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Sample records for brucei bloodstream form

  1. Ribose 5-phosphate isomerase B knockdown compromises Trypanosoma brucei bloodstream form infectivity.

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    Loureiro, Inês; Faria, Joana; Clayton, Christine; Macedo-Ribeiro, Sandra; Santarém, Nuno; Roy, Nilanjan; Cordeiro-da-Siva, Anabela; Tavares, Joana

    2015-01-01

    Ribose 5-phosphate isomerase is an enzyme involved in the non-oxidative branch of the pentose phosphate pathway, and catalyzes the inter-conversion of D-ribose 5-phosphate and D-ribulose 5-phosphate. Trypanosomatids, including the agent of African sleeping sickness namely Trypanosoma brucei, have a type B ribose-5-phosphate isomerase. This enzyme is absent from humans, which have a structurally unrelated ribose 5-phosphate isomerase type A, and therefore has been proposed as an attractive drug target waiting further characterization. In this study, Trypanosoma brucei ribose 5-phosphate isomerase B showed in vitro isomerase activity. RNAi against this enzyme reduced parasites' in vitro growth, and more importantly, bloodstream forms infectivity. Mice infected with induced RNAi clones exhibited lower parasitaemia and a prolonged survival compared to control mice. Phenotypic reversion was achieved by complementing induced RNAi clones with an ectopic copy of Trypanosoma cruzi gene. Our results present the first functional characterization of Trypanosoma brucei ribose 5-phosphate isomerase B, and show the relevance of an enzyme belonging to the non-oxidative branch of the pentose phosphate pathway in the context of Trypanosoma brucei infection.

  2. 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

    2017-02-20

    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.

  3. 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.

  4. Biosynthesis and uptake of thiamine (vitamin B1) in bloodstream form Trypanosoma brucei brucei and interference of the vitamin with melarsen oxide activity.

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    Stoffel, Sabine A; Rodenko, Boris; Schweingruber, Anne-Marie; Mäser, Pascal; de Koning, Harry P; Schweingruber, M Ernst

    2006-02-01

    Bloodstream forms of Trypanosoma brucei brucei were cultivated in the presence and absence of thiamine (vitamin B1) and pyridoxine (vitamin B6). The vitamins do not change growth behaviour, indicating that Trypanosoma brucei is prototrophic for the two vitamins even though in silico no bona-fide thiamine-biosynthetic genes could be identified in the T. brucei genome. Intracellularly, thiamine is mainly present in its diphosphate form. We were unable to detect significant uptake of [3H]thiamine and structural thiamine analogues such as pyrithiamine, oxithiamine and amprolium were not toxic for the bloodstream forms of T. brucei, indicating that the organism does not have an efficient uptake system for thiamine and its analogues. We have previously shown that, in the fission yeast Saccharomyces pombe, the toxicity of melarsen oxide, the pharmacologically active derivative of the frontline sleeping sickness drug melarsoprol, is abolished by thiamine and the drug is taken up by a thiamine-regulated membrane protein which is responsible for the utilization of thiamine. We show here that thiamine also has weak effects on melarsen oxide-induced growth inhibition and lysis in T. brucei. These effects were consistent with a low affinity of thiamine for the P2 adenosine transporter that is responsible for uptake of melaminophenyl arsenicals in African trypanosomes.

  5. Bloodstream form pre-adaptation to the tsetse fly in Trypanosoma brucei.

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    Rico, Eva; Rojas, Federico; Mony, Binny M; Szoor, Balazs; Macgregor, Paula; Matthews, Keith R

    2013-01-01

    African trypanosomes are sustained in the bloodstream of their mammalian hosts by their extreme capacity for antigenic variation. However, for life cycle progression, trypanosomes also must generate transmission stages called stumpy forms that are pre-adapted to survive when taken up during the bloodmeal of the disease vector, tsetse flies. These stumpy forms are rather different to the proliferative slender forms that maintain the bloodstream parasitaemia. Firstly, they are non proliferative and morphologically distinct, secondly, they show particular sensitivity to environmental cues that signal entry to the tsetse fly and, thirdly, they are relatively robust such that they survive the changes in temperature, pH and proteolytic environment encountered within the tsetse midgut. These characteristics require regulated changes in gene expression to pre-adapt the parasite and the use of environmental sensing mechanisms, both of which allow the rapid initiation of differentiation to tsetse midgut procyclic forms upon transmission. Interestingly, the generation of stumpy forms is also regulated and periodic in the mammalian blood, this being governed by a density-sensing mechanism whereby a parasite-derived signal drives cell cycle arrest and cellular development both to optimize transmission and to prevent uncontrolled parasite multiplication overwhelming the host. In this review we detail recent developments in our understanding of the molecular mechanisms that underpin the production of stumpy forms in the mammalian bloodstream and their signal perception pathways both in the mammalian bloodstream and upon entry into the tsetse fly. These discoveries are discussed in the context of conserved eukaryotic signaling and differentiation mechanisms. Further, their potential to act as targets for therapeutic strategies that disrupt parasite development either in the mammalian bloodstream or upon their transmission to tsetse flies is also discussed.

  6. 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.

  7. Mathematical modelling of polyamine metabolism in bloodstream-form Trypanosoma brucei: an application to drug target identification.

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    Xu Gu

    Full Text Available We present the first computational kinetic model of polyamine metabolism in bloodstream-form Trypanosoma brucei, the causative agent of human African trypanosomiasis. We systematically extracted the polyamine pathway from the complete metabolic network while still maintaining the predictive capability of the pathway. The kinetic model is constructed on the basis of information gleaned from the experimental biology literature and defined as a set of ordinary differential equations. We applied Michaelis-Menten kinetics featuring regulatory factors to describe enzymatic activities that are well defined. Uncharacterised enzyme kinetics were approximated and justified with available physiological properties of the system. Optimisation-based dynamic simulations were performed to train the model with experimental data and inconsistent predictions prompted an iterative procedure of model refinement. Good agreement between simulation results and measured data reported in various experimental conditions shows that the model has good applicability in spite of there being gaps in the required data. With this kinetic model, the relative importance of the individual pathway enzymes was assessed. We observed that, at low-to-moderate levels of inhibition, enzymes catalysing reactions of de novo AdoMet (MAT and ornithine production (OrnPt have more efficient inhibitory effect on total trypanothione content in comparison to other enzymes in the pathway. In our model, prozyme and TSHSyn (the production catalyst of total trypanothione were also found to exhibit potent control on total trypanothione content but only when they were strongly inhibited. Different chemotherapeutic strategies against T. brucei were investigated using this model and interruption of polyamine synthesis via joint inhibition of MAT or OrnPt together with other polyamine enzymes was identified as an optimal therapeutic strategy.

  8. 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 Trypanosomiasi

  9. Involvement of lysosomes in the uptake of macromolecular material by bloodstream forms of Trypanosoma brucei.

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    Opperdoes, F R; Van Roy, J

    1982-09-01

    To investigate whether the lysosomes of Trypanosoma brucei are capable of uptake of macromolecules after internalization by the cell, we used Triton WR-1339, a non-digestible macromolecular compound, which is known to cause a marked decrease in the density of hepatic lysosomes due to massive intralysosomal storage. Intraperitoneal administration of 0.4 g/kg Triton WR-1339 to rats infected with T. brucei led to the development of a large vacuole in the trypanosomes between nucleus and kinetoplast within 22 h. Higher doses (2 g/kg) led to the disappearance of the trypanosomes from the blood and resulted in permanent cures (greater than 100 days). Lysosomes isolated from the trypanosomes of animals treated with a sub-curative dose showed a decrease in equilibrium density of 0.03 g/cm3 in sucrose gradients. These lysosomes were partly damaged as evidenced by a reduction in latency and an increase in the non-sedimentable part of lysosomal enzymes. We conclude that acid proteinase and alpha-mannosidase-containing organelles of T. brucei take up exogenous macromolecules and must therefore be considered as true lysosomes and that Triton WR-1339 acts in T. brucei as a true lysosomotropic drug. Its trypanocidal action probably results from an interference with lysosomal function.

  10. 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.

  11. A luciferase based viability assay for ATP detection in 384-well format for high throughput whole cell screening of Trypanosoma brucei brucei bloodstream form strain 427

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    Avery Vicky M

    2009-11-01

    Full Text Available Abstract Background Human African Trypanosomiasis (HAT is caused by two trypanosome species, Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense. Current drugs available for the treatment of HAT have significant issues related to toxicity, administration regimes with limited effectiveness across species and disease stages, thus there is a considerable need to find alternative drugs. A well recognised approach to identify new drug candidates is high throughput screening (HTS of large compound library collections. Results We describe here the development of a luciferase based viability assay in 384-well plate format suitable for HTS of T.b.brucei. The parameters that were explored to determine the final HTS assay conditions are described in detail and include DMSO tolerability, Z', diluents and cell inoculum density. Reference compound activities were determined for diminazene, staurosporine and pentamidine and compared to previously published IC50 data obtained. The assay has a comparable sensitivity to reference drugs and is more cost effective than the 96-well format currently reported for T.b.brucei. Conclusion Due to the reproducibility and sensitivity of this assay it is recommended for potential HTS application. As it is commercially available this assay can also be utilised in many laboratories for both large and small scale screening.

  12. Diverse effects on mitochondrial and nuclear functions elicited by drugs and genetic knockdowns in bloodstream stage Trypanosoma brucei.

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    Christal Worthen

    Full Text Available BACKGROUND: The options for treating the fatal disease human African trypanosomiasis are limited to a few drugs that are toxic or facing increasing resistance. New drugs that kill the causative agents, subspecies of Trypanosoma brucei, are therefore urgently needed. Little is known about the cellular mechanisms that lead to death of the pathogenic bloodstream stage. METHODOLOGY/PRINCIPAL FINDINGS: We therefore conducted the first side by side comparison of the cellular effects of multiple death inducers that target different systems in bloodstream form parasites, including six drugs (pentamidine, prostaglandin D(2, quercetin, etoposide, camptothecin, and a tetrahydroquinoline and six RNAi knockdowns that target distinct cellular functions. All compounds tested were static at low concentrations and killed at high concentrations. Dead parasites were rapidly quantified by forward and side scatter during flow cytometry, as confirmed by ethidium homodimer and esterase staining, making these assays convenient for quantitating parasite death. The various treatments yielded different combinations of defects in mitochondrial potential, reactive oxygen species, cell cycle, and genome segregation. No evidence was seen for phosphatidylserine exposure, a marker of apoptosis. Reduction in ATP levels lagged behind decreases in live cell number. Even when the impact on growth was similar at 24 hours, drug-treated cells showed dramatic differences in their ability to further proliferate, demonstrating differences in the reversibility of effects induced by the diverse compounds. CONCLUSIONS/SIGNIFICANCE: Parasites showed different phenotypes depending on the treatment, but none of them were clear predictors of whether apparently live cells could go on to proliferate after drugs were removed. We therefore suggest that clonal proliferation assays may be a useful step in selecting anti-trypanosomal compounds for further development. Elucidating the genetic or

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

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    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.

  14. Genome-wide expression profiling of in vivo-derived bloodstream parasite stages and dynamic analysis of mRNA alterations during synchronous differentiation in Trypanosoma brucei

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    Ghazal Peter

    2009-09-01

    Full Text Available Abstract Background Trypanosomes undergo extensive developmental changes during their complex life cycle. Crucial among these is the transition between slender and stumpy bloodstream forms and, thereafter, the differentiation from stumpy to tsetse-midgut procyclic forms. These developmental events are highly regulated, temporally reproducible and accompanied by expression changes mediated almost exclusively at the post-transcriptional level. Results In this study we have examined, by whole-genome microarray analysis, the mRNA abundance of genes in slender and stumpy forms of T.brucei AnTat1.1 cells, and also during their synchronous differentiation to procyclic forms. In total, five biological replicates representing the differentiation of matched parasite populations derived from five individual mouse infections were assayed, with RNAs being derived at key biological time points during the time course of their synchronous differentiation to procyclic forms. Importantly, the biological context of these mRNA profiles was established by assaying the coincident cellular events in each population (surface antigen exchange, morphological restructuring, cell cycle re-entry, thereby linking the observed gene expression changes to the well-established framework of trypanosome differentiation. Conclusion Using stringent statistical analysis and validation of the derived profiles against experimentally-predicted gene expression and phenotypic changes, we have established the profile of regulated gene expression during these important life-cycle transitions. The highly synchronous nature of differentiation between stumpy and procyclic forms also means that these studies of mRNA profiles are directly relevant to the changes in mRNA abundance within individual cells during this well-characterised developmental transition.

  15. Cofactor-independent phosphoglycerate mutase is an essential gene in procyclic form Trypanosoma brucei.

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    Djikeng, Appolinaire; Raverdy, Sylvine; Foster, Jeremy; Bartholomeu, Daniella; Zhang, Yinhua; El-Sayed, Najib M; Carlow, Clotilde

    2007-03-01

    Glycolysis and gluconeogenesis are, in part, driven by the interconversion of 3- and 2-phosphoglycerate (3-PG and 2-PG) which is performed by phosphoglycerate mutases (PGAMs) which can be cofactor dependant (dPGAM) or cofactor independent (iPGAM). The African trypanosome, Trypanosoma brucei, possesses the iPGAM form which is thought to play an important role in glycolysis. Here, we report on the use of RNA interference to down-regulate the T. brucei iPGAM in procyclic form T. brucei and evaluation of the resulting phenotype. We first demonstrated biochemically that depletion of the steady state levels of iPGM mRNA correlates with a marked reduction of enzyme activity. We further show that iPGAM is required for cell growth in procyclic T. brucei.

  16. 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.

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

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    Moreno, S Andrea; Nava, Mayerly

    2015-06-01

    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.

  18. The glycosylphosphatidylinositol-PLC in Trypanosoma brucei forms a linear array on the exterior of the flagellar membrane before and after activation.

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    Hanrahan, Orla; Webb, Helena; O'Byrne, Robert; Brabazon, Elaine; Treumann, Achim; Sunter, Jack D; Carrington, Mark; Voorheis, H Paul

    2009-06-01

    Bloodstream forms of Trypanosoma brucei contain a glycosylphosphatidylinositol-specific phospholipase C (GPI-PLC) that cleaves the GPI-anchor of the variable surface glycoprotein (VSG). Its location in trypanosomes has been controversial. Here, using confocal microscopy and surface labelling techniques, we show that the GPI-PLC is located exclusively in a linear array on the outside of the flagellar membrane, close to the flagellar attachment zone, but does not co-localize with the flagellar attachment zone protein, FAZ1. Consequently, the GPI-PLC and the VSG occupy the same plasma membrane leaflet, which resolves the topological problem associated with the cleavage reaction if the VSG and the GPI-PLC were on opposite sides of the membrane. The exterior location requires the enzyme to be tightly regulated to prevent VSG release under basal conditions. During stimulated VSG release in intact cells, the GPI-PLC did not change location, suggesting that the release mechanism involves lateral diffusion of the VSG in the plane of the membrane to the fixed position of the GPI-PLC.

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

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    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

  20. In vitro cultivation of Trypanosoma acomys: production of insect stages and bloodstream forms.

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    Maraghi, S; Wallbanks, K R; Molyneux, D H; Abdel-Hafez, S K

    1995-01-01

    When Trypanosoma acomys bloodstream forms were cultivated at 37 degrees C in Schneider's Drosophila medium supplemented with 20% (v/v) heat-inactivated foetal calf serum (FCS), with Microtus agrestis embryonic fibroblasts in RPMI 1640 medium supplemented with 20% FCS or in Baltz's medium supplemented with 10% FCS, the parasites transformed and largely remained as epimastigotes. Epimastigotes were also usually the commonest stage observed when the parasites were co-cultivated with a mosquito cell line at 27 degrees C. However, if these cultures were initiated with the supernatant suspensions from fibroblast cultures that had been cryopreserved, trypomastigotes, including bloodstream-like forms, were the predominant stage for the first 4 days of culture. It is suggested that the glycerol supplement or the temperature changes stimulated this unusual morphogenesis. At 27 degrees C, T. acomys was incapable of multiplying and died when cultured in fresh Schneider's Drosophila medium supplemented with 20% FCS, but co-cultivation with the mosquito cell lines or cultivation in cell-free supernatants from 1-week-old mosquito cell cultures was successful at this temperature; most of the parasites multiplied as epimastigotes.

  1. Proline Metabolism is Essential for Trypanosoma brucei brucei Survival in the Tsetse Vector

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    Mantilla, Brian S.; Dyer, Naomi A.; Biran, Marc; Bringaud, Frédéric; Lehane, Michael J.; Acosta-Serrano, Alvaro

    2017-01-01

    Adaptation to different nutritional environments is essential for life cycle completion by all Trypanosoma brucei sub-species. In the tsetse fly vector, L-proline is among the most abundant amino acids and is mainly used by the fly for lactation and to fuel flight muscle. The procyclic (insect) stage of T. b. brucei uses L-proline as its main carbon source, relying on an efficient catabolic pathway to convert it to glutamate, and then to succinate, acetate and alanine as the main secreted end products. Here we investigated the essentiality of an undisrupted proline catabolic pathway in T. b. brucei by studying mitochondrial Δ1-pyrroline-5-carboxylate dehydrogenase (TbP5CDH), which catalyzes the irreversible conversion of gamma-glutamate semialdehyde (γGS) into L-glutamate and NADH. In addition, we provided evidence for the absence of a functional proline biosynthetic pathway. TbP5CDH expression is developmentally regulated in the insect stages of the parasite, but absent in bloodstream forms grown in vitro. RNAi down-regulation of TbP5CDH severely affected the growth of procyclic trypanosomes in vitro in the absence of glucose, and altered the metabolic flux when proline was the sole carbon source. Furthermore, TbP5CDH knocked-down cells exhibited alterations in the mitochondrial inner membrane potential (ΔΨm), respiratory control ratio and ATP production. Also, changes in the proline-glutamate oxidative capacity slightly affected the surface expression of the major surface glycoprotein EP-procyclin. In the tsetse, TbP5CDH knocked-down cells were impaired and thus unable to colonize the fly’s midgut, probably due to the lack of glucose between bloodmeals. Altogether, our data show that the regulated expression of the proline metabolism pathway in T. b. brucei allows this parasite to adapt to the nutritional environment of the tsetse midgut. PMID:28114403

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

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    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.

  3. Deletion of a novel protein kinase with PX and FYVE-related domains increases the rate of differentiation of Trypanosoma brucei.

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    Vassella, E; Krämer, R; Turner, C M; Wankell, M; Modes, C; van den Bogaard, M; Boshart, M

    2001-07-01

    Growth control of African trypanosomes in the mammalian host is coupled to differentiation of a non-dividing life cycle stage, the stumpy bloodstream form. We show that a protein kinase with novel domain architecture is important for growth regulation. Zinc finger kinase (ZFK) has a kinase domain related to RAC and S6 kinases flanked by a FYVE-related zinc finger and a phox (PX) homology domain. To investigate the function of the kinase during cyclical development, a stable transformation procedure for bloodstream forms of differentiation-competent (pleomorphic) Trypanosoma brucei strains was established. Deletion of both allelic copies of ZFK by homologous recombination resulted in reduced growth of bloodstream-form parasites in culture, which was correlated with an increased rate of differentiation to the non-dividing stumpy form. Growth and differentiation rates were returned to wild-type level by ectopic ZFK expression. The phenotype is stage-specific, as growth of procyclic (insect form) trypanosomes was unaffected, and Deltazfk/Deltazfk clones were able to undergo full cyclical development in the tsetse fly vector. Deletion of ZFK in a differentiation-defective (monomorphic) strain of T. brucei did not change its growth rate in the bloodstream stage. This suggests a function of ZFK associated with the trypanosomes' decision between either cell cycle progression, as slender bloodstream form, or differentiation to the non-dividing stumpy form.

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

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    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.

  5. 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

    2016-01-01

    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 (ptrypanosomiasis. PMID:27855164

  6. Single molecule analysis of Trypanosoma brucei DNA replication dynamics.

    Science.gov (United States)

    Calderano, Simone Guedes; Drosopoulos, William C; Quaresma, Marina Mônaco; Marques, Catarina A; Kosiyatrakul, Settapong; McCulloch, Richard; Schildkraut, Carl L; Elias, Maria Carolina

    2015-03-11

    Eukaryotic genome duplication relies on origins of replication, distributed over multiple chromosomes, to initiate DNA replication. A recent genome-wide analysis of Trypanosoma brucei, the etiological agent of sleeping sickness, localized its replication origins to the boundaries of multigenic transcription units. To better understand genomic replication in this organism, we examined replication by single molecule analysis of replicated DNA. We determined the average speed of replication forks of procyclic and bloodstream form cells and we found that T. brucei DNA replication rate is similar to rates seen in other eukaryotes. We also analyzed the replication dynamics of a central region of chromosome 1 in procyclic forms. We present evidence for replication terminating within the central part of the chromosome and thus emanating from both sides, suggesting a previously unmapped origin toward the 5' extremity of chromosome 1. Also, termination is not at a fixed location in chromosome 1, but is rather variable. Importantly, we found a replication origin located near an ORC1/CDC6 binding site that is detected after replicative stress induced by hydroxyurea treatment, suggesting it may be a dormant origin activated in response to replicative stress. Collectively, our findings support the existence of more replication origins in T. brucei than previously appreciated.

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

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    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.

  8. 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.

  9. Deviating the level of proliferating cell nuclear antigen in Trypanosoma brucei elicits distinct mechanisms for inhibiting proliferation and cell cycle progression.

    Science.gov (United States)

    Valenciano, Ana L; Ramsey, Aaron C; Mackey, Zachary B

    2015-01-01

    The DNA replication machinery is spatially and temporally coordinated in all cells to reproduce a single exact copy of the genome per division, but its regulation in the protozoan parasite Trypanosoma brucei is not well characterized. We characterized the effects of altering the levels of proliferating cell nuclear antigen, a key component of the DNA replication machinery, in bloodstream form T. brucei. This study demonstrated that tight regulation of TbPCNA levels was critical for normal proliferation and DNA replication in the parasite. Depleting TbPCNA mRNA reduced proliferation, severely diminished DNA replication, arrested the synthesis of new DNA and caused the parasites to accumulated in G2/M. Attenuating the parasite by downregulating TbPCNA caused it to become hypersensitive to hydroxyurea. Overexpressing TbPCNA in T. brucei arrested proliferation, inhibited DNA replication and prevented the parasite from exiting G2/M. These results indicate that distinct mechanisms of cell cycle arrest are associated with upregulating or downregulating TbPCNA. The findings of this study validate deregulating intra-parasite levels of TbPCNA as a potential strategy for therapeutically exploiting this target in bloodstream form T. brucei.

  10. An essential signal peptide peptidase identified in an RNAi screen of serine peptidases of Trypanosoma brucei.

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    Catherine X Moss

    Full Text Available The serine peptidases of Trypanosoma brucei have been viewed as potential drug targets. In particular, the S9 prolyl oligopeptidase subfamily is thought to be a good avenue for drug discovery. This is based on the finding that some S9 peptidases are secreted and active in the mammalian bloodstream, and that they are a class of enzyme against which drugs have successfully been developed. We collated a list of all serine peptidases in T. brucei, identifying 20 serine peptidase genes, of which nine are S9 peptidases. We screened all 20 serine peptidases by RNAi to determine which, if any, are essential for bloodstream form T. brucei survival. All S9 serine peptidases were dispensable for parasite survival in vitro, even when pairs of similar genes, coding for oligopeptidase B or prolyl oligopeptidase, were targeted simultaneously. We also found no effect on parasite survival in an animal host when the S9 peptidases oligopeptidase B, prolyl oligopeptidase or dipeptidyl peptidase 8 were targeted. The only serine peptidase to emerge from the RNAi screen as essential was a putative type-I signal peptide peptidase (SPP1. This gene was essential for parasite survival both in vitro and in vivo. The growth defect conferred by RNAi depletion of SPP1 was rescued by expression of a functional peptidase from an RNAi resistant SPP1 gene. However, expression of catalytically inactive SPP1 was unable to rescue cells from the SPP1 depleted phenotype, demonstrating that SPP1 serine peptidase activity is necessary for T. brucei survival.

  11. 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. PMID:28082973

  12. Mitochondrial outer membrane proteome of Trypanosoma brucei reveals novel factors required to maintain mitochondrial morphology.

    Science.gov (United States)

    Niemann, Moritz; Wiese, Sebastian; Mani, Jan; Chanfon, Astrid; Jackson, Christopher; Meisinger, Chris; Warscheid, Bettina; Schneider, André

    2013-02-01

    Trypanosoma brucei is a unicellular parasite that causes devastating diseases in humans and animals. It diverged from most other eukaryotes very early in evolution and, as a consequence, has an unusual mitochondrial biology. Moreover, mitochondrial functions and morphology are highly regulated throughout the life cycle of the parasite. The outer mitochondrial membrane defines the boundary of the organelle. Its properties are therefore key for understanding how the cytosol and mitochondria communicate and how the organelle is integrated into the metabolism of the whole cell. We have purified the mitochondrial outer membrane of T. brucei and characterized its proteome using label-free quantitative mass spectrometry for protein abundance profiling in combination with statistical analysis. Our results show that the trypanosomal outer membrane proteome consists of 82 proteins, two-thirds of which have never been associated with mitochondria before. 40 proteins share homology with proteins of known functions. The function of 42 proteins, 33 of which are specific to trypanosomatids, remains unknown. 11 proteins are essential for the disease-causing bloodstream form of T. brucei and therefore may be exploited as novel drug targets. A comparison with the outer membrane proteome of yeast defines a set of 17 common proteins that are likely present in the mitochondrial outer membrane of all eukaryotes. Known factors involved in the regulation of mitochondrial morphology are virtually absent in T. brucei. Interestingly, RNAi-mediated ablation of three outer membrane proteins of unknown function resulted in a collapse of the network-like mitochondrion of procyclic cells and for the first time identified factors that control mitochondrial shape in T. brucei.

  13. 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 Cerrado conservation and sustainable development.

  14. Inhibitors of the mitochondrial cytochrome b-c1 complex inhibit the cyanide-insensitive respiration of Trypanosoma brucei.

    Science.gov (United States)

    Turrens, J F; Bickar, D; Lehninger, A L

    1986-06-01

    The cyanide-insensitive respiration of bloodstream trypomastigote forms of Trypanosoma brucei (75 +/- 8 nmol O2 min-1(mg protein)-1) is completely inhibited by the mitochondrial ubiquinone-like inhibitors 2-hydroxy-3-undecyl-1,4-naphthoquinone (UHNQ) and 5-n-undecyl-6-hydroxy-4,7-dioxobenzothiazole (UHDBT). The Ki values for UHDBT (30 nM) and UHNQ (2 microM) are much lower than the reported Ki for salicylhydroxamic acid (SHAM) (5 microM), a widely used inhibitor of the cyanide-insensitive oxidase. UHNQ also stimulated the glycerol-3-phosphate-dependent reduction of phenazine methosulfate, demonstrating that the site of UHNQ inhibition is on the terminal oxidase of the cyanide-insensitive respiration of T. brucei. These results suggest that a ubiquinone-like compound may act as an electron carrier between the two enzymatic components of the cyanide-insensitive glycerol-3-phosphate oxidase.

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

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    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.

  16. Advancing Trypanosoma brucei genome annotation through ribosome profiling and spliced leader mapping.

    Science.gov (United States)

    Parsons, Marilyn; Ramasamy, Gowthaman; Vasconcelos, Elton J R; Jensen, Bryan C; Myler, Peter J

    2015-08-01

    Since the initial publication of the trypanosomatid genomes, curation has been ongoing. Here we make use of existing Trypanosoma brucei ribosome profiling data to provide evidence of ribosome occupancy (and likely translation) of mRNAs from 225 currently unannotated coding sequences (CDSs). A small number of these putative genes correspond to extra copies of previously annotated genes, but 85% are novel. The median size of these novels CDSs is small (81 aa), indicating that past annotation work has excelled at detecting large CDSs. Of the unique CDSs confirmed here, over half have candidate orthologues in other trypanosomatid genomes, most of which were not yet annotated as protein-coding genes. Nonetheless, approximately one-third of the new CDSs were found only in T. brucei subspecies. Using ribosome footprints, RNA-Seq and spliced leader mapping data, we updated previous work to definitively revise the start sites for 414 CDSs as compared to the current gene models. The data pointed to several regions of the genome that had sequence errors that altered coding region boundaries. Finally, we consolidated this data with our previous work to propose elimination of 683 putative genes as protein-coding and arrive at a view of the translatome of slender bloodstream and procyclic culture form T. brucei.

  17. 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.

  18. In Vitro Trypanocidal Activity of Antibodies to Bacterially Ex­pressed Trypanosoma brucei Tubulin

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    GW Lubega

    2012-09-01

    Full Text Available Background: There are only four drugs for treating African trypanosomiasis, a devastating disease in sub-Saharan Africa. With slow discovery of better drugs, vaccination is viewed as the best method of control. We previously showed that antibodies to native Trypanosoma brucei brucei tubulin inhibit the growth of trypanosomes in culture. Here, we aimed to determine the effect of antibodies to bacte­rially expressed trypanosome tubulin on T. brucei brucei growth. Methods: T. brucei brucei alpha and beta tubulin genes were individually expressed in Escherichia coli under the tryptophan promoter. Monoclonal tubulin antibodies reacted specifically with the ex­pressed tubulins with no cross-reaction with the opposite tubulin. Rabbits were immunized with 450μg each of the concentrated recombinant tubulin, and production of antibodies assessed by ELISA and Western blotting. The effect of polyclonal antibodies on trypanosome growth was deter­mined by culturing bloodstream T. brucei brucei in up to 25% of antisera. Results: Low antisera dilutions (25% from the immunized rabbits inhibited trypanosome growth. The most cytotoxic antisera were from one rabbit immunized with a mixture of both alpha and beta tubulins. However, the result was not reproduced in other rabbits and there was no apparent effect on growth at higher antisera dilutions. Conclusion: Antibodies to bacterially expressed trypanosome tubulin are not effective at killing cul­tured bloodstream trypanosomes.

  19. 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.

  20. 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

  1. 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.

  2. Contribution of Glucose Transport to the Control of the Glycolytic Flux in Trypanosoma brucei

    Science.gov (United States)

    Bakker, Barbara M.; Walsh, Michael C.; Ter Kuile, Benno H.; Mensonides, Femke I. C.; Michels, Paul A. M.; Opperdoes, Fred R.; Westerhoff, Hans V.

    1999-08-01

    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 transport activity independently of the glycolytic flux. Phloretin proved a competitive inhibitor. When the effect of the intracellular glucose concentration on the inhibition was taken into account, the flux control coefficient of the glucose transporter was between 0.3 and 0.5 at 5 mM glucose. Because the flux control coefficients of all steps in a metabolic pathway sum to 1, this result proves that glucose transport is not the rate-limiting step of trypanosome glycolysis. Under physiological conditions, transport shares the control with other steps. At glucose concentrations much lower than physiological, the glucose carrier assumed all control, in close agreement with model predictions.

  3. The threonine degradation pathway of the Trypanosoma brucei procyclic form: the main carbon source for lipid biosynthesis is under metabolic control.

    Science.gov (United States)

    Millerioux, Yoann; Ebikeme, Charles; Biran, Marc; Morand, Pauline; Bouyssou, Guillaume; Vincent, Isabel M; Mazet, Muriel; Riviere, Loïc; Franconi, Jean-Michel; Burchmore, Richard J S; Moreau, Patrick; Barrett, Michael P; Bringaud, Frédéric

    2013-10-01

    The Trypanosoma brucei procyclic form resides within the digestive tract of its insect vector, where it exploits amino acids as carbon sources. Threonine is the amino acid most rapidly consumed by this parasite, however its role is poorly understood. Here, we show that the procyclic trypanosomes grown in rich medium only use glucose and threonine for lipid biosynthesis, with threonine's contribution being ∼ 2.5 times higher than that of glucose. A combination of reverse genetics and NMR analysis of excreted end-products from threonine and glucose metabolism, shows that acetate, which feeds lipid biosynthesis, is also produced primarily from threonine. Interestingly, the first enzymatic step of the threonine degradation pathway, threonine dehydrogenase (TDH, EC 1.1.1.103), is under metabolic control and plays a key role in the rate of catabolism. Indeed, a trypanosome mutant deleted for the phosphoenolpyruvate decarboxylase gene (PEPCK, EC 4.1.1.49) shows a 1.7-fold and twofold decrease of TDH protein level and activity, respectively, associated with a 1.8-fold reduction in threonine-derived acetate production. We conclude that TDH expression is under control and can be downregulated in response to metabolic perturbations, such as in the PEPCK mutant in which the glycolytic metabolic flux was redirected towards acetate production.

  4. Trypanosoma brucei brucei: effects of ferrous iron and heme on ecto-nucleoside triphosphate diphosphohydrolase activity.

    Science.gov (United States)

    Leite, Milane S; Thomaz, Rachel; Oliveira, José Henrique M; Oliveira, Pedro L; Meyer-Fernandes, José Roberto

    2009-02-01

    Trypanosoma brucei brucei is the causative agent of animal African trypanosomiasis, also called nagana. Procyclic vector form resides in the midgut of the tsetse fly, which feeds exclusively on blood. Hemoglobin digestion occurs in the midgut resulting in an intense release of free heme. In the present study we show that the magnesium-dependent ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase) activity of procyclic T. brucei brucei is inhibited by ferrous iron and heme. The inhibition of E-NTPDase activity by ferrous iron, but not by heme, was prevented by pre-incubation of cells with catalase. However, antioxidants that permeate cells, such as PEG-catalase and N-acetyl-cysteine prevented the inhibition of E-NTPDase by heme. Ferrous iron was able to induce an increase in lipid peroxidation, while heme did not. Therefore, both ferrous iron and heme can inhibit E-NTPDase activity of T. brucei brucei by means of formation of reactive oxygen species, but apparently acting through distinct mechanisms.

  5. Parasite-based screening and proteome profiling reveal orlistat, an FDA-approved drug, as a potential anti Trypanosoma brucei agent.

    Science.gov (United States)

    Yang, Peng-Yu; Wang, Min; Liu, Kai; Ngai, Mun Hong; Sheriff, Omar; Lear, Martin J; Sze, Siu Kwan; He, Cynthia Y; Yao, Shao Q

    2012-07-02

    Trypanosoma brucei is a parasite that causes African sleeping sickness in humans and nagana in livestock and is transmitted by the tsetse fly. There is an urgent need for the development of new drugs against African trypanosomiasis due to the lack of vaccines and effective drugs. Orlistat (also called tetrahydrolipstatin or THL) is an FDA-approved antiobesity drug targeting primarily the pancreatic and gastric lipases within the gastrointestinal tract. It shows potential activities against tumors, mycobacteria, and parasites. Herein, we report the synthesis and evaluation of an expanded set of orlistat-like compounds, some of which showed highly potent trypanocidal activities in both the bloodstream form (BSF) and the procyclic form (PCF) of T. brucei. Subsequent in situ parasite-based proteome profiling was carried out to elucidate potential cellular targets of the drug in both forms. Some newly identified targets were further validated by the labeling of recombinantly expressed enzymes in Escherichia coli lysates. Bioimaging experiments with a selected compound were carried out to study the cellular uptake of the drug in T. brucei. Results indicated that orlistat is much more efficiently taken up by the BSF than the PCF of T. brucei and has clear effects on the morphology of mitochondria, glycosomes, and the endoplasmic reticulum in both BSF and PCF cells. These results support specific effects of orlistat on these organelles and correlate well with our in situ proteome profiling. Given the economic challenges of de novo drug development for neglected diseases, we hope that our findings will stimulate further research towards the conversion of orlistat-like compounds into new trypanocidal drugs.

  6. 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 ...

  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.

    Science.gov (United States)

    Carvalho, Alcione Silva de; Salomão, Kelly; Castro, Solange Lisboa de; Conde, Taline Ramos; Zamith, Helena Pereira da Silva; Caffarena, Ernesto Raúl; Hall, Belinda Suzette; Wilkinson, Shane Robert; Boechat, Núbia

    2014-06-01

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

    OpenAIRE

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

    2015-01-01

    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-silencin...

  9. Identification and characterization of an unusual class I myosin involved in vesicle traffic in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Diana Spitznagel

    Full Text Available Myosins are a multimember family of motor proteins with diverse functions in eukaryotic cells. African trypanosomes possess only two candidate myosins and thus represent a useful system for functional analysis of these motors. One of these candidates is an unusual class I myosin (TbMyo1 that is expressed at similar levels but organized differently during the life cycle of Trypanosoma brucei. This myosin localizes to the polarized endocytic pathway in bloodstream forms of the parasite. This organization is actin dependent. Knock down of TbMyo1 results in a significant reduction in endocytic activity, a cessation in cell division and eventually cell death. A striking morphological feature in these cells is an enlargement of the flagellar pocket, which is consistent with an imbalance in traffic to and from the surface. In contrast TbMyo1 is distributed throughout procyclic forms of the tsetse vector and a loss of approximately 90% of the protein has no obvious effects on growth or morphology. These results reveal a life cycle stage specific requirement for this myosin in essential endocytic traffic and represent the first description of the involvement of a motor protein in vesicle traffic in these parasites.

  10. Identification and characterization of an unusual class I myosin involved in vesicle traffic in Trypanosoma brucei.

    Science.gov (United States)

    Spitznagel, Diana; O'Rourke, John F; Leddy, Neal; Hanrahan, Orla; Nolan, Derek P

    2010-01-01

    Myosins are a multimember family of motor proteins with diverse functions in eukaryotic cells. African trypanosomes possess only two candidate myosins and thus represent a useful system for functional analysis of these motors. One of these candidates is an unusual class I myosin (TbMyo1) that is expressed at similar levels but organized differently during the life cycle of Trypanosoma brucei. This myosin localizes to the polarized endocytic pathway in bloodstream forms of the parasite. This organization is actin dependent. Knock down of TbMyo1 results in a significant reduction in endocytic activity, a cessation in cell division and eventually cell death. A striking morphological feature in these cells is an enlargement of the flagellar pocket, which is consistent with an imbalance in traffic to and from the surface. In contrast TbMyo1 is distributed throughout procyclic forms of the tsetse vector and a loss of approximately 90% of the protein has no obvious effects on growth or morphology. These results reveal a life cycle stage specific requirement for this myosin in essential endocytic traffic and represent the first description of the involvement of a motor protein in vesicle traffic in these parasites.

  11. Identification of a new EF-hand superfamily member from Trypanosoma brucei

    Science.gov (United States)

    Wong, S.; Kretsinger, R. H.; Campbell, D. A.

    1992-01-01

    We identified several open reading frames between the regions encoding calmodulin and ubiquitin-EP52/1 in the genome of Trypanosoma brucei. One of these, EFH5, encodes a protein 192 amino acids long. The EFH5 transcript is present in poly(A)+ mRNA and is present at similar levels in the mammalian bloodstream form and the insect procyclic form. EFH5 contains four EF-hand homolog domains, two of which are inferred to bind Ca2+ ions. We expressed EFH5 as a fusion protein in Escherichia coli and demonstrated calcium-binding activity of the fusion protein using the 45Ca-overlay technique. The function of EFH5 remains unknown; however, as the fourth EF-hand homolog identified in trypanosomes, it attests to the broad range of functions assumed by calcium functioning as a second messenger. EFH5, which is most closely related to LAV1-2 from Physarum, represents a distinct subfamily among the EF-hand-containing proteins.

  12. The Role of Folate Transport in Antifolate Drug Action in Trypanosoma brucei*

    Science.gov (United States)

    Dewar, Simon; Sienkiewicz, Natasha; Ong, Han B.; Wall, Richard J.; Horn, David

    2016-01-01

    The aim of this study was to identify and characterize mechanisms of resistance to antifolate drugs in African trypanosomes. Genome-wide RNAi library screens were undertaken in bloodstream form Trypanosoma brucei exposed to the antifolates methotrexate and raltitrexed. In conjunction with drug susceptibility and folate transport studies, RNAi knockdown was used to validate the functions of the putative folate transporters. The transport kinetics of folate and methotrexate were further characterized in whole cells. RNA interference target sequencing experiments identified a tandem array of genes encoding a folate transporter family, TbFT1–3, as major contributors to antifolate drug uptake. RNAi knockdown of TbFT1–3 substantially reduced folate transport into trypanosomes and reduced the parasite's susceptibly to the classical antifolates methotrexate and raltitrexed. In contrast, knockdown of TbFT1–3 increased susceptibly to the non-classical antifolates pyrimethamine and nolatrexed. Both folate and methotrexate transport were inhibited by classical antifolates but not by non-classical antifolates or biopterin. Thus, TbFT1–3 mediates the uptake of folate and classical antifolates in trypanosomes, and TbFT1–3 loss-of-function is a mechanism of antifolate drug resistance. PMID:27703008

  13. Melarsoprol- and pentamidine-resistant Trypanosoma brucei rhodesiense populations and their cross-resistance.

    Science.gov (United States)

    Bernhard, Sonja C; Nerima, Barbara; Mäser, Pascal; Brun, Reto

    2007-11-01

    Resistance to melarsoprol and pentamidine was induced in bloodstream-form Trypanosoma brucei rhodesiense STIB 900 in vitro, and drug sensitivity was determined for melarsoprol, pentamidine and furamidine. The resistant populations were also inoculated into immunosuppressed mice to verify infectivity and to monitor whether rodent passage selects for clones with altered drug sensitivity. After proliferation in the mouse, trypanosomes were isolated and their IC(50) values to the three drugs were determined. To assess the stability of drug-induced resistance, drug pressure was ceased for 2 months and the drug sensitivity was determined again. Resistance was stable, with a few exceptions that are discussed. Drug IC(50)s indicated cross-resistance among all drugs, but to varying extents: resistance of the melarsoprol-selected and pentamidine-selected trypanosomes to pentamidine was the same, but the pentamidine-selected trypanosome population showed lower resistance to melarsoprol than the melarsoprol-selected trypanosomes. Interestingly, both resistant populations revealed the same intermediate cross-resistance to furamidine. Resistant trypanosome populations were characterised by molecular means, referring to the status of the TbAT1 gene. The melarsoprol-selected population apparently had lost TbAT1, whereas in the pentamidine-selected trypanosome population it was still present.

  14. Fluorinated Sterols Are Suicide Inhibitors of Ergosterol Biosynthesis and Growth in Trypanosoma brucei.

    Science.gov (United States)

    Leaver, David J; Patkar, Presheet; Singha, Ujjal K; Miller, Matthew B; Haubrich, Brad A; Chaudhuri, Minu; Nes, W David

    2015-10-22

    Trypanosoma brucei, the causal agent for sleeping sickness, depends on ergosterol for growth. Here, we describe the effects of a mechanism-based inhibitor, 26-fluorolanosterol (26FL), which converts in vivo to a fluorinated substrate of the sterol C24-methyltransferase essential for sterol methylation and function of ergosterol, and missing from the human host. 26FL showed potent inhibition of ergosterol biosynthesis and growth of procyclic and bloodstream forms while having no effect on cholesterol biosynthesis or growth of human epithelial kidney cells. During exposure of cloned TbSMT to 26-fluorocholesta-5,7,24-trienol, the enzyme is gradually killed as a consequence of the covalent binding of the intermediate C25 cation to the active site (kcat/kinact = 0.26 min(-1)/0.24 min(-1); partition ratio of 1.08), whereas 26FL is non-productively bound. These results demonstrate that poisoning of ergosterol biosynthesis by a 26-fluorinated Δ(24)-sterol is a promising strategy for developing a new treatment for trypanosomiasis.

  15. Synchronous expression of individual metacyclic variant surface glycoprotein genes in Trypanosoma brucei.

    Science.gov (United States)

    Ramey-Butler, Kiantra; Ullu, Elisabetta; Kolev, Nikolay G; Tschudi, Christian

    2015-01-01

    One distinctive feature of the Trypanosoma brucei life cycle is the presence of two discrete populations that are based on differential expression of variant surface glycoproteins (VSGs). Both are adapted to the environmental pressures they face and more importantly, both contribute directly to transmission. Metacyclics in the tsetse fly enable transmission to a new mammalian host, whereas bloodstream trypanosomes must avoid immune destruction to the extent that sufficient numbers are available for transmission, when the insect vector takes a blood meal. At present, there are few investigations on the molecular aspects of parasite biology in the tsetse vector and specifically about the activation of metacyclic VSG gene expression. Here we used an established in vitro differentiation system based on the overexpression of the RNA-binding protein 6 (RBP6), to monitor two metacyclic VSGs (VSG 397 and VSG 653) during development from procyclics to infectious metacyclic forms. We observed that activation of these two mVSGs was simultaneous both at the transcript and protein level, and manifested by the appearance of only one of the mVSGs in individual cells.

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

    Directory of Open Access Journals (Sweden)

    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.

  17. 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.

  18. 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...

  19. 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 activitie

  20. Localization of serum resistance-associated protein in Trypanosoma brucei rhodesiense and transgenic Trypanosoma brucei brucei.

    Science.gov (United States)

    Bart, Jean-Mathieu; Cordon-Obras, Carlos; Vidal, Isabel; Reed, Jennifer; Perez-Pastrana, Esperanza; Cuevas, Laureano; Field, Mark C; Carrington, Mark; Navarro, Miguel

    2015-10-01

    African trypanosomes infect a broad range of mammals, but humans and some higher primates are protected by serum trypanosome lytic factors that contain apolipoprotein L1 (ApoL1). In the human-infective subspecies of Trypanosoma brucei, Trypanosoma brucei rhodesiense, a gene product derived from the variant surface glycoprotein gene family member, serum resistance-associated protein (SRA protein), protects against ApoL1-mediated lysis. Protection against trypanosome lytic factor requires the direct interaction between SRA protein and ApoL1 within the endocytic apparatus of the trypanosome, but some uncertainty remains as to the precise mechanism and location of this interaction. In order to provide more insight into the mechanism of SRA-mediated resistance to trypanosome lytic factor, we assessed the localization of SRA in T. b. rhodesiense EATRO3 using a novel monoclonal antibody raised against SRA together with a set of well-characterized endosomal markers. By three-dimensional deconvolved immunofluorescence single-cell analysis, combined with double-labelling immunoelectron microscopy, we found that ≈ 50% of SRA protein localized to the lysosome, with the remaining population being distributed through the endocytic pathway, but apparently absent from the flagellar pocket membrane. These data suggest that the SRA/trypanolytic factor interaction is intracellular, with the concentration within the endosomes potentially crucial for ensuring a high efficiency.

  1. Replacing paper data collection forms with electronic data entry in the field: findings from a study of community-acquired bloodstream infections in Pemba, Zanzibar

    Directory of Open Access Journals (Sweden)

    Thriemer Kamala

    2012-02-01

    Full Text Available Abstract Background Entering data on case report forms and subsequently digitizing them in electronic media is the traditional way to maintain a record keeping system in field studies. Direct data entry using an electronic device avoids this two-step process. It is gaining in popularity and has replaced the paper-based data entry system in many studies. We report our experiences with paper- and PDA-based data collection during a fever surveillance study in Pemba Island, Zanzibar, Tanzania. Methods Data were collected on a 14-page case report paper form in the first period of the study. The case report paper forms were then replaced with handheld computers (personal digital assistants or PDAs. The PDAs were used for screening and clinical data collection, including a rapid assessment of patient eligibility, real time errors, and inconsistency checking. Results A comparison of paper-based data collection with PDA data collection showed that direct data entry via PDA was faster and 25% cheaper. Data was more accurate (7% versus 1% erroneous data and omission did not occur with electronic data collection. Delayed data turnaround times and late error detections in the paper-based system which made error corrections difficult were avoided using electronic data collection. Conclusions Electronic data collection offers direct data entry at the initial point of contact. It has numerous advantages and has the potential to replace paper-based data collection in the field. The availability of information and communication technologies for direct data transfer has the potential to improve the conduct of public health research in resource-poor settings.

  2. Anti-trypanosomal effect of Peristrophe bicalyculata extract on Trypanosoma brucei brucei-infected rats

    Institute of Scientific and Technical Information of China (English)

    Abdulazeez Mansurah Abimbola; Ibrahim Abdulrazak Baba; Edibo Zakari Yenusa; Sidali Joseph Omanibe; Idris Habeeb Oladimeji

    2013-01-01

    Objective: To investigate the in vitro and in vivo effect of whole plant extracts of Peristrophe bicalyculata on Trypanosoma brucei brucei-infected rats. Methods: The experiment was divided into two phases: In the first phase, the anti-trypanosomal activity of the hot water, cold water, methanol and butanol extracts of the whole plant were determined by incubating with Trypanosoma brucei brucei. The cold water extract was partially-purified and the anti-trypanosomal activity of the fractions determined. In the second phase, Trypanosoma brucei brucei-infected rats were treated with fraction 2c for nine days. Packed cell volume (PCV), high density lipoprotein (HDL), low density lipoprotein (LDL), total cholesterol (TC), triacylglycerol (TAG), aspartate aminotransferase, alanine aminotransferases (ALT), alkaline phosphatase (ALP), total and direct bilirubin levels were determined at the end of the experiment. Results:Cold water extract immobilized 90%of the parasites after 60 min of incubation, and fraction 2c completely immobilized the parasites after 35 min. It significantly increased PCV in Trypanosoma brucei brucei-infected rats. Decreased TC, TAG, HDL and LDL levels of infected rats increased significantly when rats were treated with the fraction, while elevated levels of total bilirubin and ALT also decreased. The difference in urea, direct bilirubin and ALP was not significant when infected rats were compared to rats in other groups. Conclusions:The ability of the plant to ameliorate the infection-induced biochemical changes calls for detailed investigation of the potentials of the plant for antitrypanosomiasis drug delivery.

  3. 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.

  4. 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

    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.

  5. Structural and Functional Highlights of Vacuolar Soluble Protein 1 from Pathogen Trypanosoma brucei brucei.

    Science.gov (United States)

    Jamwal, Abhishek; Round, Adam R; Bannwarth, Ludovic; Venien-Bryan, Catherine; Belrhali, Hassan; Yogavel, Manickam; Sharma, Amit

    2015-12-18

    Trypanosoma brucei (T. brucei) is responsible for the fatal human disease called African trypanosomiasis, or sleeping sickness. The causative parasite, Trypanosoma, encodes soluble versions of inorganic pyrophosphatases (PPase), also called vacuolar soluble proteins (VSPs), which are localized to its acidocalcisomes. The latter are acidic membrane-enclosed organelles rich in polyphosphate chains and divalent cations whose significance in these parasites remains unclear. We here report the crystal structure of T. brucei brucei acidocalcisomal PPases in a ternary complex with Mg(2+) and imidodiphosphate. The crystal structure reveals a novel structural architecture distinct from known class I PPases in its tetrameric oligomeric state in which a fused EF hand domain arranges around the catalytic PPase domain. This unprecedented assembly evident from TbbVSP1 crystal structure is further confirmed by SAXS and TEM data. SAXS data suggest structural flexibility in EF hand domains indicative of conformational plasticity within TbbVSP1.

  6. Structural and Functional Highlights of Vacuolar Soluble Protein 1 from Pathogen Trypanosoma brucei brucei*

    Science.gov (United States)

    Jamwal, Abhishek; Round, Adam R.; Bannwarth, Ludovic; Venien-Bryan, Catherine; Belrhali, Hassan; Yogavel, Manickam; Sharma, Amit

    2015-01-01

    Trypanosoma brucei (T. brucei) is responsible for the fatal human disease called African trypanosomiasis, or sleeping sickness. The causative parasite, Trypanosoma, encodes soluble versions of inorganic pyrophosphatases (PPase), also called vacuolar soluble proteins (VSPs), which are localized to its acidocalcisomes. The latter are acidic membrane-enclosed organelles rich in polyphosphate chains and divalent cations whose significance in these parasites remains unclear. We here report the crystal structure of T. brucei brucei acidocalcisomal PPases in a ternary complex with Mg2+ and imidodiphosphate. The crystal structure reveals a novel structural architecture distinct from known class I PPases in its tetrameric oligomeric state in which a fused EF hand domain arranges around the catalytic PPase domain. This unprecedented assembly evident from TbbVSP1 crystal structure is further confirmed by SAXS and TEM data. SAXS data suggest structural flexibility in EF hand domains indicative of conformational plasticity within TbbVSP1. PMID:26494625

  7. Identification and characterization of hundreds of potent and selective inhibitors of Trypanosoma brucei growth from a kinase-targeted library screening campaign.

    Directory of Open Access Journals (Sweden)

    Rosario Diaz

    2014-10-01

    Full Text Available In the interest of identification of new kinase-targeting chemotypes for target and pathway analysis and drug discovery in Trypanosomal brucei, a high-throughput screen of 42,444 focused inhibitors from the GlaxoSmithKline screening collection was performed against parasite cell cultures and counter-screened against human hepatocarcinoma (HepG2 cells. In this way, we have identified 797 sub-micromolar inhibitors of T. brucei growth that are at least 100-fold selective over HepG2 cells. Importantly, 242 of these hit compounds acted rapidly in inhibiting cellular growth, 137 showed rapid cidality. A variety of in silico and in vitro physicochemical and drug metabolism properties were assessed, and human kinase selectivity data were obtained, and, based on these data, we prioritized three compounds for pharmacokinetic assessment and demonstrated parasitological cure of a murine bloodstream infection of T. brucei rhodesiense with one of these compounds (NEU-1053. This work represents a successful implementation of a unique industrial-academic collaboration model aimed at identification of high quality inhibitors that will provide the parasitology community with chemical matter that can be utilized to develop kinase-targeting tool compounds. Furthermore these results are expected to provide rich starting points for discovery of kinase-targeting tool compounds for T. brucei, and new HAT therapeutics discovery programs.

  8. Identification and characterization of hundreds of potent and selective inhibitors of Trypanosoma brucei growth from a kinase-targeted library screening campaign.

    Science.gov (United States)

    Diaz, Rosario; Luengo-Arratta, Sandra A; Seixas, João D; Amata, Emanuele; Devine, William; Cordon-Obras, Carlos; Rojas-Barros, Domingo I; Jimenez, Elena; Ortega, Fatima; Crouch, Sabrinia; Colmenarejo, Gonzalo; Fiandor, Jose Maria; Martin, Jose Julio; Berlanga, Manuela; Gonzalez, Silvia; Manzano, Pilar; Navarro, Miguel; Pollastri, Michael P

    2014-10-01

    In the interest of identification of new kinase-targeting chemotypes for target and pathway analysis and drug discovery in Trypanosomal brucei, a high-throughput screen of 42,444 focused inhibitors from the GlaxoSmithKline screening collection was performed against parasite cell cultures and counter-screened against human hepatocarcinoma (HepG2) cells. In this way, we have identified 797 sub-micromolar inhibitors of T. brucei growth that are at least 100-fold selective over HepG2 cells. Importantly, 242 of these hit compounds acted rapidly in inhibiting cellular growth, 137 showed rapid cidality. A variety of in silico and in vitro physicochemical and drug metabolism properties were assessed, and human kinase selectivity data were obtained, and, based on these data, we prioritized three compounds for pharmacokinetic assessment and demonstrated parasitological cure of a murine bloodstream infection of T. brucei rhodesiense with one of these compounds (NEU-1053). This work represents a successful implementation of a unique industrial-academic collaboration model aimed at identification of high quality inhibitors that will provide the parasitology community with chemical matter that can be utilized to develop kinase-targeting tool compounds. Furthermore these results are expected to provide rich starting points for discovery of kinase-targeting tool compounds for T. brucei, and new HAT therapeutics discovery programs.

  9. Translation Regulation and RNA Granule Formation after Heat Shock of Procyclic Form Trypanosoma brucei: Many Heat-Induced mRNAs Are also Increased during Differentiation to Mammalian-Infective Forms

    Science.gov (United States)

    Minia, Igor; Merce, Clementine; Terrao, Monica

    2016-01-01

    African trypanosome procyclic forms multiply in the midgut of tsetse flies, and are routinely cultured at 27°C. Heat shocks of 37°C and above result in general inhibition of translation, and severe heat shock (41°C) results in sequestration of mRNA in granules. The mRNAs that are bound by the zinc-finger protein ZC3H11, including those encoding refolding chaperones, escape heat-induced translation inhibition. At 27°C, ZC3H11 mRNA is predominantly present as an untranslated cytosolic messenger ribonucleoprotein particle, but after heat shocks of 37°C—41°C, the ZC3H11 mRNA moves into the polysomal fraction. To investigate the scope and specificities of heat-shock translational regulation and granule formation, we analysed the distributions of mRNAs on polysomes at 27°C and after 1 hour at 39°C, and the mRNA content of 41°C heat shock granules. We found that mRNAs that bind to ZC3H11 remained in polysomes at 39°C and were protected from sequestration in granules at 41°C. As previously seen for starvation stress granules, the mRNAs that encode ribosomal proteins were excluded from heat-shock granules. 70 mRNAs moved towards the polysomal fraction after the 39°C heat shock, and 260 increased in relative abundance. Surprisingly, many of these mRNAs are also increased when trypanosomes migrate to the tsetse salivary glands. It therefore seems possible that in the wild, temperature changes due to diurnal variations and periodic intake of warm blood might influence the efficiency with which procyclic forms develop into mammalian-infective forms. PMID:27606618

  10. Wild chimpanzees are infected by Trypanosoma brucei

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    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.

  11. A Protein Complex Map of Trypanosoma brucei.

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    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.

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

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    Matyáš Síma

    2011-06-01

    Full Text Available BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

  13. Parasite development and host responses during the establishment of Trypanosoma brucei infection transmitted by tsetse fly.

    Science.gov (United States)

    Barry, J D; Emergy, D L

    1984-02-01

    Following inoculation of Trypanosoma brucei into large mammals by the tsetse fly a local skin reaction, the 'chancre', develops due to trypanosome proliferation. We have cannulated the afferent and efferent lymphatics of the draining lymph node in goats and examined the onset of a cellular reaction, the emigration of the parasite from the chancre and the development of both antigenic variation and the specific immune response. The chancre first became detectable by day 3 post-infection, peaked by day 6 and then subsided. Lymphocyte output increased 6- to 8-fold by day 10 and the number of lymphoblasts increased 50-fold in this period. Both then declined. Trypanosomes were detected in lymph 1-2 days before the chancre, peaked by days 5-6, declined during development of the chancre and then peaked again. The bloodstream population appeared by days 4-5 and displayed different kinetics from that in lymph. Recirculation of parasites through the lymphatics ensued. Lymph-borne trypanosome populations were highly pleomorphic. Parasites in lymph expressed firstly a mixture of the Variable Antigen Types (VATs) which are found characteristically in the tsetse fly, this being followed by a mixture of other VATs. The two groups overlapped in appearance. In the bloodstream the same sequence of events occurred although 2 or 3 days later. The specific antibody response, as measured by radioimmunoassay and agglutination, arose within a few days of the first detection of each VAT. Activities appeared first in the lymph and then in plasma.

  14. 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

  15. Motility modes of the parasite Trypanosoma brucei

    Science.gov (United States)

    Temel, Fatma Zeynep; Qu, Zijie; McAllaster, Michael; de Graffenried, Christopher; Breuer, Kenneth

    2015-11-01

    The parasitic single-celled protozoan Trypanosoma brucei causes African Sleeping Sickness, which is a fatal disease in humans and animals that threatens more than 60 million people in 36 African countries. Cell motility plays a critical role in the developmental phases and dissemination of the parasite. Unlike many other motile cells such as bacteria Escherichia coli or Caulobacter crescentus, the flagellum of T. brucei is attached along the length of its awl-like body, producing a unique mode of motility that is not fully understood or characterized. Here, we report on the motility of T. brucei, which swims using its single flagellum employing both rotating and undulating propulsion modes. We tracked cells in real-time in three dimensions using fluorescent microscopy. Data obtained from experiments using both short-term tracking within the field of view and long-term tracking using a tracking microscope were analyzed. Motility modes and swimming speed were analyzed as functions of cell size, rotation rate and undulation pattern. Research supported by NSF.

  16. Screening North American plant extracts in vitro against Trypanosoma brucei, the causative agent for Human African Trypanosomiasis

    Science.gov (United States)

    Natural products extracts from 522 plants collected from different parts of the North America were screened in vitro against trypamastigote forms of Trypanosoma brucei. The active extracts(150)with >90% inhibition at 20ug/mL concentrations from the plants namely, Alnus rubra, Hoita macrostachya, S...

  17. Cell-penetrating peptide TP10 shows broad-spectrum activity against both Plasmodium falciparum and Trypanosoma brucei brucei.

    Science.gov (United States)

    Arrighi, Romanico B G; Ebikeme, Charles; Jiang, Yang; Ranford-Cartwright, Lisa; Barrett, Michael P; Langel, Ulo; Faye, Ingrid

    2008-09-01

    Malaria and trypanosomiasis are diseases which afflict millions and for which novel therapies are urgently required. We have tested two well-characterized cell-penetrating peptides (CPPs) for antiparasitic activity. One CPP, designated TP10, has broad-spectrum antiparasitic activity against Plasmodium falciparum, both blood and mosquito stages, and against blood-stage Trypanosoma brucei brucei.

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

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    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.

  19. Classical clinical signs in rats experimemtally infected with Trypanosoma brucei

    Institute of Scientific and Technical Information of China (English)

    Nwoha Rosemary Ijeoma Ogechi; Omamegbe Joseph Omolathebu

    2015-01-01

    Objective:To investigate clinical signs in Trypanosoma brucei infection in albino rats. Methods:Fourteen rats grouped into 2 with 7 rats in each group were used to determine classical clinical manifestation of Trypanosoma brucei infection in rats. Group A rats were uninfected control and Group B rats were infected with Trypanosoma brucei. Results:Parasitaemia was recorded in Group B by (3.86±0.34) d and the peak of parasitaemia was observed at Day 5 post infection. Classical signs observed included squint eyes, raised whiskers, lethargy, no weight loss, pyrexia, isolation from the other rats, and starry hair coat. Conclusions:These signs could be diagnostic or aid in diagnosis of Trypanosoma brucei infection in rats.

  20. Exosome secretion affects social motility in Trypanosoma brucei

    Science.gov (United States)

    Shaked, Hadassa; Arvatz, Gil; Tkacz, Itai Dov; Binder, Lior; Waldman Ben-Asher, Hiba; Okalang, Uthman; Chikne, Vaibhav; Cohen-Chalamish, Smadar; Michaeli, Shulamit

    2017-01-01

    Extracellular vesicles (EV) secreted by pathogens function in a variety of biological processes. Here, we demonstrate that in the protozoan parasite Trypanosoma brucei, exosome secretion is induced by stress that affects trans-splicing. Following perturbations in biogenesis of spliced leader RNA, which donates its spliced leader (SL) exon to all mRNAs, or after heat-shock, the SL RNA is exported to the cytoplasm and forms distinct granules, which are then secreted by exosomes. The exosomes are formed in multivesicular bodies (MVB) utilizing the endosomal sorting complexes required for transport (ESCRT), through a mechanism similar to microRNA secretion in mammalian cells. Silencing of the ESCRT factor, Vps36, compromised exosome secretion but not the secretion of vesicles derived from nanotubes. The exosomes enter recipient trypanosome cells. Time-lapse microscopy demonstrated that cells secreting exosomes or purified intact exosomes affect social motility (SoMo). This study demonstrates that exosomes are delivered to trypanosome cells and can change their migration. Exosomes are used to transmit stress signals for communication between parasites. PMID:28257521

  1. Proteomics and the Trypanosoma brucei cytoskeleton: advances and opportunities.

    Science.gov (United States)

    Portman, Neil; Gull, Keith

    2012-08-01

    Trypanosoma brucei is the etiological agent of devastating parasitic disease in humans and livestock in sub-saharan Africa. The pathogenicity and growth of the parasite are intimately linked to its shape and form. This is in turn derived from a highly ordered microtubule cytoskeleton that forms a tightly arrayed cage directly beneath the pellicular membrane and numerous other cytoskeletal structures such as the flagellum. The parasite undergoes extreme changes in cellular morphology during its life cycle and cell cycles which require a high level of integration and coordination of cytoskeletal processes. In this review we will discuss the role that proteomics techniques have had in advancing our understanding of the molecular composition of the cytoskeleton and its functions. We then consider future opportunities for the application of these techniques in terms of addressing some of the unanswered questions of trypanosome cytoskeletal cell biology with particular focus on the differences in the composition and organisation of the cytoskeleton through the trypanosome life-cycle.

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

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    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.

  3. 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.

  4. Computer algorithms to detect bloodstream infections.

    Science.gov (United States)

    Trick, William E; Zagorski, Brandon M; Tokars, Jerome I; Vernon, Michael O; Welbel, Sharon F; Wisniewski, Mary F; Richards, Chesley; Weinstein, Robert A

    2004-09-01

    We compared manual and computer-assisted bloodstream infection surveillance for adult inpatients at two hospitals. We identified hospital-acquired, primary, central-venous catheter (CVC)-associated bloodstream infections by using five methods: retrospective, manual record review by investigators; prospective, manual review by infection control professionals; positive blood culture plus manual CVC determination; computer algorithms; and computer algorithms and manual CVC determination. We calculated sensitivity, specificity, predictive values, plus the kappa statistic (kappa) between investigator review and other methods, and we correlated infection rates for seven units. The kappa value was 0.37 for infection control review, 0.48 for positive blood culture plus manual CVC determination, 0.49 for computer algorithm, and 0.73 for computer algorithm plus manual CVC determination. Unit-specific infection rates, per 1,000 patient days, were 1.0-12.5 by investigator review and 1.4-10.2 by computer algorithm (correlation r = 0.91, p = 0.004). Automated bloodstream infection surveillance with electronic data is an accurate alternative to surveillance with manually collected data.

  5. Effect of ivermectin on Trypanosoma brucei brucei in experimentally infected mice

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    Udensi K. Udensi & A.F. Fagbenro-Beyioku

    2012-09-01

    Full Text Available Background & objectives: Human and livestock African trypanosomiasis, otherwise known as sleeping sickness,is a neglected tropical disease of public health importance in west and central Africa. In view of the adverse sideeffects of the antitrypanosomal drugs, the relatively few side effects observed in ivermectin use, and becauseboth onchocerciasis and typanosomiasis occur in overlapping foci in Africa, it would be desirable if the ivermectinthat has been used successfully on onchocerciasis management could also be used in the control and treatmentof trypanosomiasis.Method: In this study, prophylactic and therapeutic effects of ivermectin (Mectizan were investigated in albinomice infected with a Nigerian strain of Trypanosoma brucei brucei.Results: A 300 μg/ml/kg dose had the most effective impact because it showed the highest mean survival time of12 days in both the treatment and prophylactic groups of mice. This dose also enhanced the defence capacity ofthe treated groups. It also had positive influence on the packed cell volume (PCV and the state of anaemia inthe trypanosome infected mice, hence, improving their survivability.Interpretation & conclusions: Our report indicates that using the 300 μg/ml/kg dose of ivermectin increases themean survival period from 5 to 12 days. This suggests that ivermectin could be possibly used in the treatment oftrypanosomiasis. Further studies will be required to show whether proper treatment may entail a single dose, asused in this study; an increased number of doses, or combinations with other drugs.

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

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    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.

  7. 布氏锥虫葡糖基磷脂酰肌醇(GPI)的研究进展%RESEARCH PROSPECTS ON GLYCOSYLPHOSPHATIDYLINOSITOL (GPI) OF TRYPANOSOMA BRUCEI

    Institute of Scientific and Technical Information of China (English)

    原丽红; 林本夫; 王祥生; 李莲瑞

    2004-01-01

    布氏锥虫(Trypanosoma brucei)是一种原虫性寄生虫,通过采采蝇(tsets fly)的传播感染人和其它哺乳动物,导致人的昏睡病和家畜的那卡那病。布氏锥虫有两个截然不同的生活阶段,即血液期(bloodstream stage,寄生于哺乳动物血细胞内)和昆虫期(insect stage,又叫循环期或感染期,寄生于采采蝇的中肠内)。

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

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    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.

  9. Scanning and three-dimensional electron microscopy methods for the study of Trypanosoma brucei and Leishmania mexicana flagella.

    Science.gov (United States)

    Gluenz, Eva; Wheeler, Richard John; Hughes, Louise; Vaughan, Sue

    2015-01-01

    Three-dimensional electron microscopy tools have revolutionized our understanding of cell structure and molecular complexes in biology. Here, we describe methods for studying flagellar ultrastructure and biogenesis in two unicellular parasites-Trypanosoma brucei and Leishmania mexicana. We describe methods for the preparation of these parasites for scanning electron microscopy cellular electron tomography, and serial block face scanning electron microscopy (SBFSEM). These parasites have a highly ordered cell shape and form, with a defined positioning of internal cytoskeletal structures and organelles. We show how knowledge of these can be used to dissect cell cycles in both parasites and identify the old flagellum from the new in T. brucei. Finally, we demonstrate the use of SBFSEM three-dimensional models for analysis of individual whole cells, demonstrating the excellent potential this technique has for future studies of mutant cell lines.

  10. TbFlabarin, a flagellar protein of Trypanosoma brucei, highlights differences between Leishmania and Trypanosoma flagellar-targeting signals.

    Science.gov (United States)

    Tetaud, Emmanuel; Lefebvre, Michèle; M'Bang-Benet, Diane-Ethna; Crobu, Lucien; Blancard, Corinne; Sterkers, Yvon; Pages, Michel; Bastien, Patrick; Merlin, Gilles

    2016-07-01

    TbFlabarin is the Trypanosoma brucei orthologue of the Leishmania flagellar protein LdFlabarin but its sequence is 33% shorter than LdFlabarin, as it lacks a C-terminal domain that is indispensable for LdFlabarin to localize to the Leishmania flagellum. TbFlabarin is mainly expressed in the procyclic forms of the parasite and localized to the flagellum, but only when two palmitoylable cysteines at positions 3 and 4 are present. TbFlabarin is more strongly attached to the membrane fraction than its Leishmania counterpart, as it resists complete solubilization with as much as 0.5% NP-40. Expression ablation by RNA interference did not change parasite growth in culture, its morphology or apparent motility. Heterologous expression showed that neither TbFlabarin in L. amazonensis nor LdFlabarin in T. brucei localized to the flagellum, revealing non-cross-reacting targeting signals between the two species.

  11. Dynein Light Chain LC8 Is Required for RNA Polymerase I-Mediated Transcription in Trypanosoma brucei, Facilitating Assembly and Promoter Binding of Class I Transcription Factor A.

    Science.gov (United States)

    Kirkham, Justin K; Park, Sung Hee; Nguyen, Tu N; Lee, Ju Huck; Günzl, Arthur

    2016-01-01

    Dynein light chain LC8 is highly conserved among eukaryotes and has both dynein-dependent and dynein-independent functions. Interestingly, LC8 was identified as a subunit of the class I transcription factor A (CITFA), which is essential for transcription by RNA polymerase I (Pol I) in the parasite Trypanosoma brucei. Given that LC8 has never been identified with a basal transcription factor and that T. brucei relies on RNA Pol I for expressing the variant surface glycoprotein (VSG), the key protein in antigenic variation, we investigated the CITFA-specific role of LC8. Depletion of LC8 from mammalian-infective bloodstream trypanosomes affected cell cycle progression, reduced the abundances of rRNA and VSG mRNA, and resulted in rapid cell death. Sedimentation analysis, coimmunoprecipitation of recombinant proteins, and bioinformatic analysis revealed an LC8 binding site near the N terminus of the subunit CITFA2. Mutation of this site prevented the formation of a CITFA2-LC8 heterotetramer and, in vivo, was lethal, affecting assembly of a functional CITFA complex. Gel shift assays and UV cross-linking experiments identified CITFA2 as a promoter-binding CITFA subunit. Accordingly, silencing of LC8 or CITFA2 resulted in a loss of CITFA from RNA Pol I promoters. Hence, we discovered an LC8 interaction that, unprecedentedly, has a basal function in transcription.

  12. Nanomolar Inhibitors of Trypanosoma brucei RNA Triphosphatase

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    Paul Smith

    2016-02-01

    Full Text Available Eukaryal taxa differ with respect to the structure and mechanism of the RNA triphosphatase (RTPase component of the mRNA capping apparatus. Protozoa, fungi, and certain DNA viruses have a metal-dependent RTPase that belongs to the triphosphate tunnel metalloenzyme (TTM superfamily. Because the structures, active sites, and chemical mechanisms of the TTM-type RTPases differ from those of mammalian RTPases, the TTM RTPases are potential targets for antiprotozoal, antifungal, and antiviral drug discovery. Here, we employed RNA interference (RNAi knockdown methods to show that Trypanosoma brucei RTPase Cet1 (TbCet1 is necessary for proliferation of procyclic cells in culture. We then conducted a high-throughput biochemical screen for small-molecule inhibitors of the phosphohydrolase activity of TbCet1. We identified several classes of chemicals—including chlorogenic acids, phenolic glycopyranosides, flavonoids, and other phenolics—that inhibit TbCet1 with nanomolar to low-micromolar 50% inhibitory concentrations (IC50s. We confirmed the activity of these compounds, and tested various analogs thereof, by direct manual assays of TbCet1 phosphohydrolase activity. The most potent nanomolar inhibitors included tetracaffeoylquinic acid, 5-galloylgalloylquinic acid, pentagalloylglucose, rosmarinic acid, and miquelianin. TbCet1 inhibitors were less active (or inactive against the orthologous TTM-type RTPases of mimivirus, baculovirus, and budding yeast (Saccharomyces cerevisiae. Our results affirm that a TTM RTPase is subject to potent inhibition by small molecules, with the caveat that parallel screens against TTM RTPases from multiple different pathogens may be required to fully probe the chemical space of TTM inhibition.

  13. 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...

  14. Comparative genomics reveals two novel RNAi factors in Trypanosoma brucei and provides insight into the core machinery.

    Directory of Open Access Journals (Sweden)

    Rebecca L Barnes

    Full Text Available The introduction ten years ago of RNA interference (RNAi as a tool for molecular exploration in Trypanosoma brucei has led to a surge in our understanding of the pathogenesis and biology of this human parasite. In particular, a genome-wide RNAi screen has recently been combined with next-generation Illumina sequencing to expose catalogues of genes associated with loss of fitness in distinct developmental stages. At present, this technology is restricted to RNAi-positive protozoan parasites, which excludes T. cruzi, Leishmania major, and Plasmodium falciparum. Therefore, elucidating the mechanism of RNAi and identifying the essential components of the pathway is fundamental for improving RNAi efficiency in T. brucei and for transferring the RNAi tool to RNAi-deficient pathogens. Here we used comparative genomics of RNAi-positive and -negative trypanosomatid protozoans to identify the repertoire of factors in T. brucei. In addition to the previously characterized Argonaute 1 (AGO1 protein and the cytoplasmic and nuclear Dicers, TbDCL1 and TbDCL2, respectively, we identified the RNA Interference Factors 4 and 5 (TbRIF4 and TbRIF5. TbRIF4 is a 3'-5' exonuclease of the DnaQ superfamily and plays a critical role in the conversion of duplex siRNAs to the single-stranded form, thus generating a TbAGO1-siRNA complex required for target-specific cleavage. TbRIF5 is essential for cytoplasmic RNAi and appears to act as a TbDCL1 cofactor. The availability of the core RNAi machinery in T. brucei provides a platform to gain mechanistic insights in this ancient eukaryote and to identify the minimal set of components required to reconstitute RNAi in RNAi-deficient parasites.

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

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    Elizabeth R Sharlow

    Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: The novel chemotypes identified here could represent leads for future therapeutic development against the African trypanosome.

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

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    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.

  17. Bloodstream infections in HIV-infected patients.

    Science.gov (United States)

    Taramasso, Lucia; Tatarelli, Paola; Di Biagio, Antonio

    2016-04-02

    In the combined antiretroviral therapy era, HIV-infected patients remain a vulnerable population for the onset of bloodstream infections (BSI). Worldwide, nontyphoid salmonellae, Streptococcus pneumoniae, Escherichia coli, Staphylococcus aureus and coagulase negative staphylococci are the most important pathogens. Intravenous catheter associated infection, skin-soft tissue infection and endocarditis are associated with Gram-positive bacteremia. Among the Gram-negative, nontyphoidal Salmonella have been previously correlated to sepsis. Other causes of BSI in HIV-infected patients are mycobacteria and fungi. Mycobacteria constitute a major cause of BSI in limited resource countries. Fungal BSI are not frequent and among them Cryptococcus neoformans is the most common life-threatening infection. The degree of immunosuppression remains the key prognostic factor leading to the development of BSI.

  18. In vitro antitrypanosomal activity of plant terpenes against Trypanosoma brucei.

    Science.gov (United States)

    Otoguro, Kazuhiko; Iwatsuki, Masato; Ishiyama, Aki; Namatame, Miyuki; Nishihara-Tukashima, Aki; Kiyohara, Hiroaki; Hashimoto, Toshihiro; Asakawa, Yoshinori; Omura, Satoshi; Yamada, Haruki

    2011-11-01

    During the course of screening to discover antitrypanosomal compounds, 24 known plant terpenes (6 sesquiterpenes, 14 sesquiterpene lactones and 4 diterpenes) were evaluated for in vitro antitrypanosomal activity against Trypanosoma brucei brucei. Among them, 22 terpenes exhibited antitrypanosomal activity. In particular, α-eudesmol, hinesol, nardosinone and 4-peroxy-1,2,4,5-tetrahydro-α-santonin all exhibited selective and potent antitrypanosomal activities in vitro. Detailed here in an in vitro antitrypanosomal properties and cytotoxicities of the 24 terpenes compared with two therapeutic antitrypanosomal drugs (eflornithine and suramin). This finding represents the first report of promising trypanocidal activity of these terpenes. Present results also provide some valuable insight with regard to structure-activity relationships and the possible mode of action of the compounds.

  19. 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.

  20. Processing of the glycosomal matrix-protein import receptor PEX5 of Trypanosoma brucei

    Energy Technology Data Exchange (ETDEWEB)

    Gualdrón-López, Melisa [Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Brussels (Belgium); Michels, Paul A.M., E-mail: paul.michels@uclouvain.be [Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Brussels (Belgium)

    2013-02-01

    Highlights: ► Most eukaryotic cells have a single gene for the peroxin PEX5. ► PEX5 is sensitive to in vitro proteolysis in distantly related organisms. ► TbPEX5 undergoes N-terminal truncation in vitro and possibly in vivo. ► Truncated TbPEX5 is still capable of binding PTS1-containing proteins. ► PEX5 truncation is physiologically relevant or an evolutionary conserved artifact. -- Abstract: Glycolysis in kinetoplastid protists such as Trypanosoma brucei is compartmentalized in peroxisome-like organelles called glycosomes. Glycosomal matrix-protein import involves a cytosolic receptor, PEX5, which recognizes the peroxisomal-targeting signal type 1 (PTS1) present at the C-terminus of the majority of matrix proteins. PEX5 appears generally susceptible to in vitro proteolytic processing. On western blots of T. brucei, two PEX5 forms are detected with apparent M{sub r} of 100 kDa and 72 kDa. 5′-RACE-PCR showed that TbPEX5 is encoded by a unique transcript that can be translated into a protein of maximally 72 kDa. However, recombinant PEX5 migrates aberrantly in SDS–PAGE with an apparent M{sub r} of 100 kDa, similarly as observed for the native peroxin. In vitro protease susceptibility analysis of native and {sup 35}S-labelled PEX5 showed truncation of the 100 kDa form at the N-terminal side by unknown parasite proteases, giving rise to the 72 kDa form which remains functional for PTS1 binding. The relevance of these observations is discussed.

  1. Intraclonal mating occurs during tsetse transmission of Trypanosoma brucei

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    Ferris Vanessa

    2009-09-01

    Full Text Available Abstract Background Mating in Trypanosoma brucei is a non-obligatory event, triggered by the co-occurrence of different strains in the salivary glands of the vector. Recombinants that result from intra- rather than interclonal mating have been detected, but only in crosses of two different trypanosome strains. This has led to the hypothesis that when trypanosomes recognize a different strain, they release a diffusible factor or pheromone that triggers mating in any cell in the vicinity whether it is of the same or a different strain. This idea assumes that the trypanosome can recognize self and non-self, although there is as yet no evidence for the existence of mating types in T. brucei. Results We investigated intraclonal mating in T. b. brucei by crossing red and green fluorescent lines of a single strain, so that recombinant progeny can be detected in the fly by yellow fluorescence. For strain 1738, seven flies had both red and green trypanosomes in the salivary glands and, in three, yellow trypanosomes were also observed, although they could not be recovered for subsequent analysis. Nonetheless, both red and non-fluorescent clones from these flies had recombinant genotypes as judged by microsatellite and karyotype analyses, and some also had raised DNA contents, suggesting recombination or genome duplication. Strain J10 produced similar results indicative of intraclonal mating. In contrast, trypanosome clones recovered from other flies showed that genotypes can be transmitted with fidelity. When a yellow hybrid clone expressing both red and green fluorescent protein genes was transmitted, the salivary glands contained a mixture of fluorescent-coloured trypanosomes, but only yellow and red clones were recovered. While loss of the GFP gene in the red clones could have resulted from gene conversion, some of these clones showed loss of heterozygosity and raised DNA contents as in the other single strain transmissions. Our observations suggest

  2. 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.

  3. When Prostate Cancer Circulates in the Bloodstream

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    Virginie Vlaeminck-Guillem

    2015-10-01

    Full Text Available Management of patients with prostate cancer is currently based on imperfect clinical, biological, radiological and pathological evaluation. Prostate cancer aggressiveness, including metastatic potential, remains difficult to accurately estimate. In an attempt to better adapt therapeutics to an individual (personalized medicine, reliable evaluation of the intrinsic molecular biology of the tumor is warranted, and particularly for all tumor sites (primary tumors and secondary sites at any time of the disease progression. As a consequence of their natural tendency to grow (passive invasion or as a consequence of an active blood vessel invasion by metastase-initiating cells, tumors shed various materials into the bloodstream. Major efforts have been recently made to develop powerful and accurate methods able to detect, quantify and/or analyze all these circulating tumor materials: circulating tumors cells, disseminating tumor cells, extracellular vesicles (including exosomes, nucleic acids, etc. The aim of this review is to summarize current knowledge about these circulating tumor materials and their applications in translational research.

  4. Rab23 is a flagellar protein in Trypanosoma brucei

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    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.

  5. Selective inhibition of 6-phosphogluconate dehydrogenase from Trypanosoma brucei

    Science.gov (United States)

    Bertelli, Massimo; El-Bastawissy, Eman; Knaggs, Michael H.; Barrett, Michael P.; Hanau, Stefania; Gilbert, Ian H.

    2001-05-01

    A number of triphenylmethane derivatives have been screened against 6-phosphogluconate dehydrogenase from Trypanosoma brucei and sheep liver. Some of these compounds show good inhibition of the enzymes and also selectivity towards the parasite enzyme. Modelling was undertaken to dock the compounds into the active sites of both enzymes. Using a combination of DOCK 3.5 and FLEXIDOCK a correlation was obtained between docking score and both activity for the enzymes and selectivity. Visualisation of the docked structures of the inhibitors in the active sites of the enzymes yielded a possible explanation of the selectivity for the parasite enzyme.

  6. 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.

  7. 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 th

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

    Science.gov (United States)

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

    2015-11-01

    The flagellate Trypanosoma brucei causes sleeping sickness in humans and nagana in animals. Only a few drugs are registered to treat trypanosomiasis, but those drugs show severe side effects. Also, because some pathogen strains have become resistant, new strategies are urgently needed to combat this parasitic disease. An underexplored possibility is the application of combinations of several trypanocidal agents, which may potentiate their trypanocidal activity in a synergistic fashion. 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. Alkaloids were selected that affect different molecular targets: berberine and chelerythrine (intercalation of DNA), piperine (induction of apoptosis), vinblastine (inhibition of microtubule assembly), emetine (intercalation of DNA, inhibition of protein biosynthesis), homoharringtonine (inhibition of protein biosynthesis), and digitonin (membrane permeabilization and uptake facilitation of polar compounds). Most combinations resulted in an enhanced trypanocidal effect. The addition of digitonin significantly stimulated the activity of almost all alkaloids against trypanosomes. The strongest effect was measured in a combination of digitonin with vinblastine. The highest dose reduction indexes (DRI) were measured in the two-drug combination of digitonin or piperine with vinblastine, where the dose of vinblastine could be reduced 9.07-fold or 7.05-fold, respectively. The synergistic effects of mutual combinations of alkaloids and of alkaloids with digitonin present a new avenue to treat trypanosomiasis but one which needs to be corroborated in future animal experiments.

  9. 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.

  10. SAS-4 Protein in Trypanosoma brucei Controls Life Cycle Transitions by Modulating the Length of the Flagellum Attachment Zone Filament.

    Science.gov (United States)

    Hu, Huiqing; Zhou, Qing; Li, Ziyin

    2015-12-18

    The evolutionarily conserved centriole/basal body protein SAS-4 regulates centriole duplication in metazoa and basal body duplication in flagellated and ciliated organisms. Here, we report that the SAS-4 homolog in the flagellated protozoan Trypanosoma brucei, TbSAS-4, plays an unusual role in controlling life cycle transitions by regulating the length of the flagellum attachment zone (FAZ) filament, a specialized cytoskeletal structure required for flagellum adhesion and cell morphogenesis. TbSAS-4 is concentrated at the distal tip of the FAZ filament, and depletion of TbSAS-4 in the trypomastigote form disrupts the elongation of the new FAZ filament, generating cells with a shorter FAZ associated with a longer unattached flagellum and repositioned kinetoplast and basal body, reminiscent of epimastigote-like morphology. Further, we show that TbSAS-4 associates with six additional FAZ tip proteins, and depletion of TbSAS-4 disrupts the enrichment of these FAZ tip proteins at the new FAZ tip, suggesting a role of TbSAS-4 in maintaining the integrity of this FAZ tip protein complex. Together, these results uncover a novel function of TbSAS-4 in regulating the length of the FAZ filament to control basal body positioning and life cycle transitions in T. brucei.

  11. The changing epidemiology of Staphylococcus aureus bloodstream infection

    DEFF Research Database (Denmark)

    Laupland, K B; Lyytikäinen, O; Søgaard, M;

    2012-01-01

    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...

  12. 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

  13. Neonatal bloodstream infections in a pediatric hospital in Vietnam

    DEFF Research Database (Denmark)

    Kruse, Alexandra Yasmin; Thieu Chuong, D.H.; Phuong, C.N.;

    2013-01-01

    Septicemia and bloodstream infections (BSIs) are major causes of neonatal morbidity and mortality in developing countries. We prospectively recorded all positive blood cultures (BSI) among neonates admitted consecutively to a tertiary pediatric hospital in Vietnam during a 12-month period. Among...

  14. 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.

  15. Mosaic VSGs and the scale of Trypanosoma brucei antigenic variation.

    Directory of Open Access Journals (Sweden)

    James P J Hall

    Full Text Available A main determinant of prolonged Trypanosoma brucei infection and transmission and success of the parasite is the interplay between host acquired immunity and antigenic variation of the parasite variant surface glycoprotein (VSG coat. About 0.1% of trypanosome divisions produce a switch to a different VSG through differential expression of an archive of hundreds of silent VSG genes and pseudogenes, but the patterns and extent of the trypanosome diversity phenotype, particularly in chronic infection, are unclear. We applied longitudinal VSG cDNA sequencing to estimate variant richness and test whether pseudogenes contribute to antigenic variation. We show that individual growth peaks can contain at least 15 distinct variants, are estimated computationally to comprise many more, and that antigenically distinct 'mosaic' VSGs arise from segmental gene conversion between donor VSG genes or pseudogenes. The potential for trypanosome antigenic variation is probably much greater than VSG archive size; mosaic VSGs are core to antigenic variation and chronic infection.

  16. Pathogenesis of anemia in Trypanosoma brucei-infected mice.

    Science.gov (United States)

    Amole, B O; Clarkson, A B; Shear, H L

    1982-01-01

    The pathogenesis of anemia was studied in trypanosome-infected mice. A strain of Trypanosoma brucei, TREU 667, was used which first produces an acute phase marked by waves of parasitemia. Erythrocytes from infected animals were coated with immunoglobulin M during or just before the waves of anemia and parasitological crises. Erythrocytes from normal animals could be sensitized with "precrisis" sera presumably containing antigen and antibody. These data suggest that anemia during the acute phase is due to sensitization of erythrocytes with immunoglobulin M-antigen complexes. The anemia is partially compensated by a strong erythropoietic response. The acute phase is followed by a chronic phase marked by a constant high parasitemia and immunosuppression. The less marked anemia occurring during this latter phase is due to hemodilution and perhaps a low but significant immune response to the parasites, which causes continuing erythrocyte sensitization by immunoglobulin M-antigen complexes. PMID:7201455

  17. Trypanosoma brucei: a putative RNA polymerase II promoter.

    Science.gov (United States)

    Bayele, Henry K

    2009-12-01

    RNA polymerase II (pol II) promoters are rare in the African trypanosome Trypanosoma brucei because gene regulation in the parasite is complex and polycistronic. Here, we describe a putative pol II promoter and its structure-function relationship. The promoter has features of an archetypal eukaryotic pol II promoter including putative canonical CCAAT and TATA boxes, and an initiator element. However, the spatial arrangement of these elements is only similar to yeast pol II promoters. Deletion mapping and transcription assays enabled delineation of a minimal promoter that could drive orientation-independent reporter gene expression suggesting that it may be a bidirectional promoter. In vitro transcription in a heterologous nuclear extract revealed that the promoter can be recognized by the basal eukaryotic transcription complex. This suggests that the transcription machinery in the parasite may be very similar to those of other eukaryotes.

  18. 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.

  19. Central line-associated bloodstream infections: prevention and management.

    Science.gov (United States)

    Weber, David J; Rutala, William A

    2011-03-01

    Approximately 80,000 central venous line-associated bloodstream infections (CLA-BSI) occur in the United States each year. CLA-BSI is most commonly caused by coagulase-negative staphylococci, Staphylococcus aureus, Candida spp, and aerobic gram-negative bacilli. These organisms commonly gain entrance in into the bloodstream via the catheter-skin interface (insertion site) or via the catheter hub. Use of strict aseptic technique for insertion is the key method for the prevention of CLA-BSI. Various methods can be used to reduce unacceptably high rates of CLA-BSI, including use of an antiseptic- or antibiotic-impregnated catheter, daily chlorhexidine baths/washes, and placement of a chlorhexidine-impregnated sponge over the insertion site.

  20. Prosthetic valve endocarditis and bloodstream infection due to Mycobacterium chimaera.

    Science.gov (United States)

    Achermann, Yvonne; Rössle, Matthias; Hoffmann, Matthias; Deggim, Vanessa; Kuster, Stefan; Zimmermann, Dieter R; Bloemberg, Guido; Hombach, Michael; Hasse, Barbara

    2013-06-01

    Prosthetic valve endocarditis (PVE) due to fast-growing nontuberculous mycobacteria (NTM) has been reported anecdotally. Reports of PVE with slowly growing NTM, however, are lacking. We present here one case of PVE and one case of bloodstream infection caused by Mycobacterium chimaera. Randomly amplified polymorphic DNA (RAPD)-PCR indicated a relatedness of the two M. chimaera strains. Both patients had heart surgery 2 years apart from each other. A nosocomial link was not detected.

  1. Prosthetic Valve Endocarditis and Bloodstream Infection Due to Mycobacterium chimaera

    OpenAIRE

    Achermann, Yvonne; Rössle, Matthias; Hoffmann, Matthias; Deggim, Vanessa; Kuster, Stefan; Zimmermann, Dieter R.; Bloemberg, Guido; Hombach, Michael; Hasse, Barbara

    2013-01-01

    Prosthetic valve endocarditis (PVE) due to fast-growing nontuberculous mycobacteria (NTM) has been reported anecdotally. Reports of PVE with slowly growing NTM, however, are lacking. We present here one case of PVE and one case of bloodstream infection caused by Mycobacterium chimaera. Randomly amplified polymorphic DNA (RAPD)-PCR indicated a relatedness of the two M. chimaera strains. Both patients had heart surgery 2 years apart from each other. A nosocomial link was not detected.

  2. Endothelial JAM-A promotes reovirus viremia and bloodstream dissemination.

    Science.gov (United States)

    Lai, Caroline M; Boehme, Karl W; Pruijssers, Andrea J; Parekh, Vrajesh V; Van Kaer, Luc; Parkos, Charles A; Dermody, Terence S

    2015-02-01

    Viruses that cause systemic disease often spread through the bloodstream to infect target tissues. Although viremia is an important step in the pathogenesis of many viruses, how viremia is established is not well understood. Reovirus has been used to dissect mechanisms of viral pathogenesis and is being evaluated in clinical trials as an oncolytic agent. After peroral entry into mice, reovirus replicates within the gastrointestinal tract and disseminates systemically via hematogenous or neural routes. Junctional adhesion molecule-A (JAM-A) is a tight junction protein that serves as a receptor for reovirus. JAM-A is required for establishment of viremia and viral spread to sites of secondary replication. JAM-A also is expressed on the surface of circulating hematopoietic cells. To determine contributions of endothelial and hematopoietic JAM-A to reovirus dissemination and pathogenesis, we generated strains of mice with altered JAM-A expression in these cell types and assessed bloodstream spread of reovirus strain type 1 Lang (T1L), which disseminates solely by hematogenous routes. We found that endothelial JAM-A but not hematopoietic JAM-A facilitates reovirus T1L bloodstream entry and egress. Understanding how viruses establish viremia may aid in development of inhibitors of this critical step in viral pathogenesis and foster engineering of improved oncolytic viral vectors.

  3. 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.

  4. Association of a novel preribosomal complex in Trypanosoma brucei determined by fluorescence resonance energy transfer.

    Science.gov (United States)

    Wang, Lei; Ciganda, Martin; Williams, Noreen

    2013-02-01

    We have previously reported that the trypanosome-specific proteins P34 and P37 form a unique preribosomal complex with ribosomal protein L5 and 5S rRNA in the nucleoplasm. We hypothesize that this novel trimolecular complex is necessary for stabilizing 5S rRNA in Trypanosoma brucei and is essential for the survival of the parasite. In vitro quantitative analysis of the association between the proteins L5 and P34 is fundamental to our understanding of this novel complex and thus our ability to exploit its unique characteristics. Here we used in vitro fluorescence resonance energy transfer (FRET) to analyze the association between L5 and P34. First, we demonstrated that FRET can be used to confirm the association between L5 and P34. We then determined that the binding constant for L5 and P34 is 0.60 ± 0.03 μM, which is in the range of protein-protein binding constants for RNA binding proteins. In addition, we used FRET to identify the critical regions of L5 and P34 involved in the protein-protein association. We found that the N-terminal APK-rich domain and RNA recognition motif (RRM) of P34 and the L18 domain of L5 are important for the association of the two proteins with each other. These results provide us with the framework for the discovery of ways to disrupt this essential complex.

  5. Genome-wide dissection of the quorum sensing signalling pathway in Trypanosoma brucei.

    Science.gov (United States)

    Mony, Binny M; MacGregor, Paula; Ivens, Alasdair; Rojas, Federico; Cowton, Andrew; Young, Julie; Horn, David; Matthews, Keith

    2014-01-30

    The protozoan parasites Trypanosoma brucei spp. cause important human and livestock diseases in sub-Saharan Africa. In mammalian blood, two developmental forms of the parasite exist: proliferative 'slender' forms and arrested 'stumpy' forms that are responsible for transmission to tsetse flies. The slender to stumpy differentiation is a density-dependent response that resembles quorum sensing in microbial systems and is crucial for the parasite life cycle, ensuring both infection chronicity and disease transmission. This response is triggered by an elusive 'stumpy induction factor' (SIF) whose intracellular signalling pathway is also uncharacterized. Laboratory-adapted (monomorphic) trypanosome strains respond inefficiently to SIF but can generate forms with stumpy characteristics when exposed to cell-permeable cAMP and AMP analogues. Exploiting this, we have used a genome-wide RNA interference library screen to identify the signalling components driving stumpy formation. In separate screens, monomorphic parasites were exposed to 8-(4-chlorophenylthio)-cAMP (pCPT-cAMP) or 8-pCPT-2'-O-methyl-5'-AMP to select cells that were unresponsive to these signals and hence remained proliferative. Genome-wide Ion Torrent based RNAi target sequencing identified cohorts of genes implicated in each step of the signalling pathway, from purine metabolism, through signal transducers (kinases, phosphatases) to gene expression regulators. Genes at each step were independently validated in cells naturally capable of stumpy formation, confirming their role in density sensing in vivo. The putative RNA-binding protein, RBP7, was required for normal quorum sensing and promoted cell-cycle arrest and transmission competence when overexpressed. This study reveals that quorum sensing signalling in trypanosomes shares similarities to fundamental quiescence pathways in eukaryotic cells, its components providing targets for quorum-sensing interference-based therapeutics.

  6. MIF Contributes to Trypanosoma brucei Associated Immunopathogenicity Development

    Science.gov (United States)

    Stijlemans, Benoît; Leng, Lin; Brys, Lea; Sparkes, Amanda; Vansintjan, Liese; Caljon, Guy; Raes, Geert; Van Den Abbeele, Jan; Van Ginderachter, Jo A.; Beschin, Alain

    2014-01-01

    African trypanosomiasis is a chronic debilitating disease affecting the health and economic well-being of many people in developing countries. The pathogenicity associated with this disease involves a persistent inflammatory response, whereby M1-type myeloid cells, including Ly6Chigh inflammatory monocytes, are centrally implicated. A comparative gene analysis between trypanosusceptible and trypanotolerant animals identified MIF (macrophage migrating inhibitory factor) as an important pathogenic candidate molecule. Using MIF-deficient mice and anti-MIF antibody treated mice, we show that MIF mediates the pathogenic inflammatory immune response and increases the recruitment of inflammatory monocytes and neutrophils to contribute to liver injury in Trypanosoma brucei infected mice. Moreover, neutrophil-derived MIF contributed more significantly than monocyte-derived MIF to increased pathogenic liver TNF production and liver injury during trypanosome infection. MIF deficient animals also featured limited anemia, coinciding with increased iron bio-availability, improved erythropoiesis and reduced RBC clearance during the chronic phase of infection. Our data suggest that MIF promotes the most prominent pathological features of experimental trypanosome infections (i.e. anemia and liver injury), and prompt considering MIF as a novel target for treatment of trypanosomiasis-associated immunopathogenicity. PMID:25255103

  7. MIF contributes to Trypanosoma brucei associated immunopathogenicity development.

    Directory of Open Access Journals (Sweden)

    Benoît Stijlemans

    2014-09-01

    Full Text Available African trypanosomiasis is a chronic debilitating disease affecting the health and economic well-being of many people in developing countries. The pathogenicity associated with this disease involves a persistent inflammatory response, whereby M1-type myeloid cells, including Ly6C(high inflammatory monocytes, are centrally implicated. A comparative gene analysis between trypanosusceptible and trypanotolerant animals identified MIF (macrophage migrating inhibitory factor as an important pathogenic candidate molecule. Using MIF-deficient mice and anti-MIF antibody treated mice, we show that MIF mediates the pathogenic inflammatory immune response and increases the recruitment of inflammatory monocytes and neutrophils to contribute to liver injury in Trypanosoma brucei infected mice. Moreover, neutrophil-derived MIF contributed more significantly than monocyte-derived MIF to increased pathogenic liver TNF production and liver injury during trypanosome infection. MIF deficient animals also featured limited anemia, coinciding with increased iron bio-availability, improved erythropoiesis and reduced RBC clearance during the chronic phase of infection. Our data suggest that MIF promotes the most prominent pathological features of experimental trypanosome infections (i.e. anemia and liver injury, and prompt considering MIF as a novel target for treatment of trypanosomiasis-associated immunopathogenicity.

  8. Proteins associated with SF3a60 in T. brucei.

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    Benson Nyambega

    Full Text Available Trypanosoma brucei relies on Spliced leader trans splicing to generate functional messenger RNAs. Trans splicing joins the specialized SL exon from the SL RNA to pre-mRNAs and is mediated by the trans-spliceosome, which is made up of small nuclear ribonucleoprotein particles and non-snRNP factors. Although the trans spliceosome is essential for trypanosomatid gene expression, not all spliceosomal protein factors are known and of these, only a few are completely characterized. In this study, we have characterized the trypanosome Splicing Factor, SF3a60, the only currently annotated SF3a component. As expected, epitope-tagged SF3a60 localizes in the trypanosome nucleus. SF3a60 is essential for cell viability but its depletion seem to have no detectable effect on trans-splicing. In addition, we used SF3a60 as bait in a Yeast-2-hybrid system screen and identified its interacting protein factors. The interactions with SF3a120, SF3a66 and SAP130 were confirmed by tandem affinity purification and mass spectrometry.

  9. A trans-spliced telomerase RNA dictates telomere synthesis in Trypanosoma brucei

    Institute of Scientific and Technical Information of China (English)

    Ranjodh Sandhu; Samantha Sanford; Shrabani Basu; MinA Park; Unnati M Pandya; Bibo Li; Kausik Chakrabarti

    2013-01-01

    Telomerase is a ribonucleoprotein enzyme typically required for sustained cell proliferation.Although both telomerase activity and the telomerase catalytic protein component,TbTERT,have been identified in the eukaryotic pathogen Trypanosoma brucei,the RNA molecule that dictates telomere synthesis remains unknown.Here,we identify the RNA component of Trypanosoma brucei telomerase,TbTR,and provide phylogenetic and in vivo evidence for TbTR's native folding and activity.We show that TbTR is processed through trans-splicing,and is a capped transcript that interacts and copurifies with TbTERT in vivo.Deletion of TbTR caused progressive shortening of telomeres at a rate of 3-5 bp/population doubling (PD),which can be rescued by ectopic expression of a wild-type allele of TbTR in an apparent dose-dependent manner.Remarkably,introduction of mutations in the TbTR template domain resulted in corresponding mutant telomere sequences,demonstrating that telomere synthesis in T.brucei is dependent on TbTR.We also propose a secondary structure model for TbTR based on phylogenetic analysis and chemical probing experiments,thus defining TbTR domains that may have important functional implications in telomere synthesis.Identification and characterization of TbTR not only provide important insights into T.brucei telomere functions,which have been shown to play important roles in T.brucei pathogenesis,but also offer T.brucei as an attractive model system for studying telomerase biology in pathogenic protozoa and for comparative analysis of telomerase function with higher eukaryotes.

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

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    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

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

    Science.gov (United States)

    Coburn, Phillip S.; Wiskur, Brandt J.; Miller, Frederick C.; LaGrow, Austin L.; Astley, Roger A.; Elliott, Michael H.; Callegan, Michelle C.

    2016-01-01

    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 permeability is

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

    Science.gov (United States)

    Coburn, Phillip S; Wiskur, Brandt J; Miller, Frederick C; LaGrow, Austin L; Astley, Roger A; Elliott, Michael H; Callegan, Michelle C

    2016-01-01

    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 permeability is

  13. 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.

  14. Bloodstream infection caused by nontoxigenic Corynebacterium diphtheriae in an immunocompromised host in the United States.

    Science.gov (United States)

    Wojewoda, Christina M; Koval, Christine E; Wilson, Deborah A; Chakos, Mary H; Harrington, Susan M

    2012-06-01

    Corynebacterium species are well-known causes of catheter-related bloodstream infections. Toxigenic strains of Corynebacterium diphtheriae cause respiratory diphtheria. We report a bloodstream infection caused by a nontoxigenic strain of C. diphtheriae and discuss the epidemiology, possible sources of the infection, and the implications of rapid species identification of corynebacteria.

  15. The cell cycle regulated transcriptome of Trypanosoma brucei.

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    Stuart K Archer

    Full Text Available Progression of the eukaryotic cell cycle requires the regulation of hundreds of genes to ensure that they are expressed at the required times. Integral to cell cycle progression in yeast and animal cells are temporally controlled, progressive waves of transcription mediated by cell cycle-regulated transcription factors. However, in the kinetoplastids, a group of early-branching eukaryotes including many important pathogens, transcriptional regulation is almost completely absent, raising questions about the extent of cell-cycle regulation in these organisms and the mechanisms whereby regulation is achieved. Here, we analyse gene expression over the Trypanosoma brucei cell cycle, measuring changes in mRNA abundance on a transcriptome-wide scale. We developed a "double-cut" elutriation procedure to select unperturbed, highly synchronous cell populations from log-phase cultures, and compared this to synchronization by starvation. Transcriptome profiling over the cell cycle revealed the regulation of at least 430 genes. While only a minority were homologous to known cell cycle regulated transcripts in yeast or human, their functions correlated with the cellular processes occurring at the time of peak expression. We searched for potential target sites of RNA-binding proteins in these transcripts, which might earmark them for selective degradation or stabilization. Over-represented sequence motifs were found in several co-regulated transcript groups and were conserved in other kinetoplastids. Furthermore, we found evidence for cell-cycle regulation of a flagellar protein regulon with a highly conserved sequence motif, bearing similarity to consensus PUF-protein binding motifs. RNA sequence motifs that are functional in cell-cycle regulation were more widespread than previously expected and conserved within kinetoplastids. These findings highlight the central importance of post-transcriptional regulation in the proliferation of parasitic kinetoplastids.

  16. A search for Trypanosoma brucei rhodesiense diagnostic antigens by proteomic screening and targeted cloning.

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    Theresa Manful

    Full Text Available BACKGROUND: The only available diagnostic method for East African trypanosomiasis is light microscopy of blood samples. A simple immunodiagnostic would greatly aid trypanosomiasis control. METHODOLOGY AND PRINCIPAL FINDINGS: To find trypanosome proteins that are specifically recognised by sera from human sleeping sickness patients, we have screened the Trypanosoma brucei brucei proteome by Western blotting. Using cytosolic, cytoskeletal and glycosomal fractions, we found that the vast majority of abundant trypanosome proteins is not specifically recognised by patient sera. We identified phosphoglycerate kinase (PGKC, heat shock protein (HSP70, and histones H2B and H3 as possible candidate diagnostic antigens. These proteins, plus paraflagellar rod protein 1, rhodesain (a cysteine protease, and an extracellular fragment of the Trypanosoma brucei nucleoside transporter TbNT10, were expressed in E. coli and tested for reactivity with patient and control sera. Only TbHSP70 was preferentially recognized by patient sera, but the sensitivity and specificity were insufficient for use of TbHSP70 alone as a diagnostic. Immunoprecipitation using a native protein extract revealed no specifically reacting proteins. CONCLUSIONS: No abundant T. brucei soluble, glycosomal or cytoskeletal protein is likely to be useful in diagnosis. To find useful diagnostic antigens it will therefore be necessary to use more sophisticated proteomic methods, or to test a very large panel of candidate proteins.

  17. 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 cod

  18. Dynamic Modelling under Uncertainty : The Case of Trypanosoma brucei Energy Metabolism

    NARCIS (Netherlands)

    Achcar, Fiona; Kerkhoven, Eduard J.; Bakker, Barbara M.; Barrett, Michael P.; Breitling, Rainer; Papin, Jason A.

    2012-01-01

    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 metabol

  19. Handling Uncertainty in Dynamic Models : The Pentose Phosphate Pathway in Trypanosoma brucei

    NARCIS (Netherlands)

    Kerkhoven, Eduard J.; Achcar, Fiona; Alibu, Vincent P.; Burchmore, Richard J.; Gilbert, Ian H.; Trybilo, Maciej; Driessen, Nicole N.; Gilbert, David; Breitling, Rainer; Bakker, Barbara M.; Barrett, Michael P.

    2013-01-01

    Dynamic models of metabolism can be useful in identifying potential drug targets, especially in unicellular organisms. A model of glycolysis in the causative agent of human African trypanosomiasis, Trypanosoma brucei, has already shown the utility of this approach. Here we add the pentose phosphate

  20. 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...

  1. Telomere length affects the frequency and mechanism of antigenic variation in Trypanosoma brucei.

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    Galadriel A Hovel-Miner

    Full Text Available Trypanosoma brucei is a master of antigenic variation and immune response evasion. Utilizing a genomic repertoire of more than 1000 Variant Surface Glycoprotein-encoding genes (VSGs, T. brucei can change its protein coat by "switching" from the expression of one VSG to another. Each active VSG is monoallelically expressed from only one of approximately 15 subtelomeric sites. Switching VSG expression occurs by three predominant mechanisms, arguably the most significant of which is the non-reciprocal exchange of VSG containing DNA by duplicative gene conversion (GC. How T. brucei orchestrates its complex switching mechanisms remains to be elucidated. Recent work has demonstrated that an exogenous DNA break in the active site could initiate a GC based switch, yet the source of the switch-initiating DNA lesion under natural conditions is still unknown. Here we investigated the hypothesis that telomere length directly affects VSG switching. We demonstrate that telomerase deficient strains with short telomeres switch more frequently than genetically identical strains with long telomeres and that, when the telomere is short, switching preferentially occurs by GC. Our data supports the hypothesis that a short telomere at the active VSG expression site results in an increase in subtelomeric DNA breaks, which can initiate GC based switching. In addition to their significance for T. brucei and telomere biology, the findings presented here have implications for the many diverse pathogens that organize their antigenic genes in subtelomeric regions.

  2. Nucleic acid sequence-based amplification with oligochromatography for detection of Trypanosoma brucei in clinical samples

    NARCIS (Netherlands)

    C.M. Mugasa; T. Laurent; G.J. Schoone; P.A. Kager; G.W. Lubega; H.D.F.H. Schallig

    2009-01-01

    Molecular tools, such as real-time nucleic acid sequence-based amplification (NASBA) and PCR, have been developed to detect Trypanosoma brucei parasites in blood for the diagnosis of human African trypanosomiasis (HAT). Despite good sensitivity, these techniques are not implemented in HAT control pr

  3. The major transcripts of the kinetoplast Trypanosoma brucei are very small ribosomal RNA's.

    NARCIS (Netherlands)

    I.C. Eperon; J.W.G. Janssen; J.H.J. Hoeijmakers (Jan); P. Borst (Piet)

    1983-01-01

    textabstractThe nucleotide sequence has been determined of a 2.2 kb segment of kinetoplast DNA, which encodes the major mitochondrial transcripts (12S and 9S) of Trypanosoma brucei. The sequence shows that the 12S RNA is a large subunit rRNA, although sufficiently unusual for resistance to chloramph

  4. Structure and reactivity of Trypanosoma brucei pteridine reductase: inhibition by the archetypal antifolate methotrexate.

    Science.gov (United States)

    Dawson, Alice; Gibellini, Federica; Sienkiewicz, Natasha; Tulloch, Lindsay B; Fyfe, Paul K; McLuskey, Karen; Fairlamb, Alan H; Hunter, William N

    2006-09-01

    The protozoan Trypanosoma brucei has a functional pteridine reductase (TbPTR1), an NADPH-dependent short-chain reductase that participates in the salvage of pterins, which are essential for parasite growth. PTR1 displays broad-spectrum activity with pterins and folates, provides a metabolic bypass for inhibition of the trypanosomatid dihydrofolate reductase and therefore compromises the use of antifolates for treatment of trypanosomiasis. Catalytic properties of recombinant TbPTR1 and inhibition by the archetypal antifolate methotrexate have been characterized and the crystal structure of the ternary complex with cofactor NADP+ and the inhibitor determined at 2.2 A resolution. This enzyme shares 50% amino acid sequence identity with Leishmania major PTR1 (LmPTR1) and comparisons show that the architecture of the cofactor binding site, and the catalytic centre are highly conserved, as are most interactions with the inhibitor. However, specific amino acid differences, in particular the placement of Trp221 at the side of the active site, and adjustment of the beta6-alpha6 loop and alpha6 helix at one side of the substrate-binding cleft significantly reduce the size of the substrate binding site of TbPTR1 and alter the chemical properties compared with LmPTR1. A reactive Cys168, within the active site cleft, in conjunction with the C-terminus carboxyl group and His267 of a partner subunit forms a triad similar to the catalytic component of cysteine proteases. TbPTR1 therefore offers novel structural features to exploit in the search for inhibitors of therapeutic value against African trypanosomiasis.

  5. Loop-mediated isothermal amplification (LAMP method for rapid detection of Trypanosoma brucei rhodesiense.

    Directory of Open Access Journals (Sweden)

    Zablon Kithinji Njiru

    Full Text Available Loop-mediated isothermal amplification (LAMP of DNA is a novel technique that rapidly amplifies target DNA under isothermal conditions. In the present study, a LAMP test was designed from the serum resistance-associated (SRA gene of Trypanosoma brucei rhodesiense, the cause of the acute form of African sleeping sickness, and used to detect parasite DNA from processed and heat-treated infected blood samples. The SRA gene is specific to T. b. rhodesiense and has been shown to confer resistance to lysis by normal human serum. The assay was performed at 62 degrees C for 1 h, using six primers that recognised eight targets. The template was varying concentrations of trypanosome DNA and supernatant from heat-treated infected blood samples. The resulting amplicons were detected using SYTO-9 fluorescence dye in a real-time thermocycler, visual observation after the addition of SYBR Green I, and gel electrophoresis. DNA amplification was detected within 35 min. The SRA LAMP test had an unequivocal detection limit of one pg of purified DNA (equivalent to 10 trypanosomes/ml and 0.1 pg (1 trypanosome/ml using heat-treated buffy coat, while the detection limit for conventional SRA PCR was approximately 1,000 trypanosomes/ml. The expected LAMP amplicon was confirmed through restriction enzyme RsaI digestion, identical melt curves, and sequence analysis. The reproducibility of the SRA LAMP assay using water bath and heat-processed template, and the ease in results readout show great potential for the diagnosis of T. b. rhodesiense in endemic regions.

  6. A monoclonal antibody marker for the exclusion-zone filaments of Trypanosoma brucei

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    Decossas Marion

    2008-07-01

    Full Text Available Abstract Background Trypanosoma brucei is a haemoflagellate pathogen of man, wild animals and domesticated livestock in central and southern Africa. In all life cycle stages this parasite has a single mitochondrion that contains a uniquely organised genome that is condensed into a flat disk-like structure called the kinetoplast. The kinetoplast is essential for insect form procyclic cells and therefore is a potential drug target. The kinetoplast is unique in nature because it consists of novel structural proteins and thousands of circular, interlocking, DNA molecules (kDNA. Secondly, kDNA replication is critically timed to coincide with nuclear S phase and new flagellum biogenesis. Thirdly, the kinetoplast is physically attached to the flagellum basal bodies via a structure called the tripartite attachment complex (TAC. The TAC consists of unilateral filaments (within the mitochondrion matrix, differentiated mitochondrial membranes and exclusion-zone filaments that extend from the distal end of the basal bodies. To date only one protein, p166, has been identified to be a component of the TAC. Results In the work presented here we provide data based on a novel EM technique developed to label and characterise cytoskeleton structures in permeabilised cells without extraction of mitochondrion membranes. We use this protocol to provide data on a new monoclonal antibody reagent (Mab 22 and illustrate the precise localisation of basal body-mitochondrial linker proteins. Mab 22 binds to these linker proteins (exclusion-zone filaments and provides a new tool for the characterisation of cytoskeleton mediated kinetoplast segregation. Conclusion The antigen(s recognised by Mab 22 are cytoskeletal, insensitive to extraction by high concentrations of non-ionic detergent, extend from the proximal region of basal bodies and bind to the outer mitochondrial membrane. This protein(s is the first component of the TAC exclusion-zone fibres to be identified. Mab 22

  7. Two pathways of homologous recombination in Trypanosoma brucei.

    Science.gov (United States)

    Conway, Colin; Proudfoot, Chris; Burton, Peter; Barry, J David; McCulloch, Richard

    2002-09-01

    African trypanosomes are unicellular parasites that use DNA recombination to evade the mammalian immune response. They do this in a process called antigenic variation, in which the parasites periodically switch the expression of VSG genes that encode distinct Variant Surface Glycoprotein coats. Recombination is used to move new VSG genes into specialised bloodstream VSG transcription sites. Genetic and molecular evidence has suggested that antigenic variation uses homologous recombination, but the detailed reaction pathways are not understood. In this study, we examine the recombination pathways used by trypanosomes to integrate transformed DNA into their genome, and show that they possess at least two pathways of homologous recombination. The primary mechanism is dependent upon RAD51, but a subsidiary pathway exists that is RAD51-independent. Both pathways contribute to antigenic variation. We show that the RAD51-independent pathway is capable of recombining DNA substrates with very short lengths of sequence homology and in some cases aberrant recombination reactions can be detected using such microhomologies.

  8. Mutational analysis of Trypanosoma brucei RNA editing ligase reveals regions critical for interaction with KREPA2.

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    Vaibhav Mehta

    Full Text Available The Trypanosoma brucei parasite causes the vector-borne disease African sleeping sickness. Mitochondrial mRNAs of T. brucei undergo posttranscriptional RNA editing to make mature, functional mRNAs. The final step of this process is catalyzed by the essential ligase, T. brucei RNA Editing Ligase 1 (TbREL1 and the closely related T. brucei RNA Editing Ligase 2 (TbREL2. While other ligases such as T7 DNA ligase have both a catalytic and an oligonucleotide/oligosaccharide-binding (OB-fold domain, T. brucei RNA editing ligases contain only the catalytic domain. The OB-fold domain, which is required for interaction with the substrate RNA, is provided in trans by KREPA2 (for TbREL1 and KREPA1 (for TbREL2. KREPA2 enhancement of TbREL1 ligase activity is presumed to occur via an OB-fold-mediated increase in substrate specificity and catalysis. We characterized the interaction between TbREL1 and KREPA2 in vitro using full-length, truncated, and point-mutated ligases. As previously shown, our data indicate strong, specific stimulation of TbREL1 catalytic activity by KREPA2. We narrowed the region of contact to the final 59 C-terminal residues of TbREL1. Specifically, the TbREL1 C-terminal KWKE (441-444 sequence appear to coordinate the KREPA2-mediated enhancement of TbREL1 activities. N-terminal residues F206, T264 and Y275 are crucial for the overall activity of TbREL1, particularly for F206, a mutation of this residue also disrupts KREPA2 interaction. Thus, we have identified the critical TbREL1 regions and amino acids that mediate the KREPA2 interaction.

  9. Concentration of erythrocyte-based magnetic carriers in the bloodstream

    Energy Technology Data Exchange (ETDEWEB)

    Danilov, Y.N.; Il' ina, M.B.; Makharudov, S.Y.; Orekhov, A.N.; Rodchenko, S.A.; Samokhin, G.P.

    1986-04-01

    The writers postulated that magnetic erythrocytes (ME), injected into the bloodstream, may be concentrated in an assigned region of the vascular bed with the aid of the field of a permanent magnet. To test this hypothesis, erythrocytes ''loaded'' with colloidal magnetite were used, and concentrated in experiments in vitro and in vivo. For the experiments in vivo ME were labeled with sodium pertechnetate (Na /SUP 99n/ TcO4) was estimated in ME with a Rackgamma 1270 counter by determining radioactivity in the ME suspension and in the supernatant. For the experiment in vivo, a midline laparotomy was performed on a dog weighing 14 kg under intravenous hexobarbital anesthesia. The distribution of ME was recorded by means of a gamma-camera.

  10. 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...... in Denmark. Patients with growth of non-enterococcus co-pathogens apart from the enterococcal bacteraemia were also included, as were patients with repeated enterococcal bacteraemia. Time to appropriate antimicrobial therapy was counted from the first episode. Appropriate antibiotic therapy was defined...... as any therapy with documented clinical effect, in vitro activity and a minimum treatment length of 6 days. Multivariate regression models were built to determine the independent risk factors for mortality. We included 196 patients with enterococcal bacteraemia. Appropriate antibiotics for at least 6...

  11. Reducing bloodstream infection with a chlorhexidine gel IV dressing.

    Science.gov (United States)

    Jeanes, Annette; Bitmead, James

    The use of vascular access devices (VAD) is common in healthcare provision but there is a significant risk of acquiring an infection. Central venous catheters (CVC) are associated with the highest risk of intravenous catheter-related bloodstream infection (CRBSI). 3M™ Tegaderm™ CHG IV dressing is a semi-permeable transparent adhesive dressing with an integrated gel pad containing chlorhexidine gluconate 2%. This product was reviewed by the National Institute for Health and Care Excellence (NICE) in 2015, recommending that Tegaderm CHG could be used for CVC and arterial line dressings in high-dependency and intensive-care settings. This article discusses issues around CRBSI, interventions to reduce the risk of CRBSI, and the use of Tegaderm CHG dressing.

  12. Biofilm formation is a risk factor for mortality in patients with Candida albicans bloodstream infection—Scotland, 2012–2013

    Science.gov (United States)

    Rajendran, R.; Sherry, L.; Nile, C.J.; Sherriff, A.; Johnson, E.M.; Hanson, M.F.; Williams, C.; Munro, C.A.; Jones, B.J.; Ramage, G.

    2016-01-01

    Bloodstream infections caused by Candida species remain a significant cause of morbidity and mortality in hospitalized patients. Biofilm formation by Candida species is an important virulence factor for disease pathogenesis. A prospective analysis of patients with Candida bloodstream infection (n = 217) in Scotland (2012–2013) was performed to assess the risk factors associated with patient mortality, in particular the impact of biofilm formation. Candida bloodstream isolates (n = 280) and clinical records for 157 patients were collected through 11 different health boards across Scotland. Biofilm formation by clinical isolates was assessed in vitro with standard biomass assays. The role of biofilm phenotype on treatment efficacy was also evaluated in vitro by treating preformed biofilms with fixed concentrations of different classes of antifungal. Available mortality data for 134 patients showed that the 30-day candidaemia case mortality rate was 41%, with predisposing factors including patient age and catheter removal. Multivariate Cox regression survival analysis for 42 patients showed a significantly higher mortality rate for Candida albicans infection than for Candida glabrata infection. Biofilm-forming ability was significantly associated with C. albicans mortality (34 patients). Finally, in vitro antifungal sensitivity testing showed that low biofilm formers and high biofilm formers were differentially affected by azoles and echinocandins, but not by polyenes. This study provides further evidence that the biofilm phenotype represents a significant clinical entity, and that isolates with this phenotype differentially respond to antifungal therapy in vitro. Collectively, these findings show that greater clinical understanding is required with respect to Candida biofilm infections, and the implications of isolate heterogeneity. PMID:26432192

  13. T rypanosoma brucei histone H1 inhibits RNA polymerase I transcription and is important for parasite fitness in vivo

    OpenAIRE

    Pena, Ana C.; Pimentel, Mafalda R; Manso, Helena; Vaz-Drago, Rita; Pinto-Neves, Daniel; Aresta-Branco, Francisco; Rijo-Ferreira, Filipa; Guegan, Fabien; Pedro Coelho, Luis; Carmo-Fonseca, Maria; Barbosa-Morais, Nuno L.; Figueiredo, Luisa M.

    2014-01-01

    T rypanosoma brucei is a unicellular parasite that causes sleeping sickness in humans. Most of its transcription is constitutive and driven by RNA polymerase II. RNA polymerase I (Pol I) transcribes not only ribosomal RNA genes, but also protein-encoding genes, including variant surface glycoproteins (VSGs) and procyclins. In T . brucei, histone H1 (H1) is required for VSG silencing and chromatin condensation. However, whether H1 has a genome-wide role in transcription is unknown. Here, using...

  14. 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

  15. Cefotaxime resistance and outcome of Klebsiella spp bloodstream infection.

    Science.gov (United States)

    Ortega, M; Marco, F; Soriano, A; Almela, M; Martínez, J A; López, J; Pitart, C; Mensa, J

    2011-12-01

    We attempt to describe the epidemiology and outcome associated with cefotaxime-resistant (CTX-R) Klebsiella spp bacteraemia. Klebsiella spp bloodstream infection episodes prospectively collected through a blood culture surveillance programme from January 1991 to December 2008 in a single institution were analysed. A total of 910 monomicrobial episodes of Klebsiella spp bacteraemia were identified during the study period. The most important sources were from urinary tract infection, unknown sources, billiary focus and catheter related infection. There were 112 (12%) CTX-R isolates. Out of 112 isolates, 98 were CTX-R by Extended-Spectrum β-Lactamase production. Shock on presentation and mortality were significantly more frequent in CTX-R than in CTX susceptible isolates. Inappropriate empirical therapy was received in 50 (45%) cases in the CTX-R Klebsiella spp group (13 cases of death, 26%). Predictive factors associated with CTX-R Klebsiella spp isolate were: previous β-lactam therapy (OR = 4.16), nosocomial acquired bacteraemia (OR = 1.93), solid organ trasplantation (OR = 2.09) and shock (OR = 1.90). Independent risk factors associated with mortality in Klebsiella spp bacteraemia were: age (OR = 1.03), liver cirrhosis (OR = 2.63), ultimately or rapidly fatal prognosis of underlying disease (OR = 2.44), shock (OR = 8.60), pneumonia (OR = 4.96) or intraabdominal (OR = 3.85) source of bacteraemia and CTX-R isolate (OR = 4.63). Klebsiella spp is an important cause of bloodstream infection. CTX-R isolates have been increasing since 2000. CTX-R is an independent factor associated with mortality in Klebsiella spp bacteraemia.

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

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    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.

  17. 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.

  18. Clinical and hematological study of Trypanosoma brucei and Trypanosoma congolense in cattle in Mosul City, Iraq

    Directory of Open Access Journals (Sweden)

    Al-Badrani, B. A

    2012-03-01

    Full Text Available An out-break of trypanosomosis was reported and subsequently investigated in Mosul city, Iraq. Twenty seven blood samples were received at the Clinical pathology Laboratory of Veterinary Teaching Hospital, University of Mosul, from fifteen cows (2-5 years old and twelve calves (10-12 months old of different farms located around Mosul city. Clinical signs of the infected animals revealed fever, progressive weight loss, anemia, and frequent recumbent position. Identification of trypanosome species were based on their motility using morphological differentiation on Giemsa or Leishman stained that showed trypomastigot which can be classified according to the biometrical data into T. brucei and T. congolense. A decreased was also observed in some blood parameters. To our knowledge, this is the first record of T. brucei and T. congolense infection in cattle. This study also suggested that trypanosomosis is associated with introduction of exotic breeds of cattle into Mosul, Iraq.

  19. Bacillus Cereus Catheter Related Bloodstream Infection in a Patient with Acute Lymphoblastic Leukemia

    OpenAIRE

    N Gurler; Oksuz, L; M Muftuoglu; Sargin, FD; Besisik, SK

    2012-01-01

    Bacillus cereus infection is rarely associated with actual infection and for this reason single positive blood culture is usually regarded as contamination . However it may cause a number of infections, such catheter-related bloodstream infections. Significant catheter-related bloodstream infections (CRBSI) caused by Bacillus spp. are mainly due to B. cereus and have been predominantly reported in immunocompromised hosts. Catheter removal is generally advised for management of infection. In t...

  20. Comparative analysis of the kinomes of three pathogenic trypanosomatids: Leishmania major, Trypanosoma brucei and Trypanosoma cruzi

    OpenAIRE

    Parsons, Marilyn; Worthey, Elizabeth A.; Ward, Pauline N; Mottram, Jeremy C.

    2005-01-01

    Background The trypanosomatids Leishmania major, Trypanosoma brucei and Trypanosoma cruzi cause some of the most debilitating diseases of humankind: cutaneous leishmaniasis, African sleeping sickness, and Chagas disease. These protozoa possess complex life cycles that involve development in mammalian and insect hosts, and a tightly coordinated cell cycle ensures propagation of the highly polarized cells. However, the ways in which the parasites respond to their environment and coordinate intr...

  1. Elimination of central line-associated bloodstream infections: application of the evidence.

    Science.gov (United States)

    Posa, Patricia J; Harrison, Denise; Vollman, Kathleen M

    2006-01-01

    Central line-associated bloodstream infections are considered to be an avoidable complication of care delivery. In addition to considerable morbidity and use of resources, central line-associated bloodstream infections carry an attributable morality between 12% and 25%. The estimated cost per infection is approximately 25,000 US dollars. Research over the last decade has focused on a number of care activities that have been shown to reduce the incidence of bloodstream infections related to central line placement in the critically ill patient. A significant reduction or elimination of central line-associated bloodstream infections can occur with implementation of a comprehensive central line-associated bloodstream infection prevention program that includes staff education, hand hygiene, use of maximal sterile barrier precautions, chlorhexidine gluconate skin antisepsis, avoidance of femoral lines, empowerment of staff to stop the procedure if sterile technique is broken, and daily assessment of the continued need for a central line. This article focuses on strategies for implementing a comprehensive central line-associated bloodstream infections prevention program and a tool and process for defect analysis as part of a statewide collaborative in Michigan.

  2. Alba-domain proteins of Trypanosoma brucei are cytoplasmic RNA-binding proteins that interact with the translation machinery.

    Directory of Open Access Journals (Sweden)

    Jan Mani

    Full Text Available Trypanosoma brucei and related pathogens transcribe most genes as polycistronic arrays that are subsequently processed into monocistronic mRNAs. Expression is frequently regulated post-transcriptionally by cis-acting elements in the untranslated regions (UTRs. GPEET and EP procyclins are the major surface proteins of procyclic (insect midgut forms of T. brucei. Three regulatory elements common to the 3' UTRs of both mRNAs regulate mRNA turnover and translation. The glycerol-responsive element (GRE is unique to the GPEET 3' UTR and regulates its expression independently from EP. A synthetic RNA encompassing the GRE showed robust sequence-specific interactions with cytoplasmic proteins in electromobility shift assays. This, combined with column chromatography, led to the identification of 3 Alba-domain proteins. RNAi against Alba3 caused a growth phenotype and reduced the levels of Alba1 and Alba2 proteins, indicative of interactions between family members. Tandem-affinity purification and co-immunoprecipitation verified these interactions and also identified Alba4 in sub-stoichiometric amounts. Alba proteins are cytoplasmic and are recruited to starvation granules together with poly(A RNA. Concomitant depletion of all four Alba proteins by RNAi specifically reduced translation of a reporter transcript flanked by the GPEET 3' UTR. Pulldown of tagged Alba proteins confirmed interactions with poly(A binding proteins, ribosomal protein P0 and, in the case of Alba3, the cap-binding protein eIF4E4. In addition, Alba2 and Alba3 partially cosediment with polyribosomes in sucrose gradients. Alba-domain proteins seem to have exhibited great functional plasticity in the course of evolution. First identified as DNA-binding proteins in Archaea, then in association with nuclear RNase MRP/P in yeast and mammalian cells, they were recently described as components of a translationally silent complex containing stage-regulated mRNAs in Plasmodium. Our results are

  3. The extraordinary mitochondrion and unusual citric acid cycle in Trypanosoma brucei.

    Science.gov (United States)

    van Hellemond, J J; Opperdoes, F R; Tielens, A G M

    2005-11-01

    African trypanosomes are parasitic protozoa that cause sleeping sickness and nagana. Trypanosomes are not only of scientific interest because of their clinical importance, but also because these protozoa contain several very unusual biological features, such as their specially adapted mitochondrion and the compartmentalization of glycolytic enzymes in glycosomes. The energy metabolism of Trypanosoma brucei differs significantly from that of their hosts and changes drastically during the life cycle. Despite the presence of all citric acid cycle enzymes in procyclic insect-stage T. brucei, citric acid cycle activity is not used for energy generation. Recent investigations on the influence of substrate availability on the type of energy metabolism showed that absence of glycolytic substrates did not induce a shift from a fermentative metabolism to complete oxidation of substrates. Apparently, insect-stage T. brucei use parts of the citric acid cycle for other purposes than for complete degradation of mitochondrial substrates. Parts of the cycle are suggested to be used for (i) transport of acetyl-CoA units from the mitochondrion to the cytosol for the biosynthesis of fatty acids, (ii) degradation of proline and glutamate to succinate, (iii) generation of malate, which can then be used for gluconeogenesis. Therefore the citric acid cycle in trypanosomes does not function as a cycle.

  4. Experimental Trypanosoma brucei infection at immediate post partum period:effects on dam and the offspring

    Institute of Scientific and Technical Information of China (English)

    Izuchukwu S Ochiogu; Chukwuka N Uchendu; John I Ihedioha

    2010-01-01

    Objective:To investigate the effects of immediate post-partum infection with Trypanosoma brucei (T. brucei) on dam and offspring. Methods:Sixty female Albino rats (Rattus norvegicus) weighing between 130-170 g were used as animal model. The animals were divided as follows:25 infected between 1-5 days post partum; 10 infected unbred as positive controls; and 25 uninfected as negative controls. The following parameters were evaluated:packed cell volume (PCV), level of parasitaemia, survival time, litter size and litter weight at birth and on days 7, 14 and 21 post delivery, using conventional methods. Possible trans-mammary transmission of infection to litter through milk was also assessed. Results:The results showed a comparatively (P<0.05) higher mean PCV value for the uninfected negative control on the 8th day post infection compared with the infected groups which corresponded with the increasing level of parasitaemia in the two infected groups. Mean litter size and litter weights were higher (P< 0.05) in the uninfected controls on the 21st day. Survival time in the infected groups were similar. No evidence of trans-mammary transfer of infection was recorded. Conclusion:T. brucei infection during immediate post partum period is detrimental to the dam and impairs growth of the offspring.

  5. Discovery of Inhibitors of Trypanosoma brucei by Phenotypic Screening of a Focused Protein Kinase Library.

    Science.gov (United States)

    Woodland, Andrew; Thompson, Stephen; Cleghorn, Laura A T; Norcross, Neil; De Rycker, Manu; Grimaldi, Raffaella; Hallyburton, Irene; Rao, Bhavya; Norval, Suzanne; Stojanovski, Laste; Brun, Reto; Kaiser, Marcel; Frearson, Julie A; Gray, David W; Wyatt, Paul G; Read, Kevin D; Gilbert, Ian H

    2015-11-01

    A screen of a focused kinase inhibitor library against Trypanosoma brucei rhodesiense led to the identification of seven series, totaling 121 compounds, which showed >50 % inhibition at 5 μm. Screening of these hits in a T. b. brucei proliferation assay highlighted three compounds with a 1H-imidazo[4,5-b]pyrazin-2(3H)-one scaffold that showed sub-micromolar activity and excellent selectivity against the MRC5 cell line. Subsequent rounds of optimisation led to the identification of compounds that exhibited good in vitro drug metabolism and pharmacokinetics (DMPK) properties, although in general this series suffered from poor solubility. A scaffold-hopping exercise led to the identification of a 1H-pyrazolo[3,4-b]pyridine scaffold, which retained potency. A number of examples were assessed in a T. b. brucei growth assay, which could differentiate static and cidal action. Compounds from the 1H-imidazo[4,5-b]pyrazin-2(3H)-one series were found to be either static or growth-slowing and not cidal. Compounds with the 1H-pyrazolo[3,4-b]pyridine scaffold were found to be cidal and showed an unusual biphasic nature in this assay, suggesting they act by at least two mechanisms.

  6. Epidemiology, surveillance, and prevention of bloodstream infections in hemodialysis patients.

    Science.gov (United States)

    Patel, Priti R; Kallen, Alexander J; Arduino, Matthew J

    2010-09-01

    Infections cause significant morbidity and mortality in patients undergoing hemodialysis. Bloodstream infections (BSIs) are particularly problematic, accounting for a substantial number of hospitalizations in these patients. Hospitalizations for BSI and other vascular access infections appear to have increased dramatically in hemodialysis patients since 1993. These infections frequently are related to central venous catheter (CVC) use for dialysis access. Regional initiatives that have shown successful decreases in catheter-related BSIs in hospitalized patients have generated interest in replicating this success in outpatient hemodialysis populations. Several interventions have been effective in preventing BSIs in the hemodialysis setting. Avoiding the use of CVCs in favor of access types with lower associated BSI risk is among the most important. When CVCs are used, adherence to evidence-based catheter insertion and maintenance practices can positively influence BSI rates. In addition, facility-level surveillance to detect BSIs and stimulate examination of vascular access use and care practices is essential to a comprehensive approach to prevention. This article describes the current epidemiology of BSIs in hemodialysis patients and effective prevention strategies to decrease the incidence of these devastating infections.

  7. 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.

  8. Identification of potent inhibitors of the Trypanosoma brucei methionyl-tRNA synthetase via high-throughput orthogonal screening.

    Science.gov (United States)

    Pedró-Rosa, Laura; Buckner, Frederick S; Ranade, Ranae M; Eberhart, Christina; Madoux, Franck; Gillespie, J Robert; Koh, Cho Yeow; Brown, Steven; Lohse, Jacqueline; Verlinde, Christophe L M; Fan, Erkang; Bannister, Thomas; Scampavia, Louis; Hol, Wim G J; Spicer, Timothy; Hodder, Peter

    2015-01-01

    Improved therapies for the treatment of Trypanosoma brucei, the etiological agent of the neglected tropical disease human African trypanosomiasis, are urgently needed. We targeted T. brucei methionyl-tRNA synthetase (MetRS), an aminoacyl-tRNA synthase (aaRS), which is considered an important drug target due to its role in protein synthesis, cell survival, and its significant differences in structure from its mammalian ortholog. Previous work using RNA interference of MetRS demonstrated growth inhibition of T. brucei, further validating it as an attractive target. We report the development and implementation of two orthogonal high-throughput screening assays to identify inhibitors of T. brucei MetRS. First, a chemiluminescence assay was implemented in a 1536-well plate format and used to monitor adenosine triphosphate depletion during the aminoacylation reaction. Hit confirmation then used a counterscreen in which adenosine monophosphate production was assessed using fluorescence polarization technology. In addition, a miniaturized cell viability assay was used to triage cytotoxic compounds. Finally, lower throughput assays involving whole parasite growth inhibition of both human and parasite MetRS were used to analyze compound selectivity and efficacy. The outcome of this high-throughput screening campaign has led to the discovery of 19 potent and selective T. brucei MetRS inhibitors.

  9. The Centriole Cartwheel Protein SAS-6 in Trypanosoma brucei Is Required for Probasal Body Biogenesis and Flagellum Assembly.

    Science.gov (United States)

    Hu, Huiqing; Liu, Yi; Zhou, Qing; Siegel, Sara; Li, Ziyin

    2015-09-01

    The centriole in eukaryotes functions as the cell's microtubule-organizing center (MTOC) to nucleate spindle assembly, and its biogenesis requires an evolutionarily conserved protein, SAS-6, which assembles the centriole cartwheel. Trypanosoma brucei, an early branching protozoan, possesses the basal body as its MTOC to nucleate flagellum biogenesis. However, little is known about the components of the basal body and their roles in basal body biogenesis and flagellum assembly. Here, we report that the T. brucei SAS-6 homolog, TbSAS-6, is localized to the mature basal body and the probasal body throughout the cell cycle. RNA interference (RNAi) of TbSAS-6 inhibited probasal body biogenesis, compromised flagellum assembly, and caused cytokinesis arrest. Surprisingly, overexpression of TbSAS-6 in T. brucei also impaired probasal body duplication and flagellum assembly, contrary to SAS-6 overexpression in humans, which produces supernumerary centrioles. Furthermore, we showed that depletion of T. brucei Polo-like kinase, TbPLK, or inhibition of TbPLK activity did not abolish TbSAS-6 localization to the basal body, in contrast to the essential role of Polo-like kinase in recruiting SAS-6 to centrioles in animals. Altogether, these results identified the essential role of TbSAS-6 in probasal body biogenesis and flagellum assembly and suggest the presence of a TbPLK-independent pathway governing basal body duplication in T. brucei.

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

    Directory of Open Access Journals (Sweden)

    Geraldo Sadoyma

    2006-04-01

    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. 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.

  12. Central Nervous System Parasitosis and Neuroinflammation Ameliorated by Systemic IL-10 Administration in Trypanosoma brucei-Infected Mice.

    Science.gov (United States)

    Rodgers, Jean; Bradley, Barbara; Kennedy, Peter G E; Sternberg, Jeremy M

    2015-01-01

    Invasion of the central nervous system (CNS) by African trypanosomes represents a critical step in the development of human African trypanosomiasis. In both clinical cases and experimental mouse infections it has been demonstrated that predisposition to CNS invasion is associated with a type 1 systemic inflammatory response. Using the Trypanosoma brucei brucei GVR35 experimental infection model, we demonstrate that systemic delivery of the counter-inflammatory cytokine IL-10 lowers plasma IFN-γ and TNF-α concentrations, CNS parasitosis and ameliorates neuro-inflammatory pathology and clinical symptoms of disease. The results provide evidence that CNS invasion may be susceptible to immunological attenuation.

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

    Directory of Open Access Journals (Sweden)

    Nikolay G Kolev

    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.

  14. Trypanocidal activity of organotin chlorides on Trypanosoma brucei-infected mice

    Directory of Open Access Journals (Sweden)

    Shuaibu M.N.

    2000-03-01

    Full Text Available The organotin compounds dibulyltin (DBTC and diphenyltin dichlorides (DPTC were tested for trypanocidal activity on a Trypanosoma brucei-infected mice model. At a dose of 10 mg DBTC and 15 mg DPTC/kg/day for five consecutive days, they cleared the parasites from the peripheral blood of the infected mice. Subinoculation of some healthy mice with the homogenates of liver, spleen, kidney, cerebrospinal fluid and blood from the mice considered cured, showed a few cases of relapse. The LD50 of DBTC and DPTC are 90 mg/kg and 75 mg/kg respectively.

  15. A haptoglobin-hemoglobin receptor conveys innate immunity to Trypanosoma brucei in humans

    DEFF Research Database (Denmark)

    Vanhollebeke, Benoit; De Muylder, Géraldine; Nielsen, Marianne J;

    2008-01-01

    The protozoan parasite Trypanosoma brucei is lysed by apolipoprotein L-I, a component of human high-density lipoprotein (HDL) particles that are also characterized by the presence of haptoglobin-related protein. We report that this process is mediated by a parasite glycoprotein receptor, which...... receptor also recognized the complex between hemoglobin and haptoglobin-related protein, which explains its ability to capture trypanolytic HDLs. Thus, in humans the presence of haptoglobin-related protein has diverted the function of the trypanosome haptoglobin-hemoglobin receptor to elicit innate host...

  16. Structures of aspartate aminotransferases from Trypanosoma brucei, Leishmania major and Giardia lamblia.

    Science.gov (United States)

    Abendroth, Jan; Choi, Ryan; Wall, Abigail; Clifton, Matthew C; Lukacs, Christine M; Staker, Bart L; Van Voorhis, Wesley; Myler, Peter; Lorimer, Don D; Edwards, Thomas E

    2015-05-01

    The structures of three aspartate aminotransferases (AATs) from eukaryotic pathogens were solved within the Seattle Structural Genomics Center for Infectious Disease (SSGCID). Both the open and closed conformations of AAT were observed. Pyridoxal phosphate was bound to the active site via a Schiff base to a conserved lysine. An active-site mutant showed that Trypanosoma brucei AAT still binds pyridoxal phosphate even in the absence of the tethering lysine. The structures highlight the challenges for the structure-based design of inhibitors targeting the active site, while showing options for inhibitor design targeting the N-terminal arm.

  17. Candida bloodstream infections in intensive care units: analysis of the extended prevalence of infection in intensive care unit study

    NARCIS (Netherlands)

    Kett, D.H.; Azoulay, E.; Echeverria, P.M.; Vincent, J.L.; Pickkers, P.

    2011-01-01

    OBJECTIVES: To provide a global, up-to-date picture of the prevalence, treatment, and outcomes of Candida bloodstream infections in intensive care unit patients and compare Candida with bacterial bloodstream infection. DESIGN: A retrospective analysis of the Extended Prevalence of Infection in the I

  18. Bacillus cereus catheter related bloodstream infection in a patient with acute lymphoblastic leukemia.

    Science.gov (United States)

    Gurler, N; Oksuz, L; Muftuoglu, M; Sargin, Fd; Besisik, Sk

    2012-01-01

    Bacillus cereus infection is rarely associated with actual infection and for this reason single positive blood culture is usually regarded as contamination . However it may cause a number of infections, such catheter-related bloodstream infections. Significant catheter-related bloodstream infections (CRBSI) caused by Bacillus spp. are mainly due to B. cereus and have been predominantly reported in immunocompromised hosts. Catheter removal is generally advised for management of infection. In this report, catheter-related bacteremia caused by B. cereus in a patient with acute lymphoblast c leukemia (ALL) in Istanbul Medical Faculty was presented.

  19. Trypanosoma brucei gambiense Type 1 populations from human patients are clonal and display geographical genetic differentiation.

    Science.gov (United States)

    Morrison, Liam J; Tait, Andy; McCormack, Gillian; Sweeney, Lindsay; Black, Alana; Truc, Philippe; Likeufack, Anne C L; Turner, C Michael; MacLeod, Annette

    2008-12-01

    We have rigorously tested the hypothesis that Trypanosoma brucei gambiense Type 1 is composed of genetically homogenous populations by examining the parasite population present in Human African Trypanosomiasis (HAT) patients from the Democratic Republic of Congo (DRC) and Cameroon (CAM). We amplified eight microsatellite markers by PCR directly from blood spots on FTA filters, thereby avoiding the significant parasite selection inherent in the traditional isolation techniques of rodent inoculation or in vitro culture. All microsatellite markers were polymorphic, although for four markers there was only polymorphism between the DRC and CAM populations, not within populations, suggesting very limited genetic exchange. Within the largest population from the DRC, Hardy-Weinberg equilibrium is not evident at any loci. This evidence suggests a clonal population. However, there was significant sub-structuring between the DRC and CAM samples (F(ST) = 0.32), indicating that Trypanosoma brucei gambiense Type 1 has genetically distinct clades. The data combine to indicate that genetic exchange plays a very limited role. The finding of distinct clades in different places suggests the possibility that samples from humans with clinical signs represent clonal expansions from an underlying population that requires identifying and characterising.

  20. Analysis of the Trypanosoma brucei cell cycle by quantitative DAPI imaging.

    Science.gov (United States)

    Siegel, T Nicolai; Hekstra, Doeke R; Cross, George A M

    2008-08-01

    Trypanosoma brucei has two DNA compartments: the nucleus and the kinetoplast. DNA replication of these two compartments only partially coincides. Woodward and Gull [Woodward R, Gull K. Timing of nuclear and kinetoplast DNA replication and early morphological events in the cell cycle of Trypanosoma brucei. J Cell Sci 1990;95:49-57] comprehensively studied the relative timing of the replication and segregation of nuclear DNA (nDNA) and kinetoplast DNA (kDNA). Others have since assumed the consistency of morphological indicators of cell-cycle stage among strains and conditions. We report the use of quantitative DAPI imaging to determine the cell-cycle stage of individual procyclic cells. Using this approach, we found that kinetoplast elongation occurs mainly during nuclear S phase and not during G2, as previously assumed. We confirmed this finding by sorting cells by DNA content, followed by fluorescence microscopy. In addition, simultaneous quantitative imaging at two wavelengths can be used to determine the abundance of cell-cycle-regulated proteins during the cell cycle. We demonstrate this technique by co-staining for the non-acetylated state of lysine 4 of histone H4 (H4K4), which is enriched during nuclear S phase.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Diversity and spation distribution of vectors and hosts of T. brucei gambiense in forest zones of Southern Cameroon: Epidemiological implications

    NARCIS (Netherlands)

    Massussi, J.A.; Mbida Mbida, J.A.; Djieto-Lordon, C.; Njiokou, F.; Laveissière, C.; Ploeg, van der J.D.

    2010-01-01

    Host and vector distribution of Trypanosoma brucei gambiense was studied in relation to habitat types and seasons. Six (19.35%) of the 31 mammal species recorded in Bipindi were reservoir hosts. Cercopithecus nictitans was confined to the undisturbed forest and the low intensive shifting cultivation

  3. Trypanosoma Brucei Aquaglyceroporins Facilitate the Uptake of Arsenite and Antimonite in a pH Dependent Way

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    Néstor L. Uzcátegui

    2013-09-01

    Full Text Available Background: Trypanosoma brucei is a primitive parasitic protozoan that thrives in diverse environments such as the midgut of the tsetse fly and the blood of a mammalian host. For an adequate adaptation to these environments, the parasite´s aquaglyceroporins play an important role. Methods and Results: In order to test their ability to transport trivalent arsenic and antimony, we expressed the three known Trypanosoma brucei aquaglyceroporins (TbAQPs in the heterologous systems of yeast null aquaporin mutant and Xenopus laevis oocytes. For both expression systems, we found a pH dependent intracellular accumulation of As(III or Sb(III mediated by all of the three TbAQPs, with the exception of TbAQP1-As(III uptake. Additionally, we observed that Trypanosoma brucei aquaglyceroporins allow the passage of As(III in both directions. Conclusion: Taken together, these results demonstrated that T. brucei aquaglyceroporins can serve as entry routes for As(III and Sb(III into the parasitic cell, and that this uptake is pH sensitive. Therefore, aquaporins of protozoan parasites may be considered useful as a vehicle for drug delivery.

  4. 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...

  5. A role for RAD51 and homologous recombination in Trypanosoma brucei antigenic variation

    OpenAIRE

    1999-01-01

    Antigenic variation is an immune evasion strategy used by African trypanosomes, in which the parasites periodically switch the expression of VSG genes that encode their protective variant surface glycoprotein coat. Two main routes exist for VSG switching: changing the transcriptional status between an active and an inactive copy of the site of VSG expression, called the bloodstream VSG expression site, or recombination reactions that move silent VSGs or VSG copies into the actively transcribe...

  6. Form, Fabric, and Function of a Flagellum-Associated Cytoskeletal Structure

    Directory of Open Access Journals (Sweden)

    Brooke Morriswood

    2015-11-01

    Full Text Available Trypanosoma brucei is a uniflagellated protist and the causative agent of African trypanosomiasis, a neglected tropical disease. The single flagellum of T. brucei is essential to a number of cellular processes such as motility, and has been a longstanding focus of scientific enquiry. A number of cytoskeletal structures are associated with the flagellum in T. brucei, and one such structure—a multiprotein complex containing the repeat motif protein TbMORN1—is the focus of this review. The TbMORN1-containing complex, which was discovered less than ten years ago, is essential for the viability of the mammalian-infective form of T. brucei. The complex has an unusual asymmetric morphology, and is coiled around the flagellum to form a hook shape. Proteomic analysis using the proximity-dependent biotin identification (BioID technique has elucidated a number of its components. Recent work has uncovered a role for TbMORN1 in facilitating protein entry into the cell, thus providing a link between the cytoskeleton and the endomembrane system. This review summarises the extant data on the complex, highlights the outstanding questions for future enquiry, and provides speculation as to its possible role in a size-exclusion mechanism for regulating protein entry. The review additionally clarifies the nomenclature associated with this topic, and proposes the adoption of the term “hook complex” to replace the former name “bilobe” to describe the complex.

  7. Using real time process measurements to reduce catheter related bloodstream infections in the intensive care unit

    OpenAIRE

    Wall, R; Ely, E; Elasy, T; Dittus, R; Foss, J.; Wilkerson, K; Speroff, T

    2005-01-01

    

Problem: Measuring a process of care in real time is essential for continuous quality improvement (CQI). Our inability to measure the process of central venous catheter (CVC) care in real time prevented CQI efforts aimed at reducing catheter related bloodstream infections (CR-BSIs) from these devices.

  8. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. 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 densit

  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. Bloodstream Infections in Very Low Birth Weight Infants with Intestinal Failure

    NARCIS (Netherlands)

    Cole, Conrad R.; Hansen, Nellie I.; Higgins, Rosemary D.; Bell, Edward F.; Shankaran, Seetha; Laptook, Abbot R.; Walsh, Michele C.; Hale, Ellen C.; Newman, Nancy S.; Das, Abhik; Stoll, Barbara J.

    2012-01-01

    Objective To examine pathogens and other characteristics associated with late-onset bloodstream infections (BSIs) in infants with intestinal failure (IF) as a consequence of necrotizing enterocolitis (NEC). Study design Infants weighing 401-1500 g at birth who survived for >72 hours and received car

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

    Directory of Open Access Journals (Sweden)

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

    Science.gov (United States)

    Graf, Fabrice E; Baker, Nicola; Munday, Jane C; de Koning, Harry P; Horn, David; Mäser, Pascal

    2015-08-01

    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.

  15. Phylogeny of Trypanosoma brucei and Trypanosoma evansi in naturally infected cattle in Nigeria by analysis of repetitive and ribosomal DNA sequences.

    Science.gov (United States)

    Takeet, Michael I; Peters, Sunday O; Fagbemi, Benjamin O; De Donato, Marcos; Takeet, Vivian O; Wheto, Mathew; Imumorin, Ikhide G

    2016-08-01

    In continuing efforts to better understand the genetics of bovine trypanosomosis, we assessed genetic diversity of Trypanosoma brucei and Trypanosoma evansi in naturally infected Nigerian cattle using repetitive DNA and internal transcribed spacer 1 of rDNA sequences and compared these sequences to species from other countries. The length of repetitive DNA sequences in both species ranged from 161 to 244 bp and 239 to 240 bp for T. brucei and T. evansi, respectively, while the ITS1 rDNA sequences length range from 299 to 364 bp. The mean GC content of ITS1 rDNA sequences was 33.57 %, and that of repetitive sequences were 39.9 and 31.1 % for T. brucei and T. evansi, respectively. Result from sequence alignment revealed both T. brucei and T. evansi repetitive DNA sequences to be more polymorphic than ITS1 rDNA sequences, with moderate points of deletion and insertions. T. brucei separated into two clades when subjected to phylogenetic analysis. T. evansi repetitive DNA sequences clustered tightly within the T. brucei clade while the ITS1 rDNA sequences of T. brucei were clearly separated from T. theileri and T. vivax individually used as outgroups. This study suggest that ITS1 rDNA sequences may not be suitable for phylogenetic differentiation of the Trypanozoon group and also suggest that T. evansi may be a phenotypic variant of T. brucei which may have potential implications in designing prevention and therapeutic strategies.

  16. The contribution of chromosomal translocations to antigenic variation in Trypanosoma brucei.

    Science.gov (United States)

    Van der Ploeg, L H; Cornelissen, A W

    1984-11-13

    Genomic rearrangements influencing gene expression occur throughout nature. Several of these rearrangements disrupt normal gene expression, as exemplified by the genetic alterations caused by the mobile genetic elements of maize or Drosophila (see Shapiro 1983). Other rearrangements are part of the normal developmental programme of an organism. An understanding of the control of genomic rearrangements and their effects on gene expression should contribute to our insight into the mechanism of genetic programming and cellular development. The protozoan parasite Trypanosoma brucei exhibits a variety of genomic rearrangements that influence the expression of genes that code for versions of the variant surface glycoprotein (v.s.g.), which makes up the cell surface coat. V.s.g. genes are expressed in a mutually exclusive manner. Several v.s.g. genes are activated by duplicative transposition of the gene to a telomeric expression site where they are transcribed, while others can be activated without detectable genomic rearrangements. Recently we have been able to fractionate the chromosomes of T. brucei in agarose gels (Van der Ploeg et al. 1984 a). This led to the observations that duplicative transpositions occur inter-chromosomally and that the chromosomes of T. brucei are subject to frequent recombinations that displace hundreds of kilobase pairs. At least two and possibly more telomeric expression sites can be used for v.s.g. gene transcription. How these sites are activated and inactivated is still unsolved, but this does not depend on recombinations in the vicinity of the gene. Gross genomic rearrangements occur sometimes in correlation with antigenic switching and this suggests that such rearrangements have a function in regulating the mutually exclusive transcription of the different expression sites. V.s.g. genes consist of two exons. No physical linkage of the 35 nucleotide (n.t.) mini-exon to the v.s.g. gene main exon occurred within 15 kilobase pairs in

  17. Mapping replication dynamics in Trypanosoma brucei reveals a link with telomere transcription and antigenic variation.

    Science.gov (United States)

    Devlin, Rebecca; Marques, Catarina A; Paape, Daniel; Prorocic, Marko; Zurita-Leal, Andrea C; Campbell, Samantha J; Lapsley, Craig; Dickens, Nicholas; McCulloch, Richard

    2016-05-26

    Survival of Trypanosoma brucei depends upon switches in its protective Variant Surface Glycoprotein (VSG) coat by antigenic variation. VSG switching occurs by frequent homologous recombination, which is thought to require locus-specific initiation. Here, we show that a RecQ helicase, RECQ2, acts to repair DNA breaks, including in the telomeric site of VSG expression. Despite this, RECQ2 loss does not impair antigenic variation, but causes increased VSG switching by recombination, arguing against models for VSG switch initiation through direct generation of a DNA double strand break (DSB). Indeed, we show DSBs inefficiently direct recombination in the VSG expression site. By mapping genome replication dynamics, we reveal that the transcribed VSG expression site is the only telomeric site that is early replicating - a differential timing only seen in mammal-infective parasites. Specific association between VSG transcription and replication timing reveals a model for antigenic variation based on replication-derived DNA fragility.

  18. Trypanosoma brucei Parasites Occupy and Functionally Adapt to the Adipose Tissue in Mice

    OpenAIRE

    Trindade, Sandra; Rijo-Ferreira, Filipa; Carvalho, Tânia; Pinto-Neves, Daniel; Guegan, Fabien; Aresta-Branco, Francisco; Bento, Fabio; Young, Simon A.; Pinto, Andreia; Van Den Abbeele, Jan; Ribeiro, Ruy M.; Dias, Sérgio; Smith, Terry K.; Figueiredo, Luisa M.

    2016-01-01

    This work was supported by 55007419 (HHMI) and 2151 (EMBO) to L.M.F., D.P.-N., F.B., and F.G.; FCT fellowships to S.T., F.R.-F., and F.A.-B. (SFRH/BPD/89833/2012, SFRH/BD/51286/2010, and SFRH/BD/80718/2011, respectively); Wellcome Trust grant (093228), MRC MR/M020118/1, and European Community Seventh Framework Programme under grant agreement No. 602773 (Project KINDRED) to S.A.Y. and T.K.S.; and PAI 7/41 (Belspo) and ERC-NANOSYM to J.V.D.A. Trypanosoma brucei is an extracellular parasite t...

  19. Domestic animals as potential reservoir hosts of Trypanosoma brucei gambiense in sleeping sickness foci in Cameroon

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    Njiokou F.

    2010-03-01

    Full Text Available An explanation of the endemic nature and/or the resurgence of Human African Trypanosomiasis (HAT in the historic foci in West and Central Africa may be the existence of an animal reservoir. In some HAT foci, pigs were found infected by Trypanosoma brucei gambiense but the implication of the other domestic animals was not quite evaluated. This study aims to determine the prevalence of T. b. gambiense in domestic animal species (goat, sheep, pig and dog commonly found in the four active HAT foci in Cameroon (Bipindi, Fontem, Campo and Doumé. Blood samples were collected from 307 pigs, 264 goats, 267 sheep and 37 dogs and used for parasitological (QBC, immunological (LiTat 1.3 CATT and molecular (PCR analyses. QBC detected trypanosomes in 3.88 % domestic animals while 22.7 % were sero-positive with LiTat 1.3 CATT tests. Of the 875 animals analysed, 174 (19.88 % harboured T. brucei s.l. DNA, found in each of the four types of animal and in the four localities. The infection rate significantly differed among the animal species (p < 0.0001 and localities (p < 0.0001. The PCR also revealed T. b. gambiense group 1 DNA in 27 (3.08 % domestic animals. The specific infection rates were as follows: sheep (6.74 %, goats (3.08 %, pigs (0.32 % and dogs (0 %. T. b. gambiense was found in 8 (3.92 % animals from Bipindi, 15 (4.83 % from Campo, 4 (2.59 % from Fontem-Center and none from Doumé. The infection rates significantly differed between the localities, and correlated with the intensity of HAT transmission in the foci.

  20. 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.

  1. Knockdown of Inner Arm Protein IC138 in Trypanosoma brucei Causes Defective Motility and Flagellar Detachment.

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    Corinne S Wilson

    Full Text Available Motility in the protozoan parasite Trypanosoma brucei is conferred by a single flagellum, attached alongside the cell, which moves the cell forward using a beat that is generated from tip-to-base. We are interested in characterizing components that regulate flagellar beating, in this study we extend the characterization of TbIC138, the ortholog of a dynein intermediate chain that regulates axonemal inner arm dynein f/I1. TbIC138 was tagged In situ-and shown to fractionate with the inner arm components of the flagellum. RNAi knockdown of TbIC138 resulted in significantly reduced protein levels, mild growth defect and significant motility defects. These cells tended to cluster, exhibited slow and abnormal motility and some cells had partially or fully detached flagella. Slight but significant increases were observed in the incidence of mis-localized or missing kinetoplasts. To document development of the TbIC138 knockdown phenotype over time, we performed a detailed analysis of flagellar detachment and motility changes over 108 hours following induction of RNAi. Abnormal motility, such as slow twitching or irregular beating, was observed early, and became progressively more severe such that by 72 hours-post-induction, approximately 80% of the cells were immotile. Progressively more cells exhibited flagellar detachment over time, but this phenotype was not as prevalent as immotility, affecting less than 60% of the population. Detached flagella had abnormal beating, but abnormal beating was also observed in cells with no flagellar detachment, suggesting that TbIC138 has a direct, or primary, effect on the flagellar beat, whereas detachment is a secondary phenotype of TbIC138 knockdown. Our results are consistent with the role of TbIC138 as a regulator of motility, and has a phenotype amenable to more extensive structure-function analyses to further elucidate its role in the control of flagellar beat in T. brucei.

  2. 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.

  3. 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

  4. [A retrospective study of the relationship between bacterial numbers from central venous catheter tip cultures and blood cultures for evaluating central line-associated bloodstream infections].

    Science.gov (United States)

    Ohtaki, Hirofumi; Ohkusu, Kiyofumi; Nakayama, Asami; Yonetamari, Jun; Ando, Kohei; Miyazaki, Takashi; Ohta, Hirotoshi; Furuta, Nobuyuki; Watanabe, Tamayo; Ito, Hiroyasu; Murakami, Nobuo; Seishima, Mitsuru

    2014-01-01

    Catheter-related bloodstream infection (CRBSI) is an infectious disease requiring special attention. It is a common cause of nosocomial infections; catheter insertion into the central veins particularly increases the risk of infection (CLA-BSI: central line-associated bloodstream infection). We examined the relationship between the number of bacterial colonies cultured from shredded central venous catheter (CVC) tips and from blood cultures in our hospital from 2011 to 2012. Coagulase-negative staphylococci topped the list of microbe isolated from the CVC tip culture, followed by Pseudomonas aeruginosa, Staphylococcus aureus, and Candida spp. S. aureus and Candida spp., with growth of over 15 colony-forming units in the CVC tip culture, were also detected at high rates in the blood culture. However, gramnegative bacilli (Enterobacteriaceae and P. aeruginosa) did not show a similar increase in colony number in the CVC tip culture. Because microbes adhering to shredded catheter tips are readily detected by culture, this method is useful as a routine diagnostic test. In addition, prompt clinical reporting of the bacterial number of serious CLA-BSI-causing S. aureus and Candida spp. isolated from CVC tips could contribute to earlier CLA-BSI diagnosis.

  5. 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

    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

  6. 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

  7. 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.

  8. 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.

  9. Enterococcal bloodstream infection. Design and validation of a mortality prediction rule

    OpenAIRE

    Perez-Garcia, Alejandra; Landecho, Manuel; Beunza Nuin, Juan Jose; Conde-Estévez, D; Horcajada, J.P.; Grau, S.; Gea Sánchez, Alfredo; E. Mauleón; Sorli, L.; Gómez, J.; Terradas, R.; Lucena, J.F. (Juan F.); Alegre Garrido, Félix; A. Huerta; Pozo, José Luis del

    2016-01-01

    To develop a prediction rule to describe the risk of death as a result of enterococcal bloodstream infection. A prediction rule was developed by analysing data collected from 122 patients diagnosed with enterococcal BSI admitted to the Clínica Universidad de Navarra (Pamplona, Spain); and validated by confirming its accuracy with the data of an external population (Hospital del Mar, Barcelona). According to this model, independent significant predictors for the risk of death were being diabet...

  10. Risk of vancomycin-resistant enterococci bloodstream infection among patients colonized with vancomycin-resistant enterococci

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    Ahu Kara

    2015-02-01

    Full Text Available Background:Vancomycin-resistant enterococci colonization has been reported to increase the risk of developing infections, including bloodstream infections.Aim:In this study, we aimed to share our experience with the vancomycin-resistant enterococci bloodstream infections following gastrointestinal vancomycin-resistant enterococci colonization in pediatric population during a period of 18 months.Method:A retrospective cohort of children admitted to a 400-bed tertiary teaching hospital in Izmir, Turkey whose vancomycin-resistant enterococci colonization was newly detected during routine surveillances for gastrointestinal vancomycin-resistant enterococci colonization during the period of January 2009 and December 2012 were included in this study. All vancomycin-resistant enterococci isolates found within 18 months after initial detection were evaluated for evidence of infection.Findings: Two hundred and sixteen patients with vancomycin-resistant enterococci were included in the study. Vancomycin-resistant enterococci colonization was detected in 136 patients (62.3% while they were hospitalized at intensive care units; while the remaining majority (33.0% were hospitalized at hematology-oncology department. Vancomycinresistant enterococci bacteremia was present only in three (1.55% patients. All these patients were immunosuppressed due to human immunodeficiency virus (one patient and intensive chemotherapy (two patients.Conclusion:In conclusion, our study found that 1.55% of vancomycin-resistant enterococcicolonized children had developed vancomycin-resistant enterococci bloodstream infection among the pediatric intensive care unit and hematology/oncology patients; according to our findings, we suggest that immunosupression is the key point for developing vancomycinresistant enterococci bloodstream infections.

  11. 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.

  12. Second-Generation central venous catheter in the prevention of bloodstream infection: a systematic review 1

    Science.gov (United States)

    Stocco, Janislei Gislei Dorociaki; Hoers, Hellen; Pott, Franciele Soares; Crozeta, Karla; Barbosa, Dulce Aparecida; Meier, Marineli Joaquim

    2016-01-01

    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. PMID:27508901

  13. Cost-Effectiveness of Surveillance for Bloodstream Infections for Sepsis Management in Low-Resource Settings.

    Science.gov (United States)

    Penno, Erin C; Baird, Sarah J; Crump, John A

    2015-10-01

    Bacterial sepsis is a leading cause of mortality among febrile patients in low- and middle-income countries, but blood culture services are not widely available. Consequently, empiric antimicrobial management of suspected bloodstream infection is based on generic guidelines that are rarely informed by local data on etiology and patterns of antimicrobial resistance. To evaluate the cost-effectiveness of surveillance for bloodstream infections to inform empiric management of suspected sepsis in low-resource areas, we compared costs and outcomes of generic antimicrobial management with management informed by local data on etiology and patterns of antimicrobial resistance. We applied a decision tree model to a hypothetical population of febrile patients presenting at the district hospital level in Africa. We found that the evidence-based regimen saved 534 more lives per 100,000 patients at an additional cost of $25.35 per patient, resulting in an incremental cost-effectiveness ratio of $4,739. This ratio compares favorably to standard cost-effectiveness thresholds, but should ultimately be compared with other policy-relevant alternatives to determine whether routine surveillance for bloodstream infections is a cost-effective strategy in the African context.

  14. Trypanosoma brucei rhodesiense infection in a German traveller returning from the Masai Mara area, Kenya, January 2012.

    Science.gov (United States)

    Wolf, T; Wichelhaus, T; Gottig, S; Kleine, C; Brodt, H R; Just-Nuebling, G

    2012-03-08

    In January 2012, a case of Human African Trypanosomiasis (HAT) has been identified in Germany in a traveller returning from the Masai Mara area in Kenya. The 62-year-old man had travelled to the Masai Mara game park from 18 to 19 January 2012 and developed fever on 28 January. The infection with Trypanosoma brucei rhodesiense was confirmed by laboratory testing three days hereafter.

  15. Evolutionary consequences of a large duplication event in Trypanosoma brucei: Chromosomes 4 and 8 are partial duplicons

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    Jackson Andrew P

    2007-11-01

    Full Text Available Abstract Background Gene order along the genome sequence of the human parasite Trypanosoma brucei provides evidence for a 0.5 Mb duplication, comprising the 3' regions of chromosomes 4 and 8. Here, the principal aim was to examine the contribution made by this duplication event to the T. brucei genome sequence, emphasising the consequences for gene content and the evolutionary change subsequently experienced by paralogous gene copies. The duplicated region may be browsed online at http://www.genedb.org/genedb/tryp/48dup_image.jsp Results Comparisons of trypanosomatid genomes demonstrated widespread gene loss from each duplicon, but also showed that 47% of duplicated genes were retained on both chromosomes as paralogous loci. Secreted and surface-expressed genes were over-represented among retained paralogs, reflecting a bias towards important factors at the host-parasite interface, and consistent with a dosage-balance hypothesis. Genetic divergence in both coding and regulatory regions of retained paralogs was bimodal, with a deficit in moderately divergent paralogs; in particular, non-coding sequences were either conserved or entirely remodelled. The conserved paralogs included examples of remarkable sequence conservation, but also considerable divergence of both coding and regulatory regions. Sequence divergence typically displayed strong negative selection; but several features, such as asymmetric evolutionary rates, positively-selected codons and other non-neutral substitutions, suggested that divergence of some paralogs was driven by functional change. The absence of orthologs to retained paralogs in T. congolense indicated that the duplication event was specific to T. brucei. Conclusion The duplication of this chromosomal region doubled the dosage of many genes. Rather than creating 'more of the same', these results show that paralogs were structurally modified according to various evolutionary trajectories. The retention of paralogs, and

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

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    Temidayo O Omobowale

    2015-01-01

    Full Text Available Introduction: The medicinal properties of Azadirachta indica have been harnessed for many years in the treatment of many diseases in both humans and animals. Materials and Methods: 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. Results: 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 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. Conclusion: From this study, MEAI showed significant ability to attenuate oxidative stress and inflammation during experimental T. brucei infection.

  17. Murine Models for Trypanosoma brucei gambiense disease progression--from silent to chronic infections and early brain tropism.

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    Christiane Giroud

    Full Text Available Human African trypanosomiasis (HAT caused by Trypanosoma brucei gambiense remains highly prevalent in west and central Africa and is lethal if left untreated. The major problem is that the disease often evolves toward chronic or asymptomatic forms with low and fluctuating parasitaemia producing apparently aparasitaemic serological suspects who remain untreated because of the toxicity of the chemotherapy. Whether the different types of infections are due to host or parasite factors has been difficult to address, since T. b. gambiense isolated from patients is often not infectious in rodents thus limiting the variety of isolates.T. b. gambiense parasites were outgrown directly from the cerebrospinal fluid of infected patients by in vitro culture and analyzed for their molecular polymorphisms. Experimental murine infections showed that these isolates could be clustered into three groups with different characteristics regarding their in vivo infection properties, immune response and capacity for brain invasion. The first isolate induced a classical chronic infection with a fluctuating blood parasitaemia, an invasion of the central nervous system (CNS, a trypanosome specific-antibody response and death of the animals within 6-8 months. The second group induced a sub-chronic infection resulting in a single wave of parasitaemia after infection, followed by a low parasitaemia with no parasites detected by microscope observations of blood but detected by PCR, and the presence of a specific antibody response. The third isolate induced a silent infection characterised by the absence of microscopically detectable parasites throughout, but infection was detectable by PCR during the whole course of infection. Additionally, specific antibodies were barely detectable when mice were infected with a low number of this group of parasites. In both sub-chronic and chronic infections, most of the mice survived more than one year without major clinical symptoms

  18. Quantitative Mass Spectrometry-Based Analysis of β-D-Glucosyl-5-Hydroxymethyluracil in Genomic DNA of Trypanosoma brucei

    Science.gov (United States)

    Liu, Shuo; Ji, Debin; Cliffe, Laura; Sabatini, Robert; Wang, Yinsheng

    2014-10-01

    β-D-glucosyl-5-hydroxymethyluracil (base J) is a hyper-modified nucleobase found in the nuclear DNA of kinetoplastid parasites. With replacement of a fraction of thymine in DNA, J is localized primarily in telomeric regions of all organisms carrying this modified base. The biosynthesis of J occurs in two putative steps: first, a specific thymine in DNA is recognized and converted into 5-hydroxymethyluracil (5-HmU) by J-binding proteins (JBP1 and JBP2); a glucosyl transferase (GT) subsequently glucosylates the 5-HmU to yield J. Although several recent studies revealed the roles of internal J in regulating transcription in kinetoplastids, functions of telomeric J and proteins involved in J synthesis remain elusive. Assessing the functions of base J and understanding fully its biosynthesis necessitate the measurement of its level in cells and organisms. In this study, we reported a reversed-phase HPLC coupled with tandem mass spectrometry (LC-MS/MS) method, together with the use of a surrogate internal standard (β-D-glucosyl-5-hydroxymethyl-2'-deoxycytidine, 5-gHmdC), for the accurate detection of β-D-glucosyl-5-hydroxymethyl-2'-deoxyuridine (dJ) in Trypanosoma brucei DNA. For comparison, we also measured the level of the precursor for dJ synthesis [i.e. 5-hydroxymethyl-2'-deoxyuridine (5-HmdU)]. We found that base J was not detectable in the JBP-null cells whereas it replaced approximately 0.5% thymine in wild-type cells, which was accompanied with a markedly decreased level of 5-HmdU in JBP1/JBP2-null strain relative to the wild-type strain. These results provided direct evidence supporting that JBP proteins play an important role in oxidizing thymidine to form 5-HmdU, which facilitated the generation of dJ. This is the first report about the application of LC-MS/MS for the quantification of base J. The analytical method built a solid foundation for dissecting the molecular mechanisms of J biosynthesis and assessing the biological functions of base J in the

  19. National Bloodstream Infection Surveillance in Switzerland 2008-2014: Different Patterns and Trends for University and Community Hospitals.

    Science.gov (United States)

    Buetti, Niccolò; Marschall, Jonas; Atkinson, Andrew; Kronenberg, Andreas

    2016-09-01

    OBJECTIVE To characterize the epidemiology of bloodstream infections in Switzerland, comparing selected pathogens in community and university hospitals. DESIGN Observational, retrospective, multicenter laboratory surveillance study. METHODS Data on bloodstream infections from 2008 through 2014 were obtained from the Swiss infection surveillance system, which is part of the Swiss Centre for Antibiotic Resistance (ANRESIS). We compared pathogen prevalences across 26 acute care hospitals. A subanalysis for community-acquired and hospital-acquired bloodstream infections in community and university hospitals was performed. RESULTS A total of 42,802 bloodstream infection episodes were analyzed. The most common etiologies were Escherichia coli (28.3%), Staphylococcus aureus (12.4%), and polymicrobial bloodstream infections (11.4%). The proportion of E. coli increased from 27.5% in 2008 to 29.6% in 2014 (P = .04). E. coli and S. aureus were more commonly reported in community than university hospitals (34.3% vs 22.7%, P<.001 and 13.9% vs 11.1%, P<.001, respectively). Fifty percent of episodes were community-acquired, with E. coli again being more common in community hospitals (41.0% vs 32.4%, P<.001). The proportion of E. coli in community-acquired bloodstream infections increased in community hospitals only. Community-acquired polymicrobial infections (9.9% vs 5.6%, P<.001) and community-acquired coagulase-negative staphylococci (6.7% vs 3.4%, P<0.001) were more prevalent in university hospitals. CONCLUSIONS The role of E. coli as predominant pathogen in bloodstream infections has become more pronounced. There are distinct patterns in community and university hospitals, potentially influencing empirical antibiotic treatment. Infect Control Hosp Epidemiol 2016;37:1060-1067.

  20. Lead optimization of a pyrazole sulfonamide series of Trypanosoma brucei N-myristoyltransferase inhibitors: identification and evaluation of CNS penetrant compounds as potential treatments for stage 2 human African trypanosomiasis.

    Science.gov (United States)

    Brand, Stephen; Norcross, Neil R; Thompson, Stephen; Harrison, Justin R; Smith, Victoria C; Robinson, David A; Torrie, Leah S; McElroy, Stuart P; Hallyburton, Irene; Norval, Suzanne; Scullion, Paul; Stojanovski, Laste; Simeons, Frederick R C; van Aalten, Daan; Frearson, Julie A; Brenk, Ruth; Fairlamb, Alan H; Ferguson, Michael A J; Wyatt, Paul G; Gilbert, Ian H; Read, Kevin D

    2014-12-11

    Trypanosoma brucei N-myristoyltransferase (TbNMT) is an attractive therapeutic target for the treatment of human African trypanosomiasis (HAT). From previous studies, we identified pyrazole sulfonamide, DDD85646 (1), a potent inhibitor of TbNMT. Although this compound represents an excellent lead, poor central nervous system (CNS) exposure restricts its use to the hemolymphatic form (stage 1) of the disease. With a clear clinical need for new drug treatments for HAT that address both the hemolymphatic and CNS stages of the disease, a chemistry campaign was initiated to address the shortfalls of this series. This paper describes modifications to the pyrazole sulfonamides which markedly improved blood-brain barrier permeability, achieved by reducing polar surface area and capping the sulfonamide. Moreover, replacing the core aromatic with a flexible linker significantly improved selectivity. This led to the discovery of DDD100097 (40) which demonstrated partial efficacy in a stage 2 (CNS) mouse model of HAT.

  1. Changes in blood sugar levels of rats experimentally infected withTrypanosoma brucei and treated with imidocarb dipropionate and diminazene aceturate

    Institute of Scientific and Technical Information of China (English)

    Nwoha Rosemary Ijeoma Ogechi; Omamegbe Joseph Omalathebu

    2016-01-01

    Objective:To determine the effect ofTrypanosoma brucei (T. brucei) on blood sugar level of infected rats. Methods: The experiment was done with 42 albino rats grouped into 3 groups of 14 members each. Group A was uninfected (control group), Group B was infected withT. brucei and treated with diminazene aceturate, and Group C was infected withT. brucei and treated with imidocarb dipropionate. Blood samples were collected from the media canthus of the experimental rats on Days 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 for the assessment of change in blood sugar levels. The blood sugar levels were determined with a glucometer (Accu-chek active serialNo.GN:10023338). Results: By 4 to 5 days post infection, there was a significant increase (P 0.05) was observed in the groups when compared with the control group till Day 12 of the experiment. Conclusions:T. brucei caused a significant increase in blood sugar of infected rats.

  2. Transport proteins determine drug sensitivity and resistance in a protozoan parasite, Trypanosoma brucei

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    Jane Claire Munday

    2015-03-01

    Full Text Available Drug resistance in pathogenic protozoa is very often caused by changes to the ‘transportome’ of the parasites. In Trypanosoma brucei, several transporters have been implicated in uptake of the main classes of drugs, diamidines and melaminophenyl arsenicals. The resistance mechanism had been thought to be due to loss of a transporter known to carry both types of agents: the aminopurine transporter P2, encoded by the gene TbAT1. However, although loss of P2 activity is well-documented as the cause of resistance to the veterinary diamidine diminazene aceturate (Berenil®, cross-resistance between the human-use arsenical melarsoprol and the diamidine pentamidine (MPXR is the result of loss of a separate High Affinity Pentamidine Transporter (HAPT1. A genome-wide RNAi library screen for resistance to pentamidine, published in 2012, gave the key to the genetic identity of HAPT1 by linking the phenomenon to a locus that contains the closely related T. brucei aquaglyceroporin genes TbAQP2 and TbAQP3. Further analysis determined that knockdown of only one pore, TbAQP2, produced the MPXR phenotype. TbAQP2 is an unconventional aquaglyceroporin with unique residues in the selectivity region of the pore, and it was found that in several MPXR lab strains the WT gene was either absent or replaced by a chimeric protein, recombined with parts of TbAQP3. Importantly, wild-type AQP2 was also absent in field isolates of T. b. gambiense, correlating with the outcome of melarsoprol treatment. Expression of a wild-type copy of TbAQP2 in even the most resistant strain completely reversed MPXR and re-introduced HAPT1 function and transport kinetics. Expression of TbAQP2 in Leishmania mexicana introduced a pentamidine transport activity indistinguishable from HAPT1. Although TbAQP2 has been shown to function as a classical aquaglyceroporin it is now clear that it is also a high affinity drug transporter, HAPT1. We discuss here a possible structural rationale for this

  3. Transport proteins determine drug sensitivity and resistance in a protozoan parasite, Trypanosoma brucei

    Science.gov (United States)

    Munday, Jane C.; Settimo, Luca; de Koning, Harry P.

    2015-01-01

    Drug resistance in pathogenic protozoa is very often caused by changes to the ‘transportome’ of the parasites. In Trypanosoma brucei, several transporters have been implicated in uptake of the main classes of drugs, diamidines and melaminophenyl arsenicals. The resistance mechanism had been thought to be due to loss of a transporter known to carry both types of agents: the aminopurine transporter P2, encoded by the gene TbAT1. However, although loss of P2 activity is well-documented as the cause of resistance to the veterinary diamidine diminazene aceturate (DA; Berenil®), cross-resistance between the human-use arsenical melarsoprol and the diamidine pentamidine (melarsoprol/pentamidine cross resistance, MPXR) is the result of loss of a separate high affinity pentamidine transporter (HAPT1). A genome-wide RNAi library screen for resistance to pentamidine, published in 2012, gave the key to the genetic identity of HAPT1 by linking the phenomenon to a locus that contains the closely related T. brucei aquaglyceroporin genes TbAQP2 and TbAQP3. Further analysis determined that knockdown of only one pore, TbAQP2, produced the MPXR phenotype. TbAQP2 is an unconventional aquaglyceroporin with unique residues in the “selectivity region” of the pore, and it was found that in several MPXR lab strains the WT gene was either absent or replaced by a chimeric protein, recombined with parts of TbAQP3. Importantly, wild-type AQP2 was also absent in field isolates of T. b. gambiense, correlating with the outcome of melarsoprol treatment. Expression of a wild-type copy of TbAQP2 in even the most resistant strain completely reversed MPXR and re-introduced HAPT1 function and transport kinetics. Expression of TbAQP2 in Leishmania mexicana introduced a pentamidine transport activity indistinguishable from HAPT1. Although TbAQP2 has been shown to function as a classical aquaglyceroporin it is now clear that it is also a high affinity drug transporter, HAPT1. We discuss here a

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

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    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. Crystal structures and inhibition of Trypanosoma brucei hypoxanthine–guanine phosphoribosyltransferase

    Science.gov (United States)

    Terán, David; Hocková, Dana; Česnek, Michal; Zíková, Alena; Naesens, Lieve; Keough, Dianne T.; Guddat, Luke W.

    2016-01-01

    Human African Trypanosomiasis (HAT) is a life-threatening infectious disease caused by the protozoan parasite, Trypanosoma brucei (Tbr). Due to the debilitating side effects of the current therapeutics and the emergence of resistance to these drugs, new medications for this disease need to be developed. One potential new drug target is 6-oxopurine phosphoribosyltransferase (PRT), an enzyme central to the purine salvage pathway and whose activity is critical for the production of the nucleotides (GMP and IMP) required for DNA/RNA synthesis within this protozoan parasite. Here, the first crystal structures of this enzyme have been determined, these in complex with GMP and IMP and with three acyclic nucleoside phosphonate (ANP) inhibitors. The Ki values for GMP and IMP are 30.5 μM and 77 μM, respectively. Two of the ANPs have Ki values considerably lower than for the nucleotides, 2.3 μM (with guanine as base) and 15.8 μM (with hypoxanthine as base). The crystal structures show that when two of the ANPs bind, they induce an unusual conformation change to the loop where the reaction product, pyrophosphate, is expected to bind. This and other structural differences between the Tbr and human enzymes suggest selective inhibitors for the Tbr enzyme can be designed. PMID:27786284

  6. Rediscovery of Trypanosoma (Pycnomonas) suis, a tsetse-transmitted trypanosome closely related to T. brucei.

    Science.gov (United States)

    Hutchinson, Rachel; Gibson, Wendy

    2015-12-01

    The African tsetse-transmitted trypanosomes are considered to be a well-known group of parasitic protozoa, but in 2008 a novel and distinctive trypanosome related to Trypanosoma brucei was discovered among tsetse isolates from Msubugwe in Tanzania. The host range, distribution and potential pathogenicity of this new trypanosome remain to be elucidated; such studies would be facilitated by a sensitive and specific identification method. Here, we identified two highly repetitive elements in the genome of the new trypanosome: a 177 bp repeat, which was located predominantly on the highly abundant minichromosomes, and a 138 bp repeat, which was widely dispersed in the genome. A PCR test based on each repeat was specific for the new trypanosome and sensitive to Trypanosoma (Pycnomonas) suis. We also present data on the molecular karyotype and spliced leader (SL, miniexon) repeat of the new trypanosome, both of which distinguish T. suis from other, better-known African tsetse-transmitted trypanosomes. The rediscovery of T. suis opens new lines of research into the evolution and biology of the African trypanosomes.

  7. Treatment and Outcomes in Carbapenem-resistant Klebsiella pneumoniae Bloodstream Infections

    Science.gov (United States)

    Neuner, Elizabeth A.; Yeh, Jun-Yen; Hall, Gerri S.; Sekeres, Jennifer; Endimiani, Andrea; Bonomo, Robert A.; Shrestha, Nabin K.; Fraser, Thomas G.; van Duin, David

    2010-01-01

    Carbapenem-resistant K. pneumoniae (CR-Kp) is an emerging multi-drug resistant nosocomial pathogen. This is a retrospective chart review describing the outcomes and treatment of 60 cases of CR-Kp bloodstream infections. All CR-Kp isolated from blood cultures were identified retrospectively from the microbiology laboratory from January 2007 to May 2009. Clinical information was collected from the electronic medical record. Patients with 14 day-hospital mortality were compared to those who survived 14 days. The all-cause in-hospital and 14-day mortality for all 60 CR-Kp bloodstream infections was 58.3% and 41.7%, respectively. In this collection, 98% of tested isolates were susceptible in vitro to tigecycline, compared to 86% to colistimethate, 45% to amikacin and 22% to gentamicin. Nine patients died prior to cultures being finalized, and received no therapy active against CR-Kp. In the remaining 51 patients, those who survived to day14 (n=35) were compared to non-survivor at day 14 (n=16). These patients were characterized by both chronic disease and acute illness. The 90-day readmission rate for hospital survivors was 72%. Time to active therapy was not significantly different between survivors and non-survivors, and hospital mortality was also similar regardless of therapy chosen. Pitt bacteremia score was the only significant factor associated with mortality in Cox regression analysis. In summary, CR-Kp bloodstream infections occur in patients who are chronically and acutely ill. They are associated with high 14-day mortality and poor outcomes regardless of tigecycline or other treatment regimens were selected. PMID:21396529

  8. 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 infected with 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 infection. Most (83/85, 97.6 %) non-typhoid 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.

  9. Control method exploration of nosocomial bloodstream infection and its effect evaluation

    Institute of Scientific and Technical Information of China (English)

    CHAI Wen-zhao; WANG Xiao-ting; ZHOU Jiong; LI Xin; LUO Hong-bo; LIU Da-wei

    2012-01-01

    Background Currently,slightly more than 50% of bloodstream infections (BSIs) are hospital acquired.When these infections occur in patients in intensive care units,they are associated with a high mortality rate,additional hospital days and excess hospital costs.Because of multifactor of nosocomial BSIs,measurements of control nosocomial BSIs are wide variety and lead to some confusion in practice.The aim of this study was to explore special way in accordance with self-hospital base on common principle.Methods In one ward of the Intensive Care Unit,Peking Union Medical College Hospital,at first,we divided the all operation about bloodstream way into three sections used as keypoints.By surveying keypoints respectively,some operation faults of blood way were discovered.For decreasing the mobidity of nosocomial BSls,some intervention measurements were executed.The rate of nosocomial BSIs was analyzed by chi-square test.Results According to the statistics from January to June,we received and cured 618 patients in total; among them,there were 13 cases of nosocomial BSI and the average occurrence was 2.3 cases/month.After intervention measurements from July to December 2011,we received and cured 639 patients in total with seven cases of nosocomial BSI,and the average occurrence was 1.2 cases/month (P <0.05).From January to April 2012,no nosocomial BSI occurred in the investigated ward.Conclusion Removing the operation faults of bloodstream way might decrease the nosocomial BSI rapidly and efficiently by utilizing a key point survey.

  10. Bacillus cereus Bloodstream Infection in a Preterm Neonate Complicated by Late Meningitis

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    Toshinobu Horii

    2012-01-01

    Full Text Available Central nervous system infections caused by Bacillus cereus have rarely been reported in infants. In this paper, the case of a 2-month-old low-birth-weight female who developed meningitis 45 days after resolution of a bloodstream infection (BSI is described. The pulsed-field gel electrophoresis results revealed that the patterns of both B. cereus isolates responsible for the acute meningitis and for the prior bacteraemic episode were closely related. Although the source of the infection from within the patient was not clear, it is suggested that the B. cereus BSI developed in the neonate was complicated by acute meningitis.

  11. Taurolidine is effective in the treatment of central venous catheter-related bloodstream infections in cancer patients.

    Science.gov (United States)

    Koldehoff, M; Zakrzewski, J L

    2004-11-01

    Taurolidine is an antimicrobial agent that was originally used in the local treatment of peritonitis and was shown to be effective in the prevention of catheter-related bloodstream infections (CR-BSI). In this pilot study, we used taurolidine solution as an intravenous (i.v.) lock into the totally implantable intravascular devices of 11 consecutive oncological patients with catheter-related bloodstream infections not responding to systemic antimicrobial chemotherapy. All patients recovered completely from the infection. No adverse drug effects were seen. Three patients were successfully retreated for a recurrent infection. Our data suggest a beneficial role of taurolidine i.v. lock for the therapy of catheter-related bloodstream infections in oncological patients. Taurolidine i.v. lock application is feasible and could especially be useful in infections resistant to antibiotic chemotherapy.

  12. 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.

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

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    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.

  14.   Bloodstream Bacterial Pathogens and their Antibiotic Resistance Pattern in Dhahira Region, Oman

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    PP Geethanjali

    2011-07-01

    Full Text Available Objectives: To describe the epidemiological, clinical, microbiological characteristics and antimicrobial resistance pattern of Bloodstream infections in Dhahira region, Oman.Methods: Clinical data was collected from all patients with positive blood cultures for two years period. Standard laboratory methods were used for blood culture. Antibiotic sensitivity was tested using Kirby-Bauer disc diffusion method.Results: Of the 360 bacterial pathogens isolated from 348 patients, 57.8�0were gram-positive and 42.2�0were gram-negative. The common isolates were: Streptococcus species 76 (21.1� coagulase-negative Staphylococci 75 (20.8� Escherichia coli 43 (11.9� Staphylococcus aureus 41 (11.4� Overall, mortality was 21.3�0(74/348. Staphylococcus species (Staphylococcus aureus and CoNS were more commonly resistant to Trimethoprim/ Sulphamethoxazole (35.3�20and Penicillin (25.9� Streptococcus species were resistant to Trimethoprim/Sulphamethoxazole (39.1�20and Erythromycin (19.6�Conclusion: Bloodstream infections are important causes of morbidity and mortality in our patients, especially among chronically ill elderly adult males. Prescription of proven resistant antibiotics to suspected bacteremic patients needs attention in Dhahira region.

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

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    Mariana V. Arnoni

    2007-04-01

    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.

  16. Exchange of peripherally inserted central catheters is associated with an increased risk for bloodstream infection.

    Science.gov (United States)

    McCoy, Michael; Bedwell, Susan; Noori, Shahab

    2011-06-01

    It is not uncommon that the peripherally inserted central catheter (PICC) needs to be replaced either due to blockage or migration to a peripheral position. In such circumstances, there are two methods of PICC placement: new-site insertion and exchange by using the old PICC as a guide wire. Our objective was to investigate risk of infection associated with the exchange method. In this retrospective study, data on all PICC insertions in the neonatal intensive care unit in 2004 to 2008 were obtained. In the population who needed removal of existing PICC and insertion of a new one, we compared central line-associated bloodstream infection (CLABSI) within 1 week of insertion between the two insertion methods. Of 1148 PICC insertions reviewed, 164 (103 new-site and 61 exchange insertions) were performed after removal of a blocked/malpositioned PICC and therefore comprised the study population. The rate of CLABSI was higher in the exchange method (9.8% versus 1%, P exchange method (odds ratio 25.2, 95% confidence interval: 2.17 to 292.98; P = 0.01). In infants, insertion of PICCs using the exchange method carries an increased risk of bloodstream infection.

  17. Trypanosoma brucei gambiense adaptation to different mammalian sera is associated with VSG expression site plasticity.

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    Carlos Cordon-Obras

    Full Text Available Trypanosoma brucei gambiense infection is widely considered an anthroponosis, although it has also been found in wild and domestic animals. Thus, fauna could act as reservoir, constraining the elimination of the parasite in hypo-endemic foci. To better understand the possible maintenance of T. b. gambiense in local fauna and investigate the molecular mechanisms underlying adaptation, we generated adapted cells lines (ACLs by in vitro culture of the parasites in different mammalian sera. Using specific antibodies against the Variant Surface Glycoproteins (VSGs we found that serum ACLs exhibited different VSG variants when maintained in pig, goat or human sera. Although newly detected VSGs were independent of the sera used, the consistent appearance of different VSGs suggested remodelling of the co-transcribed genes at the telomeric Expression Site (VSG-ES. Thus, Expression Site Associated Genes (ESAGs sequences were analysed to investigate possible polymorphism selection. ESAGs 6 and 7 genotypes, encoding the transferrin receptor (TfR, expressed in different ACLs were characterised. In addition, we quantified the ESAG6/7 mRNA levels and analysed transferrin (Tf uptake. Interestingly, the best growth occurred in pig and human serum ACLs, which consistently exhibited a predominant ESAG7 genotype and higher Tf uptake than those obtained in calf and goat sera. We also detected an apparent selection of specific ESAG3 genotypes in the pig and human serum ACLs, suggesting that other ESAGs could be involved in the host adaptation processes. Altogether, these results suggest a model whereby VSG-ES remodelling allows the parasite to express a specific set of ESAGs to provide selective advantages in different hosts. Finally, pig serum ACLs display phenotypic adaptation parameters closely related to human serum ACLs but distinct to parasites grown in calf and goat sera. These results suggest a better suitability of swine to maintain T. b. gambiense infection

  18. 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.

  19. Untreated human infections by Trypanosoma brucei gambiense are not 100% fatal.

    Directory of Open Access Journals (Sweden)

    Vincent Jamonneau

    Full Text Available The final outcome of infection by Trypanosoma brucei gambiense, the main agent of sleeping sickness, has always been considered as invariably fatal. While scarce and old reports have mentioned cases of self-cure in untreated patients, these studies suffered from the lack of accurate diagnostic tools available at that time. Here, using the most specific and sensitive tools available to date, we report on a long-term follow-up (15 years of a cohort of 50 human African trypanosomiasis (HAT patients from the Ivory Coast among whom 11 refused treatment after their initial diagnosis. In 10 out of 11 subjects who continued to refuse treatment despite repeated visits, parasite clearance was observed using both microscopy and polymerase chain reaction (PCR. Most of these subjects (7/10 also displayed decreasing serological responses, becoming progressively negative to trypanosome variable antigens (LiTat 1.3, 1.5 and 1.6. Hence, in addition to the "classic" lethal outcome of HAT, we show that alternative natural progressions of HAT may occur: progression to an apparently aparasitaemic and asymptomatic infection associated with strong long-lasting serological responses and progression to an apparently spontaneous resolution of infection (with negative results in parasitological tests and PCR associated with a progressive drop in antibody titres as observed in treated cases. While this study does not precisely estimate the frequency of the alternative courses for this infection, it is noteworthy that in the field national control programs encounter a significant proportion of subjects displaying positive serologic test results but negative results in parasitological testing. These findings demonstrate that a number of these subjects display such infection courses. From our point of view, recognising that trypanotolerance exists in humans, as is now widely accepted for animals, is a major step forward for future research in the field of HAT.

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

    Science.gov (United States)

    Yang, Lei; Lübeck, Mette; Ahring, Birgitte K; Lübeck, Peter S

    2016-02-01

    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 of the enzymes, pyruvate carboxylase (PYC), malate dehydrogenase (MDH), and fumarase (FUM), involved in the reductive tricarboxylic acid (rTCA) branch, were examined and compared in cells harvested from the acid production medium and a complete medium. The results showed that ambient pH had a significant impact 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 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 to an enhanced production of succinic acid in frd transformants compared with the wild-type in both pH buffered and pH non-buffered conditions with highest amount produced in the pH buffered condition (16.2 ± 0.5 g/L). This study demonstrates the feasibility of increasing succinic acid production through the cytosolic reductive pathway by genetic engineering in A. saccharolyticus.

  1. The F(0F(1-ATP synthase complex contains novel subunits and is essential for procyclic Trypanosoma brucei.

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    Alena Zíková

    2009-05-01

    Full Text Available The mitochondrial F(0F(1 ATP synthase is an essential multi-subunit protein complex in the vast majority of eukaryotes but little is known about its composition and role in Trypanosoma brucei, an early diverged eukaryotic pathogen. We purified the F(0F(1 ATP synthase by a combination of affinity purification, immunoprecipitation and blue-native gel electrophoresis and characterized its composition and function. We identified 22 proteins of which five are related to F(1 subunits, three to F(0 subunits, and 14 which have no obvious homology to proteins outside the kinetoplastids. RNAi silencing of expression of the F(1 alpha subunit or either of the two novel proteins showed that they are each essential for the viability of procyclic (insect stage cells and are important for the structural integrity of the F(0F(1-ATP synthase complex. We also observed a dramatic decrease in ATP production by oxidative phosphorylation after silencing expression of each of these proteins while substrate phosphorylation was not severely affected. Our procyclic T. brucei cells were sensitive to the ATP synthase inhibitor oligomycin even in the presence of glucose contrary to earlier reports. Hence, the two novel proteins appear essential for the structural organization of the functional complex and regulation of mitochondrial energy generation in these organisms is more complicated than previously thought.

  2. Complete coding sequence, sequence analysis and transmembrane topology modelling of Trypanosoma brucei rhodesiense putative oligosaccharyl transferase (TbOST II).

    Science.gov (United States)

    Baticados, Waren N; Inoue, Noboru; Sugimoto, Chihiro; Nagasawa, Hideyuki; Baticados, Abigail M

    2011-01-01

    The partial nucleotide sequence of putative Trypanosoma brucei rhodesiense oligosaccharyl transferase gene was previously reported. Here, we describe the determination of its full-length nucleotide sequence by Inverse PCR (IPCR), subsequent biological sequence analysis and transmembrane topology modelling. The full-length DNA sequence has an Open Reading Frame (ORF) of 2406 bp and encodes a polypeptide of 801 amino acid residues. Protein and DNA sequence analyses revealed that homologues within the genome of other kinetoplastid and various origins exist. Protein topology analysis predicted that Trypanosoma brucei rhodesiense putative oligosaccharyl transferase clone II (TbOST II) is a transmembrane protein with transmembrane helices in probably an N(cytosol)-C(cytosol) orientation. Data from the GenBank database assembly and sequence analyses in general clearly state that TbOST II is the STT3 subunit of OST in T.b. rhodesiense that necessitates further characterisation and functional studies with RNAi. TbOST II sequence had been deposited in the GenBank (accession number GU245937).

  3. 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.

  4. A proteomics approach reveals molecular manipulators of distinct cellular processes in the salivary glands of Glossina m. morsitans in response to Trypanosoma b. brucei infections

    NARCIS (Netherlands)

    Kariithi, Henry M.; Boeren, Sjef; Murungi, Edwin K.; Vlak, Just M.; Abd-Alla, Adly M.M.

    2016-01-01

    Background: Glossina m. morsitans is the primary vector of the Trypanosoma brucei group, one of the causative agents of African trypanosomoses. The parasites undergo metacyclogenesis, i.e. transformation into the mammalian-infective metacyclic trypomastigote (MT) parasites, in the salivary glands

  5. 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 expres

  6. 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 pre-em

  7. The Resistance Phenotype and Molecular Epidemiology of Klebsiella pneumoniae in Bloodstream Infections in Shanghai, China, 2012–2015

    Science.gov (United States)

    Xiao, Shu-zhen; Wang, Su; Wu, Wen-man; Zhao, Sheng-yuan; Gu, Fei-fei; Ni, Yu-xing; Guo, Xiao-kui; Qu, Jie-ming; Han, Li-zhong

    2017-01-01

    Klebsiella pneumoniae (K.pneumoniae) is a common nosocomial pathogen causing bloodstream infections. Antibiotic susceptibility surveillance and molecular characterization will facilitate prevention and management of K. pneumoniae bloodstream infections. K. pneumoniae isolates causing bloodstream infections were consecutively collected between January 2012 and December 2015 in Shanghai. Eighty isolates (20 per year) were randomly selected and enrolled in this study. Drug susceptibility were determined by the disk diffusion method. Polymerase chain reaction (PCR) was employed to detect extended-spectrum β-lactamases (ESBLs), carbapenemases, and seven housekeeping genes of K. pneumoniae. eBURST was used for multi-locus sequence typing (MLST). More than 50% isolates were resistant to cefuroxime, ampicillin-sulbactam, and piperacillin, while carbapenems had lower resistant rates than other antibiotics. Of the 80 isolates, 22 produced ESBLs, and 14 were carbapenemase producers. In the ESBL-producing K. pneumoniae isolates, the most common ESBL genes were blaSHV and blaCTX−M. Thirteen carbapenemase producers harbored blaKPC−2 and one other carried blaNDM−5. ST11 (14/80) was the most frequent sequence type (ST), followed by ST15 (7/80) and ST29 (4/80). Our data revealed high prevalence of antibiotic resistant K. pneumoniae isolates from bloodstream infections but their genetic diversity suggested no clonal dissemination in the region. Also, one K. pneumoniae isolate harbored blaNDM−5 in this study, which was firstly reported in Shanghai. PMID:28280486

  8. 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.

  9. 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

  10. A role for RAD51 and homologous recombination in Trypanosoma brucei antigenic variation.

    Science.gov (United States)

    McCulloch, R; Barry, J D

    1999-11-01

    Antigenic variation is an immune evasion strategy used by African trypanosomes, in which the parasites periodically switch the expression of VSG genes that encode their protective variant surface glycoprotein coat. Two main routes exist for VSG switching: changing the transcriptional status between an active and an inactive copy of the site of VSG expression, called the bloodstream VSG expression site, or recombination reactions that move silent VSGs or VSG copies into the actively transcribed expression site. Nothing is known about the proteins that control and catalyze these switching reactions. This study describes the cloning of a trypanosome gene encoding RAD51, an enzyme involved in DNA break repair and genetic exchange, and analysis of the role of the enzyme in antigenic variation. Trypanosomes genetically inactivated in the RAD51 gene were shown to be viable, and had phenotypes consistent with lacking functional expression of an enzyme of homologous recombination. The mutants had an impaired ability to undergo VSG switching, and it appeared that both recombinational and transcriptional switching reactions were down-regulated, indicating that RAD51 either catalyzes or regulates antigenic variation. Switching events were still detectable, however, so it appears that trypanosome factors other than RAD51 can also provide for antigenic variation.

  11. Taurolidine lock is superior to heparin lock in the prevention of catheter related bloodstream infections and occlusions.

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    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.

  12. APPROACH OF IMPROVING PRECISION IN ULTRASONIC DOPPLER BLOODSTREAM SPEED MEASUREMENT BY CHAOS-BASED FREQUENCY DETECTING

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    It is critical for cerebral vascular disease diagnosis through Doppler to detect the maximum and the minimum of the carotid blood flow speed accurately. A kind of Duffing system under an external periodic power with dump is introduced in the letter, numerical analysis is carried out by four-order Runge-Kutta method. An oscillator array is designed according to the frequency of the ultrasonic wave. When the external signals are inputted, computational algorithm is used to scan the array in turn and analyze the result, and the frequency can be determined. Based on the methods above, detecting the carotid blood flow speed accurately is realized. The Signal-to-Noise Ratio (SNR) of-20.23dB is obtained by the result of experiments. In conclusion, the SNR has been improved and the precision of the measured bloodstream speed has been increased,which can be 0.069% to 0.13%.

  13. Evidence-based measures to prevent central line-associated bloodstream infections: a systematic review

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    Daniele Cristina Perin

    Full Text Available ABSTRACT Objective: to identify evidence-based care to prevent CLABSI among adult patients hospitalized in ICUs. Method: systematic review conducted in the following databases: PubMed, Scopus, Cinahl, Web of Science, Lilacs, Bdenf and Cochrane Studies addressing care and maintenance of central venous catheters, published from January 2011 to July 2014 were searched. The 34 studies identified were organized in an instrument and assessed by using the classification provided by the Joanna Briggs Institute. Results: the studies presented care bundles including elements such as hand hygiene and maximal barrier precautions; multidimensional programs and strategies such as impregnated catheters and bandages and the involvement of facilities in and commitment of staff to preventing infections. Conclusions: care bundles coupled with education and the commitment of both staff and institutions is a strategy that can contribute to decreased rates of central line-associated bloodstream infections among adult patients hospitalized in intensive care units.

  14. Healthcare-associated Gram-negative bloodstream infections: antibiotic resistance and predictors of mortality.

    Science.gov (United States)

    Ergönül, Ö; Aydin, M; Azap, A; Başaran, S; Tekin, S; Kaya, Ş; Gülsün, S; Yörük, G; Kurşun, E; Yeşilkaya, A; Şimşek, F; Yılmaz, E; Bilgin, H; Hatipoğlu, Ç; Cabadak, H; Tezer, Y; Togan, T; Karaoğlan, I; İnan, A; Engin, A; Alışkan, H E; Yavuz, S Ş; Erdinç, Ş; Mulazimoglu, L; Azap, Ö; Can, F; Akalın, H; Timurkaynak, F

    2016-12-01

    This article describes the prevalence of antibiotic resistance and predictors of mortality for healthcare-associated (HA) Gram-negative bloodstream infections (GN-BSI). In total, 831 cases of HA GN-BSI from 17 intensive care units in different centres in Turkey were included; the all-cause mortality rate was 44%. Carbapenem resistance in Klebsiella pneumoniae was 38%, and the colistin resistance rate was 6%. Multi-variate analysis showed that age >70 years [odds ratio (OR) 2, 95% confidence interval (CI) 1.22-3.51], central venous catheter use (OR 2.1, 95% CI 1.09-4.07), ventilator-associated pneumonia (OR 1.9, 95% CI 1.1-3.16), carbapenem resistance (OR 1.8, 95% CI 1.11-2.95) and APACHE II score (OR 1.1, 95% CI 1.07-1.13) were significantly associated with mortality.

  15. Achromobacter Xylosoxidans Bloodstream Infection in Elderly Patient with Hepatocellular Carcinoma: Case Report and Review of Literature.

    Science.gov (United States)

    Raghuraman, Kausalya; Ahmed, Nishat H; Baruah, Frincy K; Grover, Rajesh K

    2015-01-01

    Achromobacter xylosoxidansis a nonfermentative Gram-negative organism, known to cause opportunistic infection in humans. We report a case of septicemia in a 76-year-old male patient with underlying hepatocellular carcinoma due to A. xylosoxidans, which showed a different antimicrobial susceptibility pattern from what is usually reported. From aerobic blood culture of the patient, A. xylosoxidans was isolated which was found to be sensitive to amoxicillin-clavulanic acid, piperacillin-tazobactam, ceftazidime, cefoperazone-sulbactam, meropenem, minocycline, tigecycline, and trimethoprim/sulfamethoxazole. The patient recovered with amoxicillin-clavulanic acid treatment, which was given empirically to the patient. The present case highlights the possible role of amoxicillin-clavulanic acid for treatment of bloodstream infection with A. xylosoxidans.

  16. Achromobacter Xylosoxidans bloodstream infection in elderly patient with Hepatocellular Carcinoma: Case report and review of literature

    Directory of Open Access Journals (Sweden)

    Kausalya Raghuraman

    2015-01-01

    Full Text Available Achromobacter xylosoxidansis a nonfermentative Gram-negative organism, known to cause opportunistic infection in humans. We report a case of septicemia in a 76-year-old male patient with underlying hepatocellular carcinoma due to A. xylosoxidans, which showed a different antimicrobial susceptibility pattern from what is usually reported. From aerobic blood culture of the patient, A. xylosoxidanswas isolated which was found to be sensitive to amoxicillin-clavulanic acid, piperacillin-tazobactam, ceftazidime, cefoperazone-sulbactam, meropenem, minocycline, tigecycline, and trimethoprim/sulfamethoxazole. The patient recovered with amoxicillin-clavulanic acid treatment, which was given empirically to the patient. The present case highlights the possible role of amoxicillin-clavulanic acid for treatment of bloodstream infection with A. xylosoxidans.

  17. Positive deviance as a strategy to prevent and control bloodstream infections in intensive care

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    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.

  18. 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

  19. Port central venous catheters-associated bloodstream infection during outpatient-based chemotherapy.

    Science.gov (United States)

    Mauri, Davide; Roumbkou, Sofia; Michalopoulou, Stella; Tsali, Lamprini; Spiliopoulou, Anastasia; Panou, Charalampos; Valachis, Antonis; Panagopoulos, Angelos; Polyzos, Nikolaos P

    2010-12-01

    Central venous catheters (CVCs) are commonly used for the administration of intravenous chemotherapy in outpatient setting. Nevertheless, outbreaks of catheter-associated bloodstream infections had been reported from oncology centers. We describe a large outbreak of CVCs-associated Klebsiella oxytoca bloodstream infection, occurring in an oncology chemotherapy outpatient unit of northern Greece between October 2006 and May 2007. The outbreak involved approximately 10% of the patients with CVCs who were receiving home-based chemotherapy, and it represents the second larger outbreak of CVCs-associated BSIs due to Klebsiella oxytoca in oncology outpatient centers. We retrospectively analyzed the chain of investigations and prophylactic/diagnostic measures taken to eradicate the infection: (1) patients' chart audit, (2) estimation of the infection among asymptomatic patients, (3) implementation of the level of awareness of medical and paramedical personnel, (4) collection of samples from environment, medications and infusion materials, (5) critical appraisal of chemotherapeutical schemes and (6) cooperation with peripheral institutions. The isolation of Klebsiella oxytoca in a chemotherapy solution (infusional 5-FU in dextrose 5% solution within a 48 h pump) from a peripheral General Hospital and the prompt transmission of the data to the chemotherapy center played a key role for the management of the infection cluster. This is the first report that evidenced the detection of Klebsiella oxytoca within a chemotherapeutical preparation. Data transmission from peripheral hospitals to the central institution resulted in an important feedback that allowed a better estimation of the infection cluster and more tailored actions for the eradication of the infection.

  20. Bloodstream infection among children presenting to a general hospital outpatient clinic in urban Nepal.

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    Rahul Pradhan

    Full Text Available BACKGROUND: There are limited data on the etiology and characteristics of bloodstream infections in children presenting in hospital outpatient settings in South Asia. Previous studies in Nepal have highlighted the importance of murine typhus as a cause of febrile illness in adults and enteric fever as a leading bacterial cause of fever among children admitted to hospital. METHODS: We prospectively studied a total of 1084 febrile children aged between 2 months and 14 years presenting to a general hospital outpatient department in Kathmandu Valley, Nepal, over two study periods (summer and winter. Blood from all patients was tested by conventional culture and by real-time PCR for Rickettsia typhi. RESULTS: Putative etiological agents for fever were identified in 164 (15% patients. Salmonella enterica serovar Typhi (S. Typhi was identified in 107 (10%, S. enterica serovar Paratyphi A (S. Paratyphi in 30 (3%, Streptococcus pneumoniae in 6 (0.6%, S. enterica serovar Typhimurium in 2 (0.2%, Haemophilus influenzae type b in 1 (0.1%, and Escherichia coli in 1 (0.1% patient. S. Typhi was the most common organism isolated from blood during both summer and winter. Twenty-two (2% patients were PCR positive for R. typhi. No significant demographic, clinical and laboratory features distinguished culture positive enteric fever and murine typhus. CONCLUSIONS: Salmonella infections are the leading cause of bloodstream infection among pediatric outpatients with fever in Kathmandu Valley. Extension of immunization programs against invasive bacterial disease to include the agents of enteric fever and pneumococcus could improve the health of children in Nepal.

  1. Bloodstream infections in intensive care unit patients: distribution and antibiotic resistance of bacteria

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    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

  2. 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

  3. 肾移植患者血流感染死亡的危险因素分析%Analysis of the risk factors for death in patients with bloodstream infections after renal transplantation

    Institute of Scientific and Technical Information of China (English)

    蒋欣; 曲青山; 李明; 邢利; 苗书斋

    2014-01-01

    OBJECTIVE To investigate the risk factors for death in patients with bloodstream infections after renal transplantation ,to provide the basis for prevention of bloodstream infections and clinical evaluation of patient prognosis .METHODS The clinical data of 217 patients with bloodstream infections after renal transplantation were retrospectively analyzed .The general information ,clinical data and related laboratory results of the patients were collected through the self-made survey form .The risk factors for death were analyzed by single factor analysis and multi factor analysis with the establishment of database .Data were analyzed by SPSS 17 .0 .RESULTS Totally 78 .80% of bloodstream infections after renal transplantation was nosocomial infections ,29 .95% were due to non-standard use of antibiotics .There were 72 cases of death in the 217 patients ,the mortality was 33 .18% .The main type of primary disease was chronic glomerulonephritis (66 .82% ) .The multivariate analysis showed that septic shock and platelet count <50 × 109/L were the independent risk factors for death in patients with blood-stream infections after renal transplantation .CONCLUSION Septic shock and platelet count <50 × 109/L are inde-pendent risk factors for death in patients with bloodstream infection after renal transplantation ,the clinical preven-tion measures should be adopted ,as soon as possible to avoid blood infection and reduce mortality in patients with renal transplantation .%目的:探讨肾移植患者血流感染死亡的危险因素,为临床评估患者预后和预防血流感染的发生提供依据。方法回顾性分析自2002年6月-2013年6月接受肾移植发生血流感染的217例患者临床资料,通过自制的调查表格收集患者的一般信息、临床资料和相关的实验室检查结果,建立数据库后通过单因素分析和多因素分析探讨肾移植患者并发血流感染死亡危险因素,数据采用SPSS 17.0进行分析。

  4. Teaching Form as Form

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2012-01-01

    understanding of form per se, or, to use an expression from this text, of form as form. This challenge can be reduced to one question: how can design teaching support students in achieving not only the ability to recognize and describe different form-related concepts in existing design (i.e. analytical...... 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 general, students enter design education as far more skilled observers with regards to function than form. They are, in other words, predisposed to observe objects asking ‘what is?’, rather than ‘how is?’. This habit has not only cognitive implications. It is closely intertwined with a rudimentary...

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

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

    Science.gov (United States)

    Graf, Fabrice E; Ludin, Philipp; Wenzler, Tanja; Kaiser, Marcel; Brun, Reto; Pyana, Patient Pati; Büscher, Philippe; de Koning, Harry P; Horn, David; Mäser, Pascal

    2013-01-01

    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.

  7. The Aurora Kinase in Trypanosoma brucei plays distinctive roles in metaphase-anaphase transition and cytokinetic initiation.

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    Ziyin Li

    2009-09-01

    Full Text Available Aurora B kinase is an essential regulator of chromosome segregation with the action well characterized in eukaryotes. It is also implicated in cytokinesis, but the detailed mechanism remains less clear, partly due to the difficulty in separating the latter from the former function in a growing cell. A chemical genetic approach with an inhibitor of the enzyme added to a synchronized cell population at different stages of the cell cycle would probably solve this problem. In the deeply branched parasitic protozoan Trypanosoma brucei, an Aurora B homolog, TbAUK1, was found to control both chromosome segregation and cytokinetic initiation by evidence from RNAi and dominant negative mutation. To clearly separate these two functions, VX-680, an inhibitor of TbAUK1, was added to a synchronized T. brucei procyclic cell population at different cell cycle stages. The unique trans-localization pattern of the chromosomal passenger complex (CPC, consisting of TbAUK1 and two novel proteins TbCPC1 and TbCPC2, was monitored during mitosis and cytokinesis by following the migration of the proteins tagged with enhanced yellow fluorescence protein in live cells with time-lapse video microscopy. Inhibition of TbAUK1 function in S-phase, prophase or metaphase invariably arrests the cells in the metaphase, suggesting an action of TbAUK1 in promoting metaphase-anaphase transition. TbAUK1 inhibition in anaphase does not affect mitotic exit, but prevents trans-localization of the CPC from the spindle midzone to the anterior tip of the new flagellum attachment zone for cytokinetic initiation. The CPC in the midzone is dispersed back to the two segregated nuclei, while cytokinesis is inhibited. In and beyond telophase, TbAUK1 inhibition has no effect on the progression of cytokinesis or the subsequent G1, S and G2 phases until a new metaphase is attained. There are thus two clearly distinct points of TbAUK1 action in T. brucei: the metaphase-anaphase transition and

  8. Pentamidine Is Not a Permeant but a Nanomolar Inhibitor of the Trypanosoma brucei Aquaglyceroporin-2.

    Science.gov (United States)

    Song, Jie; Baker, Nicola; Rothert, Monja; Henke, Björn; Jeacock, Laura; Horn, David; Beitz, Eric

    2016-02-01

    The chemotherapeutic arsenal against human African trypanosomiasis, sleeping sickness, is limited and can cause severe, often fatal, side effects. One of the classic and most widely used drugs is pentamidine, an aromatic diamidine compound introduced in the 1940s. Recently, a genome-wide loss-of-function screen and a subsequently generated trypanosome knockout strain revealed a specific aquaglyceroporin, TbAQP2, to be required for high-affinity uptake of pentamidine. Yet, the underlying mechanism remained unclear. Here, we show that TbAQP2 is not a direct transporter for the di-basic, positively charged pentamidine. Even though one of the two common cation filters of aquaglyceroporins, i.e. the aromatic/arginine selectivity filter, is unconventional in TbAQP2, positively charged compounds are still excluded from passing the channel. We found, instead, that the unique selectivity filter layout renders pentamidine a nanomolar inhibitor of TbAQP2 glycerol permeability. Full, non-covalent inhibition of an aqua(glycero)porin in the nanomolar range has not been achieved before. The remarkable affinity derives from an electrostatic interaction with Asp265 and shielding from water as shown by structure-function evaluation and point mutation of Asp265. Exchange of the preceding Leu264 to arginine abolished pentamidine-binding and parasites expressing this mutant were pentamidine-resistant. Our results indicate that TbAQP2 is a high-affinity receptor for pentamidine. Taken together with localization of TbAQP2 in the flagellar pocket of bloodstream trypanosomes, we propose that pentamidine uptake is by endocytosis.

  9. Pentamidine Is Not a Permeant but a Nanomolar Inhibitor of the Trypanosoma brucei Aquaglyceroporin-2.

    Directory of Open Access Journals (Sweden)

    Jie Song

    2016-02-01

    Full Text Available The chemotherapeutic arsenal against human African trypanosomiasis, sleeping sickness, is limited and can cause severe, often fatal, side effects. One of the classic and most widely used drugs is pentamidine, an aromatic diamidine compound introduced in the 1940s. Recently, a genome-wide loss-of-function screen and a subsequently generated trypanosome knockout strain revealed a specific aquaglyceroporin, TbAQP2, to be required for high-affinity uptake of pentamidine. Yet, the underlying mechanism remained unclear. Here, we show that TbAQP2 is not a direct transporter for the di-basic, positively charged pentamidine. Even though one of the two common cation filters of aquaglyceroporins, i.e. the aromatic/arginine selectivity filter, is unconventional in TbAQP2, positively charged compounds are still excluded from passing the channel. We found, instead, that the unique selectivity filter layout renders pentamidine a nanomolar inhibitor of TbAQP2 glycerol permeability. Full, non-covalent inhibition of an aqua(glyceroporin in the nanomolar range has not been achieved before. The remarkable affinity derives from an electrostatic interaction with Asp265 and shielding from water as shown by structure-function evaluation and point mutation of Asp265. Exchange of the preceding Leu264 to arginine abolished pentamidine-binding and parasites expressing this mutant were pentamidine-resistant. Our results indicate that TbAQP2 is a high-affinity receptor for pentamidine. Taken together with localization of TbAQP2 in the flagellar pocket of bloodstream trypanosomes, we propose that pentamidine uptake is by endocytosis.

  10. Equipe interdisciplinar reduz infecção sanguínea relacionada ao cateter venoso central em Unidade de Terapia Intensiva Pediátrica Interdisciplinary task-force reduces catheter-related bloodstream infection in a Pediatric Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    Ricardo Vilela

    2010-12-01

    Full Text Available OBJETIVO: Avaliar o impacto de intervenções interdisciplinares nos indicadores de infecção de corrente sanguínea relacionada ao cateter venoso central e microrganismos isolados, em uma Unidade de Terapia Intensiva Pediátrica. MÉTODOS: Estudo de intervenção do tipo antes e depois. Foi criado um programa educativo e constituída uma equipe interdisciplinar de intervenção composta por médicos e enfermeiros da unidade e do Serviço de Controle de Infecção Hospitalar. As intervenções foram compostas por medidas diretas e indiretas educativas e processuais. O período pré-intervenção (Fase 1, de junho de 2003 a maio de 2004, foi comparado ao período pós-intervenção nas Fases 2 (junho de 2004 a maio de 2005 e 3 (junho de 2005 a maio de 2006. As taxas de infecção foram comparadas por ANOVA, sendo significante pOBJECTIVE: To determine the impact of interdisciplinary interventions on central venous catheter-related bloodstream infections rates in a Pediatric Intensive Care Unit (PICU and on the bloodstream infection organisms. METHODS: Interventional study type before-and-after. An educational program was performed and an interdisciplinary team of interventions was created. This team was formed by nurses and doctors of the PICU and of the Infection Control Committee. The interventions were composed by direct and indirect educational and procedural measures. Task-force interventions were developed from Jun/2003 to May/2004. This pre-intervention period (Phase 1 was compared with two post-intervention periods: Phases 2 (Jun/2004 to May/2005 and 3 (Jun/2005 to May/2006. Central venous catheter-related bloodstream infection rates during the three periods were compared by ANOVA, being significant p<0.05. RESULTS: 1,234 patients were studied from June 1st 2003 to May 31, 2006. The number of central venous catheter-related bloodstream infections was 22.72 per 1,000 catheter-days in Phase 1, and 6.81 and 5.87 in Phases 2 and 3

  11. Effects of supplementing Erythrina brucei leaf as a substitute for cotton seed meal on growth performance and carcass characteristics of Sidama goats fed basal diet of natural grass hay.

    Science.gov (United States)

    Yinnesu, Asmamaw; Nurfeta, Ajebu

    2012-03-01

    The replacement value of dried Erythrina brucei leaf for cotton seed meal (CSM) on growth performance and carcass characteristics was evaluated. Twenty-five yearling buck goats (15.8 ± 1.4 kg) were assigned into five treatments in a randomized complete block design: natural grass hay alone (T1) or supplemented with 100% CSM (T2), 67% CSM + 33% E. brucei (T3), 33% CSM + 67% E. brucei (T4), and 100% E. brucei (T5) on dry matter (DM) basis. Supplemented goats consumed more (P  0.05) by the proportion of the supplements. The highest (P goats supplemented with CSM alone, whereas the lowest intake was observed in the non-supplemented group. Total CP intake decreased (P goats gained more (P goats than in the non-supplemented ones, but similar (P > 0.05) among the supplemented group. The digestibility of CP was higher (P goats, except in those goats fed E. brucei alone, than the non-supplemented group. Slaughter weight, empty body weight, hot carcass weight, dressing percentage, rib eye muscle area, and total edible offals were higher (P goats than for the non-supplemented ones. It could be concluded that E. brucei could be used as a substitute to CSM under smallholder production systems.

  12. 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 an

  13. Crystal structures of Trypanosoma brucei oligopeptidase B broaden the paradigm of catalytic regulation in prolyl oligopeptidase family enzymes.

    Science.gov (United States)

    Canning, Peter; Rea, Dean; Morty, Rory E; Fülöp, Vilmos

    2013-01-01

    Oligopeptidase B cleaves after basic amino acids in peptides up to 30 residues. As a virulence factor in bacteria and trypanosomatid pathogens that is absent in higher eukaryotes, this is a promising drug target. Here we present ligand-free open state and inhibitor-bound closed state crystal structures of oligopeptidase B from Trypanosoma brucei, the causative agent of African sleeping sickness. These (and related) structures show the importance of structural dynamics, governed by a fine enthalpic and entropic balance, in substrate size selectivity and catalysis. Peptides over 30 residues cannot fit the enzyme cavity, preventing the complete domain closure required for a key propeller Asp/Glu to fix the catalytic His and Arg in the catalytically competent conformation. This size exclusion mechanism protects larger peptides and proteins from degradation. Similar bacterial prolyl endopeptidase and archael acylaminoacyl peptidase structures demonstrate this mechanism is conserved among oligopeptidase family enzymes across all three domains of life.

  14. Crystal structures of Trypanosoma brucei oligopeptidase B broaden the paradigm of catalytic regulation in prolyl oligopeptidase family enzymes.

    Directory of Open Access Journals (Sweden)

    Peter Canning

    Full Text Available Oligopeptidase B cleaves after basic amino acids in peptides up to 30 residues. As a virulence factor in bacteria and trypanosomatid pathogens that is absent in higher eukaryotes, this is a promising drug target. Here we present ligand-free open state and inhibitor-bound closed state crystal structures of oligopeptidase B from Trypanosoma brucei, the causative agent of African sleeping sickness. These (and related structures show the importance of structural dynamics, governed by a fine enthalpic and entropic balance, in substrate size selectivity and catalysis. Peptides over 30 residues cannot fit the enzyme cavity, preventing the complete domain closure required for a key propeller Asp/Glu to fix the catalytic His and Arg in the catalytically competent conformation. This size exclusion mechanism protects larger peptides and proteins from degradation. Similar bacterial prolyl endopeptidase and archael acylaminoacyl peptidase structures demonstrate this mechanism is conserved among oligopeptidase family enzymes across all three domains of life.

  15. Functional characterization of two paralogs that are novel RNA binding proteins influencing mitochondrial transcripts of Trypanosoma brucei.

    Science.gov (United States)

    Kafková, Lucie; Ammerman, Michelle L; Faktorová, Drahomíra; Fisk, John C; Zimmer, Sara L; Sobotka, Roman; Read, Laurie K; Lukes, Julius; Hashimi, Hassan

    2012-10-01

    A majority of Trypanosoma brucei proteins have unknown functions, a consequence of its independent evolutionary history within the order Kinetoplastida that allowed for the emergence of several unique biological properties. Among these is RNA editing, needed for expression of mitochondrial-encoded genes. The recently discovered mitochondrial RNA binding complex 1 (MRB1) is composed of proteins with several functions in processing organellar RNA. We characterize two MRB1 subunits, referred to herein as MRB8170 and MRB4160, which are paralogs arisen from a large chromosome duplication occurring only in T. brucei. As with many other MRB1 proteins, both have no recognizable domains, motifs, or orthologs outside the order. We show that they are both novel RNA binding proteins, possibly representing a new class of these proteins. They associate with a similar subset of MRB1 subunits but not directly with each other. We generated cell lines that either individually or simultaneously target the mRNAs encoding both proteins using RNAi. Their dual silencing results in a differential effect on moderately and pan-edited RNAs, suggesting a possible functional separation of the two proteins. Cell growth persists upon RNAi silencing of each protein individually in contrast to the dual knockdown. Yet, their apparent redundancy in terms of cell viability is at odds with the finding that only one of these knockdowns results in the general degradation of pan-edited RNAs. While MRB8170 and MRB4160 share a considerable degree of conservation, our results suggest that their recent sequence divergence has led to them influencing mitochondrial mRNAs to differing degrees.

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

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    Iain D Kerr

    Full Text Available BACKGROUND: 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. METHODS AND FINDINGS: 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. CONCLUSIONS: 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.

    Directory of Open Access Journals (Sweden)

    Chiung-Kuang Chen

    Full Text Available 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 14alpha-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 A and 2.27 A, and from the related pathogen T. brucei (resolutions of 2.7 A and 2.6 A, 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 degrees 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

  18. Trypanosoma brucei PUF9 regulates mRNAs for proteins involved in replicative processes over the cell cycle.

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    Stuart K Archer

    2009-08-01

    Full Text Available Many genes that are required at specific points in the cell cycle exhibit cell cycle-dependent expression. In the early-diverging model eukaryote and important human pathogen Trypanosoma brucei, regulation of gene expression in the cell cycle and other processes is almost entirely post-transcriptional. Here, we show that the T. brucei RNA-binding protein PUF9 stabilizes certain transcripts during S-phase. Target transcripts of PUF9--LIGKA, PNT1 and PNT2--were identified by affinity purification with TAP-tagged PUF9. RNAi against PUF9 caused an accumulation of cells in G2/M phase and unexpectedly destabilized the PUF9 target mRNAs, despite the fact that most known Puf-domain proteins promote degradation of their target mRNAs. The levels of the PUF9-regulated transcripts were cell cycle dependent, peaking in mid- to late- S-phase, and this effect was abolished when PUF9 was targeted by RNAi. The sequence UUGUACC was over-represented in the 3' UTRs of PUF9 targets; a point mutation in this motif abolished PUF9-dependent stabilization of a reporter transcript carrying the PNT1 3' UTR. LIGKA is involved in replication of the kinetoplast, and here we show that PNT1 is also kinetoplast-associated and its over-expression causes kinetoplast-related defects, while PNT2 is localized to the nucleus in G1 phase and redistributes to the mitotic spindle during mitosis. PUF9 targets may constitute a post-transcriptional regulon, encoding proteins involved in temporally coordinated replicative processes in early G2 phase.

  19. Pathogens and antimicrobial susceptibility profiles in critically ill patients with bloodstream infections: a descriptive study

    Science.gov (United States)

    Savage, Rachel D.; Fowler, Robert A.; Rishu, Asgar H.; Bagshaw, Sean M.; Cook, Deborah; Dodek, Peter; Hall, Richard; Kumar, Anand; Lamontagne, François; Lauzier, François; Marshall, John; Martin, Claudio M.; McIntyre, Lauralyn; Muscedere, John; Reynolds, Steven; Stelfox, Henry T.; Daneman, Nick

    2016-01-01

    Background: Surveillance of antimicrobial resistance is vital to guiding empirical treatment of infections. Collating and reporting routine data on clinical isolate testing may offer more timely information about resistance patterns than traditional surveillance network methods. Methods: Using routine microbiology testing data collected from the Bacteremia Antibiotic Length Actually Needed for Clinical Effectiveness retrospective cohort study, we conducted a descriptive secondary analysis among critically ill patients in whom bloodstream infections had been diagnosed in 14 intensive care units (ICUs) in Canada. The participating sites were located within tertiary care teaching hospitals and represented 6 provinces and 10 cities. More than 80% of the study population was accrued from 2011-2013. We assessed the epidemiologic features of the infections and corresponding antimicrobial susceptibility profiles. Susceptibility testing was done according to Clinical Laboratory Standards Institute guidelines at accredited laboratories. Results: A total of 1416 pathogens were isolated from 1202 patients. The most common organisms were Escherichia coli (217 isolates [15.3%]), Staphylococcus aureus (175 [12.4%]), coagulase-negative staphylococci (117 [8.3%]), Klebsiella pneumoniae (86 [6.1%]) and Streptococcus pneumoniae (85 [6.0%]). The contribution of individual pathogens varied by site. For 13 ICUs, gram-negative susceptibility rates were high for carbapenems (95.4%), tobramycin (91.2%) and piperacillin-tazobactam (90.0%); however, the proportion of specimens susceptible to these agents ranged from 75.0%-100%, 66.7%-100% and 75.0%-100%, respectively, across sites. Fewer gram-negative bacteria were susceptible to fluoroquinolones (84.5% [range 64.1%-97.2%]). A total of 145 patients (12.1%) had infections caused by highly resistant microorganisms, with significant intersite variation (range 2.6%-24.0%, χ2 = 57.50, p < 0.001). Interpretation: We assessed the epidemiologic

  20. Clinical and microbiological characterization of carbapenem-resistant Acinetobacter baumannii bloodstream infections.

    Science.gov (United States)

    Song, Joon Young; Cheong, Hee Jin; Choi, Won Suk; Heo, Jung Yeon; Noh, Ji Yun; Kim, Woo Joo

    2011-05-01

    The incidence of carbapenem-resistant Acinetobacter baumannii infection is increasing, which might be associated with high morbidity and mortality among critically ill patients with limited therapeutic options. This study was conducted to evaluate the clinical and microbiological features of carbapenem-resistant A. baumannii bacteraemia. The medical records of 28 adult patients with this bacteraemia admitted to Korea University Guro Hospital, from January 2005 through December 2010, were reviewed. Using the 28 bloodstream isolates, we intended to detect genes encoding carbapenemases, and investigate the inoculum effect on each of the antimicrobial agents rifampicin, imipenem, colistin and tigecycline. With one blood isolate from a patient with pneumonia, rifampicin-inducible resistance was examined using the experimental mouse pneumonia model. Out of 28 carbapenem-resistant A. baumannii bloodstream infections (BIs), the most common primary focus was the central venous catheter (35.7 %) and then the lung (32.1 %). The 30 day overall mortality was 53.6 %; in most cases (80 %) the patients died within 10 days after the onset of the bacteraemia. By univariate analysis, inappropriate antimicrobial therapy (73.3 vs 30.8 %, P = 0.02), mechanical ventilation (53.3 vs 15.4 %, P = 0.04) and a high Pitt bacteraemia score (4.9±1.9 vs 2.2±1.2, P<0.01) were statistically significant risk factors for mortality, while only a high Pitt bacteraemia score (odds ratio 2.6; 95 % confidence interval 1.1-6.5) was independently associated with 30 day mortality by multivariate analysis. All 28 isolates had the bla(OXA-51)-like gene with upstream ISAbaI, 2 of which additionally had the bla(OXA-58)-like gene and the bla(OXA-23)-like gene. Inoculum effect and rifampicin inducible resistance were not detected. Considering the rapid progression to death in carbapenem-resistant A. baumannii BIs, early empirical antibiotic therapy would be warranted based on the local

  1. Bisphosphonates inhibit the growth of Trypanosoma brucei, Trypanosoma cruzi, Leishmania donovani, Toxoplasma gondii, and Plasmodium falciparum: a potential route to chemotherapy.

    Science.gov (United States)

    Martin, M B; Grimley, J S; Lewis, J C; Heath, H T; Bailey, B N; Kendrick, H; Yardley, V; Caldera, A; Lira, R; Urbina, J A; Moreno, S N; Docampo, R; Croft, S L; Oldfield, E

    2001-03-15

    We have investigated the effects in vitro of a series of bisphosphonates on the proliferation of Trypanosoma cruzi, Trypanosoma brucei rhodesiense, Leishmania donovani, Toxoplasma gondii, and Plasmodium falciparum. The results show that nitrogen-containing bisphosphonates of the type used in bone resorption therapy have significant activity against parasites, with the aromatic species having in some cases nanomolar or low-micromolar IC(50) activity values against parasite replication (e.g. o-risedronate, IC(50) = 220 nM for T. brucei rhodesiense; risedronate, IC(50) = 490 nM for T. gondii). In T. cruzi, the nitrogen-containing bisphosphonate risedronate is shown to inhibit sterol biosynthesis at a pre-squalene level, most likely by inhibiting farnesylpyrophosphate synthase. Bisphosphonates therefore appear to have potential in treating parasitic protozoan diseases.

  2. Effect of experimental single Ancylostoma caninum and mixed infections of Trypanosoma brucei and Trypanosoma congolense on the humoural immune response to anti-rabies vaccination in dogs

    Institute of Scientific and Technical Information of China (English)

    Nwoha Rosemary Ijeoma Ogechi; Anene Boniface Maduka

    2015-01-01

    Objective:To determine the effect of Ancylostoma caninum (A. caninum) and trypanosome parasites on the immune response to vaccination in dogs in endemic environments. Methods:Sixteen dogs for the experiment were grouped into 4 of 4 members each. Group I was the uninfected control one, and GPII was infected with A. caninum; GPIII was infected with A. caninum/Trypanosoma congolense (T. congolense), and GPIV was infected with Trypanosoma brucei (T. brucei)/A. caninum. The dogs were first vaccinated with antirabies vaccine before infecting GPII, GPIII and GPIV with A. caninum which were done 4 weeks after vaccination. By 2-week post-vaccination, trypanosome parasites were superimposed on both GPIII and GPIV. A secondary vaccination was given to GPI, GPII, GPIII, and GPIV by Week 12 of the experiment (4 weeks post treatment). Results:The prepatent period was (3.00 ± 1.40) days, in the conjunct infection of T. brucei/A. caninum. It was (9.00 ± 1.10) days, in conjunct T. congolense/A. caninum. The prepatent period of A. caninum was (14.0 ± 2.0) days in the single A. caninum group and (13.0 ± 1.0) days in the conjunct trypanosome/A. caninum. At the 1st week after vaccination, the antibody titer in all the vaccinated groups (GPI, GPII, GPIII, and GPIV) significantly increased (P Conclusions:It was therefore concluded that A. caninum, T. brucei and T. congolense induced immunosuppression in antirabies vaccination in dogs.

  3. Comparative analysis of the kinomes of three pathogenic trypanosomatids: Leishmania major, Trypanosoma brucei and Trypanosoma cruzi

    OpenAIRE

    Ward Pauline N; Worthey Elizabeth A; Parsons Marilyn; Mottram Jeremy C

    2005-01-01

    Abstract Background The trypanosomatids Leishmania major, Trypanosoma brucei and Trypanosoma cruzi cause some of the most debilitating diseases of humankind: cutaneous leishmaniasis, African sleeping sickness, and Chagas disease. These protozoa possess complex life cycles that involve development in mammalian and insect hosts, and a tightly coordinated cell cycle ensures propagation of the highly polarized cells. However, the ways in which the parasites respond to their environment and coordi...

  4. Bacillus Cereus catheter related bloodstream infection in a patient in a patient with acute lymphblastic leukemia

    Directory of Open Access Journals (Sweden)

    Lütfiye Öksüz

    2012-01-01

    Full Text Available Bacillus cereus infection is rarely associated with actual infection and for this reason single positive blood culture is usually regarded as contamination . However it may cause a number of infections, such catheter-related blood stream infections. Significant catheter-related bloodstream infections (CRBSI caused by Bacillus spp. are mainly due to B.cereus and have been predominantly reported in immunocompromised hosts1 . Catheter removal is generally advised for management of infection. In this report, catheter-related bacteremia caused by B.cereus in a patient with acute lymphoblastıc leukemia (ALL in Istanbul Medical Faculty was presented.A 44-year old man presented with fatigue, weight loss, epistaxis and high fever. A double-lumen Hickman–catheter (Bard 12.0 Fr, Round Dual Lumen was inserted by surgical cut-down to access the right subclavian vein which would be necessary for allogeneic stem cell transplantation. Three weeks later the patient presented with high fever and headache. Bacillus spp. was isolated from the cathether while blood culture obtained from the peripheral vein remained negative. The bacterial identification was confirmed as B.cereus using VITEK identification system It has been reported Bacillus cereus septicemia may be fatal in immunocompromised hosts despite broad-spectrum appropriate treatment10. Catheter removal is essential for prevention of recurrent bacteremia. Long-term cathater salvage should be reserved for appropriate patient group.

  5. Molecular differentiation and antifungal susceptibilities of Candida parapsilosis isolated from patients with bloodstream infections.

    Science.gov (United States)

    Tay, Sun Tee; Na, Shiang Ling; Chong, Jennifer

    2009-02-01

    The genetic heterogeneity and antifungal susceptibility patterns of Candida parapsilosis isolated from blood cultures of patients were investigated in this study. Randomly amplified polymorphic DNA (RAPD) analysis generated 5 unique profiles from 42 isolates. Based on the major DNA fragments of the RAPD profiles, the isolates were identified as RAPD type P1 (29 isolates), P2 (6 isolates), P3 (4 isolates), P4 (2 isolates) and P5 (1 isolate). Sequence analysis of the internal transcribed spacer (ITS) gene of the isolates identified RAPD type P1 as C. parapsilosis, P2 and P3 as Candida orthopsilosis, P4 as Candida metapsilosis, and P5 as Lodderomyces elongisporus. Nucleotide variations in ITS gene sequences of C. orthopsilosis and C. metapsilosis were detected. Antifungal susceptibility testing using Etests showed that all isolates tested in this study were susceptible to amphotericin B, fluconazole, ketoconazole, itraconazole and voriconazole. C. parapsilosis isolates exhibited higher MIC(50) values than those of C. orthopsilosis for all of the drugs tested in this study; however, no significant difference in the MICs for these two Candida species was observed. The fact that C. orthopsilosis and C. metapsilosis were responsible for 23.8 and 4.8 % of the cases attributed to C. parapsilosis bloodstream infections, respectively, indicates the clinical relevance of these newly described yeasts. Further investigations of the ecological niche, mode of transmission and virulence of these species are thus essential.

  6. Effectiveness of oral antibiotics for definitive therapy of Gram-negative bloodstream infections.

    Science.gov (United States)

    Kutob, Leila F; Justo, Julie Ann; Bookstaver, P Brandon; Kohn, Joseph; Albrecht, Helmut; Al-Hasan, Majdi N

    2016-11-01

    There is paucity of data evaluating intravenous-to-oral antibiotic switch options for Gram-negative bloodstream infections (BSIs). This retrospective cohort study examined the effectiveness of oral antibiotics for definitive treatment of Gram-negative BSI. Patients with Gram-negative BSI hospitalised for antibiotics were included in this study. The cohort was stratified into three groups based on bioavailability of oral antibiotics prescribed (high, ≥95%; moderate, 75-94%; and low, antibiotics were prescribed to 106, 179 and 77 patients, respectively, for definitive therapy of Gram-negative BSI. Mean patient age was 63 years, 217 (59.9%) were women and 254 (70.2%) had a urinary source of infection. Treatment failure rates were 2%, 12% and 14% in patients receiving oral antibiotics with high, moderate and low bioavailability, respectively (P = 0.02). Risk of treatment failure in the multivariate Cox model was higher in patients receiving antibiotics with moderate [adjusted hazard ratio (aHR) = 5.9, 95% CI 1.6-38.5; P = 0.005] and low bioavailability (aHR = 7.7, 95% CI 1.9-51.5; P = 0.003) compared with those receiving oral antimicrobial agents with high bioavailability. These data demonstrate the effectiveness of oral antibiotics with high bioavailability for definitive therapy of Gram-negative BSI. Risk of treatment failure increases as bioavailability of the oral regimen declines.

  7. Changes in plasma protein levels as an early indication of a bloodstream infection

    Science.gov (United States)

    Joenväärä, Sakari; Kaartinen, Johanna; Järvinen, Asko; Renkonen, Risto

    2017-01-01

    Blood culture is the primary diagnostic test performed in a suspicion of bloodstream infection to detect the presence of microorganisms and direct the treatment. However, blood culture is slow and time consuming method to detect blood stream infections or separate septic and/or bacteremic patients from others with less serious febrile disease. Plasma proteomics, despite its challenges, remains an important source for early biomarkers for systemic diseases and might show changes before direct evidence from bacteria can be obtained. We have performed a plasma proteomic analysis, simultaneously at the time of blood culture sampling from ten blood culture positive and ten blood culture negative patients, and quantified 172 proteins with two or more unique peptides. Principal components analysis, Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) and ROC curve analysis were performed to select protein(s) features which can classify the two groups of samples. We propose a number of candidates which qualify as potential biomarkers to select the blood culture positive cases from negative ones. Pathway analysis by two methods revealed complement activation, phagocytosis pathway and alterations in lipid metabolism as enriched pathways which are relevant for the condition. Data are available via ProteomeXchange with identifier PXD005022. PMID:28235076

  8. Nosocomial bloodstream infections: organisms, risk factors and resistant phenotypes in the Brazilian University Hospital

    Directory of Open Access Journals (Sweden)

    Rosineide M. Ribas

    2007-06-01

    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.

  9. 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.

  10. Haemodialysis catheter-related bloodstream infections: current treatment options and strategies for prevention.

    Science.gov (United States)

    Saxena, Anil K; Panhotra, Bodh R

    2005-03-05

    Regardless of the repeated reservations raised by countless researchers with reference to the use of catheters as vascular access for haemodialysis (HD), central venous catheters (CVCs) remain irreplaceable tools of the modern dialysis delivery system as a reliable option for the clinical situations requiring instant access to circulation, for various reasons. Patients on long-term haemodialysis are therefore at a significantly high risk for catheterrelated bloodstream infections (CRBSI) and ensuing serious complications. Although early systemic antibiotic treatment should include the coverage for Staphylococcus aureus, the pathogen with most devastating consequences including bacterial endocarditis; optimal treatment of CRBSI while preserving the catheter site, remains contentious. Nonetheless, catheter exchange over a guide wire and antimicrobial-anticoagulant "locks" have shown promising results as novel access salvage techniques. Despite the fact that a number of novel potentially useful strategies for the prevention of CRBSI are in the pipeline; equally essential however, remains the role of rigorous implementation of standard infection control measures for hygiene and aseptic handling of CVCs in long-term HD patients. The policy of increasing the AVF (arteriovenous fistula) prevalence beyond 50% while minimising the use of CVCs, dependent largely upon the timely referrals and prudently implemented pre-ESRD program - ought to have a positive impact on long-term HD outcomes.

  11. Seasonal trend and clinical presentation of Bacillus cereus bloodstream infection: association with summer and indwelling catheter.

    Science.gov (United States)

    Kato, K; Matsumura, Y; Yamamoto, M; Nagao, M; Ito, Y; Takakura, S; Ichiyama, S

    2014-08-01

    Bacillus cereus, an opportunistic pathogen, can cause fatal infection. However, B. cereus bloodstream infections (BSIs) have not been well characterised. From 2008 to 2013, B. cereus isolates from all of the specimens and patients with B. cereus BSIs were identified. Environmental samples were collected to detect B. cereus contamination. We also characterised the clinical presentation of B. cereus BSI through analyses of risk factors for BSI and mortality. A total of 217 clinical B. cereus isolates was detected. Fifty-one patients with nosocomial infections were diagnosed as B. cereus BSI, and 37 had contaminated blood cultures. The number of B. cereus isolates and BSI patients was significantly greater from June to September than from January to April (4.9 vs. 1.5 per month and 1.2 vs. 0.2, respectively). All BSIs were nosocomial and related to central or peripheral vascular catheter. Urinary catheter [odds ratio (OR) 6.93, 95% confidence interval (CI) 2.40-20.0] was the independent risk factor associated with BSI patients when compared to patients regarded as contaminated. In-hospital mortality among BSI patients was 20% and was associated with urinary catheter (OR 34.7, 95 % CI 1.89-63.6) and higher Charlson index (OR 1.99, 95 % CI 1.26-3.12). The number of B. cereus isolates and BSI increased during summer. Inpatients with indwelling vascular or urinary catheters should be carefully monitored for potential B. cereus BSIs.

  12. Bacterial bloodstream infections in liver transplantation: etiologic agents and antimicrobial susceptibility profiles.

    Science.gov (United States)

    Sganga, G; Spanu, T; Bianco, G; Fiori, B; Nure, E; Pepe, G; D'inzeo, T; Lirosi, M C; Frongillo, F; Agnes, S

    2012-09-01

    Liver transplantation (OLT) is a lifesaving procedure for the treatment of many end-stage liver diseases, but infection and acute rejection episodes still remain the main causes of morbidity and mortality. Bloodstream infections (BSIs), particularly, are the major cause of mortality among these patients. BSIs in OLT, are from intra-abdominal, biliary, respiratory, urinary, wound and/or central venous catheter sources. A certain percentage are of unknown origin. Using the computerized database of our microbiology laboratory, we analyzed all BSIs in 75 consecutive adult liver transplant patients in a single center between January 2008 and July 2011. BSIs occurred in 21/75 (28%) patients. Thirteen subjects had a single; two, two episodes, and the other six patients each >4 episodes. All episodes occurred in the first 60 days following OLT; the majority (74%), in the first month. Among 44 microorganisms recovered, 52.3% were gram-negative, the most frequent being Pseudomonas aeruginosa and Klebsiella pneumoniae; 47.7% were gram-positive, the most frequent being coagulase-negative staphylococci, particularly Staphylococcus epidermidis. Overall 65.9% of the isolates were resistant to several antibiotics: 40.9% displayed the multiding-resistant and 25% the panding-resistant phenotype. There was a high incidence of gram-negative and most importantly, resistant bacteria, which required appropriate therapy. These data showed that it is imperative to promote strategies to prevention and contain antimicrobial resistance.

  13. Risk factors and outcomes of imipenem-resistant Acinetobacter bloodstream infection in North-eastern Malaysia

    Institute of Scientific and Technical Information of China (English)

    Zakuan Zainy Deris; Mohd Nazri Shafei; Azian Harun

    2011-01-01

    Objective: To determine the risk factors and outcomes of imipenem-resistant Acinetobacterbaumannii (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.

  14. Species distribution and antifungal susceptibility profile of Candida spp. bloodstream isolates from Latin American hospitals

    Directory of Open Access Journals (Sweden)

    Godoy Patrício

    2003-01-01

    Full Text Available From March 1999 to March 2000, we conducted a prospective multicenter study of candidemia involving five tertiary care hospitals from four countries in Latin America. Yeast isolates were identified by classical methods and the antifungal susceptibility profile was determined according to the National Committee for Clinical Laboratory Standards microbroth assay method. During a 12 month-period we were able to collect a total of 103 bloodstream isolates of Candida spp. C. albicans was the most frequently isolated species accounting for 42% of all isolates. Non-albicans Candida species strains accounted for 58% of all episodes of candidemia and were mostly represented by C. tropicalis (24.2% and C. parapsilosis (21.3%. It is noteworthy that we were able to identify two cases of C. lusitaniae from different institutions. In our casuistic, non-albicans Candida species isolates related to candidemic episodes were susceptible to fluconazole. Continuously surveillance programs are needed in order to identify possible changes in the species distribution and antifungal susceptibility patterns of yeasts that may occurs after increasing the use of azoles in Latin American hospitals.

  15. Magnet® Hospital Recognition Linked to Lower Central Line-Associated Bloodstream Infection Rates.

    Science.gov (United States)

    Barnes, Hilary; Rearden, Jessica; McHugh, Matthew D

    2016-04-01

    Central-line-associated bloodstream infections (CLABSI) are among the deadliest heathcare-associated infections, with an estimated 12-25% mortality rate. In 2014, the Centers for Medicare and Medicaid Services (CMS) began to penalize hospitals for poor performance with respect to selected hospital-acquired conditions, including CLABSI. A structural factor associated with high-quality nursing care and better patient outcomes is The Magnet Recognition Program®. The purpose of this study was to explore the relationship between Magnet status and hospital CLABSI rates. We used propensity score matching to match Magnet and non-Magnet hospitals with similar hospital characteristics. In a matched sample of 291 Magnet hospitals and 291 non-Magnet hospitals, logistic regression models were used to examine whether there was a link between Magnet status and CLABSI rates. Both before and after matching, Magnet hospital status was associated with better (lower than the national average) CLABSI rates (OR = 1.60, 95%CI: 1.10, 2.33 after matching). While established programs such as Magnet recognition are consistently correlated with high-quality nursing work environments and positive patient outcomes, additional research is needed to determine whether Magnet designation produces positive patient outcomes or rewards existing excellence.

  16. Antifungal susceptibility survey of 2,000 bloodstream Candida isolates in the United States.

    Science.gov (United States)

    Ostrosky-Zeichner, Luis; Rex, John H; Pappas, Peter G; Hamill, Richard J; Larsen, Robert A; Horowitz, Harold W; Powderly, William G; Hyslop, Newton; Kauffman, Carol A; Cleary, John; Mangino, Julie E; Lee, Jeannette

    2003-10-01

    Candida bloodstream isolates (n = 2,000) from two multicenter clinical trials carried out by the National Institute of Allergy and Infectious Diseases Mycoses Study Group between 1995 and 1999 were tested against amphotericin B (AMB), flucytosine (5FC), fluconazole (FLU), itraconazole (ITR), voriconazole (VOR), posaconazole (POS), caspofungin (CFG), micafungin (MFG), and anidulafungin (AFG) using the NCCLS M27-A2 microdilution method. All drugs were tested in the NCCLS-specified RPMI 1640 medium except for AMB, which was tested in antibiotic medium 3. A sample of isolates was also tested in RPMI 1640 supplemented to 2% glucose and by using the diluent polyethylene glycol (PEG) in lieu of dimethyl sulfoxide for those drugs insoluble in water. Glucose supplementation tended to elevate the MIC, whereas using PEG tended to decrease the MIC. Trailing growth occurred frequently with azoles. Isolates were generally susceptible to AMB, 5FC, and FLU. Rates of resistance to ITR approached 20%. Although no established interpretative breakpoints are available for the candins (CFG, MFG, and AFG) and the new azoles (VOR and POS), they all exhibited excellent antifungal activity, even for those strains resistant to the other aforementioned agents.

  17. Closed Catheter Access System Implementation in Reducing Bloodstream Infection Rate in Low Birth Weight Preterm Infants

    Directory of Open Access Journals (Sweden)

    Lily eRundjan

    2015-03-01

    Full Text Available Background Bloodstream infection (BSI is one of the significant causes of morbidity and mortality encountered in a neonatal intensive care unit (NICU, especially in developing countries. Despite the implementation of infection control practices, such as strict hand hygiene, the BSI rate in our hospital is still high. The use of a closed catheter access system to reduce BSI related to intravascular catheter has hitherto never been evaluated in our hospital. Objective To determine the effects of closed catheter access system implementation in reducing the BSI rate in preterm neonates with low birth weight.Methods Randomized clinical trial was conducted on 60 low birth weight preterm infants hospitalized in the neonatal unit at Cipto Mangunkusumo Hospital, Jakarta, Indonesia from June to September, 2013. Randomized subjects either received a closed or non-closed catheter access system. Subjects were monitored for 2 weeks for the development of BSI based on clinical signs, abnormal infection parameters, and blood culture. Results Closed catheter access system implementation gave a protective effect towards the occurrence of culture-proven BSI (relative risk 0.095, 95% CI 0.011 to 0.85, p=0.026. Risk of culture-proven BSI in the control group was 10.545 (95% CI 1.227 to 90.662, p=0.026. BSI occurred in 75% of neonates without risk factors of infection in the control group compared to none in the study group.Conclusions The use of a closed catheter access system reduced the BSI in low birth weight preterm infants. Choosing the right device design, proper disinfection of device and appropriate frequency of connector change should be done simultaneously.

  18. Bacillus Cereus catheter related bloodstream infection in a patient in a patient with acute lymphblastic leukemia

    Directory of Open Access Journals (Sweden)

    Lütfiye Öksüz

    2012-01-01

    Full Text Available

    Bacillus cereus infection is rarely associated with actual infection and for this reason single positive blood culture is usually regarded as contamination . However it may cause a number of infections, such catheter-related blood stream infections. Significant catheter-related bloodstream infections (CRBSI caused by Bacillus spp. are mainly due to B.cereus and have been predominantly reported in immunocompromised hosts1 . Catheter removal is generally advised for management of infection. In this report, catheter-related bacteremia caused by B.cereus in a patient with acute lymphoblastıc leukemia (ALL in Istanbul Medical Faculty was presented.A 44-year old man presented with fatigue, weight loss, epistaxis and high fever. A double-lumen Hickman–catheter (Bard 12.0 Fr, Round Dual Lumen was inserted by surgical cut-down to access the right subclavian vein which would be necessary for allogeneic stem cell transplantation. Three weeks later the patient presented with high fever and headache. Bacillus spp. was isolated from the cathether while blood culture obtained from the peripheral vein remained negative. The bacterial identification was confirmed as B.cereus using VITEK identification system

    It has been reported Bacillus cereus septicemia may be fatal in immunocompromised hosts despite broad-spectrum appropriate treatment10. Catheter removal is essential for prevention of recurrent bacteremia. Long-term cathater salvage should be reserved for appropriate patient group.

  19. Molecular epidemiology and antimicrobial resistance of methicillin-resistant Staphylococcus aureus bloodstream isolates in Taiwan, 2010.

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    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.

  20. Prevalence and Antimicrobial Resistance of Microbes Causing Bloodstream Infections in Unguja, Zanzibar.

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    Annette Onken

    Full Text Available Bloodstream infections (BSI are frequent and cause high case-fatality rates. Urgent antibiotic treatment can save patients' lives, but antibiotic resistance can render antibiotic therapy futile. This study is the first to collect epidemiological data on BSI from Unguja, Zanzibar.Clinical data and blood for culturing and susceptibility testing of isolated microbes were obtained from 469 consecutively enrolled neonates, children and adults presenting with signs of systemic infections at Mnazi Mmoja Hospital (MMH, Zanzibar.Pathogenic bacteria were recovered from the blood of 14% of the patients (66/469. The most frequently isolated microbes were Klebsiella pneumoniae, Escherichia coli, Acinetobacter spp. and Staphylococcus aureus. Infections were community-acquired in 56 patients (85% and hospital-acquired in 8 (12% (data missing for 2 patients. BSI caused by extended-spectrum beta-lactamase (ESBL producing Enterobacteriaceae (E. coli, K. pneumoniae was found in 5 cases, of which 3 were community-acquired and 2 hospital-acquired. Three of these patients died. Six of 7 Salmonella Typhi isolates were multidrug resistant. Streptococcus pneumoniae was found in one patient only.This is the first report of ESBL-producing bacteria causing BSI from the Zanzibar archipelago. Our finding of community-acquired BSI caused by ESBL-producing bacteria is alarming, as it implies that these difficult-to-treat bacteria have already spread in the society. In the local setting these infections are virtually impossible to cure. The findings call for increased awareness of rational antibiotic use, infection control and surveillance to counteract the problem of emerging antimicrobial resistance.

  1. 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.

  2. Incidence, Clinical Characteristics and Attributable Mortality of Persistent Bloodstream Infection in the Neonatal Intensive Care Unit

    Science.gov (United States)

    Hsu, Jen-Fu; Chu, Shih-Ming; Lee, Chiang-Wen; Yang, Pong-Hong; Lien, Reyin; Chiang, Ming-Chou; Fu, Ren-Huei; Huang, Hsuan-Rong; Tsai, Ming-Horng

    2015-01-01

    Background An atypical pattern of neonatal sepsis, characterized by persistent positive blood culture despite effective antimicrobial therapy, has been correlated with adverse outcomes. However, previous studies focused only on coagulate-negative staphylococcus infection. Methods All episodes of persistent bloodstream infection (BSI), defined as 3 or more consecutive positive blood cultures with the same bacterial species, at least two of them 48 hours apart, during a single sepsis episode, were enrolled over an 8-year period in a tertiary level neonatal intensive care unit. These cases were compared with all non-persistent BSI during the same period. Results We identified 81 episodes of persistent BSI (8.5% of all neonatal late-onset sepsis) in 74 infants, caused by gram-positive pathogens (n=38, 46.9%), gram-negative pathogens (n=21, 25.9%), fungus (n=20, 24.7%) and polymicrobial bacteremia (n=2, 2.5%). Persistent BSI does not differ from non-persistent BSI in most clinical characteristics and patient demographics, but tends to have a prolonged septic course, longer duration of feeding intolerance and more frequent requirement of blood transfusions. No difference was observed for death attributable to infection (9.8% vs. 6.5%), but neonates with persistent BSI had significantly higher rates of infectious complications (29.6% vs. 9.2%, P < 0.001), death from all causes (21.6% vs. 11.7%, P = 0.025), and duration of hospitalization among survivors [median (interquartile range): 80.0 (52.5-117.5) vs. 64.0 (40.0-96.0) days, P = 0.005] than those without persistent BSI. Conclusions Although persistent BSI does not contribute directly to increased mortality, the associated morbidities, infectious complications and prolonged septic courses highlight the importance of aggressive treatment to optimize outcomes. PMID:25875677

  3. Using real time process measurements to reduce catheter related bloodstream infections in the intensive care unit

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    Wall, R; Ely, E; Elasy, T; Dittus, R; Foss, J; Wilkerson, K; Speroff, T

    2005-01-01

    

Problem: Measuring a process of care in real time is essential for continuous quality improvement (CQI). Our inability to measure the process of central venous catheter (CVC) care in real time prevented CQI efforts aimed at reducing catheter related bloodstream infections (CR-BSIs) from these devices. Design: A system was developed for measuring the process of CVC care in real time. We used these new process measurements to continuously monitor the system, guide CQI activities, and deliver performance feedback to providers. Setting: Adult medical intensive care unit (MICU). Key measures for improvement: Measured process of CVC care in real time; CR-BSI rate and time between CR-BSI events; and performance feedback to staff. Strategies for change: An interdisciplinary team developed a standardized, user friendly nursing checklist for CVC insertion. Infection control practitioners scanned the completed checklists into a computerized database, thereby generating real time measurements for the process of CVC insertion. Armed with these new process measurements, the team optimized the impact of a multifaceted intervention aimed at reducing CR-BSIs. Effects of change: The new checklist immediately provided real time measurements for the process of CVC insertion. These process measures allowed the team to directly monitor adherence to evidence-based guidelines. Through continuous process measurement, the team successfully overcame barriers to change, reduced the CR-BSI rate, and improved patient safety. Two years after the introduction of the checklist the CR-BSI rate remained at a historic low. Lessons learnt: Measuring the process of CVC care in real time is feasible in the ICU. When trying to improve care, real time process measurements are an excellent tool for overcoming barriers to change and enhancing the sustainability of efforts. To continually improve patient safety, healthcare organizations should continually measure their key clinical processes in real

  4. 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.

  5. Hospital-wide multidisciplinary, multimodal intervention programme to reduce central venous catheter-associated bloodstream infection.

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    Walter Zingg

    Full Text Available Central line-associated bloodstream infection (CLABSI is the major complication of central venous catheters (CVC. The aim of the study was to test the effectiveness of a hospital-wide strategy on CLABSI reduction. Between 2008 and 2011, all CVCs were observed individually and hospital-wide at a large university-affiliated, tertiary care hospital. CVC insertion training started from the 3rd quarter and a total of 146 physicians employed or newly entering the hospital were trained in simulator workshops. CVC care started from quarter 7 and a total of 1274 nurses were trained by their supervisors using a web-based, modular, e-learning programme. The study included 3952 patients with 6353 CVCs accumulating 61,366 catheter-days. Hospital-wide, 106 patients had 114 CLABSIs with a cumulative incidence of 1.79 infections per 100 catheters. We observed a significant quarterly reduction of the incidence density (incidence rate ratios [95% confidence interval]: 0.92 [0.88-0.96]; P<0.001 after adjusting for multiple confounders. The incidence densities (n/1000 catheter-days in the first and last study year were 2.3/1000 and 0.7/1000 hospital-wide, 1.7/1000 and 0.4/1000 in the intensive care units, and 2.7/1000 and 0.9/1000 in non-intensive care settings, respectively. Median time-to-infection was 15 days (Interquartile range, 8-22. Our findings suggest that clinically relevant reduction of hospital-wide CLABSI was reached with a comprehensive, multidisciplinary and multimodal quality improvement programme including aspects of behavioural change and key principles of good implementation practice. This is one of the first multimodal, multidisciplinary, hospital-wide training strategies successfully reducing CLABSI.

  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. Patterns and trends of pediatric bloodstream infections: a 7-year surveillance study.

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    Buetti, N; Atkinson, A; Kottanattu, L; Bielicki, J; Marschall, J; Kronenberg, A

    2017-03-01

    We characterize the epidemiology of pediatric bloodstream infections (BSIs) in Switzerland. We analyzed pathogen distribution and resistance patterns in monomicrobial and polymicrobial BSIs in children from 2008 to 2014 using data from the Swiss antibiotic resistance centre (ANRESIS). A confirmatory statistical analysis was performed comparing pathogens and resistance across 20 acute care hospitals. We identified 3,067 bacteremia episodes, of which 1,823 (59 %) were considered true BSI episodes. Overall, S. aureus (16.5 %, 300) was the most frequent pathogen, followed by E. coli (15.1 %, 276), coagulase-negative staphylococci (CoNS, 12.9 %, 235), S. pneumoniae (11.1 %, 202) and non-E. coli Enterobacteriaceae (8.7 %, 159). S. aureus and E. coli showed similar frequencies in all of the variables analyzed (e.g., hospital acquisition, hospital type, medical specialty). The proportion of these microorganisms did not change over time, resistance rates remained low (4.3 % methicillin resistance in S. aureus; 7.3 % third-/fourth-generation cephalosporin resistance in E. coli), and no significant resistance trends were observed. We observed a 50 % increase of CoNS BSIs from 2008 (9.8 %, 27) to 2014 (15.2 %, 46, p value for trend = 0.03). S. pneumoniae decreased from 17.5 % (48) to 6.6 % (20) during that timeframe (p for trend = 0.007). S. aureus and E. coli remained the most significant pathogens among pediatric BSIs in Switzerland, exhibiting low resistance rates. CoNS accounted for a greater proportion of BSIs over time. The decrease in bacteremic pneumococcal infections can likely be attributed to the introduction of the 13-valent conjugate vaccine in 2011.

  8. 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.

  9. Risk factors and outcomes for patients with bloodstream infection due to Acinetobacter baumannii-calcoaceticus complex.

    Science.gov (United States)

    Chopra, Teena; Marchaim, Dror; Johnson, Paul C; Awali, Reda A; Doshi, Hardik; Chalana, Indu; Davis, Naomi; Zhao, Jing J; Pogue, Jason M; Parmar, Sapna; Kaye, Keith S

    2014-08-01

    Identifying patients at risk for bloodstream infection (BSI) due to Acinetobacter baumannii-Acinetobacter calcoaceticus complex (ABC) and providing early appropriate therapy are critical for improving patient outcomes. A retrospective matched case-control study was conducted to investigate the risk factors for BSI due to ABC in patients admitted to the Detroit Medical Center (DMC) between January 2006 and April 2009. The cases were patients with BSI due to ABC; the controls were patients not infected with ABC. Potential risk factors were collected 30 days prior to the ABC-positive culture date for the cases and 30 days prior to admission for the controls. A total of 245 case patients were matched with 245 control patients. Independent risk factors associated with BSI due to ABC included a Charlson's comorbidity score of ≥ 3 (odds ratio [OR], 2.34; P = 0.001), a direct admission from another health care facility (OR, 4.63; P < 0.0001), a prior hospitalization (OR, 3.11; P < 0.0001), the presence of an indwelling central venous line (OR, 2.75; P = 0.011), the receipt of total parenteral nutrition (OR, 21.2; P < 0.0001), the prior receipt of β-lactams (OR, 3.58; P < 0.0001), the prior receipt of carbapenems (OR, 3.18; P = 0.006), and the prior receipt of chemotherapy (OR, 15.42; P < 0.0001). The median time from the ABC-positive culture date to the initiation of the appropriate antimicrobial therapy was 2 days (interquartile range [IQR], 1 to 3 days). The in-hospital mortality rate was significantly higher among case patients than among control patients (OR, 3.40; P < 0.0001). BSIs due to ABC are more common among critically ill and debilitated institutionalized patients, who are heavily exposed to health care settings and invasive devices.

  10. Trypanosome Motion Represents an Adaptation to the Crowded Environment of the Vertebrate Bloodstream

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    Heddergott, Niko; Krüger, Timothy; Babu, Sujin B.; Wei, Ai; Stellamanns, Erik; Uppaluri, Sravanti; Pfohl, Thomas; Stark, Holger; Engstler, Markus

    2012-01-01

    Blood is a remarkable habitat: it is highly viscous, contains a dense packaging of cells and perpetually flows at velocities varying over three orders of magnitude. Only few pathogens endure the harsh physical conditions within the vertebrate bloodstream and prosper despite being constantly attacked by host antibodies. African trypanosomes are strictly extracellular blood parasites, which evade the immune response through a system of antigenic variation and incessant motility. How the flagellates actually swim in blood remains to be elucidated. Here, we show that the mode and dynamics of trypanosome locomotion are a trait of life within a crowded environment. Using high-speed fluorescence microscopy and ordered micro-pillar arrays we show that the parasites mode of motility is adapted to the density of cells in blood. Trypanosomes are pulled forward by the planar beat of the single flagellum. Hydrodynamic flow across the asymmetrically shaped cell body translates into its rotational movement. Importantly, the presence of particles with the shape, size and spacing of blood cells is required and sufficient for trypanosomes to reach maximum forward velocity. If the density of obstacles, however, is further increased to resemble collagen networks or tissue spaces, the parasites reverse their flagellar beat and consequently swim backwards, in this way avoiding getting trapped. In the absence of obstacles, this flagellar beat reversal occurs randomly resulting in irregular waveforms and apparent cell tumbling. Thus, the swimming behavior of trypanosomes is a surprising example of micro-adaptation to life at low Reynolds numbers. For a precise physical interpretation, we compare our high-resolution microscopic data to results from a simulation technique that combines the method of multi-particle collision dynamics with a triangulated surface model. The simulation produces a rotating cell body and a helical swimming path, providing a functioning simulation method for a

  11. A multicentre analysis of epidemiology of the nosocomial bloodstream infections in Japanese university hospitals.

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    Nagao, M

    2013-09-01

    Nosocomial bloodstream infections (BSIs) are an important cause of morbidity and mortality. The current study analysed data from a concurrent surveillance programme to examine the current epidemiological trends for nosocomial BSIs at 22 Japanese university hospitals from 1 April 2008 to 31 March 2012. The number of blood culture sets taken, the rate of multiple blood culture sets and the rates of antibiotic-resistant isolates among six major nosocomial BSI pathogens (Staphylococcus aureus, Enterococcus spp., Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, and Candida spp.) not including coagulase-negative staphylococci, were evaluated. The clinical characteristics of nosocomial BSIs caused by these pathogens were also collected for 2941 patients. The number of blood culture sets taken per bed increased during the 4-year study period (from 4.07 in 2008 to 5.37 in 2011), and the rates of multiple blood culture sets also increased (from 29.9% in 2008 to 50.0% in 2011). Methicillin resistance was detected in 50.2% of S. aureus isolates. The prevalence rates of extended-spectrum beta-lactamase-producing E. coli and Klebsiella spp. isolates increased annually during the study period, and the average prevalence rates were 12.3% and 5.8%, respectively. The overall crude mortality of nosocomial BSIs due to the six pathogens evaluated was 24.5% (43.2% in ICU settings and 20.5% in non-ICU settings). Thus, our multicentre study evaluated the current epidemiological trends for nosocomial BSIs, and we found that further efforts are needed to increase the use of multiple blood culture sets and improve the prognosis of nosocomial BSIs in Japanese university hospitals.

  12. Staphylococcus species and their Methicillin-Resistance in 7424 Blood Cultures for Suspected Bloodstream Infections

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    Ariana ALMAŞ

    2011-06-01

    Full Text Available Objectives: The aim of this study was to evaluate the distribution of Staphylococcus species in bloodstream infections and to assess their susceptibility to methicillin. Material and Methods: Between January 1st 2008 - December 31st 2010, 7424 blood culture sets were submitted to the Laboratory Department of the Hospital for Clinical Infectious Diseases in Cluj-Napoca, Romania. The blood cultures were performed using BacT/Alert until January 2010 and BacT/Alert 3D automated system (bioMérieux after that date. The blood culture bottles were incubated at 37°C in a continuously monitoring system for up to 7 days. The strain identifications were performed by conventional methods, ApiStaph galleries and Vitek 2 Compact system. Susceptibility to methicillin was determined by disk diffusion method with cefoxitin disk and by using Vitek 2 Compact system. Results: From the total number of performed blood cultures, 568 were positive with Staphylococcus species. From 168 bacteriemic episodes 103 were with Staphylococcus aureus. Among 65 coagulase-negative staphylococci isolates, Staphylococcus epidermidis was the most frequently isolated species (34, followed by Staphylococcus hominis (15, Staphylococcus haemolyticus (8, Staphylococcus saprophyticus (3, Staphylococcus cohnii (1, Staphylococcus auricularis (1, and 3 strains that were not identified at species level. Methicillin resistance was encountered in 53.40% of Staphylococcus aureus strains and in 80% of coagulase-negative staphylococci. Conclusions: An important percentage of blood cultures were contaminated with Staphylococcus species. The main species identified in true bacteriemia cases were Staphylococcus aureus and Staphylococcus epidermidis. The percentage of methicillin-resistance, proved to be high not only for coagulase-negative staphylococci but also for Staphylococcus aureus.

  13. Classification of positive blood cultures: computer algorithms versus physicians' assessment - development of tools for surveillance of bloodstream infection prognosis using population-based laboratory databases

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    Gradel Kim O

    2012-09-01

    Full Text Available Abstract Background Information from blood cultures is utilized for infection control, public health surveillance, and clinical outcome research. This information can be enriched by physicians’ assessments of positive blood cultures, which are, however, often available from selected patient groups or pathogens only. The aim of this work was to determine whether patients with positive blood cultures can be classified effectively for outcome research in epidemiological studies by the use of administrative data and computer algorithms, taking physicians’ assessments as reference. Methods Physicians’ assessments of positive blood cultures were routinely recorded at two Danish hospitals from 2006 through 2008. The physicians’ assessments classified positive blood cultures as: a contamination or bloodstream infection; b bloodstream infection as mono- or polymicrobial; c bloodstream infection as community- or hospital-onset; d community-onset bloodstream infection as healthcare-associated or not. We applied the computer algorithms to data from laboratory databases and the Danish National Patient Registry to classify the same groups and compared these with the physicians’ assessments as reference episodes. For each classification, we tabulated episodes derived by the physicians’ assessment and the computer algorithm and compared 30-day mortality between concordant and discrepant groups with adjustment for age, gender, and comorbidity. Results Physicians derived 9,482 reference episodes from 21,705 positive blood cultures. The agreement between computer algorithms and physicians’ assessments was high for contamination vs. bloodstream infection (8,966/9,482 reference episodes [96.6%], Kappa = 0.83 and mono- vs. polymicrobial bloodstream infection (6,932/7,288 reference episodes [95.2%], Kappa = 0.76, but lower for community- vs. hospital-onset bloodstream infection (6,056/7,288 reference episodes [83.1%], Kappa = 0.57 and

  14. 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...

  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.

  16. 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.

  17. Loop Mediated Isothermal Amplification for Detection of Trypanosoma brucei gambiense in Urine and Saliva Samples in Nonhuman Primate Model

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    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.

  18. 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.

  19. A single amino acid substitution in the group 1 Trypanosoma brucei gambiense haptoglobin-hemoglobin receptor abolishes TLF-1 binding.

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    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.

  20. Molecular Evidence of a Trypanosoma brucei gambiense Sylvatic Cycle in the Human African Trypanosomiasis Foci of Equatorial Guinea

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    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.

  1. A global comparison of the human and T. brucei degradomes gives insights about possible parasite drug targets.

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    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.

  2. A simple method to purify biologically and antigenically preserved bloodstream trypomastigotes of Trypanosoma cruzi using Deae-cellulose columns

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    Maria Auxiliadora de Sousa

    1983-09-01

    Full Text Available A method to purify trypanosomastigotes of some strains of Trypanosoma cruzi (Y, CL, FL, F, "Berenice", "Colombiana" and "São Felipe" from mouse blood by using DEAE-cellulose columns was standardized. This procedure is a modification of the Lanham & Godfrey methods and differs in some aspects from others described to purify T. cruzi bloodstream trypomastigotes, mainly by avoidance of prior purifications of parasites. By this method, the broad trypomastigotes were mainly isolated, accounting for higher recoveries obtained with strains having higher percentages of these forms: processing of infected blood from irradiated mice could be advantageous by increasing the recovery of parasites (percentage and/or total number and elution of more slender trypomastigotes. Trypomastigotes purified by this method presented normal morphology and motility, remained infective to triatomine bugs and mice, showing in the latter prepatent periods and courses parasitemia similar to those of control parasites, and also reproducing the polymorphism pattern of each strain. Their virulence and pathogenicity also remained considerably preserved, the latter property being evaluated by LD 50 tests, mortality rates and mean survival time of inoculated mice. Moreover, these parasites presented positive, clear and peripheral immunofluorescence reaction at titres similar to those of control organisms, thus suggesting important preservation of their surface antigens.Usando colunas de DEAE-cellulose foi padronizado um método para purificação de tripomastigotas de várias cepas de Trypanosoma cruzi (Y, CL, FL, F, "Berenice", "Columbiana" e "São Felipe" a partir do sangue de camundongos. Este método é uma modificação daqueles descritos por Lanham & Godfrey e difere em vários aspectos de outros descritos para purificar as formas sanguíneas deste parasita, particularmente na dispensa de pré-purificações. Por ele foram isolados principalmente os tripomastigotas largos

  3. Molecular Identification and Echinocandin Susceptibility of Candida parapsilosis Complex Bloodstream Isolates in Italy, 2007-2014.

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    Lovero, Grazia; Borghi, Elisa; Balbino, Stella; Cirasola, Daniela; De Giglio, Osvalda; Perdoni, Federica; Caggiano, Giuseppina; Morace, Giulia; Montagna, Maria Teresa

    2016-01-01

    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 resistance, and it

  4. Molecular Identification and Echinocandin Susceptibility of Candida parapsilosis Complex Bloodstream Isolates in Italy, 2007–2014

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    Lovero, Grazia; Borghi, Elisa; Balbino, Stella; Cirasola, Daniela; De Giglio, Osvalda; Perdoni, Federica; Caggiano, Giuseppina; Morace, Giulia; Montagna, Maria Teresa

    2016-01-01

    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 resistance, and it

  5. 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

  6. Comparison of the systemic inflammatory response syndrome between monomicrobial and polymicrobial Pseudomonas aeruginosa nosocomial bloodstream infections

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    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

  7. Systemic effects of locally injected platelet rich plasma in a rat model: an analysis on muscle and bloodstream.

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    Borrione, P; Grasso, L; Racca, S; Abbadessa, G; Carriero, V; Fagnani, F; Quaranta, F; Pigozzi, F

    2015-01-01

    Abundant evidence suggests that growth factors, contained in platelets alpha granules, may play a key role in the early stages of the muscle healing process with particular regard to the inflammatory phase. Although the contents of the platelet-rich plasma preparations have been extensively studied, the biological mechanisms involved as well as the systemic effects and the related potential doping implications of this approach are still largely unknown. The aim of the present study was to investigate whether local platelet-rich plasma administration may modify the levels of specific cytokines and growth factors both in treated muscle and bloodstream in rats. An additional aim was to investigate more deeply whether the local platelet-rich plasma administration may exert systemic effects by analyzing contralateral lesioned but untreated muscles. The results showed that platelet-rich plasma treatment induced a modification of certain cytokines and growth factor levels in muscle but not in the bloodstream, suggesting that local platelet-rich plasma treatment influenced directly or, more plausibly, indirectly the synthesis or recruitment of cytokines and growth factors at the site of injury. Moreover, the observed modifications of cytokine and growth factor levels in contralateral injured but not treated muscles, strongly suggested a systemic effect of locally injected platelet-rich plasma.

  8. Evaluation of Real-time PCR and Pyrosequencing for Screening Incubating Blood Culture Bottles from Adults with Suspected Bloodstream Infection

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    McCann, Chase D.; Moore, Miranda S.; May, Larissa S.; McCarroll, Matthew; Jordan, Jeanne A.

    2015-01-01

    Several molecular platforms can identify bacteria associated with bloodstream infections, but require positive culture bottles as starting material. Here we describe results of screening 1140 blood cultures at 8 hours post-inoculation, from 918 eligible adults being evaluated for bloodstream infection. DNA was extracted and analyzed by 16S and/or 23S rRNA real-time PCR/Pyrosequencing. Compared to culture, PCR/Pyrosequencing displayed 90.9% sensitivity, 99.6% specificity, 95.7% PPV, and 99.1% NPV. Overall concordance rate was 98.9% (1127/1140). In four cases with molecular-positive/culture-negative results, medical chart reviews provided evidence of identical bacteria from subsequent blood or concomitant urine/sputum cultures. Nine culture-positive/molecular-negative cases were associated with either polymicrobial growth, grew only in the anaerobic bottle of the clinical pair, and/or were detected by PCR/Pyrosequencing after 8 hours. In summary, this approach accurately detected and identified bacteria in ~91% of culture-confirmed cases significantly sooner than the phenotypic identification was available, having the potential to improve antibiotic stewardship. PMID:25534615

  9. Evaluation of real-time PCR and pyrosequencing for screening incubating blood culture bottles from adults with suspected bloodstream infection.

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    McCann, Chase D; Moore, Miranda S; May, Larissa S; McCarroll, Matthew G; Jordan, Jeanne A

    2015-03-01

    Several molecular platforms can identify bacteria associated with bloodstream infections but require positive culture bottles as starting material. Here, we describe results of screening 1140 blood cultures at 8h postinoculation, from 918 eligible adults being evaluated for bloodstream infection. DNA was extracted and analyzed by 16S and/or 23S rRNA real-time PCR/pyrosequencing. Compared to culture, PCR/pyrosequencing displayed 90.9% sensitivity, 99.6% specificity, 95.7% positive predictive value, and 99.1% negative predictive value. Overall concordance rate was 98.9% (1127/1140). In 4 cases with molecular-positive/culture-negative results, medical chart reviews provided evidence of identical bacteria from subsequent blood or concomitant urine/sputum cultures. Nine culture-positive/molecular-negative cases were associated with either polymicrobial growth, grew only in the anaerobic bottle of the clinical pair, and/or were detected by PCR/pyrosequencing after 8h. In summary, this approach accurately detected and identified bacteria in ~91% of culture-confirmed cases significantly sooner than the phenotypic identification was available, having the potential to improve antibiotic stewardship.

  10. Clonal distribution of bone sialoprotein-binding protein gene among Staphylococcus aureus isolates associated with bloodstream infections.

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    Wiśniewska, Katarzyna; Piórkowska, Anna; Kasprzyk, Joanna; Bronk, Marek; Świeć, Krystyna

    2014-11-01

    Staphylococcus aureus is a leading cause of bloodstream infections (BSI) and diseases that may be caused by hematogenous spread. The staphylococcal adhesin, for which the association with the infections emerging as a complication of septicemia has been well documented, is a bone sialoprotein-binding protein (Bbp). The aim of the study was to assess the prevalence of a bbp gene in S. aureus bloodstream isolates associated with BSI and to investigate to what degree the distribution of this gene is linked to the clonality of the population. Spa typing, used in order to explore the genetic population structure of the isolates, yielded 29 types. Six spa clusters and seven singletons were identified. The most frequent was spa clonal complex CC021 associated with MLST CC30 (38%). The bbp gene was found in 47% of isolates. Almost all isolates (95%) clustered in spa clonal complex CC021 were positive for this gene. All isolates carrying the bbp gene were sensitive to methicillin, and if clustered in the spa CC021, belonged to agr group III. Our study shows that Bbp is not strictly associated with BSI. However, one may conclude that for clonally related S. aureus strains most commonly causing BSI, the risk of Bbp-mediated complications of septicemia is expected to be higher than for other strains.

  11. Host Characteristics and Bacterial Traits Predict Experimental Virulence for Escherichia coli Bloodstream Isolates From Patients With Urosepsis.

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    Johnson, James R; Porter, Stephen; Johnston, Brian; Kuskowski, Michael A; Spurbeck, Rachel R; Mobley, Harry L T; Williamson, Deborah A

    2015-09-01

    Background.  Extraintestinal Escherichia coli infections are common, costly, and potentially serious. A better understanding of their pathogenesis is needed. Methods.  Sixty-seven E coli bloodstream isolates from adults with urosepsis (Seattle, WA; 1980s) underwent extensive molecular characterization and virulence assessment in 2 infection models (murine subcutaneous sepsis and moth larval lethality). Statistical comparisons were made among host characteristics, bacterial traits, and experimental virulence. Results.  The 67 source patients were diverse for age, sex, and underlying medical and urological conditions. The corresponding E coli isolates exhibited diverse phylogenetic backgrounds and virulence profiles. Despite the E coli isolates' common bloodstream origin, they exhibited a broad range of experimental virulence in mice and moth larvae, in patterns that (for the murine model only) corresponded significantly with host characteristics and bacterial traits. The most highly mouse-lethal strains were enriched with classic "urovirulence" traits and typically were from younger women with anatomically and functionally normal urinary tracts. The 2 animal models corresponded poorly with one another. Conclusions.  Host compromise, including older age and urinary tract abnormalities, allows comparatively low-virulence E coli strains to cause urosepsis. Multiple E coli traits predict both experimental and epidemiological virulence. The larval lethality model cannot be a substitute for the murine sepsis model.

  12. Histone H3 Variant Regulates RNA Polymerase II Transcription Termination and Dual Strand Transcription of siRNA Loci in Trypanosoma brucei.

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    David Reynolds

    2016-01-01

    Full Text Available Base J, β-D-glucosyl-hydroxymethyluracil, is a chromatin modification of thymine in the nuclear DNA of flagellated protozoa of the order Kinetoplastida. In Trypanosoma brucei, J is enriched, along with histone H3 variant (H3.V, at sites involved in RNA Polymerase (RNAP II termination and telomeric sites involved in regulating variant surface glycoprotein gene (VSG transcription by RNAP I. Reduction of J in T. brucei indicated a role of J in the regulation of RNAP II termination, where the loss of J at specific sites within polycistronic gene clusters led to read-through transcription and increased expression of downstream genes. We now demonstrate that the loss of H3.V leads to similar defects in RNAP II termination within gene clusters and increased expression of downstream genes. Gene derepression is intensified upon the subsequent loss of J in the H3.V knockout. mRNA-seq indicates gene derepression includes VSG genes within the silent RNAP I transcribed telomeric gene clusters, suggesting an important role for H3.V in telomeric gene repression and antigenic variation. Furthermore, the loss of H3.V at regions of overlapping transcription at the end of convergent gene clusters leads to increased nascent RNA and siRNA production. Our results suggest base J and H3.V can act independently as well as synergistically to regulate transcription termination and expression of coding and non-coding RNAs in T. brucei, depending on chromatin context (and transcribing polymerase. As such these studies provide the first direct evidence for histone H3.V negatively influencing transcription elongation to promote termination.

  13. Trypanosoma brucei Invasion and T-Cell Infiltration of the Brain Parenchyma in Experimental Sleeping Sickness: Timing and Correlation with Functional Changes

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    Laperchia, Claudia; Palomba, Maria; Seke Etet, Paul F.; Rodgers, Jean; Bradley, Barbara; Montague, Paul; Grassi-Zucconi, Gigliola; Bentivoglio, Marina

    2016-01-01

    Background 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. Methodology 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. Principal findings 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. Conclusion 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. PMID:28002454

  14. 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; Kim, Soo Hyun

    2014-03-01

    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.

  15. Five-Lumen Antibiotic-Impregnated Femoral Central Venous Catheters in Severely Burned Patients: An Investigation of Device Utility and Catheter-Related Bloodstream Infection Rates.

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    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.

  16. The miRNA and mRNA Signatures of Peripheral Blood Cells in Humans Infected with Trypanosoma brucei gambiense.

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    Smiths Lueong

    Full Text Available Simple, reliable tools for diagnosis of human African Trypanosomiases could ease field surveillance and enhance patient care. In particular, current methods to distinguish patients with (stage II and without (stage I brain involvement require samples of cerebrospinal fluid. We describe here an exploratory study to find out whether miRNAs from peripheral blood leukocytes might be useful in diagnosis of human trypanosomiasis, or for determining the stage of the disease. Using microarrays, we measured miRNAs in samples from Trypanosoma brucei gambiense-infected patients (9 stage I, 10 stage II, 8 seronegative parasite-negative controls and 12 seropositive, but parasite-negative subjects. 8 miRNAs (out of 1205 tested showed significantly lower expression in patients than in seronegative, parasite-negative controls, and 1 showed increased expression. There were no clear differences in miRNAs between patients in different disease stages. The miRNA profiles could not distinguish seropositive, but parasitologically negative samples from controls and results within this group did not correlate with those from the trypanolysis test. Some of the regulated miRNAs, or their predicted mRNA targets, were previously reported changed during other infectious diseases or cancer. We conclude that the changes in miRNA profiles of peripheral blood lymphocytes in human African trypanosomiasis are related to immune activation or inflammation, are probably disease-non-specific, and cannot be used to determine the disease stage. The approach has little promise for diagnostics but might yield information about disease pathology.

  17. Genetic character of drug resistance in Trpanosoma brucei%锥虫抗药性的遗传特性

    Institute of Scientific and Technical Information of China (English)

    廖党金; 沈杰

    2000-01-01

    @@ 锥虫病是由锥虫寄生于人和动物的血液而引起人和动物的一种疾病.锥虫抗药性的产生,可能给人和家畜带来较严重的后果[1],国外于1908年已注意到锥虫的抗药性问题[2、3],而我国于1988年第一次口头报道在云南用厂方推荐的安锥赛治疗剂量难以治愈家畜锥虫病,1991年沈杰等正式报道了我国伊氏锥虫云南株和安徽株对安锥赛已产生抗药性[4].迄今,报告产生抗药性的锥虫虫种有布氏锥虫(Trypanosoma brucei)等常见的8个种,其它未报告的锥虫并不意味着不产生抗药性.已报告产生抗药性的药物有苏拉明(Suramine)等30多种抗锥虫药物.抗药性是能遗传的,对锥虫抗药性的遗传特性的了解,能帮助我们正确地选择和使用药物、减少和避免抗药性的产生及怎样消除已有的抗药性具有极其重要的作用,其次也有助于锥虫的生理、生化及生物学研究.

  18. Crystal Structures of Trypanosoma brucei Sterol 14[alpha]-Demethylase and Implications for Selective Treatment of Human Infections

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. [Assessment of diagnostic methods for the catheter-related bloodstream infections in intensive care units].

    Science.gov (United States)

    Ataman Hatipoğlu, Ciğdem; Ipekkan, Korhan; Oral, Behiç; Onde, Ufuk; Bulut, Cemal; Demiröz, Ali Pekcan

    2011-01-01

    The majority of catheter-related bloodstream infections (CR-BSI) are associated with central venous catheters (CVCs) and most of them develop in patients staying at intensive care units (ICUs). The aim of this study was to assess the performance of different methods for the diagnosis of CR-BSI in neurology and neurosurgery ICUs of our hospital. This prospective study was carried out between January 2007 and January 2008 and all of the patients were followed daily for CR-BSI after the insertion of CVCs. Blood cultures were taken simultaneously from the catheter lumen and from at least one peripheral vein when there was a suspicion of CR-BSI. Additionally, from patients whose CVCs were removed, catheter tip cultures were taken and from patients with exit site infection, cultures of the skin surrounding the catheter entrance were taken. Catheter tip cultures were done by using quantitative and semiquantitative culture methods. Blood cultures taken from the catheter lumen and peripheral vein were incubated in the BACTEC 9050 (Becton Dickinson, USA) automated blood culture system. Gram and acridine orange (AO) staining were used for the smears prepared from the catheter tips and blood cultures. To evaluate the value of culture and staining methods in the diagnosis of CR-BSI; sensitivity, specificity, positive and negative predictive values (PPV and NPV, respectively) of each method were determined. A total of 148 patients (66 male, 82 female; age range: 1-94 years, mean age: 58.7 ± 21.8 years) were included in the study, of whom 67 (45.3%) were from neurology and 81 (54.7%) were from neurosurgery ICUs. One hundred ninety-nine CVC application performed in 148 patients were evaluated. Mean duration of catheterization was 8.5 ± 5.2 days. Thirty-two episodes of CR-BSI among 199 catheterizations (16%) in 29 patients among a total of 148 patients (19.6%) were determined. The most frequently isolated microorganisms were methicillin-resistant coagulase-negative staphylococci

  20. Impact of a modified Broviac maintenance care bundle on bloodstream infections in paediatric cancer patients

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    Furtwängler, Rhoikos

    2015-11-01

    Full Text Available Background: During intensive chemotherapy, bloodstream infection (BSI represents an important complication in paediatric cancer patients. Most patients carry a long-term central venous access device (CVAD. Improved maintenance care of these vascular catheters may decrease the risk of BSI.Methods: Intervention study (adapted CVAD prevention protocol with two observation periods (P1: 09-2009 until 05-2011; P2: 09-2011 until 05-2013; prospective surveillance of all laboratory confirmed BSIs. In P2, ready to use sterile NaCl 0.9% syringes were used for CVAD flushing and octenidine/isopropanol for the disinfection of catheter hubs and 3-way stopcocks. Results: During P1, 84 patients were included versus 81 patients during P2. There were no significant differences between the two patient populations in terms of median age, gender, underlying malignancy or disease status (first illness or relapse. Nearly all CVADs were Broviac catheters. The median duration from implantation to removal of the CVAD was 192 days (Inter-quartile-range (IQR; 110–288 days in P1 and 191 days (IQR; 103–270 days in P2. 28 BSI were diagnosed in 22 patients in P1 (26% of all patients experienced at least one BSI and 15 BSI in 12 patients in P2 (15% of all patients. The corresponding results for incidence density (ID were 0.44 (CI95 0.29–0.62 for P1 vs. 0.34 (0.19–0.53 BSI per 100 inpatient days for P2 and for incidence rate (IR 7.76 (5.16–10.86 in P1 vs. 4.75 (2.66–7.43 BSI per 1,000 inpatient CVAD utilization days. In P1, 9 BSI were caused by CoNS vs. only 2 in P2 (IR 2.49; CI95 0.17–4.17 vs. 0.63; CI95 0.08–1.72. In P1 two BSI (7% lead to early removal of the device. During P2 one CVAD was prematurely removed due to a Broviac-related BSI (6.7%.Conclusion: The preventive protocol investigated in this study led to a reduction of BSI in paediatric cancer patients. This result was clinically relevant but – due to insufficient power in a single centre observation

  1. DNA microarray genotyping and virulence and antimicrobial resistance gene profiling of methicillin-resistant Staphylococcus aureus bloodstream isolates from renal patients.

    LENUS (Irish Health Repository)

    McNicholas, Sinead

    2012-02-01

    Thirty-six methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates from renal patients were genetically characterized by DNA microarray analysis and spa typing. The isolates were highly clonal, belonging mainly to ST22-MRSA-IV. The immune evasion and enterotoxin gene clusters were found in 29\\/36 (80%) and 33\\/36 (92%) isolates, respectively.

  2. DNA microarray genotyping and virulence and antimicrobial resistance gene profiling of methicillin-resistant Staphylococcus aureus bloodstream isolates from renal patients.

    LENUS (Irish Health Repository)

    McNicholas, Sinead

    2011-12-01

    Thirty-six methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates from renal patients were genetically characterized by DNA microarray analysis and spa typing. The isolates were highly clonal, belonging mainly to ST22-MRSA-IV. The immune evasion and enterotoxin gene clusters were found in 29\\/36 (80%) and 33\\/36 (92%) isolates, respectively.

  3. Evaluation of the MALDI-TOF VITEK MS™ system for the identification of Candida parapsilosis, C. orthopsilosis and C. metapsilosis from bloodstream infections.

    Science.gov (United States)

    Nobrega de Almeida Júnior, João; de Souza, Letícia Bonato; Motta, Adriana Lopes; Rossi, Flávia; Romano Di Gioia, Thais Sabato; Benard, Gil; Del Negro, Gilda Maria Barbaro

    2014-10-01

    Twenty-nine Candida parapsilosis, seventeen Candida orthopsilosis and two Candida metapsilosis bloodstream isolates were submitted for identification by VITEK-MS™ mass spectrometer. Four isolates, two C. orthopsilosis and two C. metapsilosis, were not identified. Inclusion of Superspectra of both species in this database is required to improve its discrimination power.

  4. Burden of antimicrobial resistance in European hospitals : excess mortality and length of hospital stay associated with bloodstream infections due to Escherichia coli resistant to third-generation cephalosporins

    NARCIS (Netherlands)

    de Kraker, M. E. A.; Wolkewitz, M.; Davey, P. G.; Koller, W.; Berger, J.; Nagler, J.; Icket, C.; Kalenic, S.; Horvatic, J.; Seifert, H.; Kaasch, A.; Paniara, O.; Argyropoulou, A.; Bompola, M.; Smyth, E.; Skally, M.; Raglio, A.; Dumpis, U.; Kelmere, A. Melbarde; Borg, M.; Xuereb, D.; Ghita, M. C.; Noble, M.; Kolman, J.; Grabljevec, S.; Turner, D.; Lansbury, L.; Grundmann, H.

    2011-01-01

    This study determined excess mortality and length of hospital stay (LOS) attributable to bloodstream infection (BSI) caused by third-generation-cephalosporin-resistant Escherichia coli in Europe. A prospective parallel matched cohort design was used. Cohort I consisted of patients with third-generat

  5. Etiology and epidemiology of catheter related bloodstream infections in patients receiving home parenteral nutrition in a gastromedical center at a tertiary hospital in denmark

    DEFF Research Database (Denmark)

    Nielsen, Xiaohui Chen; Chen, Ming; Hellesøe, Anne-Marie Blok

    2012-01-01

    We conducted a retrospective epidemiologic study of catheter related bloodstream infections (CRBSI) in patients receiving long-term home parenteral nutrition (HPN) from January 2002 to December 2005. Our results showed that coagulase negative staphylococci (CoNS) were the most prevalent pathogens...

  6. Taurolidine lock is highly effective in preventing catheter-related bloodstream infections in patients on home parenteral nutrition: a heparin-controlled prospective trial.

    NARCIS (Netherlands)

    Bisseling, T.M.; Willems, M.C.M.; Versleijen, M.W.J.; Hendriks, J.C.M.; Vissers, R.K.; Wanten, G.J.A.

    2010-01-01

    BACKGROUND & AIMS: Catheter-related bloodstream infections remain the major threat for Home Parenteral Nutrition programs. Taurolidine, a potent antimicrobial agent, holds promise as an effective catheter lock to prevent such infections. Aim of the present study was to compare taurolidine with hepar

  7. Absence of microbial adaptation to taurolidine in patients on home parenteral nutrition who develop catheter related bloodstream infections and use taurolidine locks

    NARCIS (Netherlands)

    Olthof, E.D.; Rentenaar, R.J.; Rijs, A.J.M.M.; Wanten, G.J.A.

    2013-01-01

    BACKGROUND & AIMS: Some home parenteral nutrition (HPN) patients develop catheter related bloodstream infections (CRBSI) despite using an anti-microbial catheter lock solution taurolidine. The aim of this study was to assess whether long-term use of taurolidine leads to selective growth of microorga

  8. Effect of a vascular access team on central line-associated bloodstream infections in infants admitted to a neonatal intensive care unit : a systematic review

    NARCIS (Netherlands)

    Legemaat, Monique M; Jongerden, IP; van Rens, Roland M F P T; Zielman, Marjanne; van den Hoogen, Agnes

    2015-01-01

    OBJECTIVE: 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. DATA SOURCES: MEDLINE, CINAHL, Embase, Web-of-Science and the Cochrane Library were searched until December 2013. STUDY

  9. Draft Genome Sequence of Extremely Drug-Resistant Pseudomonas aeruginosa (ST357) Strain CMC_VB_PA_B22862 Isolated from a Community-Acquired Bloodstream Infection

    Science.gov (United States)

    Pragasam, Agila Kumari; Yesurajan, Francis; Doss C, George Priya; George, Biju; Devanga Ragupathi, Naveen Kumar; Walia, Kamini

    2016-01-01

    Extremely drug-resistant Pseudomonas aeruginosa strains causing severe infections have become a serious concern across the world. Here, we report draft genome sequence of P. aeruginosa with an extremely drug-resistant profile isolated from a patient with community-acquired bloodstream infection in India.

  10. Bloodstream infections during the onset of necrotizing enterocolitis and their relation with the pro-inflammatory response, gut wall integrity and severity of disease in NEC

    NARCIS (Netherlands)

    Heida, F. H.; Hulscher, J. B. F.; Schurink, M.; van Vliet, M. J.; Kooi, E. M. W.; Kasper, D. C.; Pones, M.; Bos, A. F.; Benkoe, T. M.

    2015-01-01

    Introduction: Bacterial involvement is believed to play a pivotal role in the development and disease outcome of NEC. However, whether a bloodstream infection (BSI) predisposes to NEC (e.g. by activating the pro-inflammatory response) or result from the loss of gut wall integrity during NEC developm

  11. Bloodstream infections during the onset of necrotizing enterocolitis and their relation with the pro-inflammatory response, gut wall integrity and severity of disease in NEC

    NARCIS (Netherlands)

    Heida, F.H.; Hulscher, J.B.; Schurink, M.; Vliet, M.J. van; Kooi, E.M.; Kasper, D.C.; Pones, M.; Bos, A.F; Benkoe, T.M.

    2015-01-01

    INTRODUCTION: Bacterial involvement is believed to play a pivotal role in the development and disease outcome of NEC. However, whether a bloodstream infection (BSI) predisposes to NEC (e.g. by activating the pro-inflammatory response) or result from the loss of gut wall integrity during NEC developm

  12. Etiological characteristics of 108 patients with secondary bloodstream infections%继发性血流感染108例病原学特点分析

    Institute of Scientific and Technical Information of China (English)

    黄仁刚; 杨兴祥; 喻华; 龙姗姗; 林健梅; 江南

    2015-01-01

    Objective To investigate the etiological characteristics of laboratory-confirmed bloodstream infections with identi-fied infective sources. Methods The data of the patients with laboratory-confirmed bloodstream infections and identified infective sources, who were treated at Sichuan Provincial People's Hospital from Jan. 2011 to Jun. 2013 were collected to analyze the etiological characteristics retrospectively. Results A total of 108 patients with identified infective sources were enrolled in this study, of whom 93 patients suffered from monomicrobial infection, and 15 patients suffered from polymicrobial infection. Bloodstream infections were com-monly found in urinary tract, abdominal cavity and respiratory tract. Infection with Escherichia coli. accounted for 75.8%and 42.4%in patients with bloodstream infections in urinary tract and abdominal cavity, respectively; Infection with Acinetobacter baumannii ac-counted for 62.5%in patients with bloodstream infections in respiratory tract, and Acinetobacter baumannii was resistant to carbapen-em antibiotics. The 30-day mortality of 108 patients with bloodstream infections was 19.4%. The patients with bloodstream infections in urinary tract had the lowest 30-day mortality rate (3.0%), while the patients with bloodstream infections in lower respiratory tract had the highest 30-day mortality rate (45.8%). The 30-day mortality rates of the patients with bloodstream infections with non-fermentation gram negative bacillus and fungi were 55.0%and 50.0%, respectively. Conclusions The pathogen distribution of the patients with different sources of bloodstream infections varies widely. Appropriate antibiotic therapy should take infective sources, types of bacteria and drug resistance into consideration.%目的 研究感染来源明确的血流感染患者的病原学特点. 方法 收集四川省人民医院2011年1月—2013年6月实验室确诊、感染来源明确的血流感染患者临床资料,回

  13. A Novel Basal Body Protein That Is a Polo-like Kinase Substrate Is Required for Basal Body Segregation and Flagellum Adhesion in Trypanosoma brucei.

    Science.gov (United States)

    Hu, Huiqing; Zhou, Qing; Li, Ziyin

    2015-10-01

    The Polo-like kinase (PLK) in Trypanosoma brucei plays multiple roles in basal body segregation, flagellum attachment, and cytokinesis. However, the mechanistic role of TbPLK remains elusive, mainly because most of its substrates are not known. Here, we report a new substrate of TbPLK, SPBB1, and its essential roles in T. brucei. SPBB1 was identified through yeast two-hybrid screening with the kinase-dead TbPLK as the bait. It interacts with TbPLK in vitro and in vivo, and is phosphorylated by TbPLK in vitro. SPBB1 localizes to both the mature basal body and the probasal body throughout the cell cycle, and co-localizes with TbPLK at the basal body during early cell cycle stages. RNAi against SPBB1 in procyclic trypanosomes inhibited basal body segregation, disrupted the new flagellum attachment zone filament, detached the new flagellum, and caused defective cytokinesis. Moreover, RNAi of SPBB1 confined TbPLK at the basal body and the bilobe structure, resulting in constitutive phosphorylation of TbCentrin2 at the bilobe. Altogether, these results identified a basal body protein as a TbPLK substrate and its essential role in promoting basal body segregation and flagellum attachment zone filament assembly for flagellum adhesion and cytokinesis initiation.

  14. Nucleolar accumulation of RNA binding proteins induced by Actinomycin D is functional in Trypanosoma cruzi and Leishmania mexicana but not in T. brucei.

    Directory of Open Access Journals (Sweden)

    Ezequiel Názer

    Full Text Available We have recently shown in T. cruzi that a group of RNA Binding Proteins (RBPs, involved in mRNA metabolism, are accumulated into the nucleolus in response to Actinomycin D (ActD treatment. In this work, we have extended our analysis to other members of the trypanosomatid lineage. In agreement with our previous study, the mechanism seems to be conserved in L. mexicana, since both endogenous RBPs and a transgenic RBP were relocalized to the nucleolus in parasites exposed to ActD. In contrast, in T. brucei, neither endogenous RBPs (TbRRM1 and TbPABP2 nor a transgenic RBP from T. cruzi were accumulated into the nucleolus under such treatment. Interestingly, when a transgenic TbRRM1 was expressed in T. cruzi and the parasites exposed to ActD, TbRRM1 relocated to the nucleolus, suggesting that it contains the necessary sequence elements to be targeted to the nucleolus. Together, both experiments demonstrate that the mechanism behind nucleolar localization of RBPs, which is present in T. cruzi and L. mexicana, is not functional in T. brucei, suggesting that it has been lost or retained differentially during the evolution of the trypanosomatid lineage.

  15. Incidence of colonization and bloodstream infection with carbapenem-resistant Enterobacteriaceae in children receiving antineoplastic chemotherapy in Italy.

    Science.gov (United States)

    Caselli, Desiree; Cesaro, Simone; Fagioli, Franca; Carraro, Francesca; Ziino, Ottavio; Zanazzo, Giulio; Meazza, Cristina; Colombini, Antonella; Castagnola, Elio

    2016-02-01

    Few data are available on the incidence of carbapenemase-producing Enterobacteriaceae (CPE) infection or colonization in children receiving anticancer chemotherapy. We performed a nationwide survey among centers participating in the pediatric hematology-oncology cooperative study group (Associazione Italiana Ematologia Oncologia Pediatrica, AIEOP). During a 2-year observation period, we observed a threefold increase in the colonization rate, and a fourfold increase of bloodstream infection episodes, caused by CPE, with a 90-day mortality of 14%. This first nationwide Italian pediatric survey shows that the circulation of CPE strains in the pediatric hematology-oncology environment is increasing. Given the mortality rate, which is higher than for other bacterial strains, specific monitoring should be applied and the results should have implications for health-care practice in pediatric hematology-oncology.

  16. Ten-year study of species distribution and antifungal susceptibilities of Candida bloodstream isolates at a Brazilian tertiary hospital.

    Science.gov (United States)

    Bonfietti, L X; Szeszs, M W; Chang, M R; Martins, M A; Pukinskas, S R B S; Nunes, M O; Pereira, G H; Paniago, A M M; Purisco, S U; Melhem, M S C

    2012-12-01

    To describe the incidence and susceptibility profile of Candida bloodstream infections in a tertiary-care hospital, we performed a retrospective observational study from 1998 to 2007. Comorbidities and risk factors were compiled from all cases. In vitro susceptibility testing to fluconazole, itraconazole, voriconazole, and amphotericin B was performed for 100 isolates, and caspofungin was tested for C. parapsilosis complex. In a ten-year evaluation of candidemias, 44 % were caused by C. albicans, and species of the C. parapsilosis complex were the second most frequent agents (37 %). Other species presented lower incidences (C. tropicalis, 13 %, C. glabrata, 5 %, and C. krusei, 1 %). Neither C. dubliniensis nor C. metapsilosis were observed in this study. C. orthopsilosis (3 %) and C. parapsilosis stricto sensu (34 %) were also found. Species distribution was independent of catheterization, mechanical ventilation, or previous use of antifungals or corticoids. Parenteral nutrition administration was strongly related to C. glabrata infection, and the highest mortality (80 %) was observed in patients infected by this species. All C. albicans isolates showed high susceptibility to all tested drugs. However, two C. parapsilosis stricto sensu isolates presented high minimum inhibitory concentration (MIC) (4 mg/L each) to fluconazole, and one exhibited voriconazole MIC of 0.25 mg/L, highlighting the cross-resistance to these azoles. All isolates of C. tropicalis and C. glabrata showed no resistance to any drug tested. No difference was noted between C. parapsilosis and C. orthopsilosis susceptibilities to caspofungin. Our results suggest that resistance to amphotericin B, fluconazole, voriconazole, itraconazole, and caspofungin in Brazilian Candida bloodstream isolates is still uncommon.

  17. Antimicrobial Resistance and Molecular Epidemiology of Escherichia coli Causing Bloodstream Infections in Three Hospitals in Shanghai, China.

    Directory of Open Access Journals (Sweden)

    Su Wang

    Full Text Available Escherichia coli (E. coli is one of the most frequent and lethal causes of bloodstream infections (BSIs. We carried out a retrospective multicenter study on antimicrobial resistance and phylogenetic background of clinical E. coli isolates recovered from bloodstream in three hospitals in Shanghai. E. coli isolates causing BSIs were consecutively collected between Sept 2013 and Sept 2014. Ninety isolates randomly selected (30 from each hospital were enrolled in the study. Antimicrobial susceptibility testing was performed by disk diffusion. PCR was used to detect antimicrobial resistance genes coding for β-lactamases (TEM, CTX-M, OXA, etc., carbapenemases (IMP, VIM, KPC, NDM-1 and OXA-48, and phylogenetic groups. eBURST was applied for analysis of multi-locus sequence typing (MLST. The resistance rates for penicillins, second-generation cephalosporins, fluoroquinolone and tetracyclines were high (>60%. Sixty-one of the 90 (67.8% strains enrolled produced ESBLs and no carbapenemases were found. Molecular analysis showed that CTX-M-15 (25/61, CTX-M-14 (18/61 and CTX-M-55 (9/61 were the most common ESBLs. Phylogenetic group B2 predominated (43.3% and exhibited the highest rates of ESBLs production. ST131 (20/90 was the most common sequence type and almost assigned to phylogenetic group B2 (19/20. The following sequence types were ST405 (8/90 and ST69 (5/90. Among 61 ESBL-producers isolates, B2 (26, 42.6% and ST131 (18, 29.5% were also the most common phylogenetic group and sequence type. Genetic diversity showed no evidence suggesting a spread of these antimicrobial resistant isolates in the three hospitals. In order to provide more comprehensive and reliable epidemiological information for preventing further dissemination, well-designed and continuous surveillance with more hospitals participating was important.

  18. Antimicrobial Resistance and Molecular Epidemiology of Escherichia coli Causing Bloodstream Infections in Three Hospitals in Shanghai, China.

    Science.gov (United States)

    Wang, Su; Zhao, Sheng-Yuan; Xiao, Shu-Zhen; Gu, Fei-Fei; Liu, Qing-Zhong; Tang, Jin; Guo, Xiao-Kui; Ni, Yu-Xing; Han, Li-Zhong

    2016-01-01

    Escherichia coli (E. coli) is one of the most frequent and lethal causes of bloodstream infections (BSIs). We carried out a retrospective multicenter study on antimicrobial resistance and phylogenetic background of clinical E. coli isolates recovered from bloodstream in three hospitals in Shanghai. E. coli isolates causing BSIs were consecutively collected between Sept 2013 and Sept 2014. Ninety isolates randomly selected (30 from each hospital) were enrolled in the study. Antimicrobial susceptibility testing was performed by disk diffusion. PCR was used to detect antimicrobial resistance genes coding for β-lactamases (TEM, CTX-M, OXA, etc.), carbapenemases (IMP, VIM, KPC, NDM-1 and OXA-48), and phylogenetic groups. eBURST was applied for analysis of multi-locus sequence typing (MLST). The resistance rates for penicillins, second-generation cephalosporins, fluoroquinolone and tetracyclines were high (>60%). Sixty-one of the 90 (67.8%) strains enrolled produced ESBLs and no carbapenemases were found. Molecular analysis showed that CTX-M-15 (25/61), CTX-M-14 (18/61) and CTX-M-55 (9/61) were the most common ESBLs. Phylogenetic group B2 predominated (43.3%) and exhibited the highest rates of ESBLs production. ST131 (20/90) was the most common sequence type and almost assigned to phylogenetic group B2 (19/20). The following sequence types were ST405 (8/90) and ST69 (5/90). Among 61 ESBL-producers isolates, B2 (26, 42.6%) and ST131 (18, 29.5%) were also the most common phylogenetic group and sequence type. Genetic diversity showed no evidence suggesting a spread of these antimicrobial resistant isolates in the three hospitals. In order to provide more comprehensive and reliable epidemiological information for preventing further dissemination, well-designed and continuous surveillance with more hospitals participating was important.

  19. Surveillance of Candida spp bloodstream infections: epidemiological trends and risk factors of death in two Mexican tertiary care hospitals.

    Directory of Open Access Journals (Sweden)

    Dora E Corzo-Leon

    Full Text Available INTRODUCTION: Larger populations at risk, broader use of antibiotics and longer hospital stays have impacted on the incidence of Candida sp. bloodstream infections (CBSI. OBJECTIVE: To determine clinical and epidemiologic characteristics of patients with CBSI in two tertiary care reference medical institutions in Mexico City. DESIGN: Prospective and observational laboratory-based surveillance study conducted from 07/2008 to 06/2010. METHODS: All patients with CBSI were included. Identification and antifungal susceptibility were performed using CLSI M27-A3 standard procedures. Frequencies, Mann-Whitney U test or T test were used as needed. Risk factors were determined with multivariable analysis and binary logistic regression analysis. RESULTS: CBSI represented 3.8% of nosocomial bloodstream infections. Cumulative incidence was 2.8 per 1000 discharges (incidence rate: 0.38 per 1000 patient-days. C. albicans was the predominant species (46%, followed by C. tropicalis (26%. C. glabrata was isolated from patients with diabetes (50%, and elderly patients. Sixty-four patients (86% received antifungals. Amphotericin-B deoxycholate (AmBD was the most commonly used agent (66%. Overall mortality rate reached 46%, and risk factors for death were APACHE II score ≥ 16 (OR = 6.94, CI95% = 2.34-20.58, p<0.0001, and liver disease (OR = 186.11, CI95% = 7.61-4550.20, p = 0.001. Full susceptibility to fluconazole, AmBD and echinocandins among C. albicans, C. tropicalis, and C. parapsilosis was observed. CONCLUSIONS: The cumulative incidence rate in these centers was higher than other reports from tertiary care hospitals from Latin America. Knowledge of local epidemiologic patterns permits the design of more specific strategies for prevention and preemptive therapy of CBSI.

  20. Surveillance of Candida spp Bloodstream Infections: Epidemiological Trends and Risk Factors of Death in Two Mexican Tertiary Care Hospitals

    Science.gov (United States)

    Corzo-Leon, Dora E.; Alvarado-Matute, Tito; Colombo, Arnaldo L.; Cornejo-Juarez, Patricia; Cortes, Jorge; Echevarria, Juan I.; Guzman-Blanco, Manuel; Macias, Alejandro E.; Nucci, Marcio; Ostrosky-Zeichner, Luis; Ponce-de-Leon, Alfredo; Queiroz-Telles, Flavio; Santolaya, Maria E.; Thompson-Moya, Luis; Tiraboschi, Iris N.; Zurita, Jeannete; Sifuentes-Osornio, Jose

    2014-01-01

    Introduction Larger populations at risk, broader use of antibiotics and longer hospital stays have impacted on the incidence of Candida sp. bloodstream infections (CBSI). Objective To determine clinical and epidemiologic characteristics of patients with CBSI in two tertiary care reference medical institutions in Mexico City. Design Prospective and observational laboratory-based surveillance study conducted from 07/2008 to 06/2010. Methods All patients with CBSI were included. Identification and antifungal susceptibility were performed using CLSI M27-A3 standard procedures. Frequencies, Mann-Whitney U test or T test were used as needed. Risk factors were determined with multivariable analysis and binary logistic regression analysis. Results CBSI represented 3.8% of nosocomial bloodstream infections. Cumulative incidence was 2.8 per 1000 discharges (incidence rate: 0.38 per 1000 patient-days). C. albicans was the predominant species (46%), followed by C. tropicalis (26%). C. glabrata was isolated from patients with diabetes (50%), and elderly patients. Sixty-four patients (86%) received antifungals. Amphotericin-B deoxycholate (AmBD) was the most commonly used agent (66%). Overall mortality rate reached 46%, and risk factors for death were APACHE II score ≥16 (OR = 6.94, CI95% = 2.34–20.58, p<0.0001), and liver disease (OR = 186.11, CI95% = 7.61–4550.20, p = 0.001). Full susceptibility to fluconazole, AmBD and echinocandins among C. albicans, C. tropicalis, and C. parapsilosis was observed. Conclusions The cumulative incidence rate in these centers was higher than other reports from tertiary care hospitals from Latin America. Knowledge of local epidemiologic patterns permits the design of more specific strategies for prevention and preemptive therapy of CBSI. PMID:24830654

  1. High prevalence of tuberculosis and serious bloodstream infections in ambulatory individuals presenting for antiretroviral therapy in Malawi.

    Directory of Open Access Journals (Sweden)

    Richard A Bedell

    Full Text Available BACKGROUND: Tuberculosis (TB and serious bloodstream infections (BSI may contribute to the high early mortality observed among patients qualifying for antiretroviral therapy (ART with unexplained weight loss, chronic fever or chronic diarrhea. METHODS AND FINDINGS: A prospective cohort study determined the prevalence of undiagnosed TB or BSI among ambulatory HIV-infected adults with unexplained weight loss and/or chronic fever, or diarrhea in two routine program settings in Malawi. Subjects with positive expectorated sputum smears for AFB were excluded. Investigations Bacterial and mycobacterial blood cultures, cryptococcal antigen test (CrAg, induced sputum (IS for TB microscopy and solid culture, full blood count and CD4 lymphocyte count. Among 469 subjects, 52 (11% had microbiological evidence of TB; 50 (11% had a positive (non-TB blood culture and/or positive CrAg. Sixty-five additional TB cases were diagnosed on clinical and radiological grounds. Nontyphoidal Salmonellae (NTS were the most common blood culture pathogens (29 cases; 6% of participants and 52% of bloodstream isolates. Multivariate analysis of baseline clinical and hematological characteristics found significant independent associations between oral candidiasis or lymphadenopathy and TB, marked CD4 lymphopenia and NTS infection, and severe anemia and either infection, but low positive likelihood ratios (<2 for all combinations. CONCLUSIONS: We observed a high prevalence of TB and serious BSI, particularly NTS, in a program cohort of chronically ill HIV-infected outpatients. Baseline clinical and hematological characteristics were inadequate predictors of infection. HIV clinics need better rapid screening tools for TB and BSI. Clinical trials to evaluate empiric TB or NTS treatment are required in similar populations.

  2. Regional variations in fluoroquinolone non-susceptibility among Escherichia coli bloodstream infections within the Veterans Healthcare Administration

    Directory of Open Access Journals (Sweden)

    Daniel J. Livorsi

    2016-10-01

    Full Text Available Abstract Objectives We sought to define regional variations in fluoroquinolone non-susceptibility (FQ-NS among bloodstream isolates of Escherichia coli across the Veterans Health Administration (VHA in the United States. Methods We analyzed a retrospective cohort of patients managed at 136 VHA hospitals who had a blood culture positive for E.coli between 2003 and 2013. Hospitals were classified based on US Census Divisions, and regional variations in FQ-NS were analyzed. Results Twenty-four thousand five hundred twenty-three unique E.coli bloodstream infections (BSIs were identified between 2003 and 2013. 53.9 % of these were community-acquired, 30.7 % were healthcare-associated, and 15.4 % were hospital-onset BSIs. The proportion of E.coli BSIs with FQ-NS significantly varied across US Census Divisions (p < 0.001. During 2003–2013, the proportion of E.coli BSIs with FQ-NS was highest in the West South-Central Division (32.7 % and lowest in the Mountain Division (20.0 %. Multivariable analysis showed that there were universal secular trends towards higher FQ-NS rates (p < 0.001 with significant variability of slopes across US Census Divisions (p < 0.001. Conclusion There has been a universal increase in FQ-NS among E.coli BSIs within VHA, but the rate of increase has significantly varied across Census Divisions. The reasons for this variability are unclear. These findings reinforce the importance of using local data to develop and update local antibiograms and antibiotic-prescribing guidelines.

  3. Does antimicrobial use density at the ward level influence monthly central line-associated bloodstream infection rates?

    Directory of Open Access Journals (Sweden)

    Yoshida J

    2014-12-01

    Full Text Available Junichi Yoshida, Yukiko Harada, Tetsuya Kikuchi, Ikuyo Asano, Takako Ueno, Nobuo Matsubara Infection Control Committee, Shimonoseki City Hospital, Shimonoseki, Japan Abstract: The aim of this study was to elucidate risk factors, including ward antimicrobial use density (AUD, for central line-associated bloodstream infection (CLABSI as defined by the Centers for Disease Control and Prevention in a 430-bed community hospital using central venous lines with closed-hub systems. We calculated AUD as (total dose/(defined daily dose × patient days ×1,000 for a total of 20 drugs, nine wards, and 24 months. Into each line day data, we inputed AUD and device utilization ratios, number of central line days, and CLABSI. The ratio of susceptible strains in isolates were subjected to correlation analysis with AUD. Of a total of 9,997 line days over 24 months, CLABSI was present in 33 cases (3.3 ‰, 14 (42.4% of which were on surgical wards out of nine wards. Of a total of 43 strains isolated, eight (18.6% were methicillin-resistant Staphylococcus aureus (MRSA; none of the MRSA-positive patients had received cefotiam before the onset of infection. Receiver-operating characteristic analysis showed that central line day 7 had the highest accuracy. Logistic regression analysis showed the central line day showed an odds ratio of 5.511 with a 95% confidence interval of 1.936–15.690 as did AUD of cefotiam showing an odds ratio of 0.220 with 95% confidence interval of 0.00527–0.922 (P=0.038. Susceptible strains ratio and AUD showed a negative correlation (R2=0.1897. Thus, CLABSI could be prevented by making the number of central line days as short as possible. The preventative role of AUD remains to be investigated. Keywords: bloodstream infection, central line, antimicrobial use density

  4. Clinical and Microbiological Characteristics of Heteroresistant and Vancomycin-Intermediate Staphylococcus aureus from Bloodstream Infections in a Brazilian Teaching Hospital

    Science.gov (United States)

    da Costa, Thaina Miranda; Morgado, Priscylla Guimarães Migueres; Cavalcante, Fernanda Sampaio; Damasco, Andreia Paredes; Nouér, Simone Aranha; dos Santos, Kátia Regina Netto

    2016-01-01

    This study analyzed clinical and microbiological characteristics of heteroresistant (hVISA) and vancomycin-intermediate Staphylococcus aureus (VISA) from bloodstream infections (BSI) in a Brazilian teaching hospital, between 2011 and 2013. Minimum inhibitory concentrations (MIC) of antimicrobials were determined by broth microdilution method and SCCmec was detected by PCR. Isolates with a vancomycin MIC ≥ 2mg/L were cultured on BHI agar with 3, 4 or 6 mg/L (BHIa3, BHIa4 or BHIa6) of vancomycin and BHIa4 with casein (BHIa4ca). Macromethod Etest® and Etest® Glicopeptides Resistance Detection were also used. VISA and hVISA isolates were confirmed by the population analysis profile then typed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. Medical data from the patients were obtained from their medical records. Among 110 consecutive isolates, 31 (28%) were MRSA and carried the SCCmec type II (15 isolates) or IV (16 isolates). Vancomycin MIC50 and MIC90 were 1 and 2 mg/L, respectively. MRSA isolates had increased non-susceptibility to daptomycin (p = 0.0003). Six (5%) isolates were VISA, four of which were MRSA, three SCCmec type II/USA100/ST5 and one type IV/USA800/ST3192. One MRSA SCCmec II isolate grew on agar BHIa3, BHIa4 and BHIa4ca, and it was confirmed as hVISA. Among the six VISA isolates, five (83%) grew on BHIa3 and three (50%) on BHI4ca. Four of the six VISA isolates and the one hVISA isolate were from patients who had undergone dialysis. Thus, a possible dissemination of the SCCmec II/USA100/ST5 lineage may have occurred in the hospital comprising the VISA, hVISA and daptomycin non-susceptible S. aureus Brazilian isolates from health care associated bloodstream infections. PMID:27575698

  5. Epidemiological characterization of Acinetobacter baumannii bloodstream isolates from a Chinese Burn Institute: A three-year study.

    Science.gov (United States)

    Huang, Guangtao; Yin, Supeng; Xiang, Lijuan; Gong, Yali; Sun, Kedai; Luo, Xiaoqiang; Zhang, Cheng; Yang, Zichen; Deng, Liuyang; Jiang, Bei; Jin, Shouguang; Chen, Jing; Peng, Yizhi

    2016-11-01

    Acinetobacter baumannii infection is a serious threat to burn patients. Bacteremia due to A. baumannii is becoming the most common cause of mortality following burn. However, the epidemiology of A. baumannii causing burn-related bloodstream infections has rarely been reported. We retrospectively collected 81 A. baumannii isolates from the bloodstream of burn patients over a three-year period. Antibiotic susceptibility tests, the prevalence of antibiotic-resistant genes and sequence typing (ST) were conducted to characterize these strains. Most of the isolates showed an extensive drug-resistant phenotype. The resistance frequencies to imipenem and meropenem were 94% and 91%, respectively. The blaOXA-23-like gene, AmpC, IS-AmpC, PER and SIM are the five most prevalent resistant genes, and their prevalence rates are 93% (75/81), 86% (70/81), 73% (59/81), 73% (59/81) and 52% (42/81), respectively. The 81 isolates were grouped into 10 known and 18 unknown ST types, with ST368 (38%) being the most prevalent. Except for ST457 and four new types (STn2, STn6, STn11 and STn14), the remaining 23 ST types belonged to one clonal complex 92, which is most common among clinical isolate in China. The above results indicated that ST368 isolates possessing both the blaOXA-23-like gene and ampC gene were the main culprits of the increasing nosocomial A. baumannii infection in this study. More attention should be paid to monitoring the molecular epidemiology of A. baumannii isolates from burn patients to prevent further distribution. Such information may help clinicians with therapeutic decisions and infection control in the Burns Institute.

  6. A core MRB1 complex component is indispensable for RNA editing in insect and human infective stages of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Michelle L Ammerman

    Full Text Available Uridine insertion/deletion RNA editing is a unique and vital process in kinetoplastids, required for creation of translatable open reading frames in most mitochondrially-encoded RNAs. Emerging as a key player in this process is the mitochondrial RNA binding 1 (MRB1 complex. MRB1 comprises an RNA-independent core complex of at least six proteins, including the GAP1/2 guide RNA (gRNA binding proteins. The core interacts in an RNA-enhanced or -dependent manner with imprecisely defined TbRGG2 subcomplexes, Armadillo protein MRB10130, and additional factors that comprise the dynamic MRB1 complex. Towards understanding MRB1 complex function in RNA editing, we present here functional characterization of the pentein domain-containing MRB1 core protein, MRB11870. Inducible RNAi studies demonstrate that MRB11870 is essential for proliferation of both insect vector and human infective stage T. brucei. MRB11870 ablation causes a massive defect in RNA editing, affecting both pan-edited and minimally edited mRNAs, but does not substantially affect mitochondrial RNA stability or processing of precursor transcripts. The editing defect in MRB1-depleted cells occurs at the initiation stage of editing, as pre-edited mRNAs accumulate. However, the gRNAs that direct editing remain abundant in the knockdown cells. To examine the contribution of MRB11870 to MRB1 macromolecular interactions, we tagged core complexes and analyzed their composition and associated proteins in the presence and absence of MRB11870. These studies demonstrated that MRB11870 is essential for association of GAP1/2 with the core, as well as for interaction of the core with other proteins and subcomplexes. Together, these data support a model in which the MRB1 core mediates functional interaction of gRNAs with the editing machinery, having GAP1/2 as its gRNA binding constituents. MRB11870 is a critical component of the core, essential for its structure and function.

  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. 3-(3-amino-3-carboxypropyl)-5,6-Dihydrouridine is one of two novel post-transcriptional modifications in tRNALys(UUU) from Trypanosoma brucei

    DEFF Research Database (Denmark)

    Krog, Jesper Schak; Español, Yaiza; Giessing, Anders M B;

    2011-01-01

    was MALDI-TOF MS of two independent digests of the tRNA, with RNase A and RNase T1, respectively. This revealed digestion products harbouring mass-changing modifications. Next, the modifications were mapped at the nucleotide level in the RNase products by tandem MS. Comparison with the sequence......tRNA is the most heavily modified of all RNA types, with typically 10-20% of the residues being post-transcriptionally altered. Unravelling the modification pattern of a tRNA is a challenging task; there are 92 currently known tRNA modifications [1], many of which are chemically similar....... Furthermore, the tRNA has to be investigated with single-nucleotide resolution in order to ensure complete mapping of all modifications. In the present work, we characterized tRNA(Lys) (UUU) from Trypanosoma brucei, and provide a complete overview of its post-transcriptional modifications. The first step...

  9. Eleganolone, a Diterpene from the French Marine Alga Bifurcaria bifurcata Inhibits Growth of the Human Pathogens Trypanosoma brucei and Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Anne-Marie Rusig

    2013-02-01

    Full Text Available Organic extracts of 20 species of French seaweed have been screened against Trypanosoma brucei rhodesiense trypomastigotes, the parasite responsible for sleeping sickness. These extracts have previously shown potent antiprotozoal activities in vitro against Plasmodium falciparum and Leishmania donovani. The selectivity of the extracts was also evaluated by testing cytotoxicity on a mammalian L6 cell line. The ethyl acetate extract of the brown seaweed, Bifurcaria bifurcata, showed strong trypanocidal activity with a mild selectivity index (IC50 = 0.53 µg/mL; selectivity index (SI = 11.6. Bio-guided fractionation led to the isolation of eleganolone, the main diterpenoid isolated from this species. Eleganolone contributes only mildly to the trypanocidal activity of the ethyl acetate extract (IC50 = 45.0 µM, SI = 4.0. However, a selective activity against P. falciparum erythrocytic stages in vitro has been highlighted (IC50 = 7.9 µM, SI = 21.6.

  10. Eleganolone, a Diterpene from the French Marine Alga Bifurcaria bifurcata Inhibits Growth of the Human Pathogens Trypanosoma brucei and Plasmodium falciparum

    Science.gov (United States)

    Gallé, Jean-Baptiste; Attioua, Barthélémy; Kaiser, Marcel; Rusig, Anne-Marie; Lobstein, Annelise; Vonthron-Sénécheau, Catherine

    2013-01-01

    Organic extracts of 20 species of French seaweed have been screened against Trypanosoma brucei rhodesiense trypomastigotes, the parasite responsible for sleeping sickness. These extracts have previously shown potent antiprotozoal activities in vitro against Plasmodium falciparum and Leishmania donovani. The selectivity of the extracts was also evaluated by testing cytotoxicity on a mammalian L6 cell line. The ethyl acetate extract of the brown seaweed, Bifurcaria bifurcata, showed strong trypanocidal activity with a mild selectivity index (IC50 = 0.53 µg/mL; selectivity index (SI) = 11.6). Bio-guided fractionation led to the isolation of eleganolone, the main diterpenoid isolated from this species. Eleganolone contributes only mildly to the trypanocidal activity of the ethyl acetate extract (IC50 = 45.0 µM, SI = 4.0). However, a selective activity against P. falciparum erythrocytic stages in vitro has been highlighted (IC50 = 7.9 µM, SI = 21.6). PMID:23442789

  11. Bloodstream infections caused by Escherichia coli producing AmpC β-lactamases: epidemiology and clinical features.

    Science.gov (United States)

    Pascual, V; Alonso, N; Simó, M; Ortiz, G; Garcia, M C; Xercavins, M; Rivera, A; Morera, M A; Miró, E; Espejo, E; Navarro, F; Gurguí, M; Pérez, J; Rodríguez-Carballeira, M; Garau, J; Calbo, E

    2016-12-01

    The aim of the study was to investigate the epidemiology and clinical features of bloodstream infections due to Escherichia coli producing AmpC β-lactamases (AmpC-Ec-BSI). In a multi-centre case-control study, all third-generation-cephalosporin-resistant Escherichia coli BSI (3GC-Ec-BSI) isolates were analysed. Acquired bla AmpC (bla ac-AmpC) detection was done by polymerase chain reaction (PCR) and sequencing. Chromosomal bla AmpC (bla c-AmpC) expression was quantified by real-time PCR. Cases were patients with AmpC-Ec-BSI. Controls were patients with cephalosporin-susceptible E. coli BSI, matched 1:1 by sex and age. Demographics, comorbidities, intrinsic and extrinsic risk factors for antimicrobial resistance, clinical presentation and outcomes were investigated. Among 841 E. coli BSI, 17 were caused by AmpC-Ec (2 %). Eleven isolates (58.8 %) had bla ac-AmpC and six were bla c-AmpC overproducers. The mean age of cases was 66.2 years and 71 % were men. Cases were more frequently healthcare-related (82 vs. 52 % controls, p < 0.05) and presented more intrinsic and extrinsic risk factors. At least one risk factor was present in 94.1 % of cases vs. 41.7 % of controls (p = 0.002). Severity and length of stay (LOS) were higher among cases (mean Pitt Score 2.6 vs. 0.38 in controls, p = 0.03; LOS 17.5 days vs. 6 in controls, p = 0.02). Inappropriate empirical therapy (IET) was administered to 70.6 % of cases and 23.5 % of controls (p < 0.003). No differences were found in terms of cure rate at the 14th day and mortality. Bloodstream infections due to AmpC-Ec (mostly plasmid-mediated) are infrequent in our area. AmpC-Ec-BSI affects mainly patients with intrinsic risk factors and those with previous antibiotic exposure. A high proportion received IET.

  12. Clinical and Laboratory Characteristics of Patients with Nontuberculous Mycobacterium Bloodstream Infection in a Tertiary Referral Hospital in Beijing, China

    Institute of Scientific and Technical Information of China (English)

    Sai-Nan Bian; Li-Fan Zhang; Yue-Qiu Zhang; Qi-Wen Yang; Peng Wang; Ying-Chun Xu; Xiao-Chun Shi

    2016-01-01

    Background:Nontuberculous Mycobacterium (NTM) bloodstream infection (BSI) is relatively rare.We aimed in this study to evaluate the clinical characteristics,laboratory evaluation,and outcomes of patients with NTM BSI.Methods:We retrospectively reviewed the clinical records of inpatients with NTM BSI at our institution between January 2008 and January 2015 and recorded clinical parameters including age,gender,underlying disease,clinical manifestation,organs involved with NTM disease,species of NTM,laboratory data,treatment and outcome of these patients.We also reviewed the reported cases and case series ofNTM BSI by searching PubMed,EMBASE,and Wanfang databases.Data of normal distribution were expressed by mean ± standard deviation (SD).Data of nonnormal distribution were expressed by median and interquartile range (IQR).Results:Among the ten patients with NTM BSI,the median age was 51 years (IQR 29-57 years) and three patients were males.Eight patients were immunocompromised,with underlying diseases including human immunodeficiency virus (HIV) infection (one patient),rheumatic diseases (two patients),breast cancer (one patient),myelodysplastic syndrome (two patients),and aplastic anemia (two patients).Other organ(s) involved were lung (two patients),endocardium (two patients),brain,spinal cord,and soft tissue (one each patient).The median lymphocyte was 0.66 × 109/L (IQR 0.24-1.93 × 109/L).The median cluster of differentiation 4 (CD4) cell count was 179/ mm3 (IQR 82-619/mm3).Five patients died (three with hematological diseases,one with breast cancer,and one with rheumatic disease),three recovered,and two were lost to follow-up.Conclusions:We reported all cases in our hospital diagnosed with bloodstream NTM infection that was rarely reported.In this group of patients,patients usually had a high fever and could have multiple organ involvements.All patients with poor prognosis had underlying diseases.

  13. A Multinational, Preregistered Cohort Study of β-Lactam/β-Lactamase Inhibitor Combinations for Treatment of Bloodstream Infections Due to Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae

    OpenAIRE

    Gutiérrez-Gutiérrez, Belén; Pérez-Galera, Salvador; Salamanca, Elena; de Cueto, Marina; Calbo, Esther; Almirante, Benito; Viale, Pierluigi; Oliver, Antonio; Pintado, Vicente; Gasch, Oriol; Martínez-Martínez, Luis; Pitout, Johann; Akova, Murat; Peña, Carmen; José MOLINA

    2016-01-01

    The spread of extended-spectrum-β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) is leading to increased carbapenem consumption. Alternatives to carbapenems need to be investigated. We investigated whether β-lactam/β-lactamase inhibitor (BLBLI) combinations are as effective as carbapenems in the treatment of bloodstream infections (BSI) due to ESBL-E. A multinational, retrospective cohort study was performed. Patients with monomicrobial BSI due to ESBL-E were studied; specific criteri...

  14. Nationwide German Multicenter Study on Prevalence of Antibiotic Resistance in Staphylococcal Bloodstream Isolates and Comparative In Vitro Activities of Quinupristin-Dalfopristin

    OpenAIRE

    Von Eiff, Christof; Reinert, Ralf René; Kresken, Michael; Brauers, Johannes; Hafner, Dieter; Peters, Georg

    2000-01-01

    Antibiotic-resistant gram-positive bacteria have become an increasing problem in the last two decades. In order to evaluate the prevalence of antibiotic resistance in staphylococcal bloodstream isolates in Germany, 2,042 staphylococci collected in 21 tertiary-care hospitals were investigated during a 3-year period (March 1996 to March 1999). Altogether, 1,448 S. aureus isolates and 594 coagulase-negative staphylococci (CoNS) that comprised 13 different species were included. Furthermore, the ...

  15. 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.

  16. 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.

  17. The role of B-cells and IgM antibodies in parasitemia, anemia, and VSG switching in Trypanosoma brucei-infected mice.

    Directory of Open Access Journals (Sweden)

    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.

  18. Structures of Trypanosoma brucei methionyl-tRNA synthetase with urea-based inhibitors provide guidance for drug design against sleeping sickness.

    Directory of Open Access Journals (Sweden)

    Cho Yeow Koh

    2014-04-01

    Full Text Available Methionyl-tRNA synthetase of Trypanosoma brucei (TbMetRS is an important target in the development of new antitrypanosomal drugs. The enzyme is essential, highly flexible and displaying a large degree of changes in protein domains and binding pockets in the presence of substrate, product and inhibitors. Targeting this protein will benefit from a profound understanding of how its structure adapts to ligand binding. A series of urea-based inhibitors (UBIs has been developed with IC50 values as low as 19 nM against the enzyme. The UBIs were shown to be orally available and permeable through the blood-brain barrier, and are therefore candidates for development of drugs for the treatment of late stage human African trypanosomiasis. Here, we expand the structural diversity of inhibitors from the previously reported collection and tested for their inhibitory effect on TbMetRS and on the growth of T. brucei cells. The binding modes and binding pockets of 14 UBIs are revealed by determination of their crystal structures in complex with TbMetRS at resolutions between 2.2 Å to 2.9 Å. The structures show binding of the UBIs through conformational selection, including occupancy of the enlarged methionine pocket and the auxiliary pocket. General principles underlying the affinity of UBIs for TbMetRS are derived from these structures, in particular the optimum way to fill the two binding pockets. The conserved auxiliary pocket might play a role in binding tRNA. In addition, a crystal structure of a ternary TbMetRS•inhibitor•AMPPCP complex indicates that the UBIs are not competing with ATP for binding, instead are interacting with ATP through hydrogen bond. This suggests a possibility that a general 'ATP-engaging' binding mode can be utilized for the design and development of inhibitors targeting tRNA synthetases of other disease-causing pathogen.

  19. Cytosolic NADPH homeostasis in glucose-starved procyclic Trypanosoma brucei relies on malic enzyme and the pentose phosphate pathway fed by gluconeogenic flux.

    Science.gov (United States)

    Allmann, Stefan; Morand, Pauline; Ebikeme, Charles; Gales, Lara; Biran, Marc; Hubert, Jane; Brennand, Ana; Mazet, Muriel; Franconi, Jean-Michel; Michels, Paul A M; Portais, Jean-Charles; Boshart, Michael; Bringaud, Frédéric

    2013-06-21

    All living organisms depend on NADPH production to feed essential biosyntheses and for oxidative stress defense. Protozoan parasites such as the sleeping sickness pathogen Trypanosoma brucei adapt to different host environments, carbon sources, and oxidative stresses during their infectious life cycle. The procyclic stage develops in the midgut of the tsetse insect vector, where they rely on proline as carbon source, although they prefer glucose when grown in rich media. Here, we investigate the flexible and carbon source-dependent use of NADPH synthesis pathways in the cytosol of the procyclic stage. The T. brucei genome encodes two cytosolic NADPH-producing pathways, the pentose phosphate pathway (PPP) and the NADP-dependent malic enzyme (MEc). Reverse genetic blocking of those pathways and a specific inhibitor (dehydroepiandrosterone) of glucose-6-phosphate dehydrogenase together established redundancy with respect to H2O2 stress management and parasite growth. Blocking both pathways resulted in ∼10-fold increase of susceptibility to H2O2 stress and cell death. Unexpectedly, the same pathway redundancy was observed in glucose-rich and glucose-depleted conditions, suggesting that gluconeogenesis can feed the PPP to provide NADPH. This was confirmed by (i) a lethal phenotype of RNAi-mediated depletion of glucose-6-phosphate isomerase (PGI) in the glucose-depleted Δmec/Δmec null background, (ii) an ∼10-fold increase of susceptibility to H2O2 stress observed for the Δmec/Δmec/(RNAi)PGI double mutant when compared with the single mutants, and (iii) the (13)C enrichment of glycolytic and PPP intermediates from cells incubated with [U-(13)C]proline, in the absence of glucose. Gluconeogenesis-supported NADPH supply may also be important for nucleotide and glycoconjugate syntheses in the insect host.

  20. A 12-year review of Staphylococcus aureus bloodstream infections in haemodialysis patients: more work to be done.

    LENUS (Irish Health Repository)

    Fitzgerald, S F

    2012-02-01

    Staphylococcus aureus bloodstream infections (BSI) are a significant cause of morbidity and mortality in haemodialysis patients. This study describes a 12-year retrospective review of S. aureus BSI in a large haemodialysis centre in a tertiary referral hospital. The overall rate of S. aureus BSI was 17.9 per 100 patient-years (range 9.7-36.8). The rate of meticillin-resistant S. aureus (MRSA) BSI was 5.6 per 100 patient-years (range 0.9-13.8). Infective complications occurred in 11% of episodes, the most common being infective endocarditis (7.6%). Ten percent of patients died within 30 days of S. aureus being isolated from blood. Most cases of S. aureus BSI (83%) were related to vascular catheters. The provision of lower-risk vascular access, such as arteriovenous fistulae, and reduced use of intravascular catheters should be priorities in all haemodialysis units. Where alternative vascular access cannot be established, interventions to reduce the risk of catheter-related infections should be implemented to reduce morbidity and mortality in this vulnerable patient group.

  1. POLYCLONAL OUTBREAK OF BLOODSTREAM INFECTIONS CAUSED BY Burkholderia cepacia COMPLEX IN HEMATOLOGY AND BONE MARROW TRANSPLANT OUTPATIENT UNITS

    Directory of Open Access Journals (Sweden)

    Icaro Boszczowski

    2014-01-01

    Full Text Available Aim: The objective was to describe an outbreak of bloodstream infections by Burkholderia cepacia complex (Bcc in bone marrow transplant and hematology outpatients. Methods: On February 15, 2008 a Bcc outbreak was suspected. 24 cases were identified. Demographic and clinical data were evaluated. Environment and healthcare workers' (HCW hands were cultured. Species were determined and typed. Reinforcement of hand hygiene, central venous catheter (CVC care, infusion therapy, and maintenance of laminar flow cabinet were undertaken. 16 different HCWs had cared for the CVCs. Multi-dose heparin and saline were prepared on counter common to both units. Findings: 14 patients had B. multivorans (one patient had also B. cenopacia, six non-multivorans Bcc and one did not belong to Bcc. Clone A B. multivorans occurred in 12 patients (from Hematology; in 10 their CVC had been used on February 11/12. Environmental and HCW cultures were negative. All patients were treated with meropenem, and ceftazidime lock-therapy. Eight patients (30% were hospitalized. No deaths occurred. After control measures (multidose vial for single patient; CVC lock with ceftazidime; cleaning of laminar flow cabinet; hand hygiene improvement; use of cabinet to store prepared medication, no new cases occurred. Conclusions: This polyclonal outbreak may be explained by a common source containing multiple species of Bcc, maybe the laminar flow cabinet common to both units. There may have been contamination by B. multivorans (clone A of multi-dose vials.

  2. Candida albicans bloodstream isolates in a German university hospital are genetically heterogenous and susceptible to commonly used antifungals.

    Science.gov (United States)

    Huyke, Johanna; Martin, Ronny; Walther, Grit; Weber, Michael; Kaerger, Kerstin; Bougnoux, Marie-Elisabeth; Elias, Johannes; Kurzai, Oliver

    2015-10-01

    From an eight-year-span, 99 Candida bloodstream isolates were collected at the University Hospital Wuerzburg, Germany. In this study, all strains were analyzed using molecular and phenotypic typing methods. Confirmatory species identification revealed three isolates that were initially diagnosed as C. albicans to be actually C. dubliniensis. Two isolates contained a mixed culture of C. albicans and C. glabrata, in one of the specimens both species could be separated while it was not possible to recover C. albicans in the other sample. The remaining 95 C. albicans isolates were profiled by multilocus sequence typing (MLST). Phylogenetic analyses showed a highly heterogenous collection of strains, associated with many different clades and constituting a set of new diploid sequence types (DST). For all strains with identical DST, patient data were reviewed for potential nosocomial transmission. In addition, all isolates were tested for their susceptibility to amphotericin B, caspofungin, fluconazole, itraconazole, posaconazole and voriconazole. No clinically relevant resistance could be detected. Furthermore, these data underline that correlation between minimal inhibitory concentrations for caspofungin and anidulafungin is low.

  3. The impact of HIV infection on blood leukocyte responsiveness to bacterial stimulation in asymptomatic patients and patients with bloodstream infection

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    Michaëla A M Huson

    2016-05-01

    Full Text Available Introduction: HIV-induced changes in cytokine responses to bacteria may influence susceptibility to bacterial infections and the consequent inflammatory response. Methods: We examined the impact of HIV on whole blood responsiveness to bacterial stimulation in asymptomatic subjects and patients with bacterial bloodstream infection (BSI. Whole blood was stimulated ex vivo with two bacterial Toll-like receptor agonists (lipopolysaccharide and lipoteichoic acid and two pathogens (Streptococcus pneumoniae and non-typhoidal Salmonella, which are relevant in HIV-positive patients. Production of interferon-γ, tumour necrosis factor-α, interleukin-1β and interleukin-6 was used as a read-out. Results: In asymptomatic subjects, HIV infection was associated with reduced interferon-γ, release after stimulation and priming of the pro-inflammatory cytokine response to non-typhoidal Salmonella. In patients with BSI, we found no such priming effect, nor was there evidence for more profound sepsis-induced immunosuppression in BSI patients with HIV co-infection. Conclusions: These results suggest a complex effect of HIV on leukocyte responses to bacteria. However, in patients with sepsis, leukocyte responses were equally blunted in patients with and without HIV infection.

  4. The Antibiotic Resistance Profiles of Bacterial Strains Isolated from Patients with Hospital-Acquired Bloodstream and Urinary Tract Infections

    Directory of Open Access Journals (Sweden)

    Hamed Ghadiri

    2012-01-01

    Full Text Available Treatment of nosocomial infections is becoming difficult due to the increasing trend of antibiotics resistance. Current knowledge on antibiotic resistance pattern is essential for appropriate therapy. We aimed to evaluate antibiotic resistance profiles in nosocomial bloodstream and urinary tract pathogens. A total of 129 blood stream and 300 urinary tract positive samples were obtained from patients referring to Besat hospital over a two-year period (2009 and 2010. Antibiotic sensitivity was ascertained using the Kirby-Bauer disk diffusion technique according to CLSI guidelines. Patient's data such as gender and age were recorded. The ratio of gram-negative to gram-positive bacteria in BSIs was 1.6 : 1. The most prevalent BSI pathogen was Coagulase-Negative Staphylococci (CoNS. The highest resistance rate of CoNS was against penicillin (91.1% followed by ampicillin (75.6%, and the lowest rate was against vancomycin (4.4%. Escherichia coli was the most prevalent pathogen isolated from urinary tract infections (UTIs. Ratio of gram-negative to gram-positive bacteria was 3.2 : 1. The highest resistance rate of E. coli isolates was against nalidixic acid (57.7%. The present study showed that CoNS and E. coli are the most common causative agents of nosocomial BSIs and UTIs, and control of infection needs to be addressed in both antibiotic prescription and general hygiene.

  5. Erratum to: Seasonal trend and clinical presentation of Bacillus cereus bloodstream infection: association with summer and indwelling catheter.

    Science.gov (United States)

    Kato, K; Matsumura, Y; Yamamoto, M; Nagao, M; Ito, Y; Takakura, S; Ichiyama, S

    2016-05-01

    Bacillus cereus, an opportunistic pathogen, can cause fatal infection. However, B. cereus bloodstream infections (BSIs) have not been well characterised. From 2008 to 2013, B. cereus isolates from all of the specimens and patients with B. cereus BSIs were identified. Environmental samples were collected to detect B. cereus contamination. We also characterised the clinical presentation of B. cereus BSI through analyses of risk factors for BSI and mortality. A total of 143 clinical B. cereus isolates was detected. Fifty-one patients with nosocomial infections were diagnosed as B. cereus BSI, and 37 had contaminated blood cultures. The number of B. cereus isolates and BSI patients was significantly greater from June to September than from January to April (3.4 vs. 1.0 per month and 1.4 vs. 0.2, respectively). All BSIs were nosocomial and related to central or peripheral vascular catheter. Urinary catheter [odds ratio (OR) 6.93, 95 % confidence interval (CI) 2.40-20.0] was the independent risk factor associated with BSI patients when compared to patients regarded as contaminated. In-hospital mortality among BSI patients was 20 % and was associated with urinary catheter (OR 12.3, 95 % CI 0.67-225, p=0.045) and higher Charlson index (OR 1.99, 95 % CI 1.26-3.12). The number of B. cereus isolates and BSI increased during summer. Inpatients with indwelling vascular or urinary catheters should be carefully monitored for potential B. cereus BSIs.

  6. Risk factors for mortality in patients with bloodstream infections during the pre-engraftment period after hematopoietic stem cell transplantation

    Science.gov (United States)

    Karpov, Igor; Milanovich, Natalia; Uss, Anatoly; Iskrov, Igor

    2016-01-01

    Background Bloodstream infections (BSI) remain a frequent complication during the pre-engraftment period after hematopoietic stem cell transplantation (HSCT), resulting in high mortality rates. This study evaluated risk factors for mortality in hematopoietic stem cell transplant recipients with BSI in the pre-engraftment period. Methods This prospective case control study was performed at the Center of Hematology and Bone Marrow Transplantation in Minsk, Republic of Belarus. Data relating to patient age and gender, date and type of transplantation, conditioning chemotherapy regimen, microorganisms isolated from blood, and antibacterial therapy were prospectively collected from all hematopoietic stem cell recipients with microbiologically proven cases of BSI in the pre-engraftment period. The primary outcome was all-cause 30-day mortality after onset of febrile neutropenia. Results A total of 135 adult patients with microbiologically proven BSI after HSCT were studied, with 65.2% of cases caused by gram-negative microorganisms and 21.5% by non-fermenting bacteria. Inadequate empiric antibacterial therapy and isolation of carbapenem-resistant non-fermenting gram-negative bacteria (Acinetobacter baumannii and Pseudomonas aeruginosa) were independently associated with increased all-cause 30-day mortality in these patients. Conclusion The risk factors for mortality in adult patients with BSI in the pre-engraftment period after HSCT were inadequacy of empirical antibacterial therapy and isolation of carbapenem-resistant A. baumannii or P. aeruginosa. PMID:27382554

  7. Development of subsequent bloodstream infection in patients with positive Hickman catheter blood cultures and negative peripheral blood cultures.

    Science.gov (United States)

    Park, Ki-Ho; Cho, Oh-Hyun; Lee, Sang-Oh; Choi, Sang-Ho; Kim, Yang Soo; Woo, Jun Hee; Kim, Mi-Na; Kim, Dae-Young; Lee, Jung-Hee; Lee, Je-Hwan; Lee, Kyoo-Hyung; Lee, Dae Ho; Suh, Cheolwon; Kim, Sung-Han

    2011-05-01

    There are limited data on the incidence of subsequent bloodstream infection (BSI) and the effect of systemic antibiotics in patients who had positive catheter-drawn blood cultures (CBC) and negative peripheral blood cultures (PBC). We retrospectively reviewed all paired blood cultures from patients with Hickman catheter in the hematology-oncology ward between January 1997 and December 2008. There were 112 episodes with positive CBC and negative PBC. Nine episodes (8.0%; 95% CI, 3.0-13.1%) led to subsequent BSI within 28 days. Subsequent BSI developed in 6 of 31 episodes (19%) where empiric antibiotics were inappropriate but in 3 of 81 episodes (4%) where empiric antibiotics were appropriate (P = 0.01). Subsequent candidemia (50%, 2 of 4) was more common than subsequent bacteremia (6%, 7 of 108) (P = 0.03). In conclusion, for patients with positive CBC and negative PBC, the overall incidence of subsequent BSI was 8.0%, and inappropriate empiric antibiotics was associated with subsequent BSI.

  8. Carbapenemase-producing Klebsiella pneumoniae bloodstream infections: lowering mortality by antibiotic combination schemes and the role of carbapenems.

    Science.gov (United States)

    Daikos, George L; Tsaousi, Sophia; Tzouvelekis, Leonidas S; Anyfantis, Ioannis; Psichogiou, Mina; Argyropoulou, Athina; Stefanou, Ioanna; Sypsa, Vana; Miriagou, Vivi; Nepka, Martha; Georgiadou, Sarah; Markogiannakis, Antonis; Goukos, Dimitris; Skoutelis, Athanasios

    2014-01-01

    Carbapenemase-producing Klebsiella pneumoniae strains (CP-Kps) are currently among the most important nosocomial pathogens. An observational study was conducted during 2009 to 2010 in two hospitals located in a high-prevalence area (Athens, Greece). The aims were (i) to evaluate the clinical outcome of patients with CP-Kp bloodstream infections (BSIs), (ii) to identify predictors of mortality, and (iii) to evaluate the various antibiotic schemes employed. A total of 205 patients with CP-Kp BSIs were identified: 163 (79.5%) were infected with KPC or KPC and VIM, and 42 were infected with VIM producers. For definitive treatment, 103 patients received combination therapy (two or more active drugs), 72 received monotherapy (one active drug), and 12 received therapy with no active drug. The remaining 18 patients died within 48 h after the onset of bacteremia. The all-cause 28-day mortality was 40%. A significantly higher mortality rate was observed in patients treated with monotherapy than in those treated with combination therapy (44.4% versus 27.2%; P=0.018). The lowest mortality rate (19.3%) was observed in patients treated with carbapenem-containing combinations. In the Cox proportion hazards model, ultimately fatal disease (hazards ratio [HR], 3.25; 95% confidence interval [CI], 1.51 to 7.03; P=0.003), the presence of rapidly fatal underlying diseases (HR, 4.20; 95% CI, 2.19 to 8.08; Pcarbapenem-containing regimens.

  9. High MICs for Vancomycin and Daptomycin and Complicated Catheter-Related Bloodstream Infections with Methicillin-Sensitive Staphylococcus aureus

    Science.gov (United States)

    Viedma, Esther; Chaves, Fernando; Lalueza, Antonio; Fortún, Jesús; Loza, Elena; Pujol, Miquel; Ardanuy, Carmen; Morales, Isabel; de Cueto, Marina; Resino-Foz, Elena; Morales-Cartagena, Alejandra; Rico, Alicia; Romero, María P.; Orellana, María Ángeles; López-Medrano, Francisco; Fernández-Ruiz, Mario; Aguado, José María

    2016-01-01

    We investigated the prognostic role of high MICs for antistaphylococcal agents in patients with methicillin-sensitive Staphylococcus aureus catheter-related bloodstream infection (MSSA CRBSI). We prospectively reviewed 83 episodes from 5 centers in Spain during April 2011–June 2014 that had optimized clinical management and analyzed the relationship between E-test MICs for vancomycin, daptomycin, oxacillin, and linezolid and development of complicated bacteremia by using multivariate analysis. Complicated MSSA CRBSI occurred in 26 (31.3%) patients; MICs for vancomycin and daptomycin were higher in these patients (optimal cutoff values for predictive accuracy = 1.5 μg/mL and 0.5 μg/mL). High MICs for vancomycin (hazard ratio 2.4, 95% CI 1.2–5.5) and daptomycin (hazard ratio 2.4, 95% CI 1.1–5.9) were independent risk factors for development of complicated MSSA CRBSI. Our data suggest that patients with MSSA CRBSI caused by strains that have high MICs for vancomycin or daptomycin are at increased risk for complications. PMID:27192097

  10. Comparison of severity of illness scoring systems for patients with nosocomial bloodstream infection due to Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Wenzel Richard P

    2006-08-01

    Full Text Available Abstract Background Several acute illness severity scores have been proposed for evaluating patients on admission to intensive care units but these have not been compared for patients with nosocomial bloodstream infection (nBSI. We compared three severity of illness scoring systems for predicting mortality in patients with nBSI due to Pseudomonas aeruginosa. Methods We performed a historical cohort study on 63 adults in intensive care units with P. aeruginosa monomicrobial nBSI. Results The Acute Physiology, Age, Chronic Health Evaluation II (APACHE II, Sequential Organ Failure Assessment (SOFA, and Simplified Acute Physiologic Score (SAPS II, were calculated daily from 2 days prior through 2 days after the first positive blood culture. Calculation of the area under the receiver operating characteristic (ROC curve confirmed that APACHE II and SAPS II at day -1 and SOFA at day +1 were better predictors of outcome than days -2, 0 and day 2 of BSI. By stepwise logistic regression analysis of these three scoring systems, SAPS II (OR: 13.03, CI95% 2.51–70.49 and APACHE II (OR: 12.51, CI95% 3.12–50.09 on day -1 were the best predictors for mortality. Conclusion SAPS II and APACHE II are more accurate than the SOFA score for predicting mortality in this group of patients at day -1 of BSI.

  11. Surveillance of bloodstream infections in pediatric cancer centers – what have we learned and how do we move on?

    Directory of Open Access Journals (Sweden)

    Simon, Arne

    2016-05-01

    Full Text Available Pediatric patients receiving conventional chemotherapy for malignant disease face an increased risk of bloodstream infection (BSI. Since BSI may represent an acute life-threatening event in patients with profound immunosuppression, and show further negative impact on quality of life and anticancer treatment, the prevention of BSI is of paramount importance to improve and guarantee patients’ safety during intensive treatment. The great majority of all pediatric cancer patients (about 85% have a long-term central venous access catheter in use (type Broviac or Port; CVAD. Referring to the current surveillance definitions a significant proportion of all BSI in pediatric patients with febrile neutropenia is categorized as CVAD- BSI. This state of the art review summarizes the epidemiology and the distinct pathogen profile of BSI in pediatric cancer patients from the perspective of infection surveillance. Problems in executing the current surveillance definition in this patient population are discussed and a new concept for the surveillance of BSI in pediatric cancer patients is outlined.

  12. Bloodstream infection after umbilical cord blood transplantation using reduced-intensity stem cell transplantation for adult patients.

    Science.gov (United States)

    Narimatsu, Hiroto; Matsumura, Tomoko; Kami, Masahiro; Miyakoshi, Shigesaburo; Kusumi, Eiji; Takagi, Shinsuke; Miura, Yuji; Kato, Daisuke; Inokuchi, Chiho; Myojo, Tomohiro; Kishi, Yukiko; Murashige, Naoko; Yuji, Koichiro; Masuoka, Kazuhiro; Yoneyama, Akiko; Wake, Atsushi; Morinaga, Shinichi; Kanda, Yoshinobu; Taniguchi, Shuichi

    2005-06-01

    Bloodstream infection (BSI) is a significant problem after cord blood transplantation (CBT). However, little information has been reported on BSI after reduced-intensity CBT (RI-CBT). We retrospectively reviewed the medical records of 102 patients. The median age of the patients was 55 years (range, 17-79 years). Preparative regimens comprised fludarabine 125 to 150 mg/m 2 , melphalan 80 to 140 mg/m 2 , or busulfan 8 mg/kg and total body irradiation 2 to 8 Gy. Prophylaxis against graft-versus-host disease comprised cyclosporin or tacrolimus. BSI developed within 100 days of RI-CBT in 32 patients. The cumulative incidence of BSI was 25% at day 30 and 32% at day 100. The median onset was day 15 (range, 1-98 days). Causative organisms included Pseudomonas aeruginosa (n = 12), Staphylococcus epidermidis (n = 11), Staphylococcus aureus (n = 6), Enterococcus faecium (n = 4), Enterococcus faecalis (n = 4), Stenotrophomonas maltophilia (n = 4), and others (n = 7). Of the 32 patients with BSI, 25 (84%) died within 100 days after RI-CBT. BSI was the direct cause of death in 8 patients (25%). Univariate analysis failed to identify any significant risk factors. BSI clearly represents a significant and fatal complication after RI-CBT. Further studies are warranted to determine clinical characteristics, identify patients at high risk of BSI, and establish therapeutic strategies.

  13. 3-(Oxazolo[4,5-b]pyridin-2-yl)anilides as a novel class of potent inhibitors for the kinetoplastid Trypanosoma brucei, the causative agent for human African trypanosomiasis.

    Science.gov (United States)

    Ferrins, Lori; Rahmani, Raphaël; Sykes, Melissa L; Jones, Amy J; Avery, Vicky M; Teston, Eliott; Almohaywi, Basmah; Yin, JieXiang; Smith, Jason; Hyland, Chris; White, Karen L; Ryan, Eileen; Campbell, Michael; Charman, Susan A; Kaiser, Marcel; Baell, Jonathan B

    2013-08-01

    A whole organism high-throughput screen of approximately 87,000 compounds against Trypanosoma brucei brucei led to the recent discovery of several novel compound classes with low micromolar activity against this organism and without appreciable cytotoxicity to mammalian cells. Herein we report a structure-activity relationship (SAR) investigation around one of these hit classes, the 3-(oxazolo[4,5-b]pyridin-2-yl)anilides. Sharp SAR is revealed, with our most active compound (5) exhibiting an IC₅₀ of 91 nM against the human pathogenic strain T.b. rhodesiense and being more than 700 times less toxic towards the L6 mammalian cell line. Physicochemical properties are attractive for many compounds in this series. For the most potent representatives, we show that solubility and metabolic stability are key parameters to target during future optimisation.

  14. 成人原发血流感染494例临床分析%Clinical analysis of adult primary bloodstream infection

    Institute of Scientific and Technical Information of China (English)

    张黎; 刘正印; 徐英春; 李太生; 杨启文; 王爱霞

    2012-01-01

    Objective Evaluate the microbiological and epidemiological characteristics of primary bloodstream infections as well as the associated patients' clinical features at Peking Union Medical College Hospital.Method Microbiological and clinical data of the adult patients with primary bloodstream infections during January 1,2008 and December 31,2009 were retrospectively collected and evaluated.Pearson x2 test was used to compare the difference between proportions and Logistic regression was used in multivariate analysis.Result Five hundred and eighty-six strains of microbes were isolated from 494 adult patients with primary bloodstream infections.There were 80 patients with polymicrobial primary bloodstream infection of the 586 isolates,coagulase-negative staphylococci ( 175,29.9% ) was the most common,followed by Escherichia coli( 93,15.9% ),Enterococcus species ( 60,10.2% ),Streptococcus species ( 41,7.0% ),and Staphylococcus Aureus (39,6.7% ).Central-line was the leading suspected infective source among the suspected infective source involving 108 (18.4%) isolates. Excluded the 108 isolates with suspected sources,77 (45.3%) out of 167 patients with the primary bloodstream infections caused by coagulasc-negative staphylococci or Staphylococcus Aureus had a central-line,with a higher proportion of the patients with a central-line than the patients with bloodstream infection caused by other pathogens ( x2 =10.419,P =0.001 ).One hundred and fourteen patients died during hospitalization,with the crude mortality rate 23.0%.Fifty-nine patients (11.9%) died due to primary bloodstream infection.The patients with polymicrobial bloodstream infection were with a higher attributable mortality( OR =2.159 ;95% CI 1.165 -4.002 ;x2 =6.194,P =0.013 ).In the multivariate analysis,the independent risk factors of crude mortality rate to primary bloodstream infections were elderly patients,central neurological disorder,mechanical ventilation,and reservation a central

  15. Narrative form

    CERN Document Server

    Keen, Suzanne

    2015-01-01

    This revised and expanded handbook concisely introduces narrative form to advanced students of fiction and creative writing, with refreshed references and new discussions of cognitive approaches to narrative, nonfiction, and narrative emotions.

  16. Risk factors for bloodstream infections in 66 patients in ICU%ICU 66例血流感染患者危险因素分析

    Institute of Scientific and Technical Information of China (English)

    姚彬; 习慧明

    2012-01-01

    OBJECTIVE To investigate the risk factors for bloodstream infections in the intensive care unit (ICU), to analyze the distribution of pathogens and their drug resistance so as to provide basis for the prevention and treatment of bloodstream infections and reduce the incidence of bloodstream infections and the mortality. METHODS Totally 66 patients with bloodstream infections were investigated retrospectively in the ICU of Beijing Haidian Hospital between 2009 and 2011, the risk factors for bloodstream infections, the distribution of pathogens, and the drug resistance characteristics were analyzed. RESULTS A total of 70 strains of pathogens were isolated from 66 patients with bloodstream infections, including 32 (45. 7%) strains of gram-negative bacteria,28 (40. 0%) strains of gram-positive bacteria, and 10 (14.3%) strains of fungi; the main pathogens causing bloodstream infections were coagulase-negative Staphylococci (25. 7%), Acinetobacter baumannii (12.9%), Yeast (12. 9%), Burkholderia cepacia (10.0%), Enterococcus feces (8.6%), and Escherichia coli (8. 6%). Those patients with the bloodstream infections had poor prognosis and the mortality rate was high, up to 69. 23%. The chronic underlying disease, low immunity, invasive operation,and the abuse of antibiotics were risk factors of bloodstream infections. CONCLUSION The distribution of the gram-negative bacteria is as basically same as the gram-positive bacteria in the pathogens causing blood stream infections in the ICU during the three years. A. baumannii is the main species of gram-negative bacteria, and coagulase-negative Staphylococci was the predominant species of gram-positive bacteria. The strict aseptic operation, careful nursing of catheter, intensifying the blood culture, and reasonable use of antibiotics are the effective measures to prevent and treat the bloodstream infections.%目的 了解重症监护病房(ICU)血流感染的危险因素、病原菌分布特点及其耐药性,为更好地预防

  17. Comparison of pathogen DNA isolation methods from large volumes of whole blood to improve molecular diagnosis of bloodstream infections.

    Directory of Open Access Journals (Sweden)

    Anne J M Loonen

    Full Text Available For patients suffering from bloodstream infections (BSI molecular diagnostics from whole blood holds promise to provide fast and adequate treatment. However, this approach is hampered by the need of large blood volumes. Three methods for pathogen DNA isolation from whole blood were compared, i.e. an enzymatic method (MolYsis, 1-5 ml, the novel non-enzymatic procedure (Polaris, 1-5 ml, and a method that does not entail removal of human DNA (Triton-Tris-EDTA EasyMAG, 200 µl. These methods were evaluated by processing blood spiked with 0-1000 CFU/ml of Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. Downstream detection was performed with real-time PCR assays. Polaris and MolYsis processing followed by real-time PCRs enabled pathogen detection at clinically relevant concentrations of 1-10 CFU/ml blood. By increasing sample volumes, concurrent lower cycle threshold (Ct values were obtained at clinically relevant pathogen concentrations, demonstrating the benefit of using larger blood volumes. A 100% detection rate at a concentration of 10 CFU/ml for all tested pathogens was obtained with the Polaris enrichment, whereas comparatively lower detection rates were measured for MolYsis (50-67% and EasyMAG (58-79%. For the samples with a concentration of 1 CFU/ml Polaris resulted in most optimal detection rates of 70-75% (MolYsis 17-50% and TTE-EasyMAG 20-36%. The Polaris method was more reproducible, less labour intensive, and faster (45 minutes (including Qiagen DNA extraction vs. 2 hours (MolYsis. In conclusion, Polaris and MolYsis enrichment followed by DNA isolation and real-time PCR enables reliable and sensitive detection of bacteria and fungi from 5 ml blood. With Polaris results are available within 3 hours, showing potential for improved BSI diagnostics.

  18. Bloodstream infection in patients with end-stage renal disease in a teaching hospital in central-western Brazil

    Directory of Open Access Journals (Sweden)

    Tamara Trelha Gauna

    2013-08-01

    Full Text Available Introduction Vascular access in patients undergoing hemodialysis is considered a critical determinant of bloodstream infection (BSI and is associated with high morbidity and mortality. The purpose of this study was to investigate the occurrence of BSI in patients with end-stage renal disease using central venous catheters for hemodialysis. Methods A cohort study was conducted in a public teaching hospital in central-western Brazil from April 2010 to December 2011. For every patient, we noted the presence of hyperemia/exudation upon catheter insertion, as well as fever, shivering, and chills during hemodialysis. Results Fifty-nine patients were evaluated. Thirty-five (59.3% patients started dialysis due to urgency, 37 (62.7% had BSI, and 12 (20% died. Hyperemia at the catheter insertion site (64.9% was a significant clinical manifestation in patients with BSI. Statistical analysis revealed 1.7 times more cases of BSI in patients with hypoalbuminemia compared with patients with normal albumin levels. The principal infective agents identified in blood cultures and catheter-tip cultures were Staphylococcus species (24 cases, non-fermentative Gram-negative bacilli (7 cases of Stenotrophomonas maltophilia and 5 cases of Chryseobacterium indologenes, and Candida species (6. Among the Staphylococci identified, 77.7% were methicillin-resistant, coagulase-negative Staphylococci. Of the bacteria isolated, the most resistant were Chryseobacterium indologenes and Acinetobacter baumannii. Conclusions Blood culture was demonstrated to be an important diagnostic test and identified over 50% of positive BSI cases. The high frequency of BSI and the isolation of multiresistant bacteria were disturbing findings. Staphylococcus aureus was the most frequently isolated microorganism, although Gram-negative bacteria predominated overall. These results highlight the importance of infection prevention and control measures in dialysis units.

  19. Differential Gel Electrophoresis (DIGE) Evaluation of Naphthoimidazoles Mode of Action: A Study in Trypanosoma cruzi Bloodstream Trypomastigotes

    Science.gov (United States)

    Brunoro, Giselle Villa Flor; Faça, Vitor Marcel; Caminha, Marcelle Almeida; Ferreira, André Teixeira da Silva; Trugilho, Monique; de Moura, Kelly Cristina Gallan; Perales, Jonas; Valente, Richard Hemmi; Menna-Barreto, Rubem Figueiredo Sadok

    2016-01-01

    Background The obligate intracellular protozoan Trypanosoma cruzi is the causative agent of Chagas disease, a neglected illness affecting millions of people in Latin America that recently entered non-endemic countries through immigration, as a consequence of globalization. The chemotherapy for this disease is based mainly on benznidazole and nifurtimox, which are very efficient nitroderivatives against the acute stage but present limited efficacy during the chronic phase. Our group has been studying the trypanocidal effects of naturally occurring quinones and their derivatives, and naphthoimidazoles derived from β-lapachone N1, N2 and N3 were the most active. To assess the molecular mechanisms of action of these compounds, we applied proteomic techniques to analyze treated bloodstream trypomastigotes, which are the clinically relevant stage of the parasite. Methodology/Principal Findings The approach consisted of quantification by 2D-DIGE followed by MALDI-TOF/TOF protein identification. A total of 61 differentially abundant protein spots were detected when comparing the control with each N1, N2 or N3 treatment, for 34 identified spots. Among the differentially abundant proteins were activated protein kinase C receptor, tubulin isoforms, asparagine synthetase, arginine kinase, elongation factor 2, enolase, guanine deaminase, heat shock proteins, hypothetical proteins, paraflagellar rod components, RAB GDP dissociation inhibitor, succinyl-CoA ligase, ATP synthase subunit B and methionine sulfoxide reductase. Conclusion/Significance Our results point to different modes of action for N1, N2 and N3, which indicate a great variety of metabolic pathways involved and allow for novel perspectives on the development of trypanocidal agents. PMID:27551855

  20. Nosocomial bloodstream infection in patients caused by Staphylococcus aureus: drug susceptibility, outcome, and risk factors for hospital mortality

    Institute of Scientific and Technical Information of China (English)

    CHEN Rong; YAN Zhong-qiang; FENG Dan; LUO Yan-ping; WANG Lei-li; SHEN Ding-xia

    2012-01-01

    Background Previous studies have different viewpoints about the clinical impact of methicillin resistance on mortality of hospital-acquired bloodstream infection (BSI) patients with Staphylococcus aureus (S.aureus).The objective of this study was to investigate the mortality of hospital-acquired BSI with S.aureus in a military hospital and analyze the risk factors for the hospital mortality.Methods A retrospective cohort study was performed in patients admitted to the biggest military tertiary teaching hospital in China between January 2006 and May 2011.All included patients had clinically significant nosocomial BSI with S.aureus.Multivariate Logistic regression analysis was used to identify the risk factors for hospital mortality of patients with S.aureus BSI.Results One hundred and eighteen patients of more than one year old were identified as clinically and microbiologically confirmed nosocomial bacteraemia due to S.aureus,and 75 out of 118 patients were infected with methicillin-resistant S.aureus (MRSA).The overall mortality of nosocomial S.aureus BSI was 28.0%.Methicillin resistance in S.aureus bacteremia was associated with significant increase in the length of hospitalization and high proportion of inappropriate empirical antibiotic treatment.After Logistic regression analysis,the severity of clinical manifestations (APACHE Ⅱ score) (odds ratio (OR) 1.22,95% confidence interval (CI) 1.12-1.34) and inadequacy of empirical antimicrobial therapy (OR 0.25,95% CI 0.09-0.69) remained as risk factors for hospital mortality.Conclusions Nosocomial S.aureus BSI was associated with high in-hospital mortality.Methicillin resistance in S.aureus has no significant impact on the outcome of patients with staphylococcal bacteremia.Proper empirical antimicrobial therapy is very important to the prognosis.

  1. Clinical and molecular characteristics of bloodstream infections caused by Candida albicans in children from 2003 to 2011.

    Science.gov (United States)

    Tsai, M-H; Wang, S-H; Hsu, J-F; Lin, L-C; Chu, S-M; Huang, H-R; Chiang, M-C; Fu, R-H; Lu, J-J; Huang, Y-C

    2015-11-01

    We investigated the clinical and molecular characteristics of Candida albicans bloodstream infection (BSI) in children from a tertiary-level medical centre in Taiwan over a 9-year period from January 2003 to December 2011. We performed multilocus sequence typing (MLST) to investigate the genetic relatedness of these C. albicans BSI isolates. A total of 79 episodes of C. albicans BSI in 76 paediatric patients were identified, including 41 (51.9%) from the paediatric intensive care unit, 24 (30.4%) from the neonatal intensive care unit and 14 (17.7%) from general wards. More than half (59.5%) of these patients had underlying chronic co-morbidities, and the majority (94.9%) had a catheter or some other artificial device. All the isolates were susceptible to the antifungal agents tested. Only 32.9% (26/79) received effective antifungal agents within 24 h of onset of candidaemia. Twenty-five (31.6%) patients had persistent candidaemia (>3 days after the start of antifungal treatment) and candidaemia-attributable mortality rate was 22.8% (18/79). The 72 isolates available for MLST yielded 53 unique diploid sequence types (DSTs). Forty-five DSTs were singletons and eight DSTs were shared by 27 (37.5%) isolates. Seventy-one (98.6%) isolates were clustered within previously known clades. Based on the definition of two or more strains with shared DST occurring within a period of 90 days, 10.1% of the infections were categorized as nosocomial clusters, most commonly identified in the intensive care units. Although cluster-associated candidaemia was not associated with a higher mortality rate, none of the clusters were identified by the hospital infection control team.

  2. Comparison of the clinical risk factors between Candida albicans and Candida non-albicans species for bloodstream infection.

    Science.gov (United States)

    Shigemura, Katsumi; Osawa, Kayo; Jikimoto, Takumi; Yoshida, Hiroyuki; Hayama, Brian; Ohji, Goh; Iwata, Kentaro; Fujisawa, Masato; Arakawa, Soichi

    2014-04-01

    The purpose of this study is to investigate the risk factors and susceptibilities to antifungal agents of Candida albicans and Candida non-albicans species (spp.) in candidemia cases in Kobe University Hospital. We investigated all consecutive patients with candida bloodstream infection (BSI) from 2008-2013 for whose full data were available for analyses, examining clinical factors such as gender, general complications, postoperative status or susceptibilities to antifungal agents. These factors were also compared between Candida albicans spp. and Candida non-albicans by univariate and multivariate analyses. Univariate analyses showed a significantly higher rate of Candida non-albicans species BSI patients cancer (odds ratio (OR) (95% confidence interval (CI))=2.29 (1.04-5.06) and P=0.040), chemotherapy (OR=4.35 (1.11-17.1) and P=0.035), fluconazole (FLCZ) resistance (OR=77.3 (4.51-1324) and P=0.003), and itraconazole (ITCZ) resistance (OR=15.6 (5.39-45.1) and PCandida albicans. Multivariate analyses demonstrated that Candida non-albicans spp. had significantly higher rate of chemotherapy (OR=4.44 (1.04-19.0) and P=0.045), FLCZ resistance (OR=5.87 (2.01-17.1) and P=0.001), and ITCZ resistance (OR=18.7(5.77-60.4) and PCandida albicans. In conclusion, this study revealed several risk factors for BSI with Candida albicans (underlying cardiovascular diseases and postoperative status) and Candida non-albicans spp. (cancer and chemotherapy), and demonstrated that Candida non-albicans spp. were more resistant to FLCZ and ITCZ than Candida albicans.

  3. Clinical and microbiological characteristics of bloodstream infections in a tertiary hospital in Maceió, Alagoas, Brazil

    Directory of Open Access Journals (Sweden)

    Maria Tereza Freitas Tenório

    2010-04-01

    Full Text Available We observed the clinical and microbiological characteristics of several stages of bloodstream infections (BSI, as well as the mortality attributed to it in a tertiary hospital in the northeast of Brazil (in the city of Maceió, Alagoas. A prospective cohort of 143 patients who had at least one positive blood culture was enrolled in the study. Their clinical evolution was followed up for 30 days from October 2005 to December 2006. The relation among the qualitative variables was verified through Chi-square test. The significance level was 5%. The statistical package adopted was SPSS 15.0 for Windows. Up to the thirtieth day, 30.1% of the patients presented bacteremia and 69.9% developed sepsis.Among these, 20.3% developed severe sepsis and 10.5% septic shock. The mortality attributed to it was 37.8%. In bacteremia, sepsis, severe sepsis, and septic shock conditions, mortality rates were 9.3%, 50%, 65.5%, and 84.6%, respectively. Respiratory (32.2% and urinary (14% sources and the ones related to central venous catheter (14% were prevalent. In the wards 55.12% of the cases developed sepsis, whereas in the intensive care units, the rate was 87.69% (p < 0.05. Chronic renal failure, diabetes melitus, and neuropathy were present in 21.7%, 26.6%, and 29.4% of the cases, respectively. Coagulase-negative Staphylococcus (25.9%, Staphylococcus aureus (21%, and Klebsiella pneumoniae (14% were the most present microorganism in the sample. The high morbidity and mortality rates in this study are attributed to the lack of knowledge on BSI characteristics and on instituted protocols for detection and treatment in early stages.

  4. EFFECT OF INFLIXIMAB ON PARAMETERS OF REMODELING OF ARTERIAL BLOODSTREAM, RANKL AND OSTEOPROTEGERIN LEVELS IN PATIENTS WITH RHEUMATOID ARTHRITIS

    Directory of Open Access Journals (Sweden)

    Larisa Aleksandrovna Knyazeva

    2013-01-01

    Full Text Available Objective. To study the effect of infliximab (INF on serum levels of RANKL and osteoprotegerin (OPG, as well as on structural and functional properties of the vascular wall in patients with rheumatoid arthritis (RA.Material and Methods. A total of 79 RA patients who corresponded to the classification criteria ACR (1987 or ACR/EULAR (2010 and were seronegative for IgM rheumatoid factor (RF were examined. The mean age of patients was 43.6±8.5 years. The serum levels of OPG and RANKL were determined by ELISA (Biomedica, Austria; the common carotid arteries (CCAs were visualized using an Acuson X/10 ultrasonic complex equipped with a 7 MHz linear sensor in the β-mode prior to therapy and after 12-month therapy with INF.Results and Discussion. An increased OPG level was observed mostly in patients with RA duration up to 1 year; an increase in RANKL level was pronounced stronger in patients with PA duration over 2 years. The disturbance of structural and functional properties of the arterial bloodstream was revealed, manifesting itself as an increase in the intimamedia complex thickness, diameter and rigidity index of CCA that were stronger pronounced in patients with late onset RA. A correlation analysis showed the presence of reliable relationship between the RANKL and OPG levels and CCA remodeling parameters. INF therapy showed high clinical effectiveness and correction effect on the RANKL/OPG system. In addition, it was accompanied by a reduction of signs of CCA remodeling, which was stronger pronounced in patients with early RA.Conclusion. The results prove the reasonability of using INF at early stages of RA in order to optimize the therapy and achieve more efficient control of cardiovascular complications.

  5. The Likelihood of Hospital Readmission among Patients with Hospital-Onset Central Line-Associated Bloodstream Infections

    Science.gov (United States)

    Khong, Carolyn; Baggs, James; Kleinbaum, David; Cochran, Ronda; Jernigan, John A.

    2015-01-01

    Objective We sought to determine whether central line-associated bloodstream infections (CLABSI) increase the likelihood of readmission. Design Retrospective matched cohort study for the years 2008–2009. Setting Acute care hospitals. Participants Medicare recipients. CLABSI and readmission status were determined by linking National Healthcare Safety Network surveillance data to the Centers for Medicare & Medicaid Services’ Medical Provider and Analysis Review in eight states. Frequency matching was used on ICD-9-CM procedure code category and intensive care unit status. Methods We compared the rate of readmission among patients with and without CLABSI during an index hospitalization. Cox proportional hazard analysis was used to assess rate of readmission (the first hospitalization within 30 days post-index discharge). Multivariate models included the following covariates: race, sex, length of index hospitalization stay central line procedure code, GAGNE co-morbidity score, and individual chronic conditions. Results Of the 8,097 patients, 2,260 were readmitted within 30 days (27.9%). The rate of first readmission was 7.1 events/person-year (PY) for CLABSI patients and 4.3 events/PY for non-CLABSI patients (p <0.001). The final model revealed a small but significant increase in the rate of 30 day readmissions for patients with a CLABSI compared to similar non-CLABSI patients. In the first readmission for CLABSI patients, we also observed an increase in diagnostic categories consistent with CLABSI including septicemia and complications of a device. Conclusions Our analysis found a statistically significant association between CLABSI status and readmission, suggesting that CLABSI may have adverse health impact that extends beyond hospital discharge. PMID:25990620

  6. Impact of Inadequate Empirical Therapy on the Mortality of Patients with Bloodstream Infections: a Propensity Score-Based Analysis

    Science.gov (United States)

    Retamar, Pilar; Portillo, María M.; López-Prieto, María Dolores; Rodríguez-López, Fernando; de Cueto, Marina; García, María V.; Gómez, María J.; del Arco, Alfonso; Muñoz, Angel; Sánchez-Porto, Antonio; Torres-Tortosa, Manuel; Martín-Aspas, Andrés; Arroyo, Ascensión; García-Figueras, Carolina; Acosta, Federico; Corzo, Juan E.; León-Ruiz, Laura; Escobar-Lara, Trinidad

    2012-01-01

    The impact of the adequacy of empirical therapy on outcome for patients with bloodstream infections (BSI) is key for determining whether adequate empirical coverage should be prioritized over other, more conservative approaches. Recent systematic reviews outlined the need for new studies in the field, using improved methodologies. We assessed the impact of inadequate empirical treatment on the mortality of patients with BSI in the present-day context, incorporating recent methodological recommendations. A prospective multicenter cohort including all BSI episodes in adult patients was performed in 15 hospitals in Andalucía, Spain, over a 2-month period in 2006 to 2007. The main outcome variables were 14- and 30-day mortality. Adjusted analyses were performed by multivariate analysis and propensity score-based matching. Eight hundred one episodes were included. Inadequate empirical therapy was administered in 199 (24.8%) episodes; mortality at days 14 and 30 was 18.55% and 22.6%, respectively. After controlling for age, Charlson index, Pitt score, neutropenia, source, etiology, and presentation with severe sepsis or shock, inadequate empirical treatment was associated with increased mortality at days 14 and 30 (odds ratios [ORs], 2.12 and 1.56; 95% confidence intervals [95% CI], 1.34 to 3.34 and 1.01 to 2.40, respectively). The adjusted ORs after a propensity score-based matched analysis were 3.03 and 1.70 (95% CI, 1.60 to 5.74 and 0.98 to 2.98, respectively). In conclusion, inadequate empirical therapy is independently associated with increased mortality in patients with BSI. Programs to improve the quality of empirical therapy in patients with suspicion of BSI and optimization of definitive therapy should be implemented. PMID:22005999

  7. Surveillance length and validity of benchmarks for central line-associated bloodstream infection incidence rates in intensive care units.

    Directory of Open Access Journals (Sweden)

    Patricia S Fontela

    Full Text Available INTRODUCTION: Several national and regional central line-associated bloodstream infections (CLABSI surveillance programs do not require continuous hospital participation. We evaluated the effect of different hospital participation requirements on the validity of annual CLABSI incidence rate benchmarks for intensive care units (ICUs. METHODS: We estimated the annual pooled CLABSI incidence rates for both a real regional (<100 ICUs and a simulated national (600 ICUs surveillance program, which were used as a reference for the simulations. We simulated scenarios where the annual surveillance participation was randomly or non-randomly reduced. Each scenario's annual pooled CLABSI incidence rate was estimated and compared to the reference rates in terms of validity, bias, and proportion of simulation iterations that presented valid estimates (ideal if ≥ 90%. RESULTS: All random scenarios generated valid CLABSI incidence rates estimates (bias -0.37 to 0.07 CLABSI/1000 CVC-days, while non-random scenarios presented a wide range of valid estimates (0 to 100% and higher bias (-2.18 to 1.27 CLABSI/1000 CVC-days. In random scenarios, the higher the number of participating ICUs, the shorter the participation required to generate ≥ 90% valid replicates. While participation requirements in a countrywide program ranged from 3 to 13 surveillance blocks (1 block = 28 days, requirements for a regional program ranged from 9 to 13 blocks. CONCLUSIONS: Based on the results of our model of national CLABSI reporting, the shortening of participation requirements may be suitable for nationwide ICU CLABSI surveillance programs if participation months are randomly chosen. However, our regional models showed that regional programs should opt for continuous participation to avoid biased benchmarks.

  8. Risk factors for catheter-related bloodstream infection: a prospective multicenter study in Brazilian intensive care units

    Directory of Open Access Journals (Sweden)

    Daniela Bicudo

    2011-08-01

    Full Text Available INTRODUCTION: Central venous catheters (CVC are devices of great importance in health care. The advantages gained from the use of catheters outweigh the complications that might result from their use, among which bloodstream infections (BSI. In spite of its importance, few national studies have addressed this issue. OBJECTIVE: The aim this study was to determine the incidence of BSI in patients with CVC, hospitalized in ICU, as well as the variables associated with this complication. METHODS: Multicentric cohort study carried out at ICUs of three hospitals at Universidade Federal de São Paulo complex. RESULTS: A total of 118 cases of BSI in 11.546 catheters day were observed: 10.22 BSI per 1,000 catheters day. On average, BSI was associated to seven additional days of hospital stay in our study (p < 0.001, with a significant difference between types of catheters. Concerning the place of insertion, there was no statistical difference in BSI rates. CONCLUSION: We concluded that a patient who uses a catheter for longer than 13 days presents a progressive risk for infection of approximately three times higher in relation to a patient who uses the catheter for less than 13 days (p < 0.001. The median duration of catheter use was 14 days among patients with BSI and 9 days in patients without infection (p < 0.001. There was higher prevalence of Gram-negative infections. The risk factors for BSI were utilization of multiple-lumen catheters, duration of catheterization and ICU length of stay.

  9. FACTORS ASSOCIATED WITH MORTALITY AMONG PATIENTS WITH CENTRAL VENOUS CATHETER-RELATED BLOODSTREAM INFECTION IN AN INTENSIVE CARE UNIT

    Directory of Open Access Journals (Sweden)

    Priscilla Roberta Silva Rocha

    2012-01-01

    Full Text Available Central venous catheterization is a common practice in the management of critically ill patients and is associated with various complications, such as Bloodstream Infections (BSI, which are major determinants of increased morbidity, mortality and healthcare expenses. Few studies have addressed factors that predict mortality in patients with this complication. The aim of this study was to investigate factors associated with mortality in patients with Central Venous Catheter (CVC-related BSI in an intensive care unit of a tertiary care hospital in the Federal District, Brazil. This was a retrospective and observational study, in which all CVC-related BSI that occurred between January 2008 and December 2010 were reviewed. We obtained demographic, clinical, biochemical and microbiological data from medical records and investigated its association with mortality during ICU stay. There were 4,504 ICU admissions during the study period and 68 were complicated by CVC-related BSI (4.09 per 1000 catheter-days, most due to gram-negative organisms (45.6%. Overall mortality was 59.7%. Death risk was significantly associated with mechanical ventilation (OR 27.8, 95% CI 3.28-250, p-1 in survivors vs. 73.9 mg dL-1 in non-survivors, p = 0.001. Mortality was not associated with other clinical or biochemical features, neither with microbiological variables, although lethality was high among patients with gram-positive infections (77% Vs 58.33% for fungi and 54.83% for gram-negative. CVC-related BSI was associated with high absolute mortality, which was predicted by mechanical ventilation and a higher number of invasive devices other than the CVC. Knowledge of local factors predictive of mortality is critical for planning strategies to reduce death risk associated with this complication.

  10. Fri form

    DEFF Research Database (Denmark)

    Jensen, Henrik

    2006-01-01

    Dette Kompendiun er lavet i forbindelse med en workshop i møbeldesign. En række af form-Z's værktøjer til konstruktion af dobbeltkrumme flader gennemgås. Kompendiet kan bruges til selvstudie.......Dette Kompendiun er lavet i forbindelse med en workshop i møbeldesign. En række af form-Z's værktøjer til konstruktion af dobbeltkrumme flader gennemgås. Kompendiet kan bruges til selvstudie....

  11. Admission to hospital with community-onset bloodstream infection during the 'after hours' is not associated with an increased risk for death.

    Science.gov (United States)

    Laupland, Kevin B

    2010-12-01

    Several studies conducted in diverse patient populations have found that patients presenting with acute illness during weekends or evening/nights are at increased risk for death. This study was conducted to examine whether patients with community-onset bloodstream infections who are admitted during evenings, nights, and weekends suffer increased mortality rates. All residents within the Calgary area who had first admissions with community-onset bloodstream infections during 2000-2008 were included. One thousand eight hundred and seventy-eight (27%) patients were admitted on a weekend. Among all admissions, 2753 (40%) were during the hours of 08:00-17:59, 1996 (29%) during 18:00-22:59, and 2174 (31%) during 23:00-07:59. More than two-thirds (n = 4867; 70%) of cases were admitted during the 'after hours' (evenings, nights, and/or weekends). The 30-day case-fatality rate was 13% (882/6923) and did not significantly vary between daytime (364/2753; 13%), evening (246/1996; 12%), and night (272/2174; 13%) admissions (p = 0.6), or with patients admitted on weekends as compared to weekdays (252/1878 (13%) vs. 630/5045 (12%); p = 0.3). Admission during the after hours (weekends and evenings/nights) was not associated with increased risk for death in logistic regression analysis (odds ratio 0.99, 95% confidence interval 0.83-1.16; p = 0.88). Admission with community-onset bloodstream infection during the after hours is not associated with adverse outcome in this region.

  12. Impact of changes in CLSI and EUCAST breakpoints for susceptibility in bloodstream infections due to extended-spectrum β-lactamase-producing Escherichia coli.

    Science.gov (United States)

    Rodríguez-Baño, J; Picón, E; Navarro, M D; López-Cerero, L; Pascual, A

    2012-09-01

    The impact of recent changes in and discrepancies between the breakpoints for cephalosporins and other antimicrobials, as determined by CLSI and European Committee on Antimicrobial Susceptibility Testing (EUCAST), was analysed in patients with bloodstream infections caused by extended-spectrum β-lactamase (ESBL) producing Escherichia coli in Spain, was analysed. We studied a cohort of 191 episodes of bloodstream infection caused by ESBL-producing E. coli in 13 Spanish hospitals; the susceptibility of isolates to different antimicrobials was investigated by microdilution and interpreted according to recommendations established in 2009 and 2010 by CLSI, and in 2011 by EUCAST. Overall, 58.6% and 14.7% of isolates were susceptible to ceftazidime, and 35.1% and 14.7% to cefepime using the CLSI-2010 and EUCAST-2009/2011 recommendations, respectively (all isolates would have been considered resistant using the previous guidelines). Discrepancies between the CLSI-2010 and the EUCAST-2011 recommendations were statistically significant for other antimicrobials only in the case of amikacin (98.4% versus 75.9% of susceptible isolates; p <0.01). The results varied depending on the ESBL produced. No significant differences were found in the percentage of patients classified as receiving appropriate therapy, following the different recommendations. Four out of 11 patients treated with active cephalosporins according to CLSI-2010 guidelines died (all had severe sepsis or shock); these cases would have been considered resistant according to EUCAST-2011. In conclusion, by using current breakpoints, extended-spectrum cephalosporins would be regarded as active agents for treating a significant proportion of patients with bloodstream infections caused by ESBL-producing E. coli.

  13. Cosmic Forms

    CERN Document Server

    Kleman, Maurice

    2011-01-01

    The continuous 1D defects of an isotropic homogeneous material in an Euclidean 3D space are classified by a construction method, the Volterra process (VP). We employ the same method to classify the continuous 2D defects (which we call \\textit{cosmic forms}) of a vacuum in a 4D maximally symmetric spacetime. These defects fall into three different classes: i)- $m$-forms, akin to 3D space disclinations, related to ordinary rotations and analogous to Kibble's global cosmic strings (except that being continuous any deficit angle is allowed); ii)- $t$-forms, related to Lorentz boosts (hyperbolic rotations); iii)- $r$-forms, never been considered so far, related to null rotations. A detailed account of their metrics is presented. Their inner structure in many cases appears as a non-singular \\textit{core} separated from the outer part by a timelike hypersurface with distributional curvature and/or torsion, yielding new types of geometrical interactions with cosmic dislocations and other cosmic disclinations. Whereas...

  14. Automorphic Forms

    DEFF Research Database (Denmark)

    von Essen, Flemming Brændgaard

    systems. For automorphic forms wrt. Hecke triangle groups and Fuchsian groups with no elliptic elements and genus 0, we show that some logarithms of multiplier systems can be interpreted as a linking number. Finally we show a "twisted" version of the prime geodesics theorem, and logarithms of multiplier...

  15. Trypanosoma evansi contains two auxiliary enzymes of glycolytic metabolism: Phosphoenolpyruvate carboxykinase and pyruvate phosphate dikinase.

    Science.gov (United States)

    Rivero, Luz Amira; Concepción, Juan Luis; Quintero-Troconis, Ender; Quiñones, Wilfredo; Michels, Paul A M; Acosta, Héctor

    2016-06-01

    Trypanosoma evansi is a monomorphic protist that can infect horses and other animal species of economic importance for man. Like the bloodstream form of the closely related species Trypanosoma brucei, T. evansi depends exclusively on glycolysis for its free-energy generation. In T. evansi as in other kinetoplastid organisms, the enzymes of the major part of the glycolytic pathway are present within organelles called glycosomes, which are authentic but specialized peroxisomes. Since T. evansi does not undergo stage-dependent differentiations, it occurs only as bloodstream forms, it has been assumed that the metabolic pattern of this parasite is identical to that of the bloodstream form of T. brucei. However, we report here the presence of two additional enzymes, phosphoenolpyruvate carboxykinase and PPi-dependent pyruvate phosphate dikinase in T. evansi glycosomes. Their colocalization with glycolytic enzymes within the glycosomes of this parasite has not been reported before. Both enzymes can make use of PEP for contributing to the production of ATP within the organelles. The activity of these enzymes in T. evansi glycosomes drastically changes the model assumed for the oxidation of glucose by this parasite.

  16. Use of Six Sigma strategies to pull the line on central line-associated bloodstream infections in a neurotrauma intensive care unit.

    Science.gov (United States)

    Loftus, Kelli; Tilley, Terry; Hoffman, Jason; Bradburn, Eric; Harvey, Ellen

    2015-01-01

    The creation of a consistent culture of safety and quality in an intensive care unit is challenging. We applied the Six Sigma Define-Measure-Analyze-Improve-Control (DMAIC) model for quality improvement (QI) to develop a long-term solution to improve outcomes in a high-risk neurotrauma intensive care unit. We sought to reduce central line utilization as a cornerstone in preventing central line-associated bloodstream infections (CLABSIs). This study describes the successful application of the DMAIC model in the creation and implementation of evidence-based quality improvement designed to reduce CLABSIs to below national benchmarks.

  17. Detection of mcr-1 encoding plasmid-mediated colistin-resistant Escherichia coli isolates from human bloodstream infection and imported chicken meat, Denmark 2015

    DEFF Research Database (Denmark)

    Hasman, H.; Hammerum, A. M.; Hansen, F.;

    2015-01-01

    The plasmid-mediated colistin resistance gene, mcr-1, was detected in an Escherichia coli isolate from a Danish patient with bloodstream infection and in five E. coli isolates from imported chicken meat. One isolate from chicken meat belonged to the epidemic spreading sequence type ST131. In addi....... In addition to IncI2*, an incX4 replicon was found to be linked to mcr-1. This report follows a recent detection of mcr-1 in E. coli from animals, food and humans in China....

  18. The decline of typhoid and the rise of non-typhoid salmonellae and fungal infections in a changing HIV landscape: bloodstream infection trends over 15 years in southern Vietnam.

    Science.gov (United States)

    Nga, Tran Vu Thieu; Parry, Christopher M; Le, Thuy; Lan, Nguyen Phu Huong; Diep, To Song; Campbell, James I; Hoang, Nguyen Van Minh; Dung, Le Thi; Wain, John; Dolecek, Christiane; Farrar, Jeremy J; Chau, Nguyen Van Vinh; Hien, Tran Tinh; Day, Jeremy N; Baker, Stephen

    2012-01-01

    The etiological spectrum of bloodstream infections is variable between industrialized and developing countries and even within a defined location over time. We investigated trends in bloodstream infections at an infectious disease hospital in Ho Chi Minh City, Vietnam, from 1994-2008. Amongst 66,111 blood cultures performed, a clinically relevant pathogen was isolated in 7645 episodes (positivity rate; 116/1000 cultures). Salmonella Typhi was the predominant pathogen until 2002; however, a considerable annual decline in the proportion of S. Typhi was observed (OR 0.6993, 95% CI [0.6885, 0.7103], pSalmonella (NTS), Cryptococcus neoformans and Penicillium marneffei, concurrent with increasing HIV prevalence. These data document a substantial longitudinal shift in bloodstream infection etiology in southern Vietnam. We propose such changes are related to increasing economic prosperity and HIV prevalence, and this pattern marks a substantial change in the epidemiology of invasive salmonellosis in Southeast Asia.

  19. A comparative proteomic analysis reveals a new bi-lobe protein required for bi-lobe duplication and cell division in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Qing Zhou

    Full Text Available A Golgi-associated bi-lobed structure was previously found to be important for Golgi duplication and cell division in Trypanosoma brucei. To further understand its functions, comparative proteomics was performed on extracted flagellar complexes (including the flagellum and flagellum-associated structures such as the basal bodies and the bi-lobe and purified flagella to identify new bi-lobe proteins. A leucine-rich repeats containing protein, TbLRRP1, was characterized as a new bi-lobe component. The anterior part of the TbLRRP1-labeled bi-lobe is adjacent to the single Golgi apparatus, and the posterior side is tightly associated with the flagellar pocket collar marked by TbBILBO1. Inducible depletion of TbLRRP1 by RNA interference inhibited duplication of the bi-lobe as well as the adjacent Golgi apparatus and flagellar pocket collar. Formation of a new flagellum attachment zone and subsequent cell division were also inhibited, suggesting a central role of bi-lobe in Golgi, flagellar pocket collar and flagellum attachment zone biogenesis.

  20. `In crystallo' substrate binding triggers major domain movements and reveals magnesium as a co-activator of Trypanosoma brucei pyruvate kinase.

    Science.gov (United States)

    Zhong, Wenhe; Morgan, Hugh P; McNae, Iain W; Michels, Paul A M; Fothergill-Gilmore, Linda A; Walkinshaw, Malcolm D

    2013-09-01

    The active site of pyruvate kinase (PYK) is located between the AC core of the enzyme and a mobile lid corresponding to domain B. Many PYK structures have already been determined, but the first `effector-only' structure and the first with PEP (the true natural substrate) are now reported for the enzyme from Trypanosoma brucei. PEP soaked into crystals of the enzyme with bound allosteric activator fructose 2,6-bisphosphate (F26BP) and Mg(2+) triggers a substantial 23° rotation of the B domain `in crystallo', resulting in a partially closed active site. The interplay of side chains with Mg(2+) and PEP may explain the mechanism of the domain movement. Furthermore, it is apparent that when F26BP is present but PEP is absent Mg(2+) occupies a position that is distinct from the two canonical Mg(2+)-binding sites at the active site. This third site is adjacent to the active site and involves the same amino-acid side chains as in canonical site 1 but in altered orientations. Site 3 acts to sequester Mg(2+) in a `priming' position such that the enzyme is maintained in its R-state conformation. In this way, Mg(2+) cooperates with F26BP to ensure that the enzyme is in a conformation that has a high affinity for the substrate.

  1. Coenzyme Q10 prevented full blown splenomegaly and decreased melarsoprol-induced reactive encephalopathy in mice infected with Trypanosoma brucei rhodesiense

    Institute of Scientific and Technical Information of China (English)

    James Nyabuga Nyariki; John Kibuthu Thuita; Grace Kemunto Nyambati; Alfred Orina Isaac

    2014-01-01

    Objective: To establish the modulatory effects of coenzyme Q10 on experimental trypanosome infections in mice and evaluate the risk of occurrence and severity of melarsoprol-induced post treatment reactive encephalopathy (PTRE). Methods: Female Swiss white mice were orally administered with 200 mg/kg of coenzyme Q10 after which they were intraperitoneally inoculated with Trypanasoma brucei rhodesiense (T. b. rhodesiense). The resultant infection was allowed to develop and simulate all phases of human African trypanosomiasis and PTRE. Parasitaemia development, packed cell volume, haematological and pathological changes were determined. Results:A histological study in the brain tissue of T. b. rhodesiense infected mice demonstrated neuroinflammatory pathology which was highly amplified in the PTRE-induced groups. A prominent reduction in the severity of the neuroinflammatory response was detected when coenzyme-Q10 was administered. Furthermore, the mean tissue weight of spleen to body ratio in coenzyme Q10 supplemented group was significantly (P Conclusions: The capacity of coenzyme Q10 to alter the pathogenesis of T. b. rhodesiense infection in mice and following treatment with melarsoprol, may find application by rendering humans and animals less susceptible to deleterious effects of trypanosome infection such as splenomegaly and melarsoprol-induced PTRE and neurotoxicity.

  2. Depletion of the SR-Related Protein TbRRM1 Leads to Cell Cycle Arrest and Apoptosis-Like Death in Trypanosoma brucei

    Science.gov (United States)

    Levy, Gabriela V.; Moretti, Georgina; Tekiel, Valeria S.; Sánchez, Daniel O.

    2015-01-01

    Arginine-Serine (RS) domain-containing proteins are RNA binding proteins with multiple functions in RNA metabolism. In mammalian cells this group of proteins is also implicated in regulation and coordination of cell cycle and apoptosis. In trypanosomes, an early branching group within the eukaryotic lineage, this group of proteins is represented by 3 members, two of them are SR proteins and have been recently shown to be involved in rRNA processing as well as in pre-mRNA splicing and stability. Here we report our findings on the 3rd member, the SR-related protein TbRRM1. In the present study, we showed that TbRRM1 ablation by RNA-interference in T. brucei procyclic cells leads to cell-cycle block, abnormal cell elongation compatible with the nozzle phenotype and cell death by an apoptosis-like mechanism. Our results expand the role of the trypanosomal RS-domain containing proteins in key cellular processes such as cell cycle and apoptosis-like death, roles also carried out by the mammalian SR proteins, and thus suggesting a conserved function in this phylogenetically conserved protein family. PMID:26284933

  3. The trypanosome Pumilio domain protein PUF5.

    Directory of Open Access Journals (Sweden)

    Bhaskar Anand Jha

    Full Text Available PUF proteins are a conserved family of RNA binding proteins found in all eukaryotes examined so far. This study focussed on PUF5, one of 11 PUF family members encoded in the Trypanosoma brucei genome. Native PUF5 is present at less than 50000 molecules per cell in both bloodstream and procyclic form trypanosomes. C-terminally myc-tagged PUF5 was mainly found in the cytoplasm and could be cross-linked to RNA. PUF5 knockdown by RNA interference had no effect on the growth of bloodstream forms. Procyclic forms lacking PUF5 grew normally, but expression of PUF5 bearing a 21 kDa tandem affinity purification tag inhibited growth. Knockdown of PUF5 did not have any effect on the ability of trypanosomes to differentiate from the mammalian to the insect form of the parasite.

  4. Improved hospital-level risk adjustment for surveillance of healthcare-associated bloodstream infections: a retrospective cohort study

    Directory of Open Access Journals (Sweden)

    Jones MA

    2009-09-01

    Full Text Available Abstract Background To allow direct comparison of bloodstream infection (BSI rates between hospitals for performance measurement, observed rates need to be risk adjusted according to the types of patients cared for by the hospital. However, attribute data on all individual patients are often unavailable and hospital-level risk adjustment needs to be done using indirect indicator variables of patient case mix, such as hospital level. We aimed to identify medical services associated with high or low BSI rates, and to evaluate the services provided by the hospital as indicators that can be used for more objective hospital-level risk adjustment. Methods From February 2001-December 2007, 1719 monthly BSI counts were available from 18 hospitals in Queensland, Australia. BSI outcomes were stratified into four groups: overall BSI (OBSI, Staphylococcus aureus BSI (STAPH, intravascular device-related S. aureus BSI (IVD-STAPH and methicillin-resistant S. aureus BSI (MRSA. Twelve services were considered as candidate risk-adjustment variables. For OBSI, STAPH and IVD-STAPH, we developed generalized estimating equation Poisson regression models that accounted for autocorrelation in longitudinal counts. Due to a lack of autocorrelation, a standard logistic regression model was specified for MRSA. Results Four risk services were identified for OBSI: AIDS (IRR 2.14, 95% CI 1.20 to 3.82, infectious diseases (IRR 2.72, 95% CI 1.97 to 3.76, oncology (IRR 1.60, 95% CI 1.29 to 1.98 and bone marrow transplants (IRR 1.52, 95% CI 1.14 to 2.03. Four protective services were also found. A similar but smaller group of risk and protective services were found for the other outcomes. Acceptable agreement between observed and fitted values was found for the OBSI and STAPH models but not for the IVD-STAPH and MRSA models. However, the IVD-STAPH and MRSA models successfully discriminated between hospitals with higher and lower BSI rates. Conclusion The high model goodness

  5. Characterization and Clinical Impact of Bloodstream Infection Caused by Carbapenemase-Producing Enterobacteriaceae in Seven Latin American Countries

    Science.gov (United States)

    Villegas, Maria Virginia; Pallares, Christian J.; Hernández-Gómez, Cristhian; Correa, Adriana; Álvarez, Carlos; Rosso, Fernando; Matta, Lorena; Luna, Carlos; Zurita, Jeannete; Mejía-Villatoro, Carlos; Rodríguez-Noriega, Eduardo; Seas, Carlos; Cortesía, Manuel; Guzmán-Suárez, Alfonso; Guzmán-Blanco, Manuel

    2016-01-01

    Introduction Infections caused by carbapenem-resistant Enterobacteriaceae are a public health problem associated with higher mortality rates, longer hospitalization and increased healthcare costs. We carried out a study to describe the characteristics of patients with carbapenemase-producing Enterobacteriaceae (CPE) and non-CPE bloodstream infection (BSI) from Latin American hospitals and to determine the clinical impact in terms of mortality and antibiotic therapy. Methods Between July 2013 and November 2014, we conducted a multicenter observational study in 11 hospitals from 7 Latin American countries (Argentina, Colombia, Ecuador, Guatemala, Mexico, Peru, Venezuela). Patients with BSI caused by Enterobacteriaceae were included and classified either as CPE or non-CPE based on detection of blaKPC, blaVIM, blaIMP, blaNDM and blaOXA-48 by polymerase chain reaction. Enrolled subjects were followed until discharge or death. Demographic, microbiological and clinical characteristics were collected from medical records. Both descriptive and inferential statistics were used to analyze the information. Results A total of 255 patients with Enterobacteriaceae BSI were included; CPE were identified in 53 of them. In vitro non-susceptibility to all screened antibiotics was higher in the patients with CPE BSI, remaining colistin, tigecycline and amikacin as the most active drugs. Combination therapy was significantly more frequent in the CPE BSI group (p < 0.001). The most common regimen was carbapenem + colistin or polymyxin B. The overall mortality was 37% (94/255). Overall and attributable mortality were significantly higher in patients with CPE BSI (p < 0.001); however, we found that patients with CPE BSI who received combination therapy and those who received monotherapy had similar mortality. After multivariate adjustment, CPE BSI (adjusted odds ratio [aOR] 4; 95% confidence interval [CI] 1.7–9.5; p = 0.002) and critical illness (aOR 6.5; 95% CI 3.1–13.7; p < 0

  6. Risk factors and prognosis of nosocomial bloodstream infections caused by extended-spectrum-beta-lactamase-producing Escherichia coli.

    Science.gov (United States)

    Rodríguez-Baño, Jesús; Picón, Encarnación; Gijón, Paloma; Hernández, José Ramón; Cisneros, Jose M; Peña, Carmen; Almela, Manuel; Almirante, Benito; Grill, Fabio; Colomina, Javier; Molinos, Sonia; Oliver, Antonio; Fernández-Mazarrasa, Carlos; Navarro, Gemma; Coloma, Ana; López-Cerero, Lorena; Pascual, Alvaro

    2010-05-01

    Extended-spectrum-beta-lactamase (ESBL)-producing Escherichia coli (ESBLEC) is an increasing cause of community and nosocomial infections worldwide. However, there is scarce clinical information about nosocomial bloodstream infections (BSIs) caused by these pathogens. We performed a study to investigate the risk factors for and prognosis of nosocomial BSIs due to ESBLEC in 13 Spanish hospitals. Risk factors were assessed by using a case-control-control study; 96 cases (2 to 16% of all nosocomial BSIs due to E. coli in the participating centers) were included; the most frequent ESBL was CTX-M-14 (48% of the isolates). We found CTX-M-15 in 10% of the isolates, which means that this enzyme is emerging as a cause of invasive infections in Spain. By repetitive extragenic palindromic sequence-PCR, most isolates were found to be clonally unrelated. By multivariate analysis, the risk factors for nosocomial BSIs due to ESBLEC were found to be organ transplant (odds ratio [OR]=4.8; 95% confidence interval [CI]=1.4 to 15.7), the previous use of oxyimino-beta-lactams (OR=6.0; 95% CI=3.0 to 11.8), and unknown BSI source (protective; OR=0.4; 95% CI=0.2 to 0.9), and duration of hospital stay (OR=1.02; 95% CI=1.00 to 1.03). The variables independently associated with mortality were a Pitt score of >1 (OR=3.9; 95% CI=1.2 to 12.9), a high-risk source (OR=5.5; 95% CI=1.4 to 21.9), and resistance to more than three antibiotics, apart from penicillins and cephalosporins (OR=6.5; 95% CI=1.4 to 30.0). Inappropriate empirical therapy was not associated with mortality. We conclude that ESBLEC is an important cause of nosocomial BSIs. The previous use of oxyimino-beta-lactams was the only modifiable risk factor found. Resistance to drugs other than penicillins and cephalosporins was associated with increased mortality.

  7. Incidence, risk factors, microbiology of venous catheter associated bloodstream infections - A prospective study from a tertiary care hospital

    Directory of Open Access Journals (Sweden)

    M Kaur

    2015-01-01

    Full Text Available Purpose : Central venous catheters (CVCs though indispensable in current medical and intensive care treatment, also puts patients at risk of catheter related infection (CRI resulting in increased morbidity and mortality. We analysed the incidence, risk factors, bacteriological profile and antimicrobial susceptibility pattern of the isolates in central venous catheter associated bloodstream infection (CVC-BSI in the intensive care unit (ICU patients and studied the formation of biofilm in CVCs. Materials and Methods: The following case control study included 115 patients with CVC in situ. Quantitative blood cultures (QBC and catheter tip cultures were performed for the diagnoses. Direct catheter staining was done for an early diagnosis by acridine orange (AO and Gram staining methods. Biofilm production in catheters was detected by ′tissue culture plate′ (TCP method. The results were analysed using the computer-based program statistical package for the social sciences (SPSS. Results : In 25/115 patients, definite diagnosis of CVC-BSI was made. The mean age was 48.44 ± 17.34 years (cases vs 40.10 ± 18.24 years (controls and the mean duration of catheterisation was 25.72 ± 8.73 days (cases vs 11.89 ± 6.38 days (controls. Local signs of infection (erythema, tenderness and oozing were found more significantly in CVC-BSI cases. The AO staining was more sensitive and Gram staining of catheters showed higher specificity. Staphylococcus aureus followed by Pseudomonas aeruginosa and non-albicans Candida were common CVC-BSI pathogens. Multidrug-resistant (MDR strains were isolated in bacterial agents of CVC-BSI. Non-albicans Candida and Enterococcus faecalis showed strong biofilm production. Conclusion : The incidence of CVC-BSI was 21.73% and the rate was 14.59 per 1000 catheter days. Prolonged ICU stay and longer catheterisation were major risk factors. S. aureus was isolated most commonly in CVC-BSI cases. The menace of multidrug resistance and

  8. Analysis of bloodstream infection in children with severe hematopathy%重症血液病患儿血流感染的临床分析

    Institute of Scientific and Technical Information of China (English)

    张家源; 陈玉梅; 邹尧; 张丽; 阮敏; 陈晓娟; 刘晓明; 竺晓凡

    2014-01-01

    目的:探讨重症血液病患儿治疗过程中发生血流感染的原因、感染部位、病原菌分析及治疗对策。方法选择2007年1月-2009年9月住院治疗的血液病患儿2368例,对血液病患儿血流感染的发生率、感染部位与病原菌分布及相关因素进行分析,数据采用SPSS16.0统计软件进行处理,样本率的比较采用χ2检验。结果2368例住院治疗患儿中167例患儿发生血流感染,发生率7.1%;其中发生血流感染的急性淋巴细胞白血病患儿95例、急性髓性白血病患儿61例、重型再生障碍性贫血患儿9例、恶性淋巴瘤患儿2例,分别占56.9%、36.5%、5.4%、1.2%;感染部位以口腔黏膜与呼吸道为主,分别占12.6%与10.2%;经血培养检测,共分离出病原菌167株,其中革兰阴性杆菌90株占53.9%,革兰阳性球菌71株占42.5%,革兰阳性杆菌、真菌各3株,各占1.8%;急性淋巴细胞白血病患儿中应用糖皮质激素>2周及中性粒细胞绝对值<100/mm3与血流感染高度相关。结论急性髓性白血病较急性淋巴细胞白血病患儿易发生血流感染,血液病患儿中性粒细胞绝对值<100/mm3与血流感染的发生高度相关。%OBJECTIVE To explore the causes ,sites and pathogens of bloodstream infection in children with severe hematopathy and the method to decrease the mortality of bloodstream infection .METHODS Totally 2368 children with hematopathy were selected .The incidence rate ,infected sites ,pathogen distribution and related factors for bloodstream infection in children with hematopathy were analyzed . Data were processed by SPSS16 .0 , the comparison of sample rate was conducted with χ2 test .RESULTS There were 167 cases of bloodstream infection in the 2368 hospitalized children ,indicating the incidence was 7 .1% .The children who experienced bloodstream infection included 95 children with acute lymphoblastic

  9. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry for the rapid identification of yeasts causing bloodstream infections.

    Science.gov (United States)

    Ghosh, A K; Paul, S; Sood, P; Rudramurthy, S M; Rajbanshi, A; Jillwin, T J; Chakrabarti, A

    2015-04-01

    Few studies have systematically standardised and evaluated matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of yeasts from bloodstream infections. This is rapidly becoming pertinent for early identification of yeasts and appropriate antifungal therapy. We used 354 yeast strains identified by polymerase chain reaction (PCR) sequencing for standardisation and 367 blind clinical strains for validation of our MALDI-TOF MS protocols. We also evaluated different sample preparation methods and found the on-plate formic acid extraction method as most cost- and time-efficient. The MALDI-TOF assay correctly identified 98.9% of PCR-sequenced yeasts. Novel main spectrum projections (MSP) were developed for Candida auris, C. viswanathii and Kodamaea ohmeri, which were missing from the Bruker MALDI-TOF MS database. Spectral cut-offs computed by receiver operating characteristics (ROC) analysis showed 99.4% to 100% accuracy at a log score of ≥ 1.70 for C. tropicalis, C. parapsilosis, C. pelliculosa, C. orthopsilosis, C. albicans, C. rugosa, C. guilliermondii, C. lipolytica, C. metapsilosis, C. nivariensis. The differences in the species-specific scores of our standardisation and blind validation strains were not statistically significant, implying the optimal performance of our test protocol. The MSPs of the three new species also were validated. We conclude that MALDI-TOF MS is a rapid, accurate and reliable tool for identification of bloodstream yeasts. With proper standardisation, validation and regular database expansion, its efficiency can be further enhanced.

  10. [Obesity as pathology of adipocytes: number of cells, volume of arterial bloodstream,local pools of circulation in vivo, natriuretic peptides and arterial hypertension].

    Science.gov (United States)

    Titov, V N; Dmitriev, V A

    2015-03-01

    The non-specific systemic biological reaction of arterial pressure from the level of organism. vasomotor center and proximal section of arterial bloodstream is appealed to compensate disorders of metabolism and microcirculation in distal section of arteries. This phenomenon occurs in several cases. The primarily local disorders of metabolism at autocrine level, physiological (aphysiological) death of cells, "littering" of intercellular medium become the cause of disorder of microcirculation in paracrin cenosises and deteriorate realization of biological functions of homeostasis, trophology, endoecology and adaptation. The local compensation of affected perfusion in paracrin cenosises at the expense of function of peripheral peristaltic pumps, redistribution of local bloodflow in biological reaction of endothelium-depended vaso-dilation has no possibility to eliminate disorders in realization of biological functions. The systemic increase of arterial pressure under absence of specific symptoms of symptomatic arterial hypertension is a test to detect disorder of biological functions of homeostasis, trophology, biological function of endoecology and adaptation. Allforms of arterial hypertension develop by common algorithm independently from causes of disorders of blood flow, microcirculation in distal section of arteries. The non-specific systemic compensation ofdisorders of metabolism from level of organism, in proximal section of arterial bloodstream always is the same one and results in aphysiological alterations in organs-targets. To comprehend etiological characteristics of common pathogenesis of arterial hypertension is possible in case of application of such technically complicated and still unclear in differential diagnostic of deranged functions modes of metabolomics.

  11. DNA from protozoan parasites Babesia bovis, Trypanosoma cruzi, and T. brucei is mitogenic for B lymphocytes and stimulates macrophage expression of interleukin-12, tumor necrosis factor alpha, and nitric oxide.

    Science.gov (United States)

    Shoda, L K; Kegerreis, K A; Suarez, C E; Roditi, I; Corral, R S; Bertot, G M; Norimine, J; Brown, W C

    2001-04-01

    The activation of innate immune responses by genomic DNA from bacteria and several nonvertebrate organisms represents a novel mechanism of pathogen recognition. We recently demonstrated the CpG-dependent mitogenic activity of DNA from the protozoan parasite Babesia bovis for bovine B lymphocytes (W. C. Brown, D. M. Estes, S. E. Chantler, K. A. Kegerreis, and C. E. Suarez, Infect. Immun. 66:5423-5432, 1998). However, activation of macrophages by DNA from protozoan parasites has not been demonstrated. The present study was therefore conducted to determine whether DNA from the protozan parasites B. bovis, Trypanosoma cruzi, and T. brucei activates macrophages to secrete inflammatory mediators associated with protective immunity. DNA from Escherichia coli and all three parasites stimulated B-lymphocyte proliferation and increased macrophage production of interleukin-12 (IL-12), tumor necrosis factor alpha (TNF-alpha), and nitric oxide (NO). Regulation of IL-12 and NO production occurred at the level of transcription. The amounts of IL-12, TNF-alpha, and NO induced by E. coli and protozoal DNA were strongly correlated (r2 > 0.9) with the frequency of CG dinucleotides in the genome, and immunostimulation by DNA occurred in the order E. coli > or = T. cruzi > T. brucei > B. bovis. Induction of inflammatory mediators by E. coli, T. brucei, and B. bovis DNA was dependent on the presence of unmethylated CpG dinucleotides. However, at high concentrations, E. coli and T. cruzi DNA-mediated macrophage activation was not inhibited following methylation. The recognition of protozoal DNA by B lymphocytes and macrophages may provide an important innate defense mechanism to control parasite replication and promote persistent infection.

  12. Use of chiral cell shape to ensure highly directional swimming in trypanosomes.

    Science.gov (United States)

    Wheeler, Richard John

    2017-01-01

    Swimming cells typically move along a helical path or undergo longitudinal rotation as they swim, arising from chiral asymmetry in hydrodynamic drag or propulsion bending the swimming path into a helix. Helical paths are beneficial for some forms of chemotaxis, but why asymmetric shape is so prevalent when a symmetric shape would also allow highly directional swimming is unclear. Here, I analyse the swimming of the insect life cycle stages of two human parasites; Trypanosoma brucei and Leishmania mexicana. This showed quantitatively how chirality in T. brucei cell shape confers highly directional swimming. High speed videomicrographs showed that T. brucei, L. mexicana and a T. brucei RNAi morphology mutant have a range of shape asymmetries, from wild-type T. brucei (highly chiral) to L. mexicana (near-axial symmetry). The chiral cells underwent longitudinal rotation while swimming, with more rapid longitudinal rotation correlating with swimming path directionality. Simulation indicated hydrodynamic drag on the chiral cell shape caused rotation, and the predicted geometry of the resulting swimming path matched the directionality of the observed swimming paths. This simulation of swimming path geometry showed that highly chiral cell shape is a robust mechanism through which microscale swimmers can achieve highly directional swimming at low Reynolds number. It is insensitive to random variation in shape or propulsion (biological noise). Highly symmetric cell shape can give highly directional swimming but is at risk of giving futile circular swimming paths in the presence of biological noise. This suggests the chiral T. brucei cell shape (associated with the lateral attachment of the flagellum) may be an adaptation associated with the bloodstream-inhabiting lifestyle of this parasite for robust highly directional swimming. It also provides a plausible general explanation for why swimming cells tend to have strong asymmetries in cell shape or propulsion.

  13. Trypanosoma brucei RNA binding proteins p34 and p37 mediate NOPP44/46 cellular localization via the exportin 1 nuclear export pathway.

    Science.gov (United States)

    Hellman, Kristina; Prohaska, Kimberly; Williams, Noreen

    2007-12-01

    We have previously identified and characterized two novel nuclear RNA binding proteins, p34 and p37, which have been shown to interact with a family of nucleolar phosphoproteins, NOPP44/46, in Trypanosoma brucei. These proteins are nearly identical, the major difference being an 18-amino-acid insert in the N terminus of p37. In order to characterize the interaction between p34 and p37 and NOPP44/46, we have utilized an RNA interference (RNAi) cell line that specifically targets p34 and p37. Within these RNAi cells, we detected a disruption of a higher-molecular-weight complex containing NOPP44/46, as well as a dramatic increase in nuclear NOPP44/46 protein levels. We demonstrated that no change occurred in NOPP44/46 mRNA steady-state levels or stability, nor was there a change in cellular protein levels. These results led us to investigate whether p34 and p37 regulate NOPP44/46 cellular localization. Examination of the p34 and p37 amino acid sequences revealed a leucine-rich nuclear export signal, which interacts with the nuclear export factor exportin 1. Immune capture experiments demonstrated that p34, p37, and NOPP44/46 associate with exportin 1. When these experiments were performed with p34/p37 RNAi cells, NOPP44/46 no longer associated with exportin 1. Sequential immune capture experiments demonstrated that p34, p37, NOPP44/46, and exportin 1 exist in a common complex. Inhibiting exportin 1-mediated nuclear export led to an increase in nuclear NOPP44/46 proteins, indicating that they are exported from the nucleus via this pathway. Together, our results demonstrate that p34 and p37 regulate NOPP44/46 cellular localization by facilitating their association with exportin 1.

  14. Structure determination of glycogen synthase kinase-3 from Leishmania major and comparative inhibitor structure-activity relationships with Trypanosoma brucei GSK-3

    Energy Technology Data Exchange (ETDEWEB)

    Ojo, Kayode K; Arakaki, Tracy L; Napuli, Alberto J; Inampudi, Krishna K; Keyloun, Katelyn R; Zhang, Li; Hol, Wim G.J.; Verlind, Christophe L.M.J.; Merritt, Ethan A; Van Voorhis, Wesley C [UWASH

    2012-04-24

    Glycogen synthase kinase-3 (GSK-3) is a drug target under intense investigation in pharmaceutical companies and constitutes an attractive piggyback target for eukaryotic pathogens. Two different GSKs are found in trypanosomatids, one about 150 residues shorter than the other. GSK-3 short (GeneDB: Tb927.10.13780) has previously been validated genetically as a drug target in Trypanosoma brucei by RNAi induced growth retardation; and chemically by correlation between enzyme and in vitro growth inhibition. Here, we report investigation of the equivalent GSK-3 short enzymes of L. major (LmjF18.0270) and L. infantum (LinJ18_V3.0270, identical in amino acid sequences to LdonGSK-3 short) and a crystal structure of LmajGSK-3 short at 2 Å resolution. The inhibitor structure-activity relationships (SARs) of L. major and L. infantum are virtually identical, suggesting that inhibitors could be useful for both cutaneous and visceral leishmaniasis. Leishmania spp. GSK-3 short has different inhibitor SARs than TbruGSK-3 short, which can be explained mostly by two variant residues in the ATP-binding pocket. Indeed, mutating these residues in the ATP-binding site of LmajGSK-3 short to the TbruGSK-3 short equivalents results in a mutant LmajGSK-3 short enzyme with SAR more similar to that of TbruGSK-3 short. The differences between human GSK-3β (HsGSK-3β) and LmajGSK-3 short SAR suggest that compounds which selectively inhibit LmajGSK-3 short may be found.

  15. Micro RNA expression profiles in peripheral blood cells of rats that were experimentally infected with Trypanosoma congolense and different Trypanosoma brucei subspecies.

    Science.gov (United States)

    Simo, Gustave; Lueong, Smiths; Grebaut, Pascal; Guny, Gerard; Hoheisel, Jörg D

    2015-08-01

    To identify miRNAs whose expression are differentially regulated during trypanosome infections a microarray targeting more than 600 rat miRNA was used to analyze the miRNA expression profiles between uninfected rats and animals infected by Trypanosoma congolense and Trypanosoma brucei s.l. The potential targets of dysregulated miRNAs as well as their biological pathways and functions were predicted using several bioinformatics software tools. Irrespective of the infecting trypanosome species, eight miRNAs (seven up- and one down-regulated) were dysregulated during infections. Moreover, other miRNAs were differentially regulated in rats infected by specific trypanosome species. Functional analyses of differentially regulated miRNAs indicated their involvement in diverse biological processes. Among these, transcription repressor activity, gene expression control as well as protein transporter activity were predominant. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis of dysregulated miRNAs revealed their involvement in several biological pathways and disease conditions. This suggests possible modulation of such pathways following trypanosome infection; for example, the MAPK signaling pathway which is known to play vital roles in apoptosis, innate immune response and response to viral infections was highly affected. Axon guidance was equally highly impacted and may indicate a cross reactivity between pathogen proteins and guidance molecules representing one pathological mechanism as it has been observed with influenza HA. Furthermore, Ingenuity pathway analyses of dysregulated miRNAs and potential targets indicated strong association with inflammatory responses, cell death and survival as well as infectious diseases. The data generated here provide valuable information to understand the regulatory function of miRNAs during trypanosome infections. They improved our knowledge on host-parasite cross-talks and provide a framework for investigations to

  16. The current understanding of arterial-catheter related bloodstream infection%当前对动脉导管相关性血流感染的认识

    Institute of Scientific and Technical Information of China (English)

    王斌; 安友仲

    2016-01-01

    导管相关性血流感染(CRBSI)是重症加强治疗病房(ICU)中常见的严重感染之一,可增加患者的病死率,延长住院时间,增加住院费用.在CRBSI中,动脉导管相关性血流感染(AC-BSI)常被忽视或低估,目前的报道显示,AC-BSI的发生率接近甚至不低于中心静脉导管相关性血流感染(CVC-BSI).一旦怀疑AC-BSI,应在留取相关培养物培养后立即拔出动脉导管,并根据患者的情况实施抗感染治疗;预防是减少AC-BSI的关键.本文作者从AC-BSI的流行病学、病原学及发病机制、危险因素、诊断、治疗和预防等方面的进展进行综述,以期为临床处理提供帮助.%Catheter-related bloodstream infection (CRBSI) is one of the common severe infections in intensive care unit (ICU),which tends to increase the mortality of patients,the length of hospital stay and the cost of hospitalization.Arterial catheter-related bloodstream infection (AC-BSI) is often overlooked or underestimated.Some studies pointed out that the incidence of AC-BSI is close to or even higher than central venous catheter related bloodstream infection (CVC-BSI),which plays an important role in catheter-related infections.Once AC-BSI is suspected,arterial catheter should be removed immediately after bacterial culture and antibiotics should be prescribed according to severities of patients.Prevention is the key to reduce AC-BSI.The research progress of epidemiology,etiology,pathogenesis,risk factors,diagnosis,treatment and prevention of AC-BSI was reviewed to facilitate the clinical decision.

  17. 肿瘤重症患者合并血液感染后死亡的相关危险因素分析%Risk Factor Analysis of Mortality Following Bloodstream Infections of Cancer Patients in Intensive Care Unit

    Institute of Scientific and Technical Information of China (English)

    张青; 张文芳; 郑珊; 李丁; 张鹏

    2012-01-01

    Objective: The present study aims to analyze the bloodstream infection profiles and assess the risk factors associated with mortality of cancer patients in the intensive care unit ( ICU ) with bloodstream infections. Methods: Medical records of cancer patients with bloodstream infections, admitted to the Tianjin Medical University Cancer Institute and Hospital during January 2010 and June 2011, were retrospectively analyzed. Results: Microbiological data of 88 cases with bloodstream infections were recorded in our study ( 56 males, 32 females; 65.8 ± 24.2 years old ). Of the total patients, 45 survived and 43 died. The most commonly seen etiological agents of bloodstream infections were coagulase-negative staphylococci in 42 cases ( 37.8% ), Escherichia coli in 15 cases (13.5% ), and Candida albicans in 9 cases ( 8.1% ). Univariate analysis showed that risk factors included mechanical ventilation for more than 7 days and duration of central venous catheterization and higher APACHE II scores, of which, mechanical ventilation of more than 7 days was the independent mortality risk factor ( odds ratio: 6.8, 95%; CI: 2.5–18.4; P 7 d、中心静脉插管以及较高的APACHE Ⅱ评分是重症肿瘤患者合并血液感染后死亡的重要危险因子,其中机械通气>7 d为独立的死亡风险因子(OR=6.8,95%CI:2.5~18.4,P<0.001).结论:凝固酶阴性葡萄球菌是引起肿瘤患者血液感染的主要病原菌,临床应据此采取相应的预防控制措施,以减少重症肿瘤患者血液感染的发生发展.

  18. Contributors Form

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    Chief Editor

    2016-06-01

    to produce preprints or reprints and translate into languages other than English for sale or free distribution; and 4 the right to republish the work in a collection of articles in any other mechanical or electronic format. We give the rights to the corresponding author to make necessary changes as per the request of the journal, do the rest of the correspondence on our behalf and he/she will act as the guarantor for the manuscript on our behalf. All persons who have made substantial contributions to the work reported in the manuscript, but who are not contributors, are named in the Acknowledgment and have given me/us their written permission to be named. If I/we do not include an Acknowledgment that means I/we have not received substantial contributions from non-contributors and no contributor has been omitted.S NoAuthors' NamesContribution (IJCME Guidelines{1 substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; 2 drafting the article or revising it critically for important intellectual content; and 3 final approval of the version to be published. Authors should meet conditions 1, 2, and 3}.SignatureDate                              Note: All the authors are required to sign independently in this form in the sequence given above. In case an author has left the institution/country and whose whereabouts are not known, the senior author may sign on his/her behalf taking the responsibility.No addition/deletion/ or any change in the sequence of the authorship will be permissible at a later stage, without valid reasons and permission of the Editor.If the authorship is contested at any stage, the article will be either returned or will not be processed for publication till the issue is solved.Maximum up to 4 authors for short communication and up to 6 authors for original article.

  19. Large IncHI2-plasmids encode extended-spectrum β-lactamases (ESBLs) in Enterobacter spp. bloodstream isolates, and support ESBL-transfer to Escherichia coli.

    Science.gov (United States)

    Nilsen, E; Haldorsen, B C; Sundsfjord, A; Simonsen, G S; Ingebretsen, A; Naseer, U; Samuelsen, O

    2013-11-01

    We investigated the prevalence of extended-spectrum β-lactamases (ESBLs) in Enterobacter spp. bloodstream isolates from 19 hospital laboratories in Norway during 2011. A total of 62/230 (27%) isolates were resistant to third-generation cephalosporins and four (1.7%) were ESBL-positive; blaCTX -M-15 (n = 3) and blaSHV -12 (n = 1). This is comparable to the prevalence of ESBLs in clinical isolates of Escherichia coli and Klebsiella pneumoniae in Norway during the same period. All ESBL-positive isolates were multidrug resistant (MDR) and harboured plasmid-mediated quinolone resistance. Three isolates supported transfer of large IncHI2-plasmids harbouring ESBL- and MDR-encoding genes to E. coli recipients by in vitro conjugation.

  20. A 5-year survey of antimicrobial susceptibility profiles of methicillin-resistant Staphylococcus aureus (MRSA) isolated from patients with bloodstream infections in Northeast Italy.

    Science.gov (United States)

    Cojutti, Piergiorgio; Scarparo, Claudio; Sartor, Assunta; Coato, Paola; Rigoli, Roberto; Pea, Federico

    2015-01-01

    A 5-year survey (2009-2013) of antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) isolated from patients with bloodstream infections was carried out in Northeast Italy. No upward creep of glycopeptides MICs was documented among 582 nonduplicate MRSA blood isolates, which were tested in accordance with broth microdilution and interpreted in accordance with EUCAST recommendations. Teicoplanin showed stably a lower MIC50 in comparison with vancomycin (0.25-0.5 versus 1 mg/L). The activities of newer anti-MRSA antibacterials stratified by glycopeptides MICs showed similar trends in MICs of either vancomycin or teicoplanin with those of daptomycin, linezolid, and tigecycline. We hypothesize that in centers with different distribution of glycopeptides MICs, downward for teicoplanin and upward for vancomycin, teicoplanin could be a more effective alternative to vancomycin for empirical treatment of MRSA-related bacteremia.

  1. Editorial on low-dose acetylsalicylic acid treatment and impact on short-term mortality in Staphylococcus aureus bloodstream infection: a propensity score-matched cohort study

    Science.gov (United States)

    Schoergenhofer, Christian; Schwameis, Michael; Lagler, Heimo

    2016-01-01

    The manuscript “Low-Dose Acetylsalicylic Acid Treatment and Impact on Short-Term Mortality in Staphylococcus aureus (S. aureus) Bloodstream Infection: A propensity Score-Matched Cohort Study” published in Critical Care Medicine by Osthoff et al. reported an association of aspirin intake with a reduced short-term mortality. Direct anti-microbial effects of aspirin and its metabolite salicylate were suggested in preclinical studies. Especially intriguing is the inclusion of a control group with Escherichia coli (E. coli) blood stream infections in this study, in which aspirin was not associated with an improved outcome. However, as other observational studies also reported benefits of aspirin in critically ill patients, randomized trials are needed to confirm the effects of low-dose aspirin. PMID:27294095

  2. Long-term, low-dose tigecycline to treat relapsing bloodstream infection due to KPC-producing Klebsiella pneumoniae after major hepatic surgery

    Directory of Open Access Journals (Sweden)

    Luca Morelli

    2015-07-01

    Full Text Available A 68-year-old male underwent a right hepatectomy, resection of the biliary convergence, and a left hepatic jejunostomy for a Klatskin tumour. The postoperative course was complicated by biliary abscesses with relapsing bloodstream infections due to Klebsiella pneumoniae carbapenemase (KPC-producing Klebsiella pneumoniae (KPC-Kp. A 2-week course of combination antibiotic therapy failed to provide source control and the bacteraemia relapsed. Success was obtained with a regimen of tigecycline 100 mg daily for 2 months, followed by tigecycline 50 mg daily for 6 months, then 50 mg every 48 h for 3 months. No side effects were reported.

  3. Carbapenems Versus Piperacillin-Tazobactam for Bloodstream Infections of Nonurinary Source Caused by Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae.

    Science.gov (United States)

    Ofer-Friedman, Hadas; Shefler, Coral; Sharma, Sarit; Tirosh, Amit; Tal-Jasper, Ruthy; Kandipalli, Deepthi; Sharma, Shruti; Bathina, Pradeep; Kaplansky, Tamir; Maskit, Moran; Azouri, Tal; Lazarovitch, Tsilia; Zaidenstein, Ronit; Kaye, Keith S; Marchaim, Dror

    2015-08-01

    A recent, frequently quoted study has suggested that for bloodstream infections (BSIs) due to extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL) Escherichia coli, treatment with β-lactam/β-lactamase inhibitors (BLBLIs) might be equivalent to treatment with carbapenems. However, the majority of BSIs originate from the urinary tract. A multicenter, multinational efficacy analysis was conducted from 2010 to 2012 to compare outcomes of patients with non-urinary ESBL BSIs who received a carbapenem (69 patients) vs those treated with piperacillin-tazobactam (10 patients). In multivariate analysis, therapy with piperacillin-tazobactam was associated with increased 90-day mortality (adjusted odds ratio, 7.9, P=.03). For ESBL BSIs of a non-urinary origin, carbapenems should be considered a superior treatment to BLBLIs.

  4. Recipient-born bloodstream infection due to extensively drug-resistant Acinetobacter baumannii after emergency heart transplant: report of a case and review of the literature.

    Science.gov (United States)

    Andini, Roberto; Agrusta, Federica; Mattucci, Irene; Malgeri, Umberto; Cavezza, Giusi; Utili, Riccardo; Durante-Mangoni, Emanuele

    2015-10-01

    Infections due to drug-resistant Gram-negative rods are an emerging risk factor for increased mortality after solid organ transplant. Extensively drug-resistant (XDR) Acinetobacter baumannii (Acb) is a major threat in several critical care settings. The limited available data on the outcome of XDR Acb infections in organ transplant recipients mostly comes from cases of donor-derived infections. However, recipients of life-saving organs are often critically ill patients, staying long term in intensive care units, and therefore at high risk for nosocomial infections. In this report, we describe our experience with the exceedingly complex management of a recipient-born XDR Acb bloodstream infection clinically ensued shortly after heart transplant. We also review the current literature on this mounting issue relevant for intensive care, transplant medicine and infectious diseases.

  5. Use of PCR coupled with electrospray ionization mass spectrometry for rapid identification of bacterial and yeast bloodstream pathogens from blood culture bottles.

    Science.gov (United States)

    Kaleta, Erin J; Clark, Andrew E; Johnson, Desiree R; Gamage, Dulini C; Wysocki, Vicki H; Cherkaoui, Abdessalam; Schrenzel, Jacques; Wolk, Donna M

    2011-01-01

    Sepsis is among the top 10 causes of mortality in the United States. Rapid administration of antibiotics is one of the most important contributors to patient survival, yet only a limited number of methods exist for rapid identification of microbes cultivated from bloodstream infections, which can lead to sepsis. While traditional single-target molecular methods have been shown to greatly improve survival for septic patients by enabling rapid deescalation of broad-spectrum antibiotics, multiplex methods offer even greater possibilities. A novel multiplex method, PCR coupled to electrospray ionization mass spectrometry (PCR/ESI-MS), was used to identify the genus and species of microorganisms found to cause human bloodstream infections. DNA was directly extracted from 234 BacT-Alert blood culture bottles, and results were compared to those obtained by clinical reference standard methods. The study results demonstrated 98.7% and 96.6% concordance at the genus and species levels, respectively. Mixtures of microbes were identified in 29 blood culture bottles, including mixed species of the same genus, as well as mixtures containing Gram-positive and Gram-negative organisms, exemplifying the PCR/ESI-MS capability to identify multiple organisms simultaneously without the need for cultivation. This study demonstrates high analytical accuracy in comparison to routine subculture of blood culture bottles and phenotypic identification of microbes. Without foreknowledge of the microorganisms potentially present, the PCR/ESI-MS methods can deliver accurate results in as little as 5 to 6 h after a positive alarm from the automated blood culture system; however, current batch mode testing limits the method's clinical utility at this time.

  6. Cessation of In-line Filters in Central Venous Catheters Does Not Significantly Influence the Incidence of Bloodstream Infections and Mortality in a Hospital Hematological Ward.

    Science.gov (United States)

    Tanaka, Hiroaki; Ambiru, Satoshi; Kawaguchi, Takeharu; Sugita, Yasumasa; Kawajiri, Chika; Nagao, Yuhei; Shimura, Takenori

    2016-01-01

    Objective The use of intravenous in-line filters is effective for the mechanical removal of large particles, precipitates, bacteria, fungi, large lipid globules, and air. However, the routine use of in-line filters remains controversial. Many patients with hematological diseases frequently suffer from bloodstream infections (BSIs) with fatal outcomes. Methods The year before cessation of an in-line filter was defined as the "filter period" and the year after its cessation was defined as the "non-filter period." The number of central line-associated bloodstream infections (CLABSIs), which are defined through surveillance, the catheter utilization rate, the number of patient deaths within 7 days after removal of the central venous catheters (CVCs), and the overall survival rate following CVC insertion were measured. Results During both periods, 84 patients had a total of 140 CVCs with a total number of catheter days of 3,407. There were 10 CVCs with CLABSIs, and the overall CLABSI rate was 2.9/1,000 catheter days, including 4 CVCs with CLABSIs (2.5/1,000 catheter days) during the filter period and 6 CVCs with CLABSIs (3.3/1,000 catheter days) during the non-filter period. The CLABSI rate, catheter utilization rate, and mortality did not differ significantly between the two periods. The only independent variable that was found to be significantly associated with the development of CLABSIs was a neutrophil count of line filters from CVCs does not significantly influence the incidence of BSIs and mortality in patients with hematological disease. To confirm our results, however, a large-scale randomized controlled study is warranted.

  7. 铜绿假单胞菌血流感染27例临床分析%Clinical analysis of bloodstream infections caused by Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    丁艳苓; 姚婉贞; 宁永忠

    2013-01-01

    Objective To analyze the clinical characteristics and antimicrobial resistance of blood stream infections caused by P. aeruginosa. Methods The clinical data were retrospectively reviewed for the patients with P. aeruginosa bloodstream infection who were treated in Peking University Third Hospital from January 2006 to December 2009. Results A total of 27 patients were found with P. aeruginosa bloodstream infection. The Charlson scores of the patients were 4. 48 ± 2. 10. All patients had fever and increased or decreased white blood cell counts when their bloodstream infection was identified. Six patients were infected by multidrug-resistant (MDR) strains. Compared with the patients with non-MDR P. aeruginosa infection, the patients infected by MDR strains had significantly higher APACHE TJ scores and Sequential Organ Failure Assessment (SOFA) scores at admission, longer stay in Intensive Care Unit (RICU and SICU), higher prevalence of multiple (two or more) antibiotics use before positive blood culture after admission, and lower proprotion of patients with appropriate antibiotic therapy after blood culture. The Charlson scores, clinical manifestation, APACHE TJ scores and SOFA scores at the time of bloodstream infection, and in-hospital mortality were similar between the two groups of patients. Conclusions The patients with P. aeruginosa bloodstream infection showed severe clinical status and high mortality rate. The MDR strains-infected patients had more severe conditions than those infected by non-MDR strains, but their clinical manifestations were similar. Patients with bloodstream infection should subject to microbiological testing and be treated with appropriate active agents as soon as possible to reduce fatality rate.%目的 探讨铜绿假单胞菌血流感染的临床特点及细菌耐药性.方法 回顾性分析北京大学第三医院2006年1月-2009年12月铜绿假单胞菌血流感染患者的临床及微生物学资料.结果 27例患者纳入分

  8. Bloodstream Infections among AIDS Patients%艾滋病并发血流感染的临床分析

    Institute of Scientific and Technical Information of China (English)

    励峰; 朱翠云; 黄琴; 孙洪清

    2012-01-01

    Objective To analyze the bloodstream infections( BSI) among AIDS patients,and study its peripheral blood routine test,its pathogens distribution, and its influence to prognosis. Methods A retrospective cohort study was conducted among 144 AIDS inpa-tients from January 2011 to March 2012 in Shanghai Public health center of Fudan University. Results All of 144 cases, the incidence rate of BSI was 19.4% (28/144). The blood cultures contained 33 different pathogens, with 8 staphylococcus strains (24.2% ) ,6 fungi strains ( 18. 2% ) ,6 salmonella strains( 18. 2% ). The peripheral red blood cell count and haematoglobin were 3. 223 × 1012/L,98. 89g/L in patients with BSI and were 3.678 × 1012/L, 109. 94g/L in patients without BSI(f =0.016 and 0.049). The peripheral blood CD4 + lymphocyte counts were 78. 3 × 106/L in patients with BSI and were 98. 75 × 106/L in patients without BS1( P = 0. 422) . The mortality of BSI and non - BSI was 32. 1% and 12. 1% (X2 =6.772, P =0.009). Conclusion The AIDS patients with BSI had a lower red blood cell count and haematoglobin than non - BSI. The common pathogens of BSI were staphylococcus among AIDS patients in our hospital. AIDS patients with BSI had a high rate of mortality. It is necessary to prevent the happening of BSI.%目的 探讨艾滋病患者血流感染的病原菌分布,与外周血细胞的相关性及其对预后的影响.方法 回顾性分析2011年1月~2012年3月在上海市公共卫生临床中心感染科住院的艾滋病并发血流感染的发病率、病原菌分布、与外周血细胞、外周血淋巴细胞计数的相关性以及病死率.结果 144例艾滋病患者中确诊血流感染(血流感染组)有19.4% (28/144),无血流感染(无血流感染组)有80.6%(116/144).培养出33株病原菌,主要是葡萄球菌8株(24.2%);真菌6株(18.2%);沙门菌6株(18.2%).血流感染组平均红细胞计数及血红蛋白分别为3.223×1012/L、98.89g/L,无血流感染组分别为3.678×1012

  9. Melarsoprol sensitivity profile of Trypanosoma brucei gambiense isolates from cured and relapsed sleeping sickness patients from the Democratic Republic of the Congo.

    Directory of Open Access Journals (Sweden)

    Patient Pyana Pati

    2014-10-01

    Full Text Available Sleeping sickness caused by Trypanosoma brucei (T.b. gambiense constitutes a serious health problem in sub-Sahara Africa. In some foci, alarmingly high relapse rates were observed in patients treated with melarsoprol, which used to be the first line treatment for patients in the neurological disease stage. Particularly problematic was the situation in Mbuji-Mayi, East Kasai Province in the Democratic Republic of the Congo with a 57% relapse rate compared to a 5% relapse rate in Masi-Manimba, Bandundu Province. The present study aimed at investigating the mechanisms underlying the high relapse rate in Mbuji-Mayi using an extended collection of recently isolated T.b. gambiense strains from Mbuji-Mayi and from Masi-Manimba.Forty five T.b. gambiense strains were used. Forty one were isolated from patients that were cured or relapsed after melarsoprol treatment in Mbuji-Mayi. In vivo drug sensitivity tests provide evidence of reduced melarsoprol sensitivity in these strains. This reduced melarsoprol sensitivity was not attributable to mutations in TbAT1. However, in all these strains, irrespective of the patient treatment outcome, the two aquaglyceroporin (AQP 2 and 3 genes are replaced by chimeric AQP2/3 genes that may be associated with resistance to pentamidine and melarsoprol. The 4 T.b. gambiense strains isolated in Masi-Manimba contain both wild-type AQP2 and a different chimeric AQP2/3. These findings suggest that the reduced in vivo melarsoprol sensitivity of the Mbuji-Mayi strains and the high relapse rates in that sleeping sickness focus are caused by mutations in the AQP2/AQP3 locus and not by mutations in TbAT1.We conclude that mutations in the TbAQP2/3 locus of the local T.b. gambiense strains may explain the high melarsoprol relapse rates in the Mbuji-Mayi focus but other factors must also be involved in the treatment outcome of individual patients.

  10. A function for a specific zinc metalloprotease of African trypanosomes.

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    Paul M Grandgenett

    2007-10-01

    Full Text Available The Trypanosoma brucei genome encodes three groups of zinc metalloproteases, each of which contains approximately 30% amino acid identity with the major surface protease (MSP, also called GP63 of Leishmania. One of these proteases, TbMSP-B, is encoded by four nearly identical, tandem genes transcribed in both bloodstream and procyclic trypanosomes. Earlier work showed that RNA interference against TbMSP-B prevents release of a recombinant variant surface glycoprotein (VSG from procyclic trypanosomes. Here, we used gene deletions to show that TbMSP-B and a phospholipase C (GPI-PLC act in concert to remove native VSG during differentiation of bloodstream trypanosomes to procyclic form. When the four tandem TbMSP-B genes were deleted from both chromosomal alleles, bloodstream B (-/- trypanosomes could still differentiate to procyclic form, but VSG was removed more slowly and in a non-truncated form compared to differentiation of wild-type organisms. Similarly, when both alleles of the single-copy GPI-PLC gene were deleted, bloodstream PLC (-/- cells could still differentiate. However, when all the genes for both TbMSP-B and GPI-PLC were deleted from the diploid genome, the bloodstream B (-/- PLC (-/- trypanosomes did not proliferate in the differentiation medium, and 60% of the VSG remained on the cell surface. Inhibitors of cysteine proteases did not affect this result. These findings demonstrate that removal of 60% of the VSG during differentiation from bloodstream to procyclic form is due to the synergistic activities of GPI-PLC and TbMSP-B.

  11. 金黄色葡萄球菌血流感染的临床特征分析%Clinical features of bloodstream infection caused by staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    路明; 姚婉贞; 王筱宏; 刘振英

    2011-01-01

    OBJECTIVE To study the clinical characteristics and antimicrobial resistance of bloodstream infections caused by Staphylococcus aureus (SAU). METHODS Patients with bloodstream infections of SAU in our hospital from 2004 to 2008 were retrospectively reviewed. RESULTS All 28 patients had fever and 60. 7% with rigor. 18 cases had metastatic infection and lung was the most common metastasizing site. 85.7% of the patients had variety of vulnerable factors. 39% complicated by septic shock and the total mortality rate was 32.0%. 6 episodes were community acquired and 50. 0% of the primary infection site were from skin or soft tissues. All the six community-acquired SAU isolates were methicillin sensitive S. aureus (MSSA). The other 22 episodes were nosocomial infections, 45. 5% were related with central venous catheters, and 72. 0% of the SAU isolates were methicillin resistant S. aureus (MRSA). All the SAU isolates acquired from community and hospital were resistant to penicillin. CONCLUSION High fever with rigor and metastatic infection are common features of SAU bloodstream infection. MRSA isolates increased gradually with high mortality rate.%目的 了解金黄色葡萄球菌血流感染的临床特征及细菌耐药情况.方法 回顾分析医院2004-2008年由金黄色葡萄球菌所致血流感染患者的临床和微生物学资料.结果 共28例患者入选,均有发热,60.7%伴寒颤,18例有迁徙灶,肺受累最常见;85.7%的患者存在易感因素,39.0%合并感染性休克,死亡率32.0%;社区感染6例,多以皮肤为原发感染灶(50.0%),均为甲氧西林敏感金黄色葡萄球菌;医院内感染22例,多与中心静脉导管相关(45.5%),72.0%为耐甲氧西林金黄色葡萄球菌(MRSA);社区和医院内感染金黄色葡萄球菌株对青霉素100.0%耐药.结论 金黄色葡萄球菌血流感染多有高热、寒颤伴有迁徙灶,MRSA逐渐增多,导致很高的死亡率.

  12. Clinical Analysis of Catheter-Related Bloodstream Infection in ICU%ICU中心静脉置管患者血性感染的临床分析

    Institute of Scientific and Technical Information of China (English)

    吴敏

    2013-01-01

    目的 对ICU中心静脉导管患者发生医院血性感染的相关情况进行分析,探讨发生特点和危险因素.方法 对785例ICU中心静脉置管患者的一般情况和临床资料进行回顾性分析,包括患者的年龄、性别、自理能力、自身免疫性疾病、置管时间、置管部位和免疫抑制剂的使用等相关性感染因素.结果 785例患者相关血性感染共发生34例,发生率4.3%.34例病原菌共检出29株,阳性率85.3%.检出以革兰氏阴性菌为主,占总检出的48.3%,其次为革兰氏阳性菌,占41.4%,再次为真菌,占10.3%.ICU中心静脉导管患者发生医院血性感染与年龄、自理能力、自身免疫性疾病、置管时间和免疫抑制剂的使用相关.结论 积极治疗患者自身免疫性疾病,对置管时间进行控制,并减少免疫抑制剂的使用,是减少ICU中心静脉导管相关血性感染的重要措施.%Objective To investigate the bloodstream infection in patients with central venous catheter in ICU,explore the risk factors.Methods Totally 785 patients with central venous catheter were chosen and studied to analyze the risk factors which might cause bloodstream infection.The correlation factors were gender,age,self-help skills,autosomal disease,insertion time,catheter site,and application of immunosuppressive.Results 34 cases catheter-related bloodstream infection cases were detected in ICU(4.3%).29 cases were detected in 34 cases of pathogens,with the positive rate of 85.3%.The most common bacteria were Gram-negative bacteria,accounting for 48.3%,followed by Gram-positive bacteria which accounting for 41.4%,and Fungi which accounting for 10.3%.The analysis of 785 cases showed that the infection rate was closely related to age,self-help skills,autosomal disease,insertion time,and application of immunosuppressive.Conclusion It was effective to reduce the infection by treating the autosomal disease positively,controlling insertion time and using

  13. Taurolidine lock solutions for the prevention of catheter-related bloodstream infections: a systematic review and meta-analysis of randomized controlled trials.

    Directory of Open Access Journals (Sweden)

    Yong Liu

    Full Text Available BACKGROUND: Catheter-related bloodstream infections (CRBSIs are a significant cause of morbidity and mortality in critically ill patients, contributing to prolonged hospital stays and increased costs. Whether taurolidine lock solutions (TLS are beneficial for the prevention of CRBSIs remains controversial. In this meta-analysis, we aim to assess the efficacy of TLS for preventing CRBSIs. METHODS: We conducted a systematic search of PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials. Eligible studies included randomized controlled trials that reported on the effects of TLS for preventing CRBSIs. The primary outcome in these studies was catheter-related bloodstream infections, with microbial distribution of CRBSI and catheter-associated thrombosis as secondary outcomes. Data were combined using random-effects models owing to significant clinical heterogeneity. RESULTS: Six randomized controlled trials (RCTs conducted from 2004 through 2013 involving 431 patients and 86,078 catheter-days were included in the review. TLS were significantly associated with a lower incidence of CRBSIs when compared to heparin lock solutions (Risk Ratio [RR], 0.34; 95% Confidence Interval [CI], 0.21-0.55. Use of TLS significantly decreased the incidence of CRBSIs from gram-negative (G- bacteria (P = 0.004; RR, 0.27; CI, 0.11-0.65, and was associated with a non-significant decrease in gram-positive (G+ bacterial infections (P = 0.07; RR, 0.41; CI, 0.15-1.09. No significant association was observed with TLS and catheter-associated thrombosis (RR, 1.99; CI, 0.75-5.28. CONCLUSIONS: The use of TLS reduced the incidence of CRBSIs without obvious adverse effects or bacterial resistance. However, the susceptibility of G+ and G- bacteria to taurolidine and the risk for catheter-associated thrombosis of TLS are indeterminate due to limited data. The results should be treated with caution due to the limited sample sizes and methodological deficiencies

  14. 抗感染中心静脉导管预防导管相关性血流感染的效果%Effect in prevention of catheter-related bloodstream infection using antiseptic impregnated central venous catheter

    Institute of Scientific and Technical Information of China (English)

    罗蕾; 秦英; 向亚娟

    2011-01-01

    Objective To evaluate the clinical effect in prevention of catheter-related bloodstream infection(CRBSI) using antiseptic impregnated central venous catheter. Methods The incidence of catheterrelated bloodstream infection was compared between 420 cases performed with antiseptic impregnated central venous catheter ( experimental group ) and 430 cases performed with general central venous catheter (control).Besides, the categories and characteristics of pathogenic bacteria which resulted in catheter-related bloodstream infection were analyzed. Results There were 66 cases of CRBSI in 850 cases, 25 cases were inserted antiseptic impregnated central venous catheter and 41 cases inserted general central venous catheter. No significant difference in the incidence between the two groups was found during 7 days(χ2 = 0. 06 ,P > 0. 05), however, the incidence of CRBSI was lower in the experimental group than of the control group after 7 days( χ2 = 3.91,4.30 ;P 0.05),7 d后实验组CRBSI感染率较对照组低,差异有统计学意义(χ2分别为3.91,4.30,P<0.05).实验组减少导管相关性血流感染的病原体主要为革兰阳性菌.结论 抗感染中心静脉导管可明显减少导管相关性血流感染的发生,有很大的临床价值.

  15. Comparison of E,E-Farnesol Secretion and the Clinical Characteristics of Candida albicans Bloodstream Isolates from Different Multilocus Sequence Typing Clades.

    Science.gov (United States)

    Jung, Sook-In; Shin, Jong Hee; Kim, Soo Hyun; Kim, Jin; Kim, Joo Hee; Choi, Min Ji; Chung, Eun-Kyung; Lee, Kyungwon; Koo, Sun Hoe; Chang, Hyun Ha; Bougnoux, Marie-Elisabeth; d'Enfert, Christophe

    2016-01-01

    Using multilocus sequence typing (MLST), Candida albicans can be subdivided into 18 different clades. Farnesol, a quorum-sensing molecule secreted by C. albicans, is thought to play an important role in the development of C. albicans biofilms and is also a virulence factor. This study evaluated whether C. albicans bloodstream infection (BSI) strains belonging to different MLST clades secrete different levels of E,E-farnesol (FOH) and whether they have different clinical characteristics. In total, 149 C. albicans BSI isolates from ten Korean hospitals belonging to clades 18 (n = 28), 4 (n = 23), 1 (n = 22), 12 (n = 17), and other clades (n = 59) were assessed. For each isolate, the FOH level in 24-hour biofilms was determined in filtered (0.45 μm) culture supernatant using high-performance liquid chromatography. Marked differences in FOH secretion from biofilms (0.10-6.99 μM) were observed among the 149 BSI isolates. Clade 18 isolates secreted significantly more FOH than did non-clade 18 isolates (mean ± SEM; 2.66 ± 0.22 vs. 1.69 ± 0.10 μM; P albicans BSI isolates belonging to the most prevalent MLST clade (clade 18) in Korea are characterized by increased levels of FOH secretion and less severe illness.

  16. A collaborative, systems-level approach to eliminating healthcare-associated MRSA, central-line-associated bloodstream infections, ventilator-associated pneumonia, and respiratory virus infections.

    Science.gov (United States)

    Henderson, Donna M; Staiger, Thomas O; Peterson, Gene N; Sinanan, Mika N; Angiulo, Cindy L; Makarewicz, Vanessa A; Wild, Lorie M; Whimbey, Estella E

    2012-01-01

    To achieve sustainable reductions in healthcare-associated infections (HAIs), the University of Washington Medical Center (UWMC) deployed a collaborative, systems-level initiative. With the sponsorship of senior leadership, multidisciplinary teams were established to address healthcare-associated methicillin-resistant Staphylococcus aureus (MRSA), central-line-associated bloodstream infections (CLABSI), ventilator-associated pneumonia (VAP), and respiratory virus infections. The goal of the initiative was to eliminate these four HAIs among medical center inpatients by 2012. In the first 24 months of the project, the number of healthcare-associated MRSA cases decreased 58%; CLABSI cases decreased 54%. Staff and provider compliance with infection prevention measures improved and remained strong, for example, 96% compliance with hand hygiene, 98% compliance with the recommended influenza vaccination program, and 100% compliance with the VAP bundle. Achieving these results required an array of coordinated, systems-level interventions. Critical project success factors were believed to include creating organizational alignment by declaring eliminating HAIs as an organizational breakthrough goal, having the organization's executive leadership highly engaged in the project, coordination by an experienced and effective project leader and manager, collaboration by multidisciplinary project teams, and promoting transparency of results across the organization.

  17. Risk factors and treatment outcomes of bloodstream infection caused by extended-spectrum cephalosporin-resistant Enterobacter species in adults with cancer.

    Science.gov (United States)

    Huh, Kyungmin; Kang, Cheol-In; Kim, Jungok; Cho, Sun Young; Ha, Young Eun; Joo, Eun-Jeong; Chung, Doo Ryeon; Lee, Nam Yong; Peck, Kyong Ran; Song, Jae-Hoon

    2014-02-01

    Treatment of Enterobacter infection is complicated due to its intrinsic resistance to cephalosporins. Medical records of 192 adults with cancer who had Enterobacter bacteremia were analyzed retrospectively to evaluate the risk factors for and the treatment outcomes in extended-spectrum cephalosporin (ESC)-resistant Enterobacter bacteremia in adults with cancer. The main outcome measure was 30-day mortality. Of the 192 patients, 53 (27.6%) had bloodstream infections caused by ESC-resistant Enterobacter species. Recent use of a third-generation cephalosporin, older age, tumor progression at last evaluation, recent surgery, and nosocomial acquisition were associated with ESC-resistant Enterobacter bacteremia. The 30-day mortality rate was significantly higher in the resistant group. Multivariate analysis showed that respiratory tract infection, tumor progression, septic shock at presentation, Enterobacter aerogenes as the culprit pathogen, and diabetes mellitus were independent risk factors for mortality. ESC resistance was significantly associated with mortality in patients with E. aerogenes bacteremia, although not in the overall patient population.

  18. Reduction of catheter-associated bloodstream infections through procedures in newborn babies admitted in a university hospital intensive care unit in Brazil

    Directory of Open Access Journals (Sweden)

    Daiane Silva Resende

    2011-12-01

    Full Text Available INTRODUCTION: Catheter-associated bloodstream infection (CA-BSI is the most common nosocomial infection in neonatal intensive care units. There is evidence that care bundles to reduce CA-BSI are effective in the adult literature. The aim of this study was to reduce CA-BSI in a Brazilian neonatal intensive care unit by means of a care bundle including few strategies or procedures of prevention and control of these infections. METHODS: An intervention designed to reduce CA-BSI with five evidence-based procedures was conducted. RESULTS: A total of sixty-seven (26.7% CA-BSIs were observed. There were 46 (32% episodes of culture-proven sepsis in group preintervention (24.1 per 1,000 catheter days [CVC days]. Neonates in the group after implementation of the intervention had 21 (19.6% episodes of CA-BSI (14.9 per 1,000 CVC days. The incidence of CA-BSI decreased significantly after the intervention from the group preintervention and postintervention (32% to 19.6%, 24.1 per 1,000 CVC days to 14.9 per 1,000 CVC days, p=0.04. In the multiple logistic regression analysis, the use of more than 3 antibiotics and length of stay >8 days were independent risk factors for BSI. CONCLUSIONS: A stepwise introduction of evidence-based intervention and intensive and continuous education of all healthcare workers are effective in reducing CA-BSI.

  19. Significance of yeasts in bloodstream infection: Epidemiology and predisposing factors of Candidaemia in adult patients at a university hospital (2010-2014).

    Science.gov (United States)

    Pongrácz, Júlia; Juhász, Emese; Iván, Miklós; Kristóf, Katalin

    2015-09-01

    The incidence of Candida bloodstream infection (BSI) has increased during the past decades. Species distribution is changing worldwide, and non-albicans Candida spp. are becoming more prevalent. Acquired resistance to antifungal agents has been documented in several reports. The aim of our study was to assess the epidemiology and antifungal susceptibility of Candida isolates from BSI at our institute. The incidence of Candida BSI increased during the first four years of our investigation, from 1.7 to 3.5 episodes / 10 000 admissions, then dropped to 2.66 episodes / 10 000 admissions in the last year. The most frequently isolated species was C. albicans (63%), followed by C. glabrata (13%), C. parapsilosis (10.2%), C. tropicalis (9.3%), and C. krusei (3.7%). One isolate each of C. kefyr, C. fabianii and C. inconspicua were detected. The percentage of C. albicans remained stable throughout the study period. The most frequent risk factors of Candida BSI in our patient population were intensive care treatment (60.4%), abdominal surgery (52.5%), and solid malignancy (30.7%). All isolates were wild-type organisms, no acquired antifungal resistance was detected.

  20. 艾滋病患者血流感染的研究%Study of bloodstream infection in HIV/AIDS patients

    Institute of Scientific and Technical Information of China (English)

    杨宗兴; 吴南屏

    2012-01-01

    血流感染(BSI)对艾滋病患者的预后有重要意义,即使在HAART时代,BSI在艾滋病患者的死亡原因中仍排在前三位.国外有较多针对艾滋病患者BSI的研究,而国内这方面的研究较少.此文就艾滋病患者BSI的发病率、病原体、诊断、预后和防治等问题作了综述.%Bloodstream infection(BSI) is of great importance to the prognosis of HIV/AIDS patients,which ranks among the first three causes of death of HIV/AIDS patients even in HAART(highly active antiretroviral therapy)era.Many studies of BSI aiming at HIV/AIDS patients have been conducted abroad,but there are few in China.Now,the studies of BSI of HIV/AIDS patients,the topics involving incidence,pathogens,diagnosis,prognosis,prevention and cure are reviewed in this article.

  1. High Incidence of Afebrile Bloodstream Infection Detected by Surveillance Blood Culture in Patients on Corticosteroid Therapy after Allogeneic Hematopoietic Stem Cell Transplantation.

    Science.gov (United States)

    Kameda, Kazuaki; Kimura, Shun-Ichi; Akahoshi, Yu; Nakano, Hirofumi; Harada, Naonori; Ugai, Tomotaka; Wada, Hidenori; Yamasaki, Ryoko; Ishihara, Yuko; Kawamura, Koji; Sakamoto, Kana; Ashizawa, Masahiro; Sato, Miki; Terasako-Saito, Kiriko; Nakasone, Hideki; Kikuchi, Misato; Yamazaki, Rie; Kanda, Junya; Kako, Shinichi; Tanihara, Aki; Nishida, Junji; Kanda, Yoshinobu

    2016-02-01

    Bloodstream infections (BSI) are still important complications after allogeneic hematopoietic stem cell transplantation (allo-SCT). Patients who are receiving corticosteroid therapy can develop BSI without fever. The utility of surveillance blood cultures in these situations is controversial. We retrospectively analyzed 74 patients who received a corticosteroid consisting of ≥.5 mg/kg prednisolone or equivalent after allo-SCT. In principle, we performed surveillance blood culture weekly for these patients. Sixteen patients (21.6%) developed definite BSI. In a multivariate analysis, a myeloablative conditioning regimen, high-risk disease status at allo-SCT, and the presence of a central venous catheter at the initiation of corticosteroid therapy were identified as independent significant risk factors for the development of definite BSI. At the first definite BSI episode, 7 patients (46.7%) were afebrile and diagnosed by surveillance blood culture. However, 6 of these 7 afebrile patients showed various signs that could be attributed to infection at the time of positive blood culture. In conclusion, patients receiving corticosteroid therapy after allo-SCT frequently develop afebrile BSI. Although surveillance blood culture might be beneficial in these situations, it also seems important to not miss the signs of BSI, even when patients are afebrile.

  2. The effect of comprehensive infection control measures on the rate of late-onset bloodstream infections in very low-birth-weight infants.

    Science.gov (United States)

    Wicker, Linda; Saslow, Judy; Shah, Sahil; Bhat, Vishwanath; Sannoh, Sulaiman; Brandon, Emma; Kemble, Nicole; Pyon, Kee; Stahl, Gary; Aghai, Zubair H

    2011-03-01

    Late-onset bloodstream infection (LOBI) is a significant problem in very low-birth-weight (VLBW) infants and can lead to increased mortality and morbidity. The incidence of LOBI in VLBW infants in our unit was >35% before 2004, much higher than 20% reported in other studies. A comprehensive infection control measure was introduced in our unit in 2005. Here we report the effects of comprehensive infection control measures on the rate of LOBI in VLBW infants. Infants in the preintervention group (born 2001 to 2004) were compared with the intervention group (born 2005 to 2008) for baseline demographics, risk factors for infection, and the rate of LOBI. LOBI was defined as a positive blood and/or cerebrospinal fluid culture after 3 days of life. Three hundred thirty-four VLBW infants were admitted to our unit during the preintervention period and 303 during the intervention period. There was no significant difference in baseline demographics and risk factors for LOBI between the two groups. The incidence of LOBI was significantly reduced from 38% before intervention to 23% after intervention ( P control measures significantly reduced the rate of LOBI in VLBW infants.

  3. Molecular epidemiology of extended-spectrum beta-lactamase (ESBL)-positive Klebsiella pneumoniae from bloodstream infections and risk factors for mortality.

    Science.gov (United States)

    Gürntke, Stephan; Kohler, Christian; Steinmetz, Ivo; Pfeifer, Yvonne; Eller, Christoph; Gastmeier, Petra; Schwab, Frank; Leistner, Rasmus

    2014-12-01

    The prevalence of extended-spectrum beta-lactamase (ESBL)-positive Klebsiella pneumoniae is growing worldwide. Infections with these bacteria are suspected to be related to increased mortality. We aimed to estimate the distribution of ESBL genotypes and to assess the impact on mortality associated with ESBL positivity in cases of bloodstream infection (BSI) due to K. pneumoniae. We performed a cohort study on patients with K. pneumoniae BSI between 2008 and 2011. Presence of ESBL genes was analyzed by PCR and sequencing. Risk factors for mortality were analyzed by Cox-proportional hazard regression. We identified 286 ESBL-negative (81%) and 66 (19%) ESBL-positive cases. 97% (n = 64) of the ESBL-positive isolates were susceptible for meropenem. The most common ESBL genotypes were CTX-M-15 (60%), SHV-5 (27%) and CTX-M-3 (5%). Significant risk factors for mortality were chronic pulmonary disease (HR 1.747) and moderate/severe renal disease (HR 2.572). ESBL positivity was not associated with increased mortality.

  4. Etiology, clinical course and outcome of healthcare-associated bloodstream infections in patients with hematological malignancies: a retrospective study of 350 patients in a Finnish tertiary care hospital.

    Science.gov (United States)

    Åttman, Emilia; Aittoniemi, Janne; Sinisalo, Marjatta; Vuento, Risto; Lyytikäinen, Outi; Kärki, Tommi; Syrjänen, Jaana; Huttunen, Reetta

    2015-01-01

    This retrospectively collected laboratory-based surveillance data includes 575 healthcare-associated bloodstream infections (BSIs) in 350 patients with hematological malignancy in Tampere University Hospital, Finland, during 1999-2001 and 2005-2010. The most common underlying diseases were acute myelogenous leukemia (n=283, 49%), followed by myeloma (n=87, 15%) and acute lymphocytic leukemia (n=76, 13%). The overall rate was 9.1 BSIs per 1000 patient-days. Gram-positive BSIs predominated and the most common pathogens were coagulase-negative staphylococci (23%), viridans streptococci (11%), enterococci (9%) and Escherichia coli (9%). Fungi caused 2% of BSIs. The 7-day and 28-day case fatalities were 5% and 10% and were highest in BSIs caused by P. aeruginosa (19% and 34%, respectively). The median age of patients with BSI has increased; it was 55.0 years during 1999-2001, compared to 59.0 years in 2005-2007 and 59.0 years in 2008-2010 (p<0.0001). Gram-positive bacteria predominated in this material. Case fatalities were low as compared to previous reports although the median age of patients increased.

  5. Nationwide German Multicenter Study on Prevalence of Antibiotic Resistance in Staphylococcal Bloodstream Isolates and Comparative In Vitro Activities of Quinupristin-Dalfopristin

    Science.gov (United States)

    von Eiff, Christof; Reinert, Ralf René; Kresken, Michael; Brauers, Johannes; Hafner, Dieter; Peters, Georg

    2000-01-01

    Antibiotic-resistant gram-positive bacteria have become an increasing problem in the last two decades. In order to evaluate the prevalence of antibiotic resistance in staphylococcal bloodstream isolates in Germany, 2,042 staphylococci collected in 21 tertiary-care hospitals were investigated during a 3-year period (March 1996 to March 1999). Altogether, 1,448 S. aureus isolates and 594 coagulase-negative staphylococci (CoNS) that comprised 13 different species were included. Furthermore, the antistaphylococcal activities of quinupristin-dalfopristin were compared with those of eight other compounds by the broth microdilution method. The rates of oxacillin resistance in Staphylococcus aureus, S. epidermidis, S. haemolyticus, and other CoNS were 13.5, 69, 90, and 34%, respectively. In oxacillin-resistant strains high rates of resistance (up to 100%) to erythromycin, clindamycin, ciprofloxacin, and gentamicin were also observed. However, no strain appeared to be resistant to vancomycin or quinupristin-dalfopristin. The streptogramin combination exhibited excellent in vitro activity against all staphylococcal species tested, regardless of the patterns of resistance to other drug classes. In terms of MICs at which 90% of the isolates are inhibited, quinupristin-dalfopristin was 2 times more active against S. aureus isolates, 4 to 16 times more active against S. haemolyticus, and 8 to 32 times more active against S. epidermidis than vancomycin or teicoplanin. PMID:10921933

  6. Hospital costs of central line-associated bloodstream infections and cost-effectiveness of closed vs. open infusion containers. The case of Intensive Care Units in Italy

    Directory of Open Access Journals (Sweden)

    Torbica Aleksandra

    2010-05-01

    Full Text Available Abstract Objectives The aim was to evaluate direct health care costs of central line-associated bloodstream infections (CLABSI and to calculate the cost-effectiveness ratio of closed fully collapsible plastic intravenous infusion containers vs. open (glass infusion containers. Methods A two-year, prospective case-control study was undertaken in four intensive care units in an Italian teaching hospital. Patients with CLABSI (cases and patients without CLABSI (controls were matched for admission departments, gender, age, and average severity of illness score. Costs were estimated according to micro-costing approach. In the cost effectiveness analysis, the cost component was assessed as the difference between production costs while effectiveness was measured by CLABSI rate (number of CLABSI per 1000 central line days associated with the two infusion containers. Results A total of 43 cases of CLABSI were compared with 97 matched controls. The mean age of cases and controls was 62.1 and 66.6 years, respectively (p = 0.143; 56% of the cases and 57% of the controls were females (p = 0.922. The mean length of stay of cases and controls was 17.41 and 8.55 days, respectively (p Conclusions CLABSI results in considerable and significant increase in utilization of hospital resources. Use of innovative technologies such as closed infusion containers can significantly reduce the incidence of healthcare acquired infection without posing additional burden on hospital budgets.

  7. Impact of ESKAPE bloodstream infection on prognosis of acute necrotizing pancreatitis%ESKAPE血流感染对急性坏死型胰腺炎预后的影响

    Institute of Scientific and Technical Information of China (English)

    杨双汇; 杨慧明; 黄耿文; 李宜雄

    2015-01-01

    目的:探讨ESKAPE血流感染对急性坏死性胰腺炎(ANP)患者预后及并发症的影响。  方法:回顾性分析2003年1月—2014年7月收治的有血培养结果的87例ANP患者,其中血培养阴性49例,阳性38例,分析血流感染,尤其是ESKAPE血流感染对ANP患者治疗结果的影响。  结果:在38例血培养阳性ANP患者的69份的病原学结果中,40.6%为ESKAPE,其中鲍曼不动杆菌占比50.0%,其余依次为屎肠球菌(14.3%)、肺炎克雷伯菌(10.7%),肠杆菌属(10.7%),金黄色葡萄球菌(7.1%)和铜绿假单胞菌(7.1%)。血流感染患者休克、呼吸衰竭、肾功能衰竭与消化道出血等并发症的发生率、病死率、住院费用及ICU住院天数均较非血流感染患者明显增高(均P  结论:血流感染明显增加ANP患者的并发症和病死率。ESKAPE是导致ANP患者血流感染的主要病原体,其与患者休克的发生密切相关。%Objective:To investigate the impact of ESAKPE bloodstream infection on the prognosis and complications in patients with acute necrotizing pancreatitis (ANP). Methods:Eighty-seven ANP patients admitted from January 2003 to July 2014 with blood culture results were retrospectively studied. Of the patients, 49 cases had negative and 38 cases had positive blood culture. hTe impact of bloodstream infection, especially ESKAPE bloodstream infection on therapeutic outcomes of these ANP patients was analyzed. Results:In the 69 pathogen test results from the 38 ANP patients with positive blood culture, 40.6%were ESAKPE pathogens that included Acinetobacter baumanni (50.0%), Enterococcus faecium (14.3%), Klebsiella pneumonia (10.7%), Enterobacter species (10.7%), Staphylococcus aureus (7.1%) and Pseudomonas aeruginosa (7.1%). Patients with bloodstream infection had significantly increased incidence of shock, respiratory failure, renal failure and digestive tract bleeding and mortality, as well as

  8. Ablation of succinate production from glucose metabolism in the procyclic trypanosomes induces metabolic switches to the glycerol 3-phosphate/dihydroxyacetone phosphate shuttle and to proline metabolism.

    Science.gov (United States)

    Ebikeme, Charles; Hubert, Jane; Biran, Marc; Gouspillou, Gilles; Morand, Pauline; Plazolles, Nicolas; Guegan, Fabien; Diolez, Philippe; Franconi, Jean-Michel; Portais, Jean-Charles; Bringaud, Frédéric

    2010-10-15

    Trypanosoma brucei is a parasitic protist that undergoes a complex life cycle during transmission from its mammalian host (bloodstream forms) to the midgut of its insect vector (procyclic form). In both parasitic forms, most glycolytic steps take place within specialized peroxisomes, called glycosomes. Here, we studied metabolic adaptations in procyclic trypanosome mutants affected in their maintenance of the glycosomal redox balance. T. brucei can theoretically use three strategies to maintain the glycosomal NAD(+)/NADH balance as follows: (i) the glycosomal succinic fermentation branch; (ii) the glycerol 3-phosphate (Gly-3-P)/dihydroxyacetone phosphate (DHAP) shuttle that transfers reducing equivalents to the mitochondrion; and (iii) the glycosomal glycerol production pathway. We showed a hierarchy in the use of these glycosomal NADH-consuming pathways by determining metabolic perturbations and adaptations in single and double mutant cell lines using a combination of NMR, ion chromatography-MS/MS, and HPLC approaches. Although functional, the Gly-3-P/DHAP shuttle is primarily used when the preferred succinate fermentation pathway is abolished in the Δpepck knock-out mutant cell line. In the absence of these two pathways (Δpepck/(RNAi)FAD-GPDH.i mutant), glycerol production is used but with a 16-fold reduced glycolytic flux. In addition, the Δpepck mutant cell line shows a 3.3-fold reduced glycolytic flux compensated by an increase of proline metabolism. The inability of the Δpepck mutant to maintain a high glycolytic flux demonstrates that the Gly-3-P/DHAP shuttle is not adapted to the procyclic trypanosome context. In contrast, this shuttle was shown earlier to be the only way used by the bloodstream forms of T. brucei to sustain their high glycolytic flux.

  9. Careers (A Course of Study). Unit V: Forms, Forms, Forms.

    Science.gov (United States)

    Turley, Kay

    Designed to enable special needs students to understand and complete various job-related forms, this set of activities devoted to forms encountered before and after one obtains a job is the fifth in a nine-unit secondary level careers course intended to provide handicapped students with the knowledge and tools necessary to succeed in the world of…

  10. Clinical impact of antimicrobial resistance in European hospitals: excess mortality and length of hospital stay related to methicillin-resistant Staphylococcus aureus bloodstream infections.

    LENUS (Irish Health Repository)

    de Kraker, Marlieke E A

    2011-04-01

    Antimicrobial resistance is threatening the successful management of nosocomial infections worldwide. Despite the therapeutic limitations imposed by methicillin-resistant Staphylococcus aureus (MRSA), its clinical impact is still debated. The objective of this study was to estimate the excess mortality and length of hospital stay (LOS) associated with MRSA bloodstream infections (BSI) in European hospitals. Between July 2007 and June 2008, a multicenter, prospective, parallel matched-cohort study was carried out in 13 tertiary care hospitals in as many European countries. Cohort I consisted of patients with MRSA BSI and cohort II of patients with methicillin-susceptible S. aureus (MSSA) BSI. The patients in both cohorts were matched for LOS prior to the onset of BSI with patients free of the respective BSI. Cohort I consisted of 248 MRSA patients and 453 controls and cohort II of 618 MSSA patients and 1,170 controls. Compared to the controls, MRSA patients had higher 30-day mortality (adjusted odds ratio [aOR] = 4.4) and higher hospital mortality (adjusted hazard ratio [aHR] = 3.5). Their excess LOS was 9.2 days. MSSA patients also had higher 30-day (aOR = 2.4) and hospital (aHR = 3.1) mortality and an excess LOS of 8.6 days. When the outcomes from the two cohorts were compared, an effect attributable to methicillin resistance was found for 30-day mortality (OR = 1.8; P = 0.04), but not for hospital mortality (HR = 1.1; P = 0.63) or LOS (difference = 0.6 days; P = 0.96). Irrespective of methicillin susceptibility, S. aureus BSI has a significant impact on morbidity and mortality. In addition, MRSA BSI leads to a fatal outcome more frequently than MSSA BSI. Infection control efforts in hospitals should aim to contain infections caused by both resistant and susceptible S. aureus.

  11. Prevention of Catheter-related Bloodstream Infection in ICU%ICU患者中心静脉导管相关性血流感染的预防

    Institute of Scientific and Technical Information of China (English)

    徐文

    2011-01-01

    Central venous catheter( CVC )is one of the most common technique for monitoring and treatment in ICU. But There is a risk of catheter-related bloodstream infection causing prolonged hospital stay and increased mortality. Positioning the CVC through the subclavian vein and using a antibiotic catheter can help to reduce the incidence of CRBSI. A bundle stratige is of a crucial role in CRBSI provention.It should include strict hand hygiene, sterilizing with mixture of 70% ethano and 2% chlorhexidine, maximal sterile barrier and regular dressing change. The efficiency of regular CVC replacement and of antibiotic based catheter lock solution are not clear, and are not recommended as a routine.%留置中心静脉导管是ICU中最常用的监测和治疗措施,但其同时存在发生导管相关性血流感染(CRBSI)的风险,从而导致患者住院时间延长和病死率升高.选择锁骨下穿刺径路、使用抗生素导管可减少CRBSI的发生.应用集束化预防措施进行置管及日常护理是预防CRBSI发生的重要措施,包括严格的手卫生、应用2%氯己定和70%乙醇混合液消毒皮肤、最大消毒屏障以及定期更换辅料.定期更换导管及使用抗生素封管对预防CRBSI效果不明确,不作为常规推荐.

  12. Meropenem for treating KPC-producing Klebsiella pneumoniae bloodstream infections: Should we get to the PK/PD root of the paradox?

    Science.go