with bigger subjects. PMID:23569782

  5. Epidemiology of bloodstream infections in patients with acute myeloid leukemia undergoing levofloxacin prophylaxis.

    Science.gov (United States)

    De Rosa, Francesco Giuseppe; Motta, Ilaria; Audisio, Ernesta; Frairia, Chiara; Busca, Alessandro; Di Perri, Giovanni; Marmont, Filippo

    2013-12-01

    Infections are a common cause of morbidity and mortality in patients with acute myeloid leukemia (AML). The evidence for efficacy of antibiotic prophylaxis in reducing the mortality rates and the incidence of bacterial infections was also reported by a systematic review published by Cochrane in 2012. The objective of our study was to report the incidence and the etiology of bloodstream infections in patients with AML undergoing levofloxacin prophylaxis during neutropenic episodes. This was a retrospective study of patients with diagnosis of AML during 2001-2007. A total of 81 patients were included in the study. Two hundred and ninetyone neutropenic episodes were studied, of which 181 were febrile. Bacteria isolated from blood cultures were mostly Gram-positives during the induction (80%) and Gram-negatives during the consolidation (72.4%) phases of chemotherapy. Resistance to ciprofloxacin was found in 78.9% of isolated E. coli and it was higher during consolidation and higher than the hospital rate. The production of extended spectrum betalactamases (ESBL) in E. coli strains was reported in 12.1%, below the reported hospital rate during the study period. Regular microbiology surveillance is needed to better understand the impact of levofloxacin prophylaxis in neutropenic patients. Our study shows that Gram-positive bacteria are predominant during the induction phase of chemotherapy and Gram-negatives during the consolidation. The rate of fluoroquinolone resistance in the latter setting, even higher than the hospital rate, may suggest to reconsider levofloxacin prophylaxis.

  6. Interaction between the flagellar pocket collar and the hook complex via a novel microtubule-binding protein in Trypanosoma brucei.

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    Anna Albisetti

    2017-11-01

    Full Text Available Trypanosoma brucei belongs to a group of unicellular, flagellated parasites that are responsible for human African trypanosomiasis. An essential aspect of parasite pathogenicity is cytoskeleton remodelling, which occurs during the life cycle of the parasite and is accompanied by major changes in morphology and organelle positioning. The flagellum originates from the basal bodies and exits the cell body through the flagellar pocket (FP but remains attached to the cell body via the flagellum attachment zone (FAZ. The FP is an invagination of the pellicular membrane and is the sole site for endo- and exocytosis. The FAZ is a large complex of cytoskeletal proteins, plus an intracellular set of four specialised microtubules (MtQ that elongate from the basal bodies to the anterior end of the cell. At the distal end of the FP, an essential, intracellular, cytoskeletal structure called the flagellar pocket collar (FPC circumvents the flagellum. Overlapping the FPC is the hook complex (HC (a sub-structure of the previously named bilobe that is also essential and is thought to be involved in protein FP entry. BILBO1 is the only functionally characterised FPC protein and is necessary for FPC and FP biogenesis. Here, we used a combination of in vitro and in vivo approaches to identify and characterize a new BILBO1 partner protein-FPC4. We demonstrate that FPC4 localises to the FPC, the HC, and possibly to a proximal portion of the MtQ. We found that the C-terminal domain of FPC4 interacts with the BILBO1 N-terminal domain, and we identified the key amino acids required for this interaction. Interestingly, the FPC4 N-terminal domain was found to bind microtubules. Over-expression studies highlight the role of FPC4 in its association with the FPC, HC and FPC segregation. Our data suggest a tripartite association between the FPC, the HC and the MtQ.

  7. Trypanosoma brucei gambiense Infections in Mice Lead to Tropism to the Reproductive Organs, and Horizontal and Vertical Transmission.

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    Nicolas Biteau

    2016-01-01

    Full Text Available Trypanosoma brucei gambiense, transmitted by the tsetse fly, is the main causative agent of Human African trypanosomosis in West Africa and poses a significant health risk to 70 million people. Disease progression varies depending on host immunity, but usually begins with a haemo-lymphatic phase, followed by parasite invasion of the central nervous system. In the current study, the tropism of T. b. gambiense 1135, causing a low level chronic 'silent' infection, was monitored in a murine model using bioluminescence imaging and PCR. A tropism to the reproductive organs, in addition to the central nervous system, after 12-18 months of infection was observed. Bioluminescent analysis of healthy females crossed with infected males showed that 50%, 62.5% and 37.5% of the female mice were subsequently positive for parasites in their ovaries, uteri and brain respectively. Although PCR confirmed the presence of parasites in the uterus of one of these mice, the blood of all mice was negative by PCR and LAMP. Subsequently, bioluminescent imaging of the offspring of infected female mice crossed with healthy males indicated parasites were present in the reproductive organs of both male (80% and female (60% offspring. These findings imply that transmission of T. b. gambiense 1135 occurs horizontally, most probably via sexual contact, and vertically in a murine model, which raises the possibility of a similar transmission in humans. This has wide reaching implications. Firstly, the observations made in this study are likely to be valid for wild animals acting as a reservoir for T. b. gambiense. Also, the reproductive organs may act as a refuge for parasites during drug treatment in a similar manner to the central nervous system. This could leave patients at risk of a relapse, ultimately allowing them to act as a reservoir for subsequent transmission by tsetse and possibly, horizontally and vertically.

  8. Trypanosoma brucei rhodesiense transmitted by a single tsetse fly bite in vervet monkeys as a model of human African trypanosomiasis.

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    John K Thuita

    Full Text Available We have investigated the pathogenicity of tsetse (Glossina pallidipes-transmitted cloned strains of Trypanosoma brucei rhodesiense in vervet monkeys. Tsetse flies were confirmed to have mature trypanosome infections by xenodiagnosis, after which nine monkeys were infected via the bite of a single infected fly. Chancres developed in five of the nine (55.6% monkeys within 4 to 8 days post infection (dpi. All nine individuals were successfully infected, with a median pre-patent period of 4 (range = 4-10 days, indicating that trypanosomes migrated from the site of fly bite to the systemic circulation rapidly and independently of the development of the chancre. The time lag to detection of parasites in cerebrospinal fluid (CSF was a median 16 (range = 8-40 days, marking the onset of central nervous system (CNS, late stage disease. Subsequently, CSF white cell numbers increased above the pre-infection median count of 2 (range = 0-9 cells/microl, with a positive linear association between their numbers and that of CSF trypanosomes. Haematological changes showed that the monkeys experienced an early microcytic-hypochromic anaemia and severe progressive thrombocytopaenia. Despite a 3-fold increase in granulocyte numbers by 4 dpi, leucopaenia occurred early (8 dpi in the monkey infection, determined mainly by reductions in lymphocyte numbers. Terminally, leucocytosis was observed in three of nine (33% individuals. The duration of infection was a median of 68 (range = 22-120 days. Strain and individual differences were observed in the severity of the clinical and clinical pathology findings, with two strains (KETRI 3741 and 3801 producing a more acute disease than the other two (KETRI 3804 and 3928. The study shows that the fly-transmitted model accurately mimics the human disease and is therefore a suitable gateway to understanding human African trypanosomiasis (HAT; sleeping sickness.

  9. Crystal Structures of Trypanosoma brucei Sterol 14[alpha]-Demethylase and Implications for Selective Treatment of Human Infections

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    Lepesheva, Galina I.; Park, Hee-Won; Hargrove, Tatiana Y.; Vanhollebeke, Benoit; Wawrzak, Zdzislaw; Harp, Joel M.; Sundaramoorthy, Munirathinam; Nes, W. David; Pays, Etienne; Chaudhuri, Minu; Villalta, Fernando; Waterman, Michael R. (ULdB); (Vanderbilt); (TTU); (Toronto); (NWU); (Meharry)

    2010-01-25

    Sterol 14{alpha}-demethylase (14DM, the CYP51 family of cytochrome P450) is an essential enzyme in sterol biosynthesis in eukaryotes. It serves as a major drug target for fungal diseases and can potentially become a target for treatment of human infections with protozoa. Here we present 1.9 {angstrom} resolution crystal structures of 14DM from the protozoan pathogen Trypanosoma brucei, ligand-free and complexed with a strong chemically selected inhibitor N-1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethyl-4-(5-phenyl-1,3,4-oxadi-azol-2-yl)benzamide that we previously found to produce potent antiparasitic effects in Trypanosomatidae. This is the first structure of a eukaryotic microsomal 14DM that acts on sterol biosynthesis, and it differs profoundly from that of the water-soluble CYP51 family member from Mycobacterium tuberculosis, both in organization of the active site cavity and in the substrate access channel location. Inhibitor binding does not cause large scale conformational rearrangements, yet induces unanticipated local alterations in the active site, including formation of a hydrogen bond network that connects, via the inhibitor amide group fragment, two remote functionally essential protein segments and alters the heme environment. The inhibitor binding mode provides a possible explanation for both its functionally irreversible effect on the enzyme activity and its selectivity toward the 14DM from human pathogens versus the human 14DM ortholog. The structures shed new light on 14DM functional conservation and open an excellent opportunity for directed design of novel antiparasitic drugs.

  10. Nifurtimox-eflornithine combination therapy for second-stage Trypanosoma brucei gambiense sleeping sickness: a randomized clinical trial in Congo.

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    Priotto, Gerardo; Kasparian, Serena; Ngouama, Daniel; Ghorashian, Sara; Arnold, Ute; Ghabri, Salah; Karunakara, Unni

    2007-12-01

    Human African trypanosomiasis caused by Trypanosoma brucei gambiense is a fatal disease. Current treatment options for patients with second-stage disease are either highly toxic or impracticable in field conditions. We compared the efficacy and safety of the nifurtimox-eflornithine drug combination with the standard eflornithine regimen for the treatment of second-stage disease. A randomized, open-label, active-control, phase III clinical trial comparing 2 arms was conducted at the Sleeping Sickness Treatment Center, which was run by Medecins Sans Frontieres, in Nkayi, Bouenza Province, Republic of Congo. Patients were screened for inclusion and randomly assigned to receive eflornithine alone (400 mg/kg per day given intravenously every 6 h for 14 days) or eflornithine (400 mg/kg per day given intravenously every 12 h for 7 days) plus nifurtimox (15 mg/kg per day given orally every 8 h for 10 days). Patients were observed for 18 months. The study's outcomes were cure and adverse events attributable to treatment. A total of 103 patients with second-stage disease were enrolled. Cure rates were 94.1% for the eflornithine group and 96.2% for the nifurtimox-eflornithine group. Drug reactions were frequent in both arms, and severe reactions affected 25.5% of patients in the eflornithine group and 9.6% of those in the nifurtimox-eflornithine group, resulting in 2 and 1 treatment suspensions, respectively. There was 1 death in the eflornithine arm and no deaths in the nifurtimox-eflornithine arm. The nifurtimox-eflornithine combination appears to be a promising first-line therapy for second-stage sleeping sickness. If our findings are corroborated by ongoing findings from additional sites (a multicenter extension of this study), the new nifurtimox-eflornithine combination therapy will mark a major and multifaceted advance over current therapies.

  11. Impregnated central venous catheters for prevention of bloodstream infection in children (the CATCH trial): a randomised controlled trial.

    Science.gov (United States)

    Gilbert, Ruth E; Mok, Quen; Dwan, Kerry; Harron, Katie; Moitt, Tracy; Millar, Mike; Ramnarayan, Padmanabhan; Tibby, Shane M; Hughes, Dyfrig; Gamble, Carrol

    2016-04-23

    Impregnated central venous catheters are recommended for adults to reduce bloodstream infections but not for children because there is not enough evidence to prove they are effective. We aimed to assess the effectiveness of any type of impregnation (antibiotic or heparin) compared with standard central venous catheters to prevent bloodstream infections in children needing intensive care. We did a randomised controlled trial of children admitted to 14 English paediatric intensive care units. Children younger than 16 years were eligible if they were admitted or being prepared for admission to a participating paediatric intensive care unit and were expected to need a central venous catheter for 3 or more days. Children were randomly assigned (1:1:1) to receive a central venous catheter impregnated with antibiotics, a central venous catheter impregnated with heparin, or a standard central venous catheter with computer generated randomisation in blocks of three and six, stratified by method of consent, site, and envelope storage location within the site. The clinician responsible for inserting the central venous catheter was not masked to allocation, but allocation was concealed from patients, their parents, and the paediatric intensive care unit personnel responsible for their care. The primary outcome was time to first bloodstream infection between 48 h after randomisation and 48 h after central venous catheter removal with impregnated (antibiotic or heparin) versus standard central venous catheters, assessed in the intention-to-treat population. Safety analyses compared central venous catheter-related adverse events in the subset of children for whom central venous catheter insertion was attempted (per-protocol population). This trial is registered with ISRCTN number, ISRCTN34884569. Between Nov 25, 2010, and Nov 30, 2012, 1485 children were recruited to this study. We randomly assigned 502 children to receive standard central venous catheters, 486 to receive

  12. Evaluating the Trends of Bloodstream Infections among Pediatric and Adult Patients at a Teaching Hospital of Kathmandu, Nepal: Role of Drug Resistant Pathogens

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    Narayan Prasad Parajuli

    2017-01-01

    Full Text Available Bloodstream infections (BSIs are among the significant causes of morbidity and mortality for patients of all age groups. However, very little is known about the trends of bacterial bloodstream infections and antimicrobial susceptibilities among pediatric and adult population from Nepal. In this study, we have investigated the different etiological agents responsible for bloodstream infections among pediatric and adult patients and the role of drug resistant organisms in these infections at a tertiary care teaching hospital of Kathmandu, Nepal. A total of 3,088 blood culture specimens obtained from pediatric and adult patients suspected to have bloodstream infections were processed by standard microbiological methods. Significant bacterial pathogens were identified by morphological, biochemical, and serological methods as suggested by American Society for Microbiology. In vitro antimicrobial susceptibility testing was performed by Kirby-Bauer disk diffusion method and interpreted according to the guidelines of Clinical and Laboratory Standards Institute. Overall, incidence of bloodstream infections among the suspected patients was 7.48%. Pediatric patients (n=90, 9.37% were the significant subgroup of patients affected with bloodstream infections compared to adults (p<0.05, CI-95%. Gram positive (n=49, 54.4% bacteria in pediatric and gram negative bacteria (n=141, 78.7% in adult patients were the most common isolates for BSI. Staphylococcus aureus (n=41, 45.6% in pediatric patients and Salmonella enterica (n=40, 28.3% in adult patients were the leading pathogens. Trends of antimicrobial resistance among isolated bacterial strains were significantly high in adults compared to pediatric patients. Methicillin resistant Staphylococcus aureus (MRSA (31.4%, extended spectrum beta-lactamase (ESBL (12.5%, and metallo-beta-lactamase (MBL (3.9% producing gram negatives were major resistant strains. Our study shows higher rates of bloodstream infections in

  13. Trypanosoma brucei Inhibition by Essential Oils from Medicinal and Aromatic Plants Traditionally Used in Cameroon (Azadirachta indica, Aframomum melegueta, Aframomum daniellii, Clausena anisata, Dichrostachys cinerea and Echinops giganteus).

    Science.gov (United States)

    Kamte, Stephane L Ngahang; Ranjbarian, Farahnaz; Campagnaro, Gustavo Daniel; Nya, Prosper C Biapa; Mbuntcha, Hélène; Woguem, Verlaine; Womeni, Hilaire Macaire; Ta, Léon Azefack; Giordani, Cristiano; Barboni, Luciano; Benelli, Giovanni; Cappellacci, Loredana; Hofer, Anders; Petrelli, Riccardo; Maggi, Filippo

    2017-07-06

    Essential oils are complex mixtures of volatile components produced by the plant secondary metabolism and consist mainly of monoterpenes and sesquiterpenes and, to a minor extent, of aromatic and aliphatic compounds. They are exploited in several fields such as perfumery, food, pharmaceutics, and cosmetics. Essential oils have long-standing uses in the treatment of infectious diseases and parasitosis in humans and animals. In this regard, their therapeutic potential against human African trypanosomiasis (HAT) has not been fully explored. In the present work, we have selected six medicinal and aromatic plants ( Azadirachta indica , Aframomum melegueta , Aframomum daniellii , Clausena anisata , Dichrostachys cinerea , and Echinops giganteus ) traditionally used in Cameroon to treat several disorders, including infections and parasitic diseases, and evaluated the activity of their essential oils against Trypanosma brucei TC221. Their selectivity was also determined with Balb/3T3 (mouse embryonic fibroblast cell line) cells as a reference. The results showed that the essential oils from A. indica , A . daniellii , and E. giganteus were the most active ones, with half maximal inhibitory concentration (IC 50 ) values of 15.21, 7.65, and 10.50 µg/mL, respectively. These essential oils were characterized by different chemical compounds such as sesquiterpene hydrocarbons, monoterpene hydrocarbons, and oxygenated sesquiterpenes. Some of their main components were assayed as well on T. brucei TC221, and their effects were linked to those of essential oils.

  14. RNA interference analyses suggest a transcript-specific regulatory role for mitochondrial RNA-binding proteins MRP1 and MRP2 in RNA editing and other RNA processing in Trypanosoma brucei

    NARCIS (Netherlands)

    Vondrusková, Eva; van den Burg, Janny; Zíková, Alena; Ernst, Nancy Lewis; Stuart, Kenneth; Benne, Rob; Lukes, Julius

    2005-01-01

    Mitochondrial RNA-binding proteins MRP1 and MRP2 occur in a heteromeric complex that appears to play a role in U-insertion/deletion editing in trypanosomes. Reduction in the levels of MRP1 (gBP21) and/or MRP2 (gBP25) mRNA by RNA interference in procyclic Trypanosoma brucei resulted in severe growth

  15. Bacterial bloodstream infections in HIV-infected adults attending a Lagos teaching hospital.

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    Adeyemi, Adeleye I; Sulaiman, Akanmu A; Solomon, Bamiro B; Chinedu, Obosi A; Victor, Inem A

    2010-08-01

    An investigation was carried out during October 2005-September 2006 to determine the prevalence of bloodstream infections in patients attending the outpatient department of the HIV/AIDS clinic at the Lagos University Teaching Hospital in Nigeria. Two hundred and one patients--86 males and 115 females--aged 14-65 years were recruited for the study. Serological diagnosis was carried out on them to confirm their HIV status. Their CD4 counts were done using the micromagnetic bead method. Twenty mL of venous blood sample collected from each patient was inoculated into a pair of Oxoid Signal blood culture bottles for 2-14 days. Thereafter, 0.1 mL of the sample was plated in duplicates on MacConkey, blood and chocolate agar media and incubated at 37 degrees C for 18-24 hours. The CD4+ counts were generally low as 67% of 140 patients sampled had Salmonella spp., S. Typhimurium (4), S. Enteritidis (2); Pseudomonas fluorescens (1), Escherichia coli (1), Ochrobactrum anthropi (1), Moraxella sp. (1), and Chryseobacterium meningosepticum. Results of antimicrobial susceptibility tests showed that coagulase-negative staphylococci had good sensitivities to vancomycin and most other antibiotics screened but were resistant mainly to ampicilin and tetracycline. The Gram-negative organisms isolated also showed resistance to ampicillin, tetracycline, chloramphenicol, and septrin. This study demonstrates that coagulase-negative staphylococci and non-typhoidal Salmonellae are the most common aetiological agents of bacteraemia among HIV-infected adults attending the Lagos University Teaching Hospital, Nigeria. The organisms were resistant to older-generation antibiotics often prescribed in this environment but were sensitive to vancomycin, cefotaxime, cefuroxime, and other new-generation antibiotics.

  16. Burn-associated bloodstream infections in pediatric burn patients: Time distribution of etiologic agents.

    Science.gov (United States)

    Devrim, İlker; Kara, Ahu; Düzgöl, Mine; Karkıner, Aytaç; Bayram, Nuri; Temir, Günyüz; Şencan, Arzu; Sorguç, Yelda; Gülfidan, Gamze; Hoşgör, Münevver

    2017-02-01

    Infections are the leading cause of morbidity and mortality in patients with burns in burn units. Bloodstream infections (BSIs) in patients with burns may result from burn wound infection, use of invasive devices such as central venous catheters, and translocation of the gastrointestinal flora. In this study, we investigated the distribution and antimicrobial drug resistance of causative pathogens in children with burns and the durational changes of microorganisms in the distribution of BSIs in children. This study was conducted at the Pediatric Burn Unit (PBU) of Dr. Behçet Uz Children Research and Training Hospital during the period of November 2008-April 2015. The study subjects were all the patients admitted to the PBU, in whom microorganisms were isolated at least from one of the cultures, including blood and catheter cultures. Gram-positive bacteria were the most common causative agents of BSI in patients with burns (66.4%), followed by gram-negative bacteria (22.1%) and fungi (11.5%). The median duration of development of BSIs caused by gram-positive bacteria from the time of burn was 5 days (ranging from 2 to 54 days of burn), which was significantly shorter than that of BSIs caused by gram-negative bacteria (12 days) and fungal pathogens (13 days). The etiologic agents of BSIs in children may differ from those in adults. Gram-negative drug-resistant bacteria such as multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii were important agents of BSI in patients with burns, especially in the long term; however, gram-positive bacteria should also be considered while deciding the antimicrobial therapy, especially in the early periods of burn. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

  17. Bloodstream Infection Incidence of Different Central Venous Catheters in Neonates: A Descriptive Cohort Study

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    Gerdina H. Dubbink-Verheij

    2017-06-01

    Full Text Available Central venous catheters (CVCs in neonates are associated with a risk of central line-associated bloodstream infections (CLABSI. Most reports on the incidence of CLABSI in neonates focus on umbilical venous catheters (UVCs and peripherally inserted central catheters (PICCs. We evaluated the incidence and risk factors for CLABSI in a cohort of neonates with femoral venous catheters (FVCs, UVCs, and PICCs, with a gestational age ≥34 weeks born between January 1, 2006 and June 30, 2013. We included 2,986 neonates with a total of 656 catheters. The CLABSI incidence rate varied from 12.3 per 1,000 catheter-days in FVCs to 10.6 per 1,000 catheter-days in UVCs and 5.3 per 1,000 catheter-days in PICCs. In a Kaplan–Meier survival analysis, we did not find a difference in CLABSI risk between the catheter types (p = 0.29. The following factors were independently associated with an increased risk of CLABSI: parenteral nutrition [hazard ratio (HR 2.60, 95% confidence interval (CI 1.25–5.41], male gender (HR 2.63, 95% CI 1.17–5.90, and higher birth weight (HR 1.04, 95% CI 1.002–1.09, whereas antibiotic treatment at birth (HR 0.25, 95% CI 0.12–0.52 was associated with a decreased risk. Conclusion: In our cohort, we did not find a difference between the CLABSI incidence in FVCs, PICCs, and UVCs. Occurrence of CLABSI is associated with parenteral nutrition, male gender, and higher birth weight. Antibiotic treatment at birth was associated with a decreased risk of CLABSI.

  18. Is zero central line-associated bloodstream infection rate sustainable? A 5-year perspective.

    Science.gov (United States)

    Erdei, Carmina; McAvoy, Linda L; Gupta, Munish; Pereira, Sunita; McGowan, Elisabeth C

    2015-06-01

    Adoption and implementation of evidence-based measures for catheter care leads to reductions in central line-associated bloodstream infection (CLABSI) rates in the NICU. The purpose of this study is to evaluate whether this rate reduction is sustainable for at least 1 year and to identify key determinants of this sustainability at the NICU of the Floating Hospital for Children at Tufts Medical Center. We reviewed the incidence of CLABSIs in the NICU temporally to the implementation of new practice policies and procedures, from July 2008 to December 2013. Adoption of standardized care practices, including bundles and checklists, was associated with a significant reduction of the CLABSI rate to zero for >370 consecutive days in our NICU in 2012. Overall, our CLABSI rates decreased from 4.1 per 1000 line days in 2009 (13 infections; 3163 line days) to 0.94 in 2013 (2 infections; 2115 line days), which represents a 77% reduction over a 5-year period. In the first quarter of 2013, there was a brief increase in CLABSI rate to 3.3 per 1000 line days; after a series of interventions, the CLABSI rate was maintained at zero for >600 days. Ongoing training, surveillance, and vigilance with catheter insertion and maintenance practices and improved documentation were identified as key drivers for success. High-quality training, strict compliance with evidence-based guidelines, and thorough documentation is associated with significant reductions in CLABSIs. Mindful organizing may lead to a better understanding of what goes into a unit's ability to handle peak demands and sustain extraordinary performance in the long-term. Copyright © 2015 by the American Academy of Pediatrics.

  19. Clinical and microbiological characteristics of bloodstream infections in hematological cancer patients

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    V. N. Chebotkevich

    2016-01-01

    Full Text Available Introduction. Bloodstream infections (BSI are life-threatening illness for immunocompromised patients with hematological malignancies.The aim of the study was to compare epidemiology, causative pathogens and outcome of hospital-acquired BSI and clarifying the role of herpes group of viruses in their development.Materials and methods. During the period 1991–2013 438 bacterial strains obtained from 360 patients (pts with hematological malignancies wеre studied. All blood cultures were incubated in the continuous monitoring system for 7 days before discard. The real-time PCR was used for human herpesviruses DNA detection: Herpes simplex viruses types 1 and 2 (HSV 1, 2, Cytomegalovirus (CMV, Epstein–Barr virus(EBV and Herpesvirus 6 (HHV-6. In this study 64 hematological cancer patients with infectious complications who fulfilled criteria of systemic inflammatory response syndrome with positive peripheral blood cultures were investigated. All pts received empirical anti-infectious therapy with subsequent correction based on the bacteriological, virological and mycological analyses.Results and discussion. A total Gram-positive (G+ accounted for 69.2 % of BSI, Gram-negative (G– for 30.8 %. Among G+ BSI Coagulase Negative Staphylococci and Staphylococcus aureus were the most frequent pathogens (58.8 %, among G– BSI Escherichia coli (13.0 % was predominant. It is shown that the development of bacteremia were significantly more frequently occurs in the case of cytomegalovirusand the Epstein–Barr virus detection.Conclusion. Further epidemiological surveillance is warranted in order emerging resistant strains and related mortality. Reactivation of CMV and EBV is significantly associated with higher incidence of bacterial BSI.

  20. Bloodstream Infection Incidence of Different Central Venous Catheters in Neonates: A Descriptive Cohort Study.

    Science.gov (United States)

    Dubbink-Verheij, Gerdina H; Bekker, Vincent; Pelsma, Iris C M; van Zwet, Erik W; Smits-Wintjens, Vivianne E H J; Steggerda, Sylke J; Te Pas, Arjan B; Lopriore, Enrico

    2017-01-01

    Central venous catheters (CVCs) in neonates are associated with a risk of central line-associated bloodstream infections (CLABSI). Most reports on the incidence of CLABSI in neonates focus on umbilical venous catheters (UVCs) and peripherally inserted central catheters (PICCs). We evaluated the incidence and risk factors for CLABSI in a cohort of neonates with femoral venous catheters (FVCs), UVCs, and PICCs, with a gestational age ≥34 weeks born between January 1, 2006 and June 30, 2013. We included 2,986 neonates with a total of 656 catheters. The CLABSI incidence rate varied from 12.3 per 1,000 catheter-days in FVCs to 10.6 per 1,000 catheter-days in UVCs and 5.3 per 1,000 catheter-days in PICCs. In a Kaplan-Meier survival analysis, we did not find a difference in CLABSI risk between the catheter types ( p  = 0.29). The following factors were independently associated with an increased risk of CLABSI: parenteral nutrition [hazard ratio (HR) 2.60, 95% confidence interval (CI) 1.25-5.41], male gender (HR 2.63, 95% CI 1.17-5.90), and higher birth weight (HR 1.04, 95% CI 1.002-1.09), whereas antibiotic treatment at birth (HR 0.25, 95% CI 0.12-0.52) was associated with a decreased risk. In our cohort, we did not find a difference between the CLABSI incidence in FVCs, PICCs, and UVCs. Occurrence of CLABSI is associated with parenteral nutrition, male gender, and higher birth weight. Antibiotic treatment at birth was associated with a decreased risk of CLABSI.

  1. Alteplase use for malfunctioning central venous catheters correlates with catheter-associated bloodstream infections.

    Science.gov (United States)

    Rowan, Courtney M; Miller, Kathryn E; Beardsley, Andrew L; Ahmed, Sheikh S; Rojas, Luis A; Hedlund, Terri L; Speicher, Richard H; Nitu, Mara E

    2013-03-01

    A catheter thrombosis and the presence of a catheter-associated bloodstream infection (CBSI) often occur simultaneously, but it is unclear if or to what degree the two complications relate. Several animal and adult studies indicate a relationship between fibrin sheaths and thrombi in the development of CBSIs. To date, there has been limited human investigation in the pediatric population to determine a clear link between the presence of a thrombus and bacteremia. The use of alteplase for malfunctioning central venous catheter may indicate the formation of intraluminal thrombus or fibrin sheath. A catheter that requires alteplase is at higher risk of a CBSI. A retrospective chart review from July 2008 to December 2010. PICU. All patients with central catheters admitted to the PICU. No interventions performed with the retrospective study. Number of total central venous catheters, number of central venous catheters that received treatment with alteplase, and number of CBSIs. Preliminary data during the study period identified 3,289 central venous catheters. Twelve percent of these catheters required at least one dose of alteplase. There were 40 CBSIs during this same time period of which 28% received alteplase during the 5 days preceding the positive blood culture. The odds ratio for getting a CBSI when alteplase is administered is 2.87 (confidence interval 1.42-5.80; p = 0.002). The average age of the central venous catheters at time of infection was not statistically different, 16.1 days in the alteplase catheters compared with 25.6 days for the catheters that did not receive alteplase (p = 0.6). There is a positive correlation between the use of alteplase for malfunctioning central venous catheters and the development of a CASBI. This is likely associated with the presence of an intraluminal fibrin sheath or thrombus. This study adds evidence linking thrombus formation to CBSI.

  2. A Predictive Model of Mortality in Patients With Bloodstream Infections due to Carbapenemase-Producing Enterobacteriaceae.

    Science.gov (United States)

    Gutiérrez-Gutiérrez, Belén; Salamanca, Elena; de Cueto, Marina; Hsueh, Po-Ren; Viale, Pierluigi; Paño-Pardo, José Ramón; Venditti, Mario; Tumbarello, Mario; Daikos, George; Pintado, Vicente; Doi, Yohei; Tuon, Felipe Francisco; Karaiskos, Ilias; Machuca, Isabel; Schwaber, Mitchell J; Azap, Özlem Kurt; Souli, Maria; Roilides, Emmanuel; Pournaras, Spyros; Akova, Murat; Pérez, Federico; Bermejo, Joaquín; Oliver, Antonio; Almela, Manel; Lowman, Warren; Almirante, Benito; Bonomo, Robert A; Carmeli, Yehuda; Paterson, David L; Pascual, Alvaro; Rodríguez-Baño, Jesús

    2016-10-01

    To develop a score to predict mortality in patients with bloodstream infections (BSIs) due to carbapenemase-producing Enterobacteriaceae (CPE). A multinational retrospective cohort study (INCREMENT project) was performed from January 1, 2004, through December 31, 2013. Patients with clinically relevant monomicrobial BSIs due to CPE were included and randomly assigned to either a derivation cohort (DC) or a validation cohort (VC). The variables were assessed on the day the susceptibility results were available, and the predictive score was developed using hierarchical logistic regression. The main outcome variable was 14-day all-cause mortality. The predictive ability of the model and scores were measured by calculating the area under the receiver operating characteristic curve. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for different cutoffs of the score. The DC and VC included 314 and 154 patients, respectively. The final logistic regression model of the DC included the following variables: severe sepsis or shock at presentation (5 points); Pitt score of 6 or more (4 points); Charlson comorbidity index of 2 or more (3 points); source of BSI other than urinary or biliary tract (3 points); inappropriate empirical therapy and inappropriate early targeted therapy (2 points). The score exhibited an area under the receiver operating characteristic curve of 0.80 (95% CI, 0.74-0.85) in the DC and 0.80 (95% CI, 0.73-0.88) in the VC. The results for 30-day all-cause mortality were similar. A validated score predictive of early mortality in patients with BSIs due to CPE was developed. clinicaltrials.gov Identifier: NCT01 764490. Copyright © 2016 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

  3. A multidisciplinary approach to reduce central line-associated bloodstream infections.

    Science.gov (United States)

    McMullan, Christine; Propper, Grace; Schuhmacher, Christine; Sokoloff, Lisa; Harris, David; Murphy, Paul; Greene, William H

    2013-02-01

    Stony Brook University Hospital (SBUH) joined a Critical Care Learning Collaborative in fall 2004. The collaborative incorporated application of central line and ventilator bundles, multidisciplinary rounding, and daily goal sheets to improve patient outcomes. In a two-year period, the initiative spread to the medical, pediatric, cardiac, and neonatal ICUs. Despite some success, the goal of eliminating central line-associated bloodstream infections (CLABSIs) was not initially realized. In response, SBUH developed a standardized central line insertion credentialing program for residents. After further review of the residual central line infection data, it was evident that many of the lines became infected after day 7 of insertion. Evaluation of the line maintenance process revealed that nursing staff were not accessing the lines using the same level of sterile technique as used during insertion. As a result, a central line maintenance protocol was developed and deployed. After cumulative efforts were undertaken, SBUH's overall CLABSI rate decreased by 59% in a five-year period and by more than 80% in the most recent 12 months. A critical feature of the approach that SBUH followed was to establish buy-in and oversight from the SICU leadership through a multidisciplinary team, which became the "learning laboratory" for many of the subsequent changes in practice. Also, the fundamental role of the Continuous Quality Improvement (CQI) Department's quality management practitioner as facilitator cannot be overstated. "Hardwiring" of process changes augmented sustainability of improvements, as did a change in the health care team's perception of central line infections--that is, from an "unavoidable complication" to "a failure."

  4. Time to positivity of blood cultures in patients with bloodstream infections: A useful prognostic tool.

    Science.gov (United States)

    Martín-Gutiérrez, Guillermo; Martín-Pérez, Carlos; Gutiérrez-Pizarraya, Antonio; Lepe, José A; Cisneros, José M; Aznar, Javier

    2017-12-01

    The time to positivity (TTP) of blood cultures in patients with bloodstream infections (BSIs) has been considered to be a possible prognostic tool for some bacterial species. However, notable differences have been found between sampling designs and statistical methods in published studies to date, which makes it difficult to compare results or to derive reliable conclusions. Our objective was to evaluate the clinical and microbiological implications of TTP among patients with BSI caused by the most common pathogens. A total of 361 episodes of BSI were reported for 332 patients. The survival of the entire cohort was measured from the time of blood culture sampling. In order to compare our results with those of previous studies, TTP was divided in three different groups based on log rank (short TTP 27h). Cox proportional hazard models were used to calculate crude and adjusted hazard ratios (HR). The Cox proportional hazard model revealed that TTP is an independent predictor of mortality (HR=1.00, p=0.031) in patients with BSIs. A higher mortality was found in the group of patients with the shortest TTP (27h) (HR=3.277, p=0.031). It seems that TTP may provide a useful prognostic tool associated with a higher risk of mortality, not only in patients with shorter TTP, but also in those with longer TTP. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  5. The impact of parenteral nutrition preparation on bloodstream infection risk and costs.

    Science.gov (United States)

    Turpin, R S; Solem, C; Pontes-Arruda, A; Sanon, M; Mehta, S; Xiaoqing Liu, F; Botteman, M

    2014-08-01

    Catheter-related bloodstream infections (BSIs) are a serious problem leading to increased morbidity, longer hospital stay, and hence, additional costs. This study evaluated the risk of BSI and the cost of parenteral nutrition (PN) in Germany. A retrospective observational chart review of patients hospitalized from October 2009 to April 2011 and receiving PN via ready-to-use three-chamber bag (MCB), single bottle (SB) or hospital compounded admixture (CPN) was conducted across Germany. Propensity score-adjusted models were used to evaluate the association between the type of PN, BSI (Cox Proportional Hazards) and hospitalization cost (generalized linear models) within a subgroup receiving all three macronutrients (lipids, amino acids, glucose). Of the 1995 patient records reviewed (MCB=816; CPN=584; SB=595), 1457 patients received all three macronutrients. After adjustment, SB was associated with an increased hazard of BSI, vs MCB without additions (hazard ratio (HR) (95% confidence interval (CI))=2.53 (1.66-3.86)) in the total cohort. Adding supplements to MCB on the ward also increased the BSI risk in both total and subgroup analyses. In patients receiving all three macronutrients, adjusted total costs were MCB (no additions): \\[euro]6,572 (95% CI: \\[euro]6,896-6263); CPN: \\[euro]6,869 (\\[euro]7,283-6479); SB: \\[euro]6,872 (\\[euro]7,242-6521); MCB (ward additions): \\[euro]7,402 (\\[euro]7,878-6955); PMCB does not appear to increase treatment costs, possibly by reducing the risk of infection. This study identified several PN preparation methods associated with a significantly increased hazard for BSI; definitive CPN findings are limited by our inability to distinguish automated from manual pharmacy compounding.

  6. Three Epidemics of Invasive Multidrug-Resistant Salmonella Bloodstream Infection in Blantyre, Malawi, 1998–2014

    Science.gov (United States)

    Feasey, Nicholas A.; Masesa, Clemens; Jassi, Chikondi; Faragher, E. Brian; Mallewa, Jane; Mallewa, Macpherson; MacLennan, Calman A.; Msefula, Chisomo; Heyderman, Robert S.; Gordon, Melita A.

    2015-01-01

    Background. The Malawi Liverpool Wellcome Trust Clinical Research Programme (MLW) has routinely collected specimens for blood culture from febrile patients, and cerebrospinal fluid from patients with suspected meningitis, presenting to Queen Elizabeth Central Hospital (QECH), Blantyre, Malawi, since 1998. Methods. We present bloodstream infection (BSI) and meningitis surveillance data from 1998 to 2014. Automated blood culture, manual speciation, serotyping, and antimicrobial susceptibility testing were performed at MLW. Population data for minimum-incidence estimates in urban Blantyre were drawn from published estimates. Results. Between 1998 and 2014, 167 028 blood cultures were taken from adult and pediatric medical patients presenting to QECH; Salmonella Typhi was isolated on 2054 occasions (1.2%) and nontyphoidal Salmonella (NTS) serovars were isolated 10 139 times (6.1%), of which 8017 (79.1%) were Salmonella Typhimurium and 1608 (15.8%) were Salmonella Enteritidis. There were 392 cases of NTS meningitis and 9 cases of Salmonella Typhi meningitis. There have been 3 epidemics of Salmonella BSI in Blantyre; Salmonella Enteritidis from 1999 to 2002, Salmonella Typhimurium from 2002 to 2008, and Salmonella Typhi, which began in 2011 and was ongoing in 2014. Multidrug resistance has emerged in all 3 serovars and is seen in the overwhelming majority of isolates, while resistance to third-generation cephalosporins and fluoroquinolones is currently uncommon but has been identified. Conclusions. Invasive Salmonella disease in Malawi is dynamic and not clearly attributable to a single risk factor, although all 3 epidemics were associated with multidrug resistance. To inform nonvaccine and vaccine interventions, reservoirs of disease and modes of transmission require further investigation. PMID:26449953

  7. Three Epidemics of Invasive Multidrug-Resistant Salmonella Bloodstream Infection in Blantyre, Malawi, 1998-2014.

    Science.gov (United States)

    Feasey, Nicholas A; Masesa, Clemens; Jassi, Chikondi; Faragher, E Brian; Mallewa, Jane; Mallewa, Macpherson; MacLennan, Calman A; Msefula, Chisomo; Heyderman, Robert S; Gordon, Melita A

    2015-11-01

    The Malawi Liverpool Wellcome Trust Clinical Research Programme (MLW) has routinely collected specimens for blood culture from febrile patients, and cerebrospinal fluid from patients with suspected meningitis, presenting to Queen Elizabeth Central Hospital (QECH), Blantyre, Malawi, since 1998. We present bloodstream infection (BSI) and meningitis surveillance data from 1998 to 2014. Automated blood culture, manual speciation, serotyping, and antimicrobial susceptibility testing were performed at MLW. Population data for minimum-incidence estimates in urban Blantyre were drawn from published estimates. Between 1998 and 2014, 167,028 blood cultures were taken from adult and pediatric medical patients presenting to QECH; Salmonella Typhi was isolated on 2054 occasions (1.2%) and nontyphoidal Salmonella (NTS) serovars were isolated 10,139 times (6.1%), of which 8017 (79.1%) were Salmonella Typhimurium and 1608 (15.8%) were Salmonella Enteritidis. There were 392 cases of NTS meningitis and 9 cases of Salmonella Typhi meningitis. There have been 3 epidemics of Salmonella BSI in Blantyre; Salmonella Enteritidis from 1999 to 2002, Salmonella Typhimurium from 2002 to 2008, and Salmonella Typhi, which began in 2011 and was ongoing in 2014. Multidrug resistance has emerged in all 3 serovars and is seen in the overwhelming majority of isolates, while resistance to third-generation cephalosporins and fluoroquinolones is currently uncommon but has been identified. Invasive Salmonella disease in Malawi is dynamic and not clearly attributable to a single risk factor, although all 3 epidemics were associated with multidrug resistance. To inform nonvaccine and vaccine interventions, reservoirs of disease and modes of transmission require further investigation. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.

  8. Outbreak of Pantoea agglomerans Bloodstream Infections at an Oncology Clinic-Illinois, 2012-2013.

    Science.gov (United States)

    Yablon, Brian R; Dantes, Raymund; Tsai, Victoria; Lim, Rachel; Moulton-Meissner, Heather; Arduino, Matthew; Jensen, Bette; Patel, Megan Toth; Vernon, Michael O; Grant-Greene, Yoran; Christiansen, Demian; Conover, Craig; Kallen, Alexander; Guh, Alice Y

    2017-03-01

    OBJECTIVE To determine the source of a healthcare-associated outbreak of Pantoea agglomerans bloodstream infections. DESIGN Epidemiologic investigation of the outbreak. SETTING Oncology clinic (clinic A). METHODS Cases were defined as Pantoea isolation from blood or catheter tip cultures of clinic A patients during July 2012-May 2013. Clinic A medical charts and laboratory records were reviewed; infection prevention practices and the facility's water system were evaluated. Environmental samples were collected for culture. Clinical and environmental P. agglomerans isolates were compared using pulsed-field gel electrophoresis. RESULTS Twelve cases were identified; median (range) age was 65 (41-78) years. All patients had malignant tumors and had received infusions at clinic A. Deficiencies in parenteral medication preparation and handling were identified (eg, placing infusates near sinks with potential for splash-back contamination). Facility inspection revealed substantial dead-end water piping and inadequate chlorine residual in tap water from multiple sinks, including the pharmacy clean room sink. P. agglomerans was isolated from composite surface swabs of 7 sinks and an ice machine; the pharmacy clean room sink isolate was indistinguishable by pulsed-field gel electrophoresis from 7 of 9 available patient isolates. CONCLUSIONS Exposure of locally prepared infusates to a contaminated pharmacy sink caused the outbreak. Improvements in parenteral medication preparation, including moving chemotherapy preparation offsite, along with terminal sink cleaning and water system remediation ended the outbreak. Greater awareness of recommended medication preparation and handling practices as well as further efforts to better define the contribution of contaminated sinks and plumbing deficiencies to healthcare-associated infections are needed. Infect Control Hosp Epidemiol 2017;38:314-319.

  9. Molecular epidemiology and antimicrobial resistance of methicillin-resistant Staphylococcus aureus bloodstream isolates in Taiwan, 2010.

    Directory of Open Access Journals (Sweden)

    Chih-Jung Chen

    Full Text Available The information of molecular characteristics and antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus (MRSA is essential for control and treatment of diseases caused by this medically important pathogen. A total of 577 clinical MRSA bloodstream isolates from six major hospitals in Taiwan were determined for molecular types, carriage of Panton-Valentine leukocidin (PVL and sasX genes and susceptibilities to 9 non-beta-lactam antimicrobial agents. A total of 17 genotypes were identified in 577 strains by pulsotyping. Five major pulsotypes, which included type A (26.2%, belonging to sequence type (ST 239, carrying type III staphylococcal chromosomal cassette mec (SCCmec, type F (18.9%, ST5-SCCmecII, type C (18.5%, ST59-SCCmecIV, type B (12.0%, ST239-SCCmecIII and type D (10.9%, ST59-SCCmecVT/IV, prevailed in each of the six sampled hospitals. PVL and sasX genes were respectively carried by ST59-type D strains and ST239 strains with high frequencies (93.7% and 99.1%, respectively but rarely detected in strains of other genotypes. Isolates of different genotypes and from different hospitals exhibited distinct antibiograms. Multi-resistance to ≥3 non-beta-lactams was more common in ST239 isolates (100% than in ST5 isolates (97.2%, P = 0.0347 and ST59 isolates (8.2%, P<0.0001. Multivariate analysis further indicated that the genotype, but not the hospital, was an independent factor associated with muti-resistance of the MRSA strains. In conclusion, five common MRSA clones with distinct antibiograms prevailed in the major hospitals in Taiwan in 2010. The antimicrobial susceptibility pattern of invasive MRSA was mainly determined by the clonal distribution.

  10. Dwell time and risk of central-line-associated bloodstream infection in neonates.

    Science.gov (United States)

    Sanderson, E; Yeo, K T; Wang, A Y; Callander, I; Bajuk, B; Bolisetty, S; Lui, K

    2017-11-01

    Umbilical venous catheters (UVCs) or peripherally inserted central catheters (PICCs), widely used in high-risk neonates, may have a threshold dwell time for subsequent increased risk of central-line-associated bloodstream infection (CLABSI). To evaluate the CLABSI risks in neonates having either UVC, PICC, or those having both sequentially. The study included 3985 infants who had UVC or PICC inserted between 2007 and 2009 cared for in 10 regional neonatal intensive care units: 1392 having UVC only (group 1), 1317 PICC only (group 2), and 1276 both UVC and PICC (group 3). There were 403 CLABSIs among 6000 venous catheters inserted, totalling 43,302 catheter-days. CLABSI rates were higher in group 3 infants who were of lowest gestation (16.9 per 1000 UVC-days and 12.5 per 1000 PICC-days; median: 28 weeks) when compared with group 1 (3.3 per 1000 UVC-days; 37 weeks) and group 2 (4.8 per 1000 PICC-days; 30 weeks). Life table and Kaplan-Meier hazard analysis showed that UVC CLABSI rate increased stepwise to 42 per 1000 UVC-days by day 10, with the highest rate in group 3 (85 per 1000 UVC-days). PICC CLABSI rates remained relatively stable at 12-20 per 1000 PICC-days. Compared to PICC, UVC had a higher adjusted CLABSI risk controlled for dwell time. Among group 3, replacing UVC electively before day 4 may have a trend of lower CLABSI risk than late replacement. There was no cut-off duration beyond which PICC should be removed electively. Early UVC removal and replacement by PICC before day 4 might be considered. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  11. Effect of Catheter Dwell Time on Risk of Central Line-Associated Bloodstream Infection in Infants.

    Science.gov (United States)

    Greenberg, Rachel G; Cochran, Keith M; Smith, P Brian; Edson, Barbara S; Schulman, Joseph; Lee, Henry C; Govindaswami, Balaji; Pantoja, Alfonso; Hardy, Doug; Curran, John; Lin, Della; Kuo, Sheree; Noguchi, Akihiko; Ittmann, Patricia; Duncan, Scott; Gupta, Munish; Picarillo, Alan; Karna, Padmani; Cohen, Morris; Giuliano, Michael; Carroll, Sheri; Page, Brandi; Guzman-Cottrill, Judith; Walker, M Whit; Garland, Jeff; Ancona, Janice K; Ellsbury, Dan L; Laughon, Matthew M; McCaffrey, Martin J

    2015-12-01

    Central venous catheters in the NICU are associated with significant morbidity and mortality because of the risk of central line-associated bloodstream infections (CLABSIs). The purpose of this study was to determine the effect of catheter dwell time on risk of CLABSI. Retrospective cohort study of 13,327 infants with 15,567 catheters (93% peripherally inserted central catheters [PICCs], 7% tunneled catheters) and 256,088 catheter days cared for in 141 NICUs. CLABSI was defined using National Health Surveillance Network criteria. We defined dwell time as the number of days from line insertion until either line removal or day of CLABSI. We generated survival curves for each week of dwell time and estimated hazard ratios for CLABSI at each week by using a Cox proportional hazards frailty model. We controlled for postmenstrual age and year, included facility as a random effect, and generated separate models by line type. Median postmenstrual age was 29 weeks (interquartile range 26-33). The overall incidence of CLABSI was 0.93 per 1000 catheter days. Increased dwell time was not associated with increased risk of CLABSI for PICCs. For tunneled catheters, infection incidence was significantly higher in weeks 7 and 9 compared with week 1. Clinicians should not routinely replace uninfected PICCs for fear of infection but should consider removing tunneled catheters before week 7 if no longer needed. Additional studies are needed to determine what daily maintenance practices may be associated with decreased risk of infection, especially for tunneled catheters. Copyright © 2015 by the American Academy of Pediatrics.

  12. Effect of Catheter Dwell Time on Risk of Central Line–Associated Bloodstream Infection in Infants

    Science.gov (United States)

    Greenberg, Rachel G.; Cochran, Keith M.; Smith, P. Brian; Edson, Barbara S.; Schulman, Joseph; Lee, Henry C.; Govindaswami, Balaji; Pantoja, Alfonso; Hardy, Doug; Curran, John; Lin, Della; Kuo, Sheree; Noguchi, Akihiko; Ittmann, Patricia; Duncan, Scott; Gupta, Munish; Picarillo, Alan; Karna, Padmani; Cohen, Morris; Giuliano, Michael; Carroll, Sheri; Page, Brandi; Guzman-Cottrill, Judith; Walker, M. Whit; Garland, Jeff; Ancona, Janice K.; Ellsbury, Dan L.; Laughon, Matthew M.

    2015-01-01

    BACKGROUND AND OBJECTIVE: Central venous catheters in the NICU are associated with significant morbidity and mortality because of the risk of central line–associated bloodstream infections (CLABSIs). The purpose of this study was to determine the effect of catheter dwell time on risk of CLABSI. METHODS: Retrospective cohort study of 13 327 infants with 15 567 catheters (93% peripherally inserted central catheters [PICCs], 7% tunneled catheters) and 256 088 catheter days cared for in 141 NICUs. CLABSI was defined using National Health Surveillance Network criteria. We defined dwell time as the number of days from line insertion until either line removal or day of CLABSI. We generated survival curves for each week of dwell time and estimated hazard ratios for CLABSI at each week by using a Cox proportional hazards frailty model. We controlled for postmenstrual age and year, included facility as a random effect, and generated separate models by line type. RESULTS: Median postmenstrual age was 29 weeks (interquartile range 26–33). The overall incidence of CLABSI was 0.93 per 1000 catheter days. Increased dwell time was not associated with increased risk of CLABSI for PICCs. For tunneled catheters, infection incidence was significantly higher in weeks 7 and 9 compared with week 1. CONCLUSIONS: Clinicians should not routinely replace uninfected PICCs for fear of infection but should consider removing tunneled catheters before week 7 if no longer needed. Additional studies are needed to determine what daily maintenance practices may be associated with decreased risk of infection, especially for tunneled catheters. PMID:26574587

  13. CHLORHEXIDINE-IMPREGNATED DRESSING FOR PREVENTION OF CATHETER-RELATED BLOODSTREAM INFECTION: A META-ANALYSIS

    Science.gov (United States)

    Safdar, Nasia; O’Horo, John C.; Ghufran, Aiman; Bearden, Allison; Didier, Maria Eugenia; Chateau, Dan; Maki, Dennis G.

    2014-01-01

    Background Catheter related bloodstream infections (CRBSI) are associated with significant morbidity and mortality and effective methods for their prevention are needed. Objective To assess the efficacy of a chlorhexidine-impregnated dressing for prevention of central venous catheter-related colonization and CRBSI using meta-analysis. Data Sources Multiple computerized database searches supplemented by manual searches including relevant conference proceedings. Study Selection Randomized controlled trials (RCT) evaluating the efficacy of a chlorhexidine-impregnated dressing compared with conventional dressings for prevention of catheter colonization and CRBSI. Data Extraction Data were extracted on patient and catheter characteristics and outcomes. Data Synthesis Pooled estimates of the relative risk (RR) and 95% confidence intervals (CI) were obtained using the DerSimonian and Laird random effects model and the Mantel-Haenszel fixed effects model. Heterogeneity was assessed using the Cochran Q statistic and I2. Subgroup analyses were used to explore heterogeneity. Results Nine RCTs met the inclusion criteria. Use of a chlorhexidine-impregnated dressing resulted in a reduced incidence of CRBSI (random effects RR 0.57, 95% CI 0.42–0.79, P=0.002). The incidence of catheter colonization was also markedly reduced in the chlorhexidine-impregnated dressing group (random effects RR 0.51, 95% CI 0.39–0.67, Pchlorhexidine-impregnated dressing is beneficial in preventing catheter colonization and, more importantly, CRBSI and warrants routine use in patients at high risk of CRBSI and CVC or arterial catheter colonization in ICUs. PMID:24674924

  14. Secular trends in nosocomial bloodstream infections: antibiotic-resistant bacteria increase the total burden of infection.

    Science.gov (United States)

    Ammerlaan, H S M; Harbarth, S; Buiting, A G M; Crook, D W; Fitzpatrick, F; Hanberger, H; Herwaldt, L A; van Keulen, P H J; Kluytmans, J A J W; Kola, A; Kuchenbecker, R S; Lingaas, E; Meessen, N; Morris-Downes, M M; Pottinger, J M; Rohner, P; dos Santos, R P; Seifert, H; Wisplinghoff, H; Ziesing, S; Walker, A S; Bonten, M J M

    2013-03-01

    It is unknown whether rising incidence rates of nosocomial bloodstream infections (BSIs) caused by antibiotic-resistant bacteria (ARB) replace antibiotic-susceptible bacteria (ASB), leaving the total BSI rate unaffected. We investigated temporal trends in annual incidence densities (events per 100 000 patient-days) of nosocomial BSIs caused by methicillin-resistant Staphylococcus aureus (MRSA), ARB other than MRSA, and ASB in 7 ARB-endemic and 7 ARB-nonendemic hospitals between 1998 and 2007. 33 130 nosocomial BSIs (14% caused by ARB) yielded 36 679 microorganisms. From 1998 to 2007, the MRSA incidence density increased from 0.2 to 0.7 (annual increase, 22%) in ARB-nonendemic hospitals, and from 3.1 to 11.7 (annual increase, 10%) in ARB-endemic hospitals (P = .2), increasing the incidence density difference between ARB-endemic and ARB-nonendemic hospitals from 2.9 to 11.0. The non-MRSA ARB incidence density increased from 2.8 to 4.1 (annual increase, 5%) in ARB-nonendemic hospitals, and from 1.5 to 17.4 (annual increase, 22%) in ARB-endemic hospitals (P nosocomial BSIs in ARB-nonendemic and ARB-endemic hospitals, respectively (P nosocomial BSI rates due to ARB occur in addition to infections caused by ASB, increasing the total burden of disease. Hospitals with high ARB infection rates in 2005 had an excess burden of BSI of 20.6 per 100 000 patient-days in a 10-year period, mainly caused by infections with ARB.

  15. A case definition for national and international neonatal bloodstream infection surveillance.

    Science.gov (United States)

    Modi, N; Doré, C J; Saraswatula, A; Richards, M; Bamford, K B; Coello, R; Holmes, A

    2009-01-01

    Neonatal bloodstream infection (BSI) is a major contributor to mortality, health service costs, and the population burden of lifelong neurodisability. BSI surveillance, an essential component of infection control, requires an unambiguous standardised case definition as variability would invalidate any comparative analyses. In neonates a high proportion of blood cultures yield a mixed growth or skin commensals, principally coagulase-negative staphylococci (CoNS). As this might represent either genuine BSI or contamination, clinical correlates are necessary, but this adds to the difficulty of agreeing an objective, standardised case definition. Utilising data from 26 UK neonatal units, the population prevalence of 12 predefined clinical signs of infection captured daily for 28 days was evaluated. The sensitivity, specificity, odds ratio and positive predictive value of each sign and sequential numbers of grouped signs were determined to develop a predictive model for a positive blood culture. Sandwich estimates of the standard errors of the logistic regression coefficients were used to take account of the correlations between these repeated measures. The model was tested in an independent data set. > or =3 clinical signs had the best predictive accuracy for a positive blood culture (76.2% specificity; 61.5%, 46.9% and 78.2% sensitivity for all positive cultures, cultures yielding CoNS, or a recognised pathogen, respectively). This study suggests that a simple case definition for national and international neonatal BSI surveillance is provided by a blood culture yielding a recognised pathogen in pure culture, or a mixed growth or skin commensal plus > or =3 predefined clinical signs.

  16. Epidemiology, species distribution and outcome of nosocomial Candida spp. bloodstream infection in Shanghai.

    Science.gov (United States)

    Yang, Zhi-Tao; Wu, Lin; Liu, Xiao-Ying; Zhou, Min; Li, Jie; Wu, Jia-Yin; Cai, Yong; Mao, En-Qiang; Chen, Er-Zhen; Lortholary, Olivier

    2014-05-06

    Yeasts, mostly Candida, are important causes of bloodstream infections (BSI), responsible for significant mortality and morbidity among hospitalized patients. The epidemiology and species distribution vary from different regions. The goals of this study were to report the current epidemiology of Candida BSI in a Shanghai Teaching Hospital and estimate the impact of appropriate antifungal therapy on the outcome. From January 2008 to December 2012, all consecutive patients who developed Candida BSI at Ruijin University Hospital were enrolled. Underlying diseases, clinical severity, species distribution, antifungal therapy and its impact on the outcome were analyzed. A total of 121 episodes of Candida BSI were identified, with an incidence of 0.32 episodes/1,000 admissions (0.21 in 2008 and 0.42 in 2012) The proportion of candidemia caused by non-albicans species (62.8%), including C. parapsilosis (19.8%), C. tropicalis (14.9%), C. glabrata (7.4%), C. guilliermondii (5.8%), C. sake (5.0%) was higher than that of candidemia caused by C. albicans (37.2%). The overall crude 28-day mortality was 28.1% and significantly reduced with appropriate empiric antifungal therapy administered within 5 days (P = 0.006). Advanced age (OR 1.04; P = 0.014), neutropenia risk factors for 28-day mortality, while appropriate empiric antifungal therapy (OR 0.369; P = 0.035) was protective against 28-day mortality. The epidemiology of candidemia in Shanghai differed from that observed in Western countries. Appropriate empiric antifungal therapy influenced the short-term survival.

  17. Trends in nosocomial bloodstream infections following health care restructuring in Alberta between 1999 and 2005.

    Science.gov (United States)

    Lee, Mao-Cheng; Saxinger, Lynora; Forgie, Sarah E; Taylor, Geoffrey

    2010-01-01

    A previous study at the University of Alberta Hospital/Stollery Children's Hospital in Edmonton, Alberta, revealed an increase in hospital-acquired bloodstream infection (BSI) rates associated with an increase in patient acuity during a period of public health care delivery restructuring between 1993 and 1996. The present study assessed trends in BSIs since the end of the restructuring. Prospective surveillance for BSIs was performed using Centers for Disease Control and Prevention (USA) criteria for infection. BSI cases between January 1, 1999, and December 31, 2005, were reviewed. Available measures of patient volumes, acuity and BSI risk factors between 1999 and 2005 were also reviewed from hospital records. The University of Alberta Hospital/Stollery Children's Hospital (617 adult and 139 pediatric beds, respectively). All pediatric and adult patients admitted during the above-specified period with one or more episodes of BSIs. There was a significant overall decline in the BSI number and rate over the study period between 1999 and 2005. The downward trend was widespread, involving both adult and pediatric populations, as well as primary and secondary BSIs. During this period, the number of hospital-wide and intensive care unit admissions, intensive care unit central venous catheter-days, total parenteral nutrition days and number of solid-organ transplants were either unchanged or increased. Gram-positive bacterial causes of BSIs showed significant downward trends, but Gram-negative bacterial and fungal etiologies were unchanged. These data imply that, over time, hospitals can gradually adjust to changing patient care circumstances and, in this example, control infectious complications of health care delivery.

  18. Nosocomial Bloodstream Infection Due to Candida spp. in China: Species Distribution, Clinical Features, and Outcomes.

    Science.gov (United States)

    Li, Ying; Du, Mingmei; Chen, Liang-An; Liu, Yunxi; Liang, Zhixin

    2016-08-01

    To investigate the distribution of Candida spp., predictors of mortality, and effects of therapeutic measures on outcomes of nosocomial bloodstream infection (BSI) due to Candida spp. This retrospective, population-based study enrolled adult patients with Candida nosocomial BSI from January 2010 to December 2014 in one tertiary care hospital. The demographics, comorbidities, species distribution, risk factors, and effects of antifungal treatment were assessed. In total, 190 episodes of Candida BSI were identified. The most prevalent species was C. albicans (38.9 %), followed by C. parapsilosis (23.2 %) and C. tropicalis (20.5 %). In vitro susceptibility testing showed that 88.9 % of Candida isolates were susceptible to fluconazole. The 30-day hospital mortality was 27.9 %, while the early mortality (within 7 days) was 16.3 %. In a multivariate regression analysis, the Acute Physiology and Chronic Health Evaluation II score [odds ratio (OR) 1.23; 95 % confidence interval (CI) 1.080-1.390; P = 0.002] and severe sepsis or septic shock (OR 15.35; 95 % CI 2.391-98.502; P = 0.004) were independently correlated with early mortality. Severe sepsis or septic shock (OR 24.75; 95 % CI 5.099-120.162; P risk factor for 30-day mortality, while proven catheter-related candidemia (OR 0.16; 95 % CI 0.031-0.810; P = 0.027) was a positive factor for 30-day mortality. Early central venous catheter removal and adequate antifungal treatment were closely related to decreased mortality in patients with primary candidemia. The proportion of candidemia caused by C. albicans was lower than that caused by non-albicans species. The severity of illness influenced early mortality, and the origin of the central venous catheter remarkably affected 30-day mortality.

  19. Is Clostridium difficile infection a risk factor for subsequent bloodstream infection?

    Science.gov (United States)

    Ulrich, Robert J; Santhosh, Kavitha; Mogle, Jill A; Young, Vincent B; Rao, Krishna

    2017-06-29

    Clostridium difficile infection (CDI) is a common nosocomial diarrheal illness increasingly associated with mortality in United States. The underlying factors and mechanisms behind the recent increases in morbidity from CDI have not been fully elucidated. Murine models suggest a mucosal barrier breakdown leads to bacterial translocation and subsequent bloodstream infection (BSI). This study tests the hypothesis that CDI is associated with subsequent BSI in humans. We conducted a retrospective cohort study on 1132 inpatients hospitalized >72 h with available stool test results for toxigenic C. difficile. The primary outcome was BSI following CDI. Secondary outcomes included 30-day mortality, colectomy, readmission, and ICU admission. Unadjusted and adjusted logistic regression models were developed. CDI occurred in 570 of 1132 patients (50.4%). BSI occurred in 86 (7.6%) patients. Enterococcus (14%) and Klebsiella (14%) species were the most common organisms. Patients with BSI had higher comorbidity scores and were more likely to be male, on immunosuppression, critically ill, and have a central venous catheter in place. Of the patients with BSI, 36 (42%) had CDI. CDI was not associated with subsequent BSI (OR 0.69; 95% CI 0.44-1.08; P = 0.103) in unadjusted analysis. In multivariable modeling, CDI appeared protective against subsequent BSI (OR 0.57; 95% CI 0.34-0.96; P = 0.036). Interaction modeling suggests a complicated relationship among CDI, BSI, antibiotic exposure, and central venous catheter use. In this cohort of inpatients that underwent testing for CDI, CDI was not a risk factor for developing subsequent BSI. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Clinical significance of coagulase-negative staphylococci isolates from nosocomial bloodstream infections.

    Science.gov (United States)

    Asaad, Ahmed Morad; Ansar Qureshi, Mohamed; Mujeeb Hasan, Syed

    2016-01-01

    Identification of coagulase-negative staphylococci (CoNS) as nosocomial pathogens or contaminants is significant for microbiologists and clinicians. This study aimed to determine the frequency of isolation and antimicrobial resistance patterns of CoNS isolates from nosocomial bloodstream infections (BSIs) and to identify risk factors associated with true bacteremia caused by these emerging pathogens in a Saudi tertiary care hospital. All CoNS-positive cultures from inpatients were identified using the standard methods during a 10-month period. Antimicrobial susceptibility testing was done using the reference broth microdilution method. A total of 208 isolates were identified; of these 75 (32.2%) were considered infection associated, and 133 (67.8%) were considered contamination. S. epidermidis accounted for 34.7% of bacteremia cases, followed by S. hominis (21.3%), S. haemolyticus (16%), and S. saprophyticus (12%). Central venous catheters (p ≤ 0.0001), prior antibiotic therapy (p ≤ 0.0001), the occurrence of more than one positive blood culture (p ≤ 0.0001), and intensive care unit (ICU) admission (p = 0.007) were all independently associated with CoNS bacteremia. Overall, all isolates were highly resistant to penicillin (94.7%), oxacillin (90.7%), and erythromycin (85.3%). The rates of susceptibility to vancomycin, daptomycin, and teicoplanin were 98.7%, 98.7%, and 93.3%, respectively. Our results further highlight that accurate identification and susceptibility testing of CoNS isolates from nosocomial BSIs are crucial to minimize excessive antibiotic use and unnecessary catheter removal. In addition, daptomycin may be an efficient alternative therapeutic option for CoNS resistant to oxacillin and other commonly used antibiotics.

  1. Epidemiology and microbiology of nosocomial bloodstream infections: analysis of 482 cases from a retrospective surveillance study.

    Science.gov (United States)

    Wu, Jian-nong; Gan, Tie-er; Zhu, Yue-xian; Cao, Jun-min; Ji, Cong-hua; Wu, Yi-hua; Lv, Bin

    2015-01-01

    In many traditional Chinese medicine (TCM) hospitals, most patients are elderly with chronic diseases. Nosocomial bloodstream infections (nBSIs) are an important cause of morbidity and mortality. A retrospective surveillance study was performed to examine the epidemiology and microbiology of nBSIs in a TCM hospital from 2009 to 2011. A total of 482 patients with nBSIs were included in the study period. The incidence rate was 5.7/1000 admissions. Escherichia coli (25.5%) was the most common Gram-negative and coagulase-negative staphylococcus (CoNS) (14.1%) was the most common Gram-positive organism isolated. One-third of the E. coli and Klebsiella pneumoniae isolated from the nBSIs were the third-generation cephalosporin-resistant. Half of the Acinetobacter species isolates were resistant to imipenem. Of all the CoNS isolates, 90.7% were resistant to methicillin. Carbapenems and glycopeptide were the most frequently used for nBSI therapy. Only about one-third of patients (157/482) received appropriate empirical therapy. Septic shock, hemodialysis, Pitt bacteremia score >4, urinary tract infection, and appropriate empirical therapy were most strongly associated with 28-d mortality. The incidence of nBSIs was low in the TCM hospital but the proportion of nBSIs due to antibiotic-resistant organisms was high. A high Pitt bacteremia score was one of the most important risk factors for mortality in nBSIs. Therefore, the implementation of appropriate empirical therapy is crucial to improve the clinical outcome of nBSIs.

  2. Characteristics of nosocomial bloodstream infections at a Hungarian cardiac surgery centre.

    Science.gov (United States)

    Trethon, András; Prinz, Gyula; Varga, Andrea; Kocsis, István

    2012-06-01

    Nosocomial bloodstream infection (BSI) is a common finding in cardiac surgery intensive care units and is associated with excess mortality and hospital costs. Additional data are needed about incidence, characteristics, predictors, associated microorganisms of nosocomial BSI in cardiac surgical patients in order to refine measures to prevent nosocomial infections and to improve recovery outcomes in this patient population. The 3912 cardio-thoracic surgery patients from all age groups were admitted to the study at the Gottsegen György Hungarian Institute of Cardiology between January 1999 and December 2000. In each patient with BSI demographic, epidemiological and clinical variables were recorded along with potential risk factors. Incidence of associated pathogens and their possible sources were evaluated and outcome and mortality risk factors were assessed. There were a total of 134 episodes of BSI. The incidence was 34.25 per 1000 admissions. The leading microorganisms were staphylococci (37.7%). Bacteremic episodes developed secondary to an identifiable source in 27.6% of the cases, or were catheter-related (16.4%). In 56% of the cases the source was not identified. The crude mortality rate was 33.3%. Higher mortality rate was associated with intracardial grafts (p < 0.05), low left ventricular ejection fraction (p < 0.04), diabetes mellitus (p < 0.05), an age above 16 years (p < 0.02), severe sepsis (p < 0.001) and high APACHE II score (p < 0.001). As the identified main sources of BSI were intravascular lines, mortality from BSI could probably be reduced by paying more attention to the prevention, early recognition and prompt management of intravascular device associated infections.

  3. Risk factors and mortality for nosocomial bloodstream infections in elderly patients.

    Science.gov (United States)

    Reunes, S; Rombaut, V; Vogelaers, D; Brusselaers, N; Lizy, C; Cankurtaran, M; Labeau, S; Petrovic, M; Blot, S

    2011-10-01

    To determine risk factors for nosocomial bloodstream infection (BSI) and associated mortality in geriatric patients in geriatric and internal medicine wards at a university hospital. Single-center retrospective (1992-2007), pairwise-matched (1:1-ratio) cohort study. Geriatric patients with nosocomial BSI were matched with controls without BSI on year of admission and length of hospitalization before onset of BSI. Demographic, microbiological, and clinical data are collected. One-hundred forty-two BSI occurred in 129 patients. Predominant microorganisms were Escherichia coli (23.2%), coagulase-negative Staphylococci (19.4%), Pseudomonas aeruginosa (8.4%), Staphylococcus aureus (7.1%), Klebsiella pneumoniae (5.8%) and Candida spp. (5.8%). Matching was successful for 109 cases. Compared to matched control subjects, cases were more frequently female, suffered more frequently from arthrosis, angina pectoris and pressure ulcers, had worse Activities of Daily Living-scores, had more often an intravenous or bladder catheter, and were more often bedridden. Logistic regression demonstrated presence of an intravenous catheter (odds ratio [OR] 7.5, 95% confidence interval [CI] 2.5-22.9) and being bedridden (OR 2.9, 95% CI 1.6-5.3) as independent risk factors for BSI. In univariate analysis nosocomial BSI was associated with increased mortality (22.0% vs. 11.0%; P=0.029). After adjustment for confounding co-variates, however, nosocomial BSI was not associated with mortality (hazard ratio 1.3, 95% CI 0.6-2.6). Being bedridden and increasing age were independent risk factors for death. Intravenous catheters and being bedridden are the main risk factors for nosocomial BSI. Although associated with higher mortality, this infectious complication seems not to be an independent risk factor for death in geriatric patients. Copyright © 2011 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  4. Population-based study of the epidemiology and the risk factors for Pseudomonas aeruginosa bloodstream infection.

    Science.gov (United States)

    Parkins, M D; Gregson, D B; Pitout, J D D; Ross, T; Laupland, K B

    2010-02-01

    Detailed population-based data on the epidemiology of Pseudomonas aeruginosa bloodstream infections are sparse. We sought to describe the incidence rate, risk factors, and outcomes associated with P. aeruginosa bacteremia in a large Canadian health region. A retrospective population-based surveillance for P. aeruginosa bacteremia was conducted in the Calgary Health Region (CHR, population:approx. 1.2 million) during the period from 2000 to 2006. A total of 284 incident cases of P. aeruginosa bacteremia were identified in CHR residents, corresponding to an annual incidence rate of 3.6/100,000.Nosocomial acquisition accounted for 45% of cases,healthcare-associated community onset for 34% of cases,and community-acquired (CA) cases for 21%. Relative to the general population, risk factors for blood stream infection included male sex, increasing age, hemodialysis,solid organ transplant, diagnosis of cancer, heart disease, HIV infection, diabetes mellitus, and/or chronic obstructive airway disease (COPD). Overall mortality was 29%. Factors associated with mortality in univariate analysis included pulmonary focus of infection and co-morbidities, including chronic liver disease, substance abuse, heart disease, COPD, and cancer, and increased with the burden of co-morbidities. Despite those patients with CA disease having fewer co-morbidities,they had a significantly higher mortality rate than either healthcare-associated cases or nosocomial cases(RR 1.88, p = 0.05). This study documents that P. aeruginosa bacteremic disease is responsible for a significant burden of illness in general populations and identifies those groups at increased risk of infection and subsequent mortality. This information can be used to identify those individuals likely to benefit from empiric anti-pseudomonal therapies.

  5. Incidence of and risk factors for nosocomial bloodstream infections in adults in the United States, 2003.

    Science.gov (United States)

    Al-Rawajfah, Omar M; Stetzer, Frank; Hewitt, Jeanne Beauchamp

    2009-11-01

    Although many studies have examined nosocomial bloodstream infection (BSI), US national estimates of incidence and case-fatality rates have seldom been reported. The purposes of this study were to generate US national estimates of the incidence and severity of nosocomial BSI and to identify risk factors for nosocomial BSI among adults hospitalized in the United States on the basis of a national probability sample. This cross-sectional study used the US Nationwide Inpatient Sample for the year 2003 to estimate the incidence and case-fatality rate associated with nosocomial BSI in the total US population. Cases of nosocomial BSI were defined by using 1 or more International Classification of Diseases, 9th Revision, Clinical Modification codes in the secondary field(s) that corresponded to BSIs that occurred at least 48 hours after admission. The comparison group consisted of all patients without BSI codes in their NIS records. Weighted data were used to generate US national estimates of nosocomial BSIs. Logistic regression was used to identify independent risk factors for nosocomial BSI. The US national estimated incidence of nosocomial BSI was 21.6 cases per 1,000 admissions, while the estimated case-fatality rate was 20.6%. Seven of the 10 leading causes of hospital admissions associated with nosocomial BSI were infection related. We estimate that 541,081 patients would have acquired a nosocomial BSI in 2003, and of these, 111,427 would have died. The final multivariate model consisted of the following risk factors: central venous catheter use (odds ratio [OR], 4.76), other infections (OR, 4.61), receipt of mechanical ventilation (OR, 4.97), trauma (OR, 1.98), hemodialysis (OR, 4.83), and malnutrition (OR, 2.50). The total maximum rescaled R(2) was 0.22. The Nationwide Inpatient Sample was useful for estimating national incidence and case-fatality rates, as well as examining independent predictors of nosocomial BSI.

  6. Bloodstream infection following 217 consecutive systemic-enteric drained pancreas transplants

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    Mark Walter

    2006-08-01

    Full Text Available Abstract Background Combined kidney pancreas transplantation (PTx evolved as excellent treatment for diabetic nephropathy. Infections remain common and serious complications. Methods 217 consecutive enteric drained PTxs performed from 1997 to 2004 were retrospectively analyzed with regard to bloodstream infection. Immunosuppression consisted of antithymocyteglobuline induction, tacrolimus, mycophenolic acid and steroids for the majority of cases. Standard perioperative antimicrobial prophylaxis consisted of pipercillin/tazobactam in combination with ciprofloxacin and fluconazole. Results One year patient, pancreas and kidney graft survival were 96.4%, 88.5% and 94.8%, surgical complication rate was 35%, rejection rate 30% and rate of infection 59%. In total 46 sepsis episodes were diagnosed in 35 patients (16% with a median onset on day 12 (range 1–45 post transplant. Sepsis source was intraabdominal infection (IAI (n = 21, a contaminated central venous line (n = 10, wound infection (n = 5, urinary tract infection (n = 2 and graft transmitted (n = 2. Nine patients (4% experienced multiple episodes of sepsis. Overall 65 pathogens (IAI sepsis 39, line sepsis 15, others 11 were isolated from blood. Gram positive cocci accounted for 50 isolates (77%: Coagulase negative staphylococci (n = 28, i.e. 43% (nine multi-resistant, Staphylococcus aureus (n = 11, i.e. 17% (four multi-resistant, enterococci (n = 9, i.e. 14% (one E. faecium. Gram negative rods were cultured in twelve cases (18%. Patients with blood borne infection had a two year pancreas graft survival of 76.5% versus 89.4% for those without sepsis (p = 0.036, patient survival was not affected. Conclusion Sepsis remains a serious complication after PTx with significantly reduced pancreas graft, but not patient survival. The most common source is IAI.

  7. Outbreak of Serratia marcescens bloodstream infections in patients receiving parenteral nutrition prepared by a compounding pharmacy.

    Science.gov (United States)

    Gupta, Neil; Hocevar, Susan N; Moulton-Meissner, Heather A; Stevens, Kelly M; McIntyre, Mary G; Jensen, Bette; Kuhar, David T; Noble-Wang, Judith A; Schnatz, Rick G; Becker, Shawn C; Kastango, Eric S; Shehab, Nadine; Kallen, Alexander J

    2014-07-01

    Compounding pharmacies often prepare parenteral nutrition (PN) and must adhere to rigorous standards to avoid contamination of the sterile preparation. In March 2011, Serratia marcescens bloodstream infections (BSIs) were identified in 5 patients receiving PN from a single compounding pharmacy. An investigation was conducted to identify potential sources of contamination and prevent further infections. Cases were defined as S. marcescens BSIs in patients receiving PN from the pharmacy between January and March 2011. We reviewed case patients' clinical records, evaluated pharmacy compounding practices, and obtained epidemiologically directed environmental cultures. Molecular relatedness of available Serratia isolates was determined by pulsed-field gel electrophoresis (PFGE). Nineteen case patients were identified; 9 died. The attack rate for patients receiving PN in March was 35%. No case patients were younger than 18 years. In October 2010, the pharmacy began compounding and filter-sterilizing amino acid solution for adult PN using nonsterile amino acids due to a national manufacturer shortage. Review of this process identified breaches in mixing, filtration, and sterility testing practices. S. marcescens was identified from a pharmacy water faucet, mixing container, and opened amino acid powder. These isolates were indistinguishable from the outbreak strain by PFGE. Compounding of nonsterile amino acid components of PN was initiated due to a manufacturer shortage. Failure to follow recommended compounding standards contributed to an outbreak of S. marcescens BSIs. Improved adherence to sterile compounding standards, critical examination of standards for sterile compounding from nonsterile ingredients, and more rigorous oversight of compounding pharmacies is needed to prevent future outbreaks. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2014. This work is written by (a) US Government employee(s) and is in the public

  8. No survival benefit with empirical vancomycin therapy for coagulase-negative staphylococcal bloodstream infections in infants.

    Science.gov (United States)

    Ericson, Jessica E; Thaden, Joshua; Cross, Heather R; Clark, Reese H; Fowler, Vance G; Benjamin, Daniel K; Cohen-Wolkowiez, Michael; Hornik, Christoph P; Smith, P Brian

    2015-04-01

    Coagulase-negative Staphylococcus (CoNS) is the most common cause of bloodstream infections (BSI) in hospitalized infants. CoNS BSI is most reliably treated with vancomycin; however, concerns about side effects and promoting resistance often delay empirical vancomycin therapy until culture results become available. All infants with CoNS BSI discharged from 348 neonatal intensive care units managed by the Pediatrix Medical Group from 1997 to 2012 were identified. Empirical vancomycin therapy was defined as vancomycin exposure on the day of the first positive blood culture. Delayed vancomycin therapy was defined as vancomycin exposure 1-3 days after the first positive blood culture. We used multivariable logistic regression with random effects for site to evaluate the association between the use of empirical vancomycin therapy versus delayed vancomycin therapy and 30-day mortality, controlling for gestational age, small-for-gestational age status, postnatal age on the day of the first positive culture, oxygen requirement, ventilator support and inotropic support on the day the first positive culture was obtained. A total of 4364 infants with CoNS BSI were identified; 2848 (65%) were treated with empirical vancomycin. The median postnatal age at first positive culture was 14 days (interquartile range: 9, 21). Unadjusted 30-day mortality was similar for infants treated with empirical vancomycin and infants treated with delayed vancomycin therapy [166/2848 (6%) vs. 69/1516 (4%); P = 0.08]. There was no significant difference in 30-day mortality on multivariable analysis [odds ratio: 1.14 (0.84, 1.56)]. The median duration of bacteremia was 1 day longer for infants with delayed vancomycin therapy [4 days (interquartile range: 2, 6) vs. 3 days (2, 5); P empirical vancomycin therapy for CoNS BSI was not associated with improved mortality.

  9. Identification and antifungal susceptibility of Candida species isolated from bloodstream infections in Konya, Turkey.

    Science.gov (United States)

    Dagi, Hatice Turk; Findik, Duygu; Senkeles, Cigdem; Arslan, Ugur

    2016-05-31

    In this study, our aim was to identify Candida species isolated from bloodstream infections and to determine their susceptibilities to various antifungal agents to demonstrate the local resistance profiles and to guide empirical treatment for clinicians. Two hundred Candida isolates (95 Candida albicans, 105 non-albicans Candida strains) were included in the study. Candida species were identified by conventional, biochemical and molecular methods. Antifungal susceptibility tests for amphotericin B, fluconazole, voriconazole, posaconazole, caspofungin and anidulafungin were performed with broth microdilution method according to the Clinical and Laboratory Standards Institute M27-A3 document. Of the 200 Candida strains, the most prevalent species were C. albicans (47.5 %), Candida glabrata (18.0 %) and Candida parapsilosis complex (14.0 %). All Candida species except for three (1.5 %) Candida kefyr strains were susceptible to amphotericin B. Only one (2.8 %) C. glabrata was resistant to fluconazole (MIC ≥ 64 μg/ml), and the others (97.2 %) exhibited dose-dependent susceptibility. All species, but C. glabrata strains, were susceptible to fluconazole. Resistance to voriconazole, posaconazole, caspofungin and anidulafungin was not detected in any strain. Candida albicans were susceptible to all antifungal drugs. Three C. kefyr strains were resistant to amphotericin B. Only one C. glabrata was resistant to fluconazole. All the strains were susceptible to voriconazole, posaconazole, caspofungin and anidulafungin. In vitro antifungal susceptibility tests should be performed to select of appropriate and effective antifungal therapy, and monitor the development of resistance.

  10. The Changing Epidemiology of Bloodstream Infections and Resistance in Hematopoietic Stem Cell Transplantation Recipients

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    Mücahit Yemişen

    2016-08-01

    Full Text Available Objective: Patients receiving hematopoietic stem cell transplantation (HSCT are exposed to highly immunosuppressive conditions and bloodstream infections (BSIs are one of the most common major complications within this period. Our aim, in this study, was to evaluate the epidemiology of BSIs in these patients retrospectively. Materials and Methods: The epidemiological properties of 312 patients with HSCT were retrospectively evaluated. Results: A total of 312 patients, followed between 2000 and 2011, who underwent autologous (62% and allogeneic (38% HSCT were included in the study. The most common underlying malignancies were multiple myeloma (28% and Hodgkin lymphoma (21.5%. A total of 142 (45% patients developed at least 1 episode of BSI and 193 separate pathogens were isolated from the blood cultures. There was a trend of increase in the numbers of BSIs in 2005-2008 and a relative increase in the proportion of gram-positive infections in recent years (2009-2011, and central venous catheter-related BSI was found to be most common source. Coagulase-negative staphylococci (49.2% and Acinetobacter baumannii (8.8% were the most common pathogens. Extended-spectrum beta-lactamase-producing strains were 23% and 22% among Escherichia coli and Klebsiella spp. isolates, respectively. Quinolone resistance was detected in 10% of Enterobacteriaceae. Resistance to carbapenems was not detected in Enterobacteriaceae, while it was seen at 11.1% and 23.5% in Pseudomonas and Acinetobacter strains, respectively. Conclusion: A shift was detected from gram-negative bacteria to gram-positive in the etiology over the years and central lines were the most common sources of BSIs.

  11. Effect of a vascular access team on central line-associated bloodstream infections in infants admitted to a neonatal intensive care unit: a systematic review.

    Science.gov (United States)

    Legemaat, Monique M; Jongerden, Irene P; van Rens, Roland M F P T; Zielman, Marjanne; van den Hoogen, Agnes

    2015-05-01

    To review the effect of a vascular access team on the incidence of central line-associated bloodstream infections in infants admitted to a neonatal intensive care unit. MEDLINE, CINAHL, Embase, Web-of-Science and the Cochrane Library were searched until December 2013. Studies that evaluated the implementation of a vascular access team, and focused on the incidence of central line-associated bloodstream infections in infants admitted to a neonatal intensive care unit, were selected. Incidence rates of central line-associated bloodstream infections were extracted, as well as information on vascular access team tasks and team composition. The quality of studies was critically appraised using the McMaster tool for quantitative studies. Seven studies involving 136 to 414 participants were included. In general, the implementation of a vascular access team coincided with the implementation of concurrent interventions. All vascular access teams included nurses, and occasionally included physicians. Main tasks included insertion and maintenance of central lines. In all studies, a relative decrease of 45-79% in central line-associated bloodstream infections was reported. A vascular access team is a promising intervention to decrease central line-associated bloodstream infections in infants admitted to a neonatal intensive care unit. However, level of evidence for effectiveness is low. Future research is required to improve the strength of evidence for vascular access teams. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Second-Generation central venous catheter in the prevention of bloodstream infection: a systematic review.

    Science.gov (United States)

    Stocco, Janislei Gislei Dorociaki; Hoers, Hellen; Pott, Franciele Soares; Crozeta, Karla; Barbosa, Dulce Aparecida; Meier, Marineli Joaquim

    2016-08-08

    to evaluate the effectiveness and safety in the use of second-generation central venous catheters impregnated in clorhexidine and silver sulfadiazine when compared with other catheters, being them impregnated or not, in order to prevent the bloodstream infection prevention. systematic review with meta-analysis. Databases searched: MEDLINE, EMBASE, CINAHL, LILACS/SciELO, Cochrane CENTRAL; search in Congress Proceedings and records from Clinical Trials. 1.235 studies were identified, 97 were pre-selected and 4 were included. In catheter-related bloodstream infection, there was no statistical significance between second-generation impregnated catheter compared with the non-impregnated ones, absolute relative risk 1,5% confidence interval 95% (3%-1%), relative risk 0,68 (confidence interval 95%, 0,40-1,15) and number needed to treat 66. In the sensitivity analysis, there was less bloodstream infection in impregnated catheters (relative risk 0,50, confidence interval 95%, 0,26-0,96). Lower colonization, absolute relative risk 9,6% (confidence interval 95%, 10% to 4%), relative risk 0,51 (confidence interval 95% from 0,38-0,85) and number needed to treat 5. the use of second-generation catheters was effective in reducing the catheter colonization and infection when a sensitivity analysis is performed. Future clinical trials are suggested to evaluate sepsis rates, mortality and adverse effects. evaluar la efectividad y seguridad del uso de catéteres venosos centrales de segunda generación, impregnados en clorhexidina y sulfadiazina de plata, comparados con otros catéteres impregnados o no impregnados, para prevención de infección de la corriente sanguínea. revisión sistemática con metaanálisis. La búsqueda fue realizada en las bases: MEDLINE, EMBASE, CINAHL, LILACS/SciELO, Cochrane CENTRAL; fueron consultados anales de congresos y registros de ensayos clínicos. fueron identificados 1.235 estudios, 97 preseleccionados y cuatro incluidos. En la infección de la

  13. Expression of Trypanosoma brucei gambiense Antigens in Leishmania tarentolae. Potential for Use in Rapid Serodiagnostic Tests (RDTs.

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    Barrie Rooney

    2015-12-01

    Full Text Available The development of rapid serodiagnostic tests for sleeping sickness and other diseases caused by kinetoplastids relies on the affordable production of parasite-specific recombinant antigens. Here, we describe the production of recombinant antigens from Trypanosoma brucei gambiense (T.b. gambiense in the related species Leishmania tarentolae (L. tarentolae, and compare their diagnostic sensitivity and specificity to native antigens currently used in diagnostic kits against a panel of human sera. A number of T.b. gambiense protein antigen candidates were chosen for recombinant expression in L. tarentolae based on current diagnostics in field use and recent findings on immunodiagnostic antigens found by proteomic profiling. In particular, the extracellular domains of invariant surface glycoprotein 65 (ISG65, variant surface glycoproteins VSG LiTat 1.3 and VSG LiTat 1.5 were fused with C-terminal histidine tags and expressed as soluble proteins in the medium of cultured, recombinant L. tarentolae. Using affinity chromatography, on average 10 mg/L of recombinant protein was purified from cultures and subsequently tested against a panel of sera from sleeping sickness patients from controls, i.e. persons without sleeping sickness living in HAT endemic countries. The evaluation on sera from 172 T.b. gambiense human African trypanosomiasis (HAT patients and from 119 controls showed very high diagnostic potential of the two recombinant VSG and the rISG65 fragments with areas under the curve between 0.97 and 0.98 compared to 0.98 and 0.99 with native VSG LiTat 1.3 and VSG LiTat 1.5 (statistically not different. Evaluation on sera from 78 T.b. rhodesiense HAT patients and from 100 controls showed an acceptable diagnostic potential of rISG65 with an area under the curve of 0.83. These results indicate that a combination of these recombinant antigens has the potential to be used in next generation rapid serodiagnostic tests. In addition, the L. tarentolae

  14. Emergence in Taiwan of novel imipenem-resistant Acinetobacter baumannii ST455 causing bloodstream infection in critical patients.

    Science.gov (United States)

    Lee, Hao-Yuan; Huang, Chih-Wei; Chen, Chyi-Liang; Wang, Yi-Hsin; Chang, Chee-Jen; Chiu, Cheng-Hsun

    2015-12-01

    Acinetobacter baumannii is one of the most important nosocomial pathogens worldwide. This study aimed to use multilocus sequence typing (MLST) for the epidemiological surveillance of A. baumannii isolates in Taiwan and analyze the clinical presentations and patients' outcome. MLST according to both Bartual's PubMLST and Pasteur's MLST schemes was applied to characterize bloodstream imipenem-resistant A. baumannii (IRAB) infection in intensive care units in a medical center. A total of 39 clinical IRAB bloodstream isolates in 2010 were enrolled. We also collected 13 imipenem-susceptible A. baumannii (ISAB) bloodstream isolates and 30 clinical sputum isolates (24 IRAB and 6 ISAB) for comparison. Clinical presentations and outcome of the patients were analyzed. We found that infection by ST455(B)/ST2(P) and inappropriate initial therapy were statistically significant risk factors for mortality. More than one-third of the IRAB isolates belonged to ST455(B)/ST2(P). Most ST455(B)/ST2(P) (80%) carried ISAba1-blaOXA-23, including 10 (66.7%) with Tn2006 (ISAba1-blaOXA-23-ISAba1) in an AbaR4-type resistance island. ST455(B)/ST2(P) appears to evolve from ST208(B)/ST2(P) of clonal complex (CC) 92(B)/CC2(P). In this hospital-based study, A. baumannii ST455 accounted for 38.5% of IRAB bacteremia, with a high mortality of 86.7%. Approximately 85% of ST455(B)/ST2(P)bacteremia had a primary source of ventilation-associated pneumonia. We report the emergence in Taiwan of IRAB ST455(B)/ST2(P), which is the current predominant clone of IRAB in our hospital and has been causing bacteremia with high mortality in critical patients. Copyright © 2015. Published by Elsevier B.V.

  15. In vivo observation of the hypo-echoic "black hole" phenomenon in rat arterial bloodstream: a preliminary Study.

    Science.gov (United States)

    Nam, Kweon-Ho; Paeng, Dong-Guk

    2014-07-01

    The "black hole," a hypo-echoic hole at the center of the bloodstream surrounded by a hyper-echoic zone in cross-sectional views, has been observed in ultrasound backscattering measurements of blood with red blood cell aggregation in in vitro studies. We investigated whether the phenomenon occurs in the in vivo arterial bloodstream of rats using a high-frequency ultrasound imaging system. Longitudinal and cross-sectional ultrasound images of the rat common carotid artery (CCA) and abdominal aorta were obtained using a 40-MHz ultrasound system. A high-frame-rate retrospective imaging mode was employed to precisely examine the dynamic changes in blood echogenicity in the arteries. When the imaging was performed with non-invasive scanning, blood echogenicity was very low in the CCA as compared with the surrounding tissues, exhibiting no hypo-echoic zone at the center of the vessel. Invasive imaging of the CCA by incising the skin and subcutaneous tissues at the imaging area provided clearer and brighter blood echo images, showing the "black hole" phenomenon near the center of the vessel in longitudinal view. The "black hole" was also observed in the abdominal aorta under direct imaging after laparotomy. The aortic "black hole" was clearly observed in both longitudinal and cross-sectional views. Although the "black hole" was always observed near the center of the arteries during the diastolic phase, it dissipated or was off-center along with the asymmetric arterial wall dilation at systole. In conclusion, we report the first in vivo observation of the hypo-echoic "black hole" caused by the radial variation of red blood cell aggregation in arterial bloodstream. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  16. Simulation of antibiotic pharmacodynamic exposure for the empiric treatment of nosocomial bloodstream infections: a report from the OPTAMA program.

    Science.gov (United States)

    Maglio, Dana; Kuti, Joseph L; Nicolau, David P

    2005-07-01

    We developed a model to predict the pharmacodynamic exposure of antibiotics against bacteria commonly implicated in nosocomial bloodstream infections to determine which dosage regimens would provide the greatest likelihood of obtaining a bactericidal effect. Pharmacodynamic exposures were simulated for 5000 subjects receiving standard doses of ceftazidime, cefepime, piperacillin/tazobactam, meropenem, imipenem, or ciprofloxacin. Exposures were indexed to the MICs of bacteria weighted by their prevalence in causing nosocomial bloodstream infections, derived from 2002 SENTRY data. Enterococci were excluded. MIC data were derived from the 2003 Meropenem Yearly Surveillance Test Information Collection resistance study. The probabilities of achieving bactericidal exposures (ie, target attainment) for each antibiotic regimen were compared. The effect of increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) on attainment of bactericidal targets was tested. All dosage regimens except ciprofloxacin and ceftazidime 1 g q8h achieved >90% likelihood of bactericidal exposure. The rank order of target attainment was as follows: imipenem 500 mg q6h, 100.0%; imipenem 1 g q8h, 99.9%; cefepime 2 g q12h, 99.4%; meropenem 1 g q8h, 98.4%; cefepime 1 g q12h, 98.2%; piperacillin/tazobactam 3.375 g q6h, 97.9%; piperacillin/tazobactam 4.5 gq8h, 95.0%; ceftazidime 2 g q8h, 94.2%; ceftazidime 1 g q8h, 71.7%; ciprofloxacin 400 mg q8h, 63.3%; and ciprofloxacin 400 mg q12h,63.0%. Target attainments dropped to or =10% prevalence. The results of this model analysis suggest that standard doses of the carbapenems, piperacillin/tazobactam, and cefepime, and higher doses of ceftazidime, may provide optimal likelihood of achieving bactericidal exposure against pathogens implicated in nosocomial bloodstream infections, excluding MRSA and enterococci. When MRSA rates are > or =10%, therapy with an antibiotic that has activity against this phenotype should be empirically initiated.

  17. Nosocomial catheter-related bloodstream infections in a pediatric intensive care unit: risk and rates associated with various intravascular technologies.

    Science.gov (United States)

    Odetola, Folafoluwa O; Moler, Frank W; Dechert, Ronald E; VanDerElzen, Kristen; Chenoweth, Carol

    2003-10-01

    Nosocomial bloodstream infections are associated with increased patient morbidity, mortality, and hospital costs. More than 90% of these infections are related to the use of intravascular catheter devices. This study was done to assess the risk and rates of catheter related-bloodstream infections (CR-BSI) associated with different intravascular technologies in a pediatric intensive care unit population. Retrospective cohort study. A 16-bed pediatric intensive care unit in a tertiary children's hospital. All admissions between July 1997 and December 1999 requiring placement of an intravascular access device for care were examined. Patients with CR-BSI were identified through ongoing surveillance using Centers for Disease Control/National Nosocomial Infections Surveillance System definitions for bloodstream infection. None. Of the 2,728 admissions during the review period, 1,043 (38.3%) required placement of an intravascular access device. Bivariate analysis revealed that patients who required intravascular cannulae for extracorporeal life support had a 10-fold increased risk of developing a CR-BSI, and patients requiring vascular access for renal replacement therapy demonstrated a 4-fold increase in the risk of developing CR-BSI compared with the referent group. There was a significant increase in the CR-BSI rate associated with the use of more intravascular access devices per patient admission. Multivariate logistic regression identified the use of extracorporeal life support therapy and the total duration of use of intravascular access devices as significant independent predictors of CR-BSI when controlling for other predictors. The use of extracorporeal life support therapy, the presence of multiple intravascular access devices, and the total duration of intravascular access device use were associated with an increase in the rate and risk of developing CR-BSI in our pediatric intensive care unit population. Larger, prospective studies may help elucidate

  18. Within-host evolution of Enterococcus faecium during longitudinal carriage and transition to bloodstream infection in immunocompromised patients.

    Science.gov (United States)

    Moradigaravand, Danesh; Gouliouris, Theodore; Blane, Beth; Naydenova, Plamena; Ludden, Catherine; Crawley, Charles; Brown, Nicholas M; Török, M Estée; Parkhill, Julian; Peacock, Sharon J

    2017-12-27

    Enterococcus faecium is a leading cause of hospital-acquired infection, particularly in the immunocompromised. Here, we use whole genome sequencing of E. faecium to study within-host evolution and the transition from gut carriage to invasive disease. We isolated and sequenced 180 E. faecium from four immunocompromised patients who developed bloodstream infection during longitudinal surveillance of E. faecium in stool and their immediate environment. A phylogenetic tree based on single nucleotide polymorphisms (SNPs) in the core genome of the 180 isolates demonstrated several distinct clones. This was highly concordant with the population structure inferred by Bayesian methods, which contained four main BAPS (Bayesian Analysis of Population Structure) groups. The majority of isolates from each patient resided in a single group, but all four patients also carried minority populations in stool from multiple phylogenetic groups. Bloodstream isolates from each case belonged to a single BAPS group, which differed in all four patients. Analysis of 87 isolates (56 from blood) belonging to a single BAPS group that were cultured from the same patient over 54 days identified 30 SNPs in the core genome (nine intergenic, 13 non-synonymous, eight synonymous), and 250 accessory genes that were variably present. Comparison of these genetic variants in blood isolates versus those from stool or environment did not identify any variants associated with bloodstream infection. The substitution rate for these isolates was estimated to be 128 (95% confidence interval 79.82 181.77) mutations per genome per year, more than ten times higher than previous estimates for E. faecium. Within-patient variation in vancomycin resistance associated with vanA was common and could be explained by plasmid loss, or less often by transposon loss. These findings demonstrate the diversity of E. faecium carriage by individual patients and significant within-host diversity of E. faecium, but do not provide

  19. Identification and Whole Genome Sequencing of the First Case of Kosakonia radicincitans Causing a Human Bloodstream Infection.

    Science.gov (United States)

    Bhatti, Micah D; Kalia, Awdhesh; Sahasrabhojane, Pranoti; Kim, Jiwoong; Greenberg, David E; Shelburne, Samuel A

    2017-01-01

    The taxonomy of Enterobacter species is rapidly changing. Herein we report a bloodstream infection isolate originally identified as Enterobacter cloacae by Vitek2 methodology that we found to be Kosakonia radicincitans using genetic means. Comparative whole genome sequencing of our isolate and other published Kosakonia genomes revealed these organisms lack the AmpC β-lactamase present on the chromosome of Enterobacter sp. A fimbriae operon primarily found in Escherichia coli O157:H7 isolates was present in our organism and other available K. radicincitans genomes. This is the first report of a Kosakonia species, which are typically associated with plants, causing a human infection.

  20. How to optimize the use of blood cultures for the diagnosis of bloodstream infections? A state-of-the art

    Directory of Open Access Journals (Sweden)

    Brigitte eLamy

    2016-05-01

    Full Text Available Bloodstream infection (BSI is a major cause of death in developed countries and the detection of microorganisms is essential in managing patients. Despite major progress has been made to improve identification of microorganisms, blood culture remains the gold standard and the first line tool for detecting BSIs. Consensus guidelines are available to ensure optimal BSI procedures, but blood culture practices often deviate from the recommendations. This review provides an update on clinical and technical issues related to blood collection and to blood culture performance, with a special focus on the blood sample strategy to optimize the sensitivity and specificity of blood cultures.

  1. Incidence of catheter-related bloodstream infections in neonates following removal of peripherally inserted central venous catheters.

    Science.gov (United States)

    Casner, Michael; Hoesli, Sandra J; Slaughter, James C; Hill, Melissa; Weitkamp, Jörn-Hendrik

    2014-01-01

    Catheter-associated bloodstream infections are a significant source of morbidity and healthcare cost in the neonatal ICU. Previous studies examining the prevalence of bloodstream infections after removal of peripherally inserted central venous catheters in neonates are equivocal. A retrospective cohort study. All infants with peripherally inserted central venous catheters treated at the Vanderbilt neonatal ICU between 2007 and 2009. We evaluated the following outcomes: 1) bloodstream infections, 2) culture-negative sepsis, 3) number of sepsis evaluations, and 4) number of significant apnea/bradycardia events comparing odds ratios between 72 hours before and 72 hours after peripherally inserted central venous catheter removal. We analyzed a total of 1,002 peripherally inserted central venous catheters in 856 individual infants with a median (interquartile range) gestational age of 31 weeks (28-37 wk) and a median birth weight of 1,469 g (960-2,690 g). Comparing 72 hours before with 72 hours after peripherally inserted central venous catheter removal did not show a difference in the prevalence of bloodstream infections (9 vs 3, p = 0.08), prevalence of culture-negative sepsis (37 vs 40, p = 0.73), number of sepsis evaluations (p = 0.42), or number of apnea/bradycardia events (p = 0.32). However, in peripherally inserted central venous catheter not used for delivery of antibiotics, there was a 3.83-fold increase in odds for culture-negative sepsis following peripherally inserted central venous catheter removal (95% confidence interval, 1.48-10.5; p = 0.001). For infants less than 1,500 g birth weight (very low birth weight), odds for culture-negative sepsis increased to 6.3-fold following removal of peripherally inserted central venous catheters not used for antibiotic delivery (95% confidence interval, 1.78-26.86; p central venous catheter removal, they suggests that very low birth weight infants not recently exposed to antibiotics are at increased odds for

  2. The changing epidemiology of Acinetobacter spp. producing OXA carbapenemases causing bloodstream infections in Brazil: a BrasNet report.

    Science.gov (United States)

    Vasconcelos, Ana Tereza R; Barth, Afonso L; Zavascki, Alexandre P; Gales, Ana C; Levin, Anna S; Lucarevschi, Bianca R; Cabral, Blenda G; Brasiliense, Danielle M; Rossi, Flavia; Furtado, Guilherme H C; Carneiro, Irna Carla R S; da Silva, Juliana O; Ribeiro, Julival; Lima, Karla V B; Correa, Luci; Britto, Maria H; Silva, Mariama T; da Conceição, Marília L; Moreira, Marina; Martino, Marinês D V; de Freitas, Marise R; Oliveira, Maura S; Dalben, Mirian F; Guzman, Ricardo D; Cayô, Rodrigo; Morais, Rosângela; Santos, Sânia A; Martins, Willames M B S

    2015-12-01

    We evaluated the epidemiology of Acinetobacter spp. recovered from patients diagnosed with bloodstream infections in 9 tertiary hospitals located in all Brazilian geographic regions between April and August 2014. Although OXA-23-producing Acinetobacter baumannii clones were disseminated in most hospitals, it was observed for the first time the spread of OXA-72 among clonally related A. baumannii isolated from distinct hospitals. Interestingly, Acinetobacter pittii was the most frequent species found in a Northern region hospital. Contrasting with the multisusceptible profile displayed by A. pittii isolates, the tetracyclines and polymyxins were the only antimicrobials active against all A. baumannii isolates. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Prognostic factors of health care-associated bloodstream infection in adult patients ≥40 years of age.

    Science.gov (United States)

    Ma, Hsuan-Yin; Hung, I-Chen; Huang, Ya-Huei; Chang, Ying-Ying; Sheng, Wang-Huei; Wang, Jann-Tay; Chie, Wei-Chu; Liu, Jen-Pei; Chen, Yee-Chun

    2017-08-22

    We investigated 401 geriatric patients and 453 middle-aged patients with health care-associated bloodstream infection (HABSI) at a medical center during January-December 2014. Compared with middle-aged patients, the geriatric group had higher 30-day mortality (31.2% vs 23.4%, P = .01). Body mass index, serum albumin concentration, Charlson comorbidity index score, vancomycin-resistant Enterococcus bacteremia, and high C-reactive protein levels predict poor outcomes for HABSI among adult patients. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  4. Three cases of mcr-1-positive colistin-resistant Escherichia coli bloodstream infections in Italy, August 2016 to January 2017.

    Science.gov (United States)

    Corbella, Marta; Mariani, Bianca; Ferrari, Carolina; Comandatore, Francesco; Scaltriti, Erika; Marone, Piero; Cambieri, Patrizia

    2017-04-20

    We describe three cases of bloodstream infection caused by colistin-resistant Escherichia coli in patients in a tertiary hospital in Italy, between August 2016 and January 2017. Whole genome sequencing detected the mcr-1 gene in three isolated strains belonging to different sequence types (STs). This occurrence of three cases with mcr-1-positive E. coli belonging to different STs in six months suggests a widespread problem in settings where high multidrug resistance is endemic such as in Italy. This article is copyright of The Authors, 2017.

  5. Modular forms

    NARCIS (Netherlands)

    Edixhoven, B.; van der Geer, G.; Moonen, B.; Edixhoven, B.; van der Geer, G.; Moonen, B.

    2008-01-01

    Modular forms are functions with an enormous amount of symmetry that play a central role in number theory, connecting it with analysis and geometry. They have played a prominent role in mathematics since the 19th century and their study continues to flourish today. Modular forms formed the

  6. Cost Analysis of Implementing Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Plus Real-Time Antimicrobial Stewardship Intervention for Bloodstream Infections.

    Science.gov (United States)

    Patel, Twisha S; Kaakeh, Rola; Nagel, Jerod L; Newton, Duane W; Stevenson, James G

    2017-01-01

    Studies evaluating rapid diagnostic testing plus stewardship intervention have consistently demonstrated improved clinical outcomes for patients with bloodstream infections. However, the cost of implementing new rapid diagnostic testing can be significant, and such testing usually does not generate additional revenue. There are minimal data evaluating the impact of adding matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for rapid organism identification and dedicating pharmacy stewardship personnel time on the total hospital costs. A cost analysis was performed utilizing patient data generated from the hospital cost accounting system and included additional costs of MALDI-TOF equipment, supplies and personnel, and dedicated pharmacist time for blood culture review and of making interventions to antimicrobial therapy. The cost analysis was performed from a hospital perspective for 3-month blocks before and after implementation of MALDI-TOF plus stewardship intervention. A total of 480 patients with bloodstream infections were included in the analysis: 247 in the preintervention group and 233 in the intervention group. Thirty-day mortality was significantly improved in the intervention group (12% versus 21%, P cost per bloodstream infection was lower in the intervention group ($42,580 versus $45,019). Intensive care unit cost per bloodstream infection accounted for the largest share of the total costs in each group and was also lower in the intervention group ($10,833 versus $13,727). Implementing MALDI-TOF plus stewardship review and intervention decreased mortality for patients with bloodstream infections. Despite the additional costs of implementing MALDI-TOF and of dedicating pharmacy stewardship personnel time to interventions, the total hospital costs decreased by $2,439 per bloodstream infection, for an approximate annual cost savings of $2.34 million. Copyright © 2016 American Society for Microbiology.

  7. A Conserved DNA Repeat Promotes Selection of a Diverse Repertoire of Trypanosoma brucei Surface Antigens from the Genomic Archive.

    Directory of Open Access Journals (Sweden)

    Galadriel Hovel-Miner

    2016-05-01

    Full Text Available African trypanosomes are mammalian pathogens that must regularly change their protein coat to survive in the host bloodstream. Chronic trypanosome infections are potentiated by their ability to access a deep genomic repertoire of Variant Surface Glycoprotein (VSG genes and switch from the expression of one VSG to another. Switching VSG expression is largely based in DNA recombination events that result in chromosome translocations between an acceptor site, which houses the actively transcribed VSG, and a donor gene, drawn from an archive of more than 2,000 silent VSGs. One element implicated in these duplicative gene conversion events is a DNA repeat of approximately 70 bp that is found in long regions within each BES and short iterations proximal to VSGs within the silent archive. Early observations showing that 70-bp repeats can be recombination boundaries during VSG switching led to the prediction that VSG-proximal 70-bp repeats provide recombinatorial homology. Yet, this long held assumption had not been tested and no specific function for the conserved 70-bp repeats had been demonstrated. In the present study, the 70-bp repeats were genetically manipulated under conditions that induce gene conversion. In this manner, we demonstrated that 70-bp repeats promote access to archival VSGs. Synthetic repeat DNA sequences were then employed to identify the length, sequence, and directionality of repeat regions required for this activity. In addition, manipulation of the 70-bp repeats allowed us to observe a link between VSG switching and the cell cycle that had not been appreciated. Together these data provide definitive support for the long-standing hypothesis that 70-bp repeats provide recombinatorial homology during switching. Yet, the fact that silent archival VSGs are selected under these conditions suggests the 70-bp repeats also direct DNA pairing and recombination machinery away from the closest homologs (silent BESs and toward the rest of

  8. A Conserved DNA Repeat Promotes Selection of a Diverse Repertoire of Trypanosoma brucei Surface Antigens from the Genomic Archive.

    Science.gov (United States)

    Hovel-Miner, Galadriel; Mugnier, Monica R; Goldwater, Benjamin; Cross, George A M; Papavasiliou, F Nina

    2016-05-01

    African trypanosomes are mammalian pathogens that must regularly change their protein coat to survive in the host bloodstream. Chronic trypanosome infections are potentiated by their ability to access a deep genomic repertoire of Variant Surface Glycoprotein (VSG) genes and switch from the expression of one VSG to another. Switching VSG expression is largely based in DNA recombination events that result in chromosome translocations between an acceptor site, which houses the actively transcribed VSG, and a donor gene, drawn from an archive of more than 2,000 silent VSGs. One element implicated in these duplicative gene conversion events is a DNA repeat of approximately 70 bp that is found in long regions within each BES and short iterations proximal to VSGs within the silent archive. Early observations showing that 70-bp repeats can be recombination boundaries during VSG switching led to the prediction that VSG-proximal 70-bp repeats provide recombinatorial homology. Yet, this long held assumption had not been tested and no specific function for the conserved 70-bp repeats had been demonstrated. In the present study, the 70-bp repeats were genetically manipulated under conditions that induce gene conversion. In this manner, we demonstrated that 70-bp repeats promote access to archival VSGs. Synthetic repeat DNA sequences were then employed to identify the length, sequence, and directionality of repeat regions required for this activity. In addition, manipulation of the 70-bp repeats allowed us to observe a link between VSG switching and the cell cycle that had not been appreciated. Together these data provide definitive support for the long-standing hypothesis that 70-bp repeats provide recombinatorial homology during switching. Yet, the fact that silent archival VSGs are selected under these conditions suggests the 70-bp repeats also direct DNA pairing and recombination machinery away from the closest homologs (silent BESs) and toward the rest of the archive.

  9. Positive deviance as a strategy to prevent and control bloodstream infections in intensive care.

    Science.gov (United States)

    Oliveira, Francimar Tinoco de; Ferreira, Maria Manuela Frederico; Araújo, Silvia Teresa Carvalho de; Bessa, Amanda Trindade Teixeira de; Moraes, Advi Catarina Barbachan; Stipp, Marluci Andrade Conceição

    2017-04-03

    To describe the application of positive deviance as a strategy to prevent and control bloodstream infections. An intervention study with nursing and medical team members working in an intensive care unit in a university hospital, between June and December 2014. The four steps of the positive defiance methodology were applied: to define, to determine, to discover and to design. In 90 days, 188 actions were observed, of these, 36.70% (n=69) were related to catheter dressing. In 81.15% (n=56) of these dressings, the professionals most adhered to the use of flexible sterile cotton-tipped swabs to perform antisepsis at catheter entry sites and fixation dressing. Positive deviance contributed to the implementation of proposals to improve work processes and team development related to problems identified in central venous catheter care. Descrever a aplicação do Positive Deviance como estratégia na prevenção e no controle da infecção de corrente sanguínea. Estudo de intervenção realizado na Unidade de Terapia Intensiva de um hospital universitário, com os membros das equipes de enfermagem e médica, de junho a dezembro de 2014. Foram aplicados os quatro passos da metodologia Positive Deviance: Definir, Determinar, Descobrir e Desenhar. Em 90 dias 188 ações foram observadas, destas, 36,70% (n=69) estavam relacionadas aos curativos dos cateteres. Em 81,15% (n=56) desses curativos, o uso da haste flexível estéril para realização da antissepsia do local de inserção do cateter e de sua placa de fixação foi a ação de maior adesão. O Positive Deviance auxiliou na implementação de propostas de melhorias de processo de trabalho e no desenvolvimento da equipe para os problemas identificados no cuidado com o cateter venoso central.

  10. Central venous catheter-related bloodstream infections in the intensive care unit

    Science.gov (United States)

    Patil, Harsha V.; Patil, Virendra C.; Ramteerthkar, M. N.; Kulkarni, R. D.

    2011-01-01

    Context: Central venous catheter-related bloodstream infection (CRBSI) is associated with high rates of morbidity and mortality in critically ill patients. Aims: This study was conducted to determine the incidence of central venous catheter-related infections (CRIs) and to identify the factors influencing it. So far, there are very few studies that have been conducted on CRBSI in the intensive care unit in India. Settings and Design: This was a prospective, observational study carried out in the medical intensive care unit (MICU) over a period of 1 year from January to December 2004. Materials and Methods: A total of 54 patients with indwelling central venous catheters of age group between 20 and 75 years were included. The catheters were cultured using the standard semiquantitative culture (SQC) method. Statistical analysis used SPSS-10 version statistical software. Results: A total of 54 CVC catheters with 319 catheter days were included in this study. Of 54 patients with CVCs studied for bacteriology, 39 (72.22%) catheters showed negative SQCs and also negative blood cultures. A total of 15 (27.77%) catheters were positive on SQC, of which 10 (18.52%) were with catheter-associated infection and four (7.41%) were with catheter-associated bacteremia; the remaining one was a probable catheter-associated bacteremia. CRIs were high among catheters that were kept in situ for more than 3 days and emergency procedures where two or more attempts were required for catheterization (P catheter in situ for >3 days, inexperienced venupucturist, more number of attempts and emergency CVC were associated with more incidence of CVCBSIs, with P catheter in situ was negatively correlated (-0.53) and number of attempts required to put CVC was positively correlated (+0.39) with incidence of CVCBSIs. Sixty-five percent of the isolates belonged to the CONS group (13/20). Staphylococcus epidermidis showed maximum susceptibility to amikacin, doxycycline and amoxycillin with clavulanic

  11. Comparison of the systemic inflammatory response syndrome between monomicrobial and polymicrobial Pseudomonas aeruginosa nosocomial bloodstream infections

    Directory of Open Access Journals (Sweden)

    Wenzel Richard P

    2005-10-01

    Full Text Available Abstract Background Some studies of nosocomial bloodstream infection (nBSI have demonstrated a higher mortality for polymicrobial bacteremia when compared to monomicrobial nBSI. The purpose of this study was to compare differences in systemic inflammatory response and mortality between monomicrobial and polymicrobial nBSI with Pseudomonas aeruginosa. Methods We performed a historical cohort study on 98 adults with P. aeruginosa (Pa nBSI. SIRS scores were determined 2 days prior to the first positive blood culture through 14 days afterwards. Monomicrobial (n = 77 and polymicrobial BSIs (n = 21 were compared. Results 78.6% of BSIs were caused by monomicrobial P. aeruginosa infection (MPa and 21.4% by polymicrobial P. aeruginosa infection (PPa. Median APACHE II score on the day of BSI was 22 for MPa and 23 for PPa BSIs. Septic shock occurred in 33.3% of PPa and in 39.0% of MPa (p = 0.64. Progression to septic shock was associated with death more frequently in PPa (OR 38.5, CI95 2.9–508.5 than MPa (OR 4.5, CI95 1.7–12.1. Maximal SIR (severe sepsis, septic shock or death was seen on day 0 for PPa BSI vs. day 1 for MPa. No significant difference was noted in the incidence of organ failure, 7-day or overall mortality between the two groups. Univariate analysis revealed that APACHE II score ≥20 at BSI onset, Charlson weighted comorbidity index ≥3, burn injury and respiratory, cardiovascular, renal and hematologic failure were associated with death, while age, malignant disease, diabetes mellitus, hepatic failure, gastrointestinal complications, inappropriate antimicrobial therapy, infection with imipenem resistant P. aeruginosa and polymicrobial nBSI were not. Multivariate analysis revealed that hematologic failure (p Conclusion In this historical cohort study of nBSI with P. aeruginosa, the incidence of septic shock and organ failure was high in both groups. Additionally, patients with PPa BSI were not more acutely ill, as judged by APACHE II

  12. Study of nosocomial primary bloodstream infections in a pediatric intensive care unit.

    Science.gov (United States)

    Lakshmi, K S; Jayashree, M; Singhi, S; Ray, P

    2007-04-01

    Bloodstream infections (BSI) are the commonest cause of nosocomial infections (NI) in PICU. Knowledge about their magnitude, risk factors and outcome are important in devising appropriate prevention and control measures. Our objective was to study the incidence, etiology, risk factors and outcome of primary BSI in PICU. A prospective cohort of 285 patients consecutively admitted to PICU from July 2003-04, having a stay of >48 h, were enrolled and monitored for BSI till discharge from ICU or death. Primary BSI was defined as per CDC criteria 1988. Data of patients with BSI was compared with those without BSI with respect to demographic details, PRISM III, primary diagnosis, nutritional status, device utilization and invasive procedures to identify risk factors for BSI. Variables significant on univariate analysis were subjected to multiple logistic regression analysis. Outcome was measured as length of PICU stay (LOS) and survival or death. There were 116 episodes of primary BSI in 86 (30%) patients; the incidence being 31.2 episodes/1000 patient days. The mean age of the patients with BSI was 3.7 +/- 3.5 years. Predominant isolates were Gram-negative (53.5%); Klebsiella pneumoniae (n = 21) being the commonest. Staphylococcus aureus (n = 18) was the most common Gram-positive organism. Seven of the 9 (77.8%) yeast isolates were Candida tropicalis. Younger age, higher PRISM III, lower hemoglobin, pre-existing infection, higher frequency and duration of device utilization (CVC, urinary catheter, endotracheal tube, mechanical ventilation) were significant risk factors on univariate analysis. On multiple logistic regressions, hemoglobin (OR 1.24, 95% CI 1.1-1.4, p = 0.002) duration of urinary catheter (OR 0.91, 95% CI 0.84-0.98, p = 0.015) and pre-existing infection (OR 0.46, 95% CI 0.23-0.93, p = 0.03) were independent risk factors for primary BSI. The median LOS was significantly longer in patients with BSI compared to those without (16 vs. 7 days, p = 0.0001) 47% of

  13. Trends in paediatric and adult bloodstream infections at a Ghanaian referral hospital: a retrospective study.

    Science.gov (United States)

    Obeng-Nkrumah, Noah; Labi, Appiah-Korang; Addison, Naa Okaikor; Labi, Juliana Ewuramma Mbiriba; Awuah-Mensah, Georgina

    2016-08-18

    Bloodstream infections (BSI) are life-threatening emergencies. Identification of the common pathogens and their susceptibility patterns is necessary for timely empirical intervention. We conducted a 4-year retrospective analysis of blood cultures from all patients excluding neonates at the Korle-Bu Teaching hospital, Ghana, from January 2010 through December 2013. Laboratory report data were used to determine BSI, blood culture contamination, pathogen profile, and antimicrobial resistance patterns. Overall, 3633 (23.16 %) out of 15,683 blood cultures were positive for various organisms. Pathogen-positive cultures accounted for 1451 (9.3 %, 95 % CI 8.5-9.8 %). Infants recorded the highest true blood culture positivity (20.9 %, n = 226/1083), followed by the elderly (13.3 %, n = 80/601), children (8.9 %, n = 708/8000) and adults (7.2 %, n = 437/6000) (p = 0.001 for Marascuilo's post hoc). Overall occurrence of BSI declined with increasing age-group (p = 0.001) but the type of isolates did not vary with age except for Citrobacter, Escherichia coli, Klebsiella, Salmonella, and Enterococcus species. Gram negative bacteria predominated in our study (59.8 %, n = 867/1451), but the commonest bacterial isolate was Staphylococcus aureus (21.9 %, n = 318/1451)-and this trend run through the various age-groups. From 2010 to 2013, we observed a significant trend of yearly increase in the frequency of BSI caused by cephalosporin-resistant enterobacteria (Chi square for trend, p = 0.001). Meropenem maintained high susceptibility among all Gram-negative organisms ranging from 96 to 100 %. Among Staphylococcus aureus, susceptibility to cloxacillin was 76.6 %. Our study shows a significantly high blood culture positivity in infants as compared to children, adults and the elderly. There was a preponderance of S. aureus and Gram-negative bacteria across all age-groups. Meropenem was the most active antibiotic for Gram-negative bacteria. Cloxacillin

  14. Molecular Identification and Echinocandin Susceptibility of Candida parapsilosis Complex Bloodstream Isolates in Italy, 2007-2014.

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    Grazia Lovero

    Full Text Available The Candida parapsilosis group encompasses three species: C. parapsilosis, C. orthopsilosis, and C. metapsilosis. Here, we describe the incidence and echinocandin susceptibility profile of bloodstream isolates of these three species collected from patients admitted to an Italian university hospital from 2007 to 2014. Molecular identification of cryptic species of the C. parapsilosis complex was performed using polymerase chain reaction amplification of the gene encoding secondary alcohol dehydrogenase, followed by digestion with the restriction enzyme BanI. Minimum inhibitory concentrations were determined using the broth microdilution method according to European Committee for Antimicrobial Susceptibility Testing (EUCAST EDef 7.2 and Clinical Laboratory Standards Institute (CLSI M27-A3 guidelines, and the results were compared with those obtained using the E-test and Sensititre methods. Of the 163 C. parapsilosis complex isolates, 136 (83.4% were identified as C. parapsilosis, and 27 (16.6% as C. orthopsilosis. The species-specific incidences were 2.9/10,000 admissions for C. parapsilosis and 0.6/10,000 admissions for C. orthopsilosis. No resistance to echinocandins was detected with any of the methods. The percent essential agreement (EA between the EUCAST and E-test/Sensititre methods for anidulafungin, caspofungin, and micafungin susceptibility was, respectively, as follows: C. parapsilosis, 95.6/97.8, 98.5/88.2, and 93.4/96.3; C. orthopsilosis, 92.6/92.6, 96.3/77.8, and 63.0/66.7. The EA between the CLSI and E-test/Sensititre methods was, respectively, as follows: C. parapsilosis, 99.3/100, 98.5/89.0, and 96.3/98.5; C. orthopsilosis, 96.3/92.6, 100/81.5, and 92.6/88.9. Only minor discrepancies, ranging from 16.9% (C. parapsilosis to 11.1% (C. orthopsilosis, were observed between the CLSI and E-test/Sensititre methods. In conclusion, this epidemiologic study shows a typical C. parapsilosis complex species distribution, no echinocandin

  15. Study of Candida Bloodstream Infections in Surgical Intensive Care Unit Patients and Susceptibility Profile of the Isolates

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    Vijaya S. Rajmane

    2015-01-01

    Full Text Available Background: The increased incidence of fungal infections in the past two decades has been overwhelming. Despite the fact that invasive fungal infections are still under-diagnosed and underreported, bloodstream infection due to Candida is now being recognized as an important public health problem especially in ICU patients with considerable morbidity, mortality and health care costs. Objective: To study the incidence, risk factors and antifungal susceptibility of Candida bloodstream infection in our hospital. Material and Methods: In the present study, the blood samples were collected from patients admitted in Surgical ICU. Samples were processed and antifungal susceptibility of the isolates was performed using standard protocol. Results: Out of total 93 patients, 14 (15.05% were positive for candidemia with equal distribution of both C. albicans and nonalbicans Candida spp. The risk factors associated with candidemia showing statistical significance were length of ICU stay > 7 days, mechanical ventilation, central venous catheters and uncontrolled diabetes. Among the patients with candidemia the mortality rate was 78.57 %. Resistance to Amphotericin B was seen in 33.33 % isolates of C. tropicalis and 100 % isolates of C. rugosa. 33.33 % of C. tropicalis and 50 % of C. rugosa showed dose dependent susceptibility to Fluconazole. Conclusion: Early diagnosis and antifungal susceptibility testing is very important in the treatment of candidemia for reducing the mortality rate.

  16. Comparison of the VersaTREK blood culture system against the Bactec9240 system in patients with suspected bloodstream infections

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    van Zyl Danie G

    2011-02-01

    Full Text Available Abstract Background To evaluate the VersaTREK (TREK Diagnostic Systems, Cleveland, Ohio blood culture system against the Bactec9240 (BD Microbiology, Cockeysville, MD, for the recovery of bloodstream pathogens. Methods Venous blood from patients with suspected bacterial sepsis was evenly distributed into bottles of each system. Positive signals were recorded and bottles processed onto standard media for organism recovery. False positive signals were regarded if no organisms were seen on Gram stain and no growth was observed. Results 177 bottles were available for analysis; the Bactec9240 system yielded 43 positive, 134 negative results and no false positive signals. The VersaTREK system had 58 positive signals with 14 being false positives. Conclusions In our setting with high background burden of immuno-compromised patients, the VersaTREK system compared favourably with the Bactec9240 in recovering blood stream aerobic and facultative anaerobic pathogens from patients with suspected bacterial sepsis. A concern is the high false positivity rate. Due to its versatility to accommodate small and large workloads as well as using smaller volumes of blood, this system may establish itself as a useful alternative for the recovery of bloodstream pathogens.

  17. Outcomes and Predictive Factors Associated with Adequacy of Antimicrobial Therapy in Patients with Central Line-Associated Bloodstream Infection.

    Science.gov (United States)

    Yokota, Paula Kiyomi Onaga; Marra, Alexandre Rodrigues; Belucci, Talita Rantin; Victor, Elivane da Silva; Dos Santos, Oscar Fernando Pavão; Edmond, Michael B

    2016-01-01

    Central venous catheters are significant risk factors for bloodstream infection (BSI), which are directly associated with increased morbidity and mortality. This study was a retrospective cohort study for the time period of July 2011-June 2014 in patients with central line-associated bloodstream infection (CLABSI) to determine the microbiological profile and antimicrobial adequacy of patients with CLABSI in a tertiary hospital. One hundred and twenty-one CLABSI cases were identified. Ninety-two percent (n = 111) of patients had monomicrobial BSI. Gram-negative bacteria were the most prevalent (49%, n = 63), with Klebsiella spp. predominating (30%, n = 19). Among the Gram-positive bacteria (n = 43, 33%), coagulase-negative staphylococci was the major pathogen (58%, n = 25), and all isolates were methicillin resistant. Antimicrobial therapy was assessed as adequate in 81% (n = 98) of cases. In-hospital mortality was 36% (n = 43 cases). Our CLABSI patients had a high mortality, although antimicrobial therapy was appropriate. Gram-negative bacteria were responsible for almost half of the cases and there was a high rate of bacteria resistance to extended-spectrum antibiotics.

  18. Five-Lumen Antibiotic-Impregnated Femoral Central Venous Catheters in Severely Burned Patients: An Investigation of Device Utility and Catheter-Related Bloodstream Infection Rates.

    Science.gov (United States)

    Friedman, Bruce C; Mian, Mohammad A H; Mullins, Robert F; Hassan, Zaheed; Shaver, Joseph R; Johnston, Krystal K

    2015-01-01

    The objective of this study is to determine the catheter-related bloodstream infection (CRBSI) rate in a severely burned patient population, many of whom required prolonged use of central venous catheters (CVCs). Between January 2008 and June 2012, 151 patients underwent placement of 455 five-lumen minocycline/rifampin-impregnated CVCs. CRBSI was defined as at least one blood culture (>100,000 colonies) and one simultaneous roll-plate CVC tip culture (>15 colony forming units) positive for the same organism. Most patients had accidental burns (81.5%) with a mean TBSA of 50%. A mean of three catheters were inserted per patient (range, 1-25). CVCs were inserted in the femoral vein (91.2%), subclavian vein (5.3%), and internal jugular vein (3.3%). Mean overall catheter indwell time was 8 days (range, 0-39 days). The overall rate of CRBSI per 1000 catheter days was 11.2; patients with a TBSA >60% experienced significantly higher rates of CRBSI than patients with a TBSA ≤60% (16.2 vs 7.3, P = .01). CVCs placed through burned skin were four times more likely to be associated with CRBSI than CVCs placed through intact skin. The most common infectious organism was Acinetobacter baumannii. Deep venous thrombosis developed in eleven patients (7%). The overall rate of CRBSI was 11.2, consistent with published rates of CRBSI in burn patients. Thus, femoral placement of 5-lumen CVCs did not result in increased CRBSI rates. These data support the safety of femoral CVC placement in burn patients, contrary to the Centers for Disease Control recommendation to avoid femoral CVC insertion.

  19. Species-Specific and Drug-Specific Differences in Susceptibility of Candida Biofilms to Echinocandins: Characterization of Less Common Bloodstream Isolates

    Science.gov (United States)

    Simitsopoulou, Maria; Peshkova, Pavla; Tasina, Efthymia; Katragkou, Aspasia; Kyrpitzi, Daniela; Velegraki, Aristea; Walsh, Thomas J.

    2013-01-01

    Candida species other than Candida albicans are increasingly recognized as causes of biofilm-associated infections. This is a comprehensive study that compared the in vitro activities of all three echinocandins against biofilms formed by different common and infrequently identified Candida isolates. We determined the activities of anidulafungin (ANID), caspofungin (CAS), and micafungin (MFG) against planktonic cells and biofilms of bloodstream isolates of C. albicans (15 strains), Candida parapsilosis (6 strains), Candida lusitaniae (16 strains), Candida guilliermondii (5 strains), and Candida krusei (12 strains) by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] assay. Planktonic and biofilm MICs were defined as ≥50% fungal damage. Planktonic cells of all Candida species were susceptible to the three echinocandins, with MICs of ≤1 mg/liter. By comparison, differences in the MIC profiles of biofilms in response to echinocandins existed among the Candida species. Thus, C. lusitaniae and C. guilliermondii biofilms were highly recalcitrant to all echinocandins, with MICs of ≥32 mg/liter. In contrast, the MICs of all three echinocandins for C. albicans and C. krusei biofilms were relatively low (MICs ≤ 1 mg/liter). While echinocandins exhibited generally high MICs against C. parapsilosis biofilms, MFG exhibited the lowest MICs against these isolates (4 mg/liter). A paradoxical growth effect was observed with CAS concentrations ranging from 8 to 64 mg/liter against C. albicans and C. parapsilosis biofilms but not against C. krusei, C. lusitaniae, or C. guilliermondii. While non-albicans Candida planktonic cells were susceptible to all echinocandins, there were drug- and species-specific differences in susceptibility among biofilms of the various Candida species, with C. lusitaniae and C. guilliermondii exhibiting profiles of high MICs of the three echinocandins. PMID:23529739

  20. Identification, Genotypic Relation, and Clinical Features of Colistin-Resistant Isolates of Acinetobacter Genomic Species 13BJ/14TU from Bloodstreams of Patients in a University Hospital

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    Lee, Seung Yeob; Shin, Jong Hee; Park, Kyung Hwa; Kim, Ju Hee; Shin, Myung Geun; Suh, Soon Pal; Ryang, Dong Wook

    2014-01-01

    Colistin resistance remains rare among clinical isolates of Acinetobacter species. We noted the emergence of colistin-resistant bloodstream isolates of the Acinetobacter genomic species (GS) 13BJ/14TU from patients at a university hospital between 2003 and 2011. We report here, for the first time, the microbiological and molecular characteristics of these isolates, with clinical features of Acinetobacter GS 13BJ/14TU bacteremia. All 11 available patient isolates were correctly identified as Acinetobacter GS 13BJ/14TU using partial rpoB gene sequencing but were misidentified using the phenotypic methods Vitek 2 (mostly as Acinetobacter baumannii), MicroScan (mostly as A. baumannii/Acinetobacter haemolyticus), and the API 20 NE system (all as A. haemolyticus). Most isolates were susceptible to commonly used antibiotics, including carbapenems, but all were resistant to colistin, for which it is unknown whether the resistance is acquired or intrinsic. However, the fact that none of the patients had a history of colistin therapy strongly suggests that Acinetobacter GS 13BJ/14TU is innately resistant to colistin. The phylogenetic tree of multilocus sequence typing (MLST) showed that all 11 isolates formed a separate cluster from other Acinetobacter species and yielded five sequence types. However, pulsed-field gel electrophoresis (PFGE) revealed 11 distinct patterns, suggesting that the bacteremia had occurred sporadically. Four patients showed persistent bacteremia (6 to 17 days), and all 11 patients had excellent outcomes with cleared bacteremia, suggesting that patients with Acinetobacter GS 13BJ/14TU-associated bacteremia show a favorable outcome. These results emphasize the importance of precise species identification, especially regarding colistin resistance in Acinetobacter species. In addition, MLST offers another approach to the identification of Acinetobacter GS 13BJ/14TU, whereas PFGE is useful for genotyping for this species. PMID:24403305

  1. Characterization of a Novel Class I Transcription Factor A (CITFA) Subunit That Is Indispensable for Transcription by the Multifunctional RNA Polymerase I of Trypanosoma brucei

    KAUST Repository

    Nguyen, T. N.

    2012-10-26

    Trypanosoma brucei is the only organism known to have evolved a multifunctional RNA polymerase I (pol I) system that is used to express the parasite\\'s ribosomal RNAs, as well as its major cell surface antigens, namely, the variant surface glycoprotein (VSG) and procyclin, which are vital for establishing successful infections in the mammalian host and the tsetse vector, respectively. Thus far, biochemical analyses of the T. brucei RNA pol I transcription machinery have elucidated the subunit structure of the enzyme and identified the class I transcription factor A (CITFA). CITFA binds to RNA pol I promoters, and its CITFA-2 subunit was shown to be absolutely essential for RNA pol I transcription in the parasite. Tandem affinity purification (TAP) of CITFA revealed the subunits CITFA-1 to -6, which are conserved only among kinetoplastid organisms, plus the dynein light chain DYNLL1. Here, by tagging CITFA-6 instead of CITFA-2, a complex was purified that contained all known CITFA subunits, as well as a novel proline-rich protein. Functional studies carried out in vivo and in vitro, as well as a colocalization study, unequivocally demonstrated that this protein is a bona fide CITFA subunit, essential for parasite viability and indispensable for RNA pol I transcription of ribosomal gene units and the active VSG expression site in the mammalian-infective life cycle stage of the parasite. Interestingly, CITFA-7 function appears to be species specific, because expression of an RNA interference (RNAi)-resistant CITFA-7 transgene from Trypanosoma cruzi could not rescue the lethal phenotype of silencing endogenous CITFA-7.

  2. The response of trypanosomes and other eukaryotes to ER stress and the spliced leader RNA silencing (SLS) pathway in Trypanosoma brucei.

    Science.gov (United States)

    Michaeli, Shulamit

    2015-01-01

    The unfolded protein response (UPR) is induced when the quality control machinery of the cell is overloaded with unfolded proteins or when one of the functions of the endoplasmic reticulum (ER) is perturbed. Here, I describe UPR in yeast and mammals, and compare it to what we know about pathogenic fungi and the parasitic protozoans from the order kinetoplastida, focusing on the novel pathway the spliced leader silencing (SLS) in Trypanosoma brucei. Trypanosomes lack conventional transcription regulation, and thus, lack most of the UPR machinery present in other eukaryotes. Trypanosome genes are transcribed in polycistronic units that are processed by trans-splicing and polyadenylation. In trans-splicing, which is essential for processing of each mRNA, an exon known as the spliced leader (SL) is added to all mRNAs from a small RNA, the SL RNA. Under severe ER stress, T. brucei elicits the SLS pathway. In SLS, the transcription of the SL RNA gene is extinguished, and the entire transcription complex dissociates from the SL RNA promoter. Induction of SLS is mediated by an ER-associated kinase (PK3) that migrates to the nucleus, where it phosphorylates the TATA-binding protein (TRF4), leading shut-off of SL RNA transcription. As a result, trans-splicing is inhibited and the parasites activate a programmed cell death (PCD) pathway. Despite the ability to sense the ER stress, the different eukaryotes, especially unicellular parasites and pathogenic fungi, developed a variety of unique and different ways to sense and adjust to this stress in a manner different from their host.

  3. The role of B-cells and IgM antibodies in parasitemia, anemia, and VSG switching in Trypanosoma brucei-infected mice.

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    Stefan Magez

    Full Text Available African trypanosomes are extracellular parasitic protozoa, predominantly transmitted by the bite of the haematophagic tsetse fly. The main mechanism considered to mediate parasitemia control in a mammalian host is the continuous interaction between antibodies and the parasite surface, covered by variant-specific surface glycoproteins. Early experimental studies have shown that B-cell responses can be strongly protective but are limited by their VSG-specificity. We have used B-cell (microMT and IgM-deficient (IgM(-/- mice to investigate the role of B-cells and IgM antibodies in parasitemia control and the in vivo induction of trypanosomiasis-associated anemia. These infection studies revealed that that the initial setting of peak levels of parasitemia in Trypanosoma brucei-infected microMT and IgM(-/- mice occurred independent of the presence of B-cells. However, B-cells helped to periodically reduce circulating parasites levels and were required for long term survival, while IgM antibodies played only a limited role in this process. Infection-associated anemia, hypothesized to be mediated by B-cell responses, was induced during infection in microMT mice as well as in IgM(-/- mice, and as such occurred independently from the infection-induced host antibody response. Antigenic variation, the main immune evasion mechanism of African trypanosomes, occurred independently from host antibody responses against the parasite's ever-changing antigenic glycoprotein coat. Collectively, these results demonstrated that in murine experimental T. brucei trypanosomiasis, B-cells were crucial for periodic peak parasitemia clearance, whereas parasite-induced IgM antibodies played only a limited role in the outcome of the infection.

  4. Kinetic and mutational analysis of the Trypanosoma brucei NBT1 nucleobase transporter expressed in Saccharomyces cerevisiae reveals structural similarities between ENT and MFS transporters.

    Science.gov (United States)

    Papageorgiou, I; De Koning, H P; Soteriadou, K; Diallinas, G

    2008-05-01

    Parasitic protozoa are unable to synthesise purines de novo and thus depend on the uptake of nucleosides and nucleobases across their plasma membrane through specific transporters. A number of nucleoside and nucleobase transporters from Trypanosoma brucei brucei and Leishmania major have recently been characterised and shown to belong to the equilibrative nucleoside transporter (ENT) family. A number of studies have demonstrated the functional importance of particular transmembrane segments (TMS) in nucleoside-specific ENT proteins. TbNBT1, one of only three bona fide nucleobase-selective members of the ENT family, has previously been shown to be a high-affinity transporter for purine nucleobases and guanosine. In this study, we use the Saccharomyces cerevisiae expression system to build a biochemical model of how TbNBT1 recognises nucleobases. We next performed random in vitro and site-directed mutagenesis to identify residues critical for TbNBT1 function. The identification of residues likely to contribute to permeant binding, when combined with a structural model of TbNBT1 obtained by homology threading, yield a tentat