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Sample records for bacterial defensin resistance

  1. A Hybrid Cationic Peptide Composed of Human β-Defensin-1 and Humanized θ-Defensin Sequences Exhibits Salt-Resistant Antimicrobial Activity

    Science.gov (United States)

    Nagaraj, Ramakrishnan; Motukupally, Swapna R.

    2014-01-01

    We have designed a hybrid peptide by combining sequences of human β-defensin-1 (HBD-1) and θ-defensin, in an attempt to generate a molecule that combines the diversity in structure and biological activity of two different peptides to yield a promising therapeutic candidate. HBD-1 was chosen as it is a natural defensin of humans that is constitutively expressed, but its antibacterial activity is considerably impaired by elevated ionic strength. θ-Defensins are expressed in human bone marrow as a pseudogene and are homologous to rhesus monkey circular minidefensins. Retrocyclins are synthetic human θ-defensins. The cyclic nature of the θ-defensin peptides makes them salt resistant, nonhemolytic, and virtually noncytotoxic in vitro. However, a nonhuman circular molecule developed for clinical use would be less viable than a linear molecule. In this study, we have fused the C-terminal region of HBD-1 to the nonapeptide sequence of a synthetic retrocyclin. Cyclization was achieved by joining the terminal ends of the hybrid peptide by a disulfide bridge. The hybrid peptide with or without the disulfide bridge exhibited enhanced antimicrobial activity against both Gram-negative and Gram-positive bacteria as well as against fungi, including clinical bacterial isolates from eye infections. The peptide retained activity in the presence of NaCl and serum and was nonhemolytic in vitro. Thus, the hybrid peptide generated holds potential as a new class of antibiotics. PMID:25348533

  2. A Defensin from the Model Beetle Tribolium castaneum Acts Synergistically with Telavancin and Daptomycin against Multidrug Resistant Staphylococcus aureus.

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    Rajmohan Rajamuthiah

    Full Text Available The red flour beetle Tribolium castaneum is a common insect pest and has been established as a model beetle to study insect development and immunity. This study demonstrates that defensin 1 from T. castaneum displays in vitro and in vivo antimicrobial activity against drug resistant Staphylococcus aureus strains. The minimum inhibitory concentration (MIC of defensin 1 against 11 reference and clinical staphylococcal isolates was between 16-64 μg/ml. The putative mode of action of the defensin peptide is disruption of the bacterial cell membrane. The antibacterial activity of defensin 1 was attenuated by salt concentrations of 1.56 mM and 25 mM for NaCl and CaCl2 respectively. Treatment of defensin 1 with the reducing agent dithiothreitol (DTT at concentrations 1.56 to 3.13 mM abolished the antimicrobial activity of the peptide. In the presence of subinhibitory concentrations of antibiotics that also target the bacterial cell envelope such as telavancin and daptomycin, the MIC of the peptide was as low as 1 μg/ml. Moreover, when tested against an S. aureus strain that was defective in D-alanylation of the cell wall, the MIC of the peptide was 0.5 μg/ml. Defensin 1 exhibited no toxicity against human erythrocytes even at 400 μg/ml. The in vivo activity of the peptide was validated in a Caenorhabditis elegans-MRSA liquid infection assay. These results suggest that defensin 1 behaves similarly to other cationic AMPs in its mode of action against S. aureus and that the activity of the peptide can be enhanced in combination with other antibiotics with similar modes of action or with compounds that have the ability to decrease D-alanylation of the bacterial cell wall.

  3. A Defensin from the Model Beetle Tribolium castaneum Acts Synergistically with Telavancin and Daptomycin against Multidrug Resistant Staphylococcus aureus.

    Science.gov (United States)

    Rajamuthiah, Rajmohan; Jayamani, Elamparithi; Conery, Annie L; Fuchs, Beth Burgwyn; Kim, Wooseong; Johnston, Tatiana; Vilcinskas, Andreas; Ausubel, Frederick M; Mylonakis, Eleftherios

    2015-01-01

    The red flour beetle Tribolium castaneum is a common insect pest and has been established as a model beetle to study insect development and immunity. This study demonstrates that defensin 1 from T. castaneum displays in vitro and in vivo antimicrobial activity against drug resistant Staphylococcus aureus strains. The minimum inhibitory concentration (MIC) of defensin 1 against 11 reference and clinical staphylococcal isolates was between 16-64 μg/ml. The putative mode of action of the defensin peptide is disruption of the bacterial cell membrane. The antibacterial activity of defensin 1 was attenuated by salt concentrations of 1.56 mM and 25 mM for NaCl and CaCl2 respectively. Treatment of defensin 1 with the reducing agent dithiothreitol (DTT) at concentrations 1.56 to 3.13 mM abolished the antimicrobial activity of the peptide. In the presence of subinhibitory concentrations of antibiotics that also target the bacterial cell envelope such as telavancin and daptomycin, the MIC of the peptide was as low as 1 μg/ml. Moreover, when tested against an S. aureus strain that was defective in D-alanylation of the cell wall, the MIC of the peptide was 0.5 μg/ml. Defensin 1 exhibited no toxicity against human erythrocytes even at 400 μg/ml. The in vivo activity of the peptide was validated in a Caenorhabditis elegans-MRSA liquid infection assay. These results suggest that defensin 1 behaves similarly to other cationic AMPs in its mode of action against S. aureus and that the activity of the peptide can be enhanced in combination with other antibiotics with similar modes of action or with compounds that have the ability to decrease D-alanylation of the bacterial cell wall.

  4. Staphylococcus aureus resistance to human defensins and evasion of neutrophil killing via the novel virulence factor MprF is based on modification of membrane lipids with L-lysine

    NARCIS (Netherlands)

    Peschel, A.; Jack, R.W.; Otto, M.; Collins, L.V.; Staubitz, P.; Nicholson, G.; Kalbacher, H.; Nieuwenhuizen, W.F.; Jung, G.; Tarkowski, A.; Kessel, K.P.M. van; Strijp, J.A.G. van

    2001-01-01

    Defensins, antimicrobial peptides of the innate immune system, protect human mucosal epithelia and skin against microbial infections and are produced in large amounts by neutrophils. The bacterial pathogen Staphylococcus aureus is insensitive to defensins by virtue of an unknown resistance mechanism

  5. Phosphoethanolamine Transferase LptA in Haemophilus ducreyi Modifies Lipid A and Contributes to Human Defensin Resistance In Vitro.

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    Michael P Trombley

    Full Text Available Haemophilus ducreyi resists the cytotoxic effects of human antimicrobial peptides (APs, including α-defensins, β-defensins, and the cathelicidin LL-37. Resistance to LL-37, mediated by the sensitive to antimicrobial peptide (Sap transporter, is required for H. ducreyi virulence in humans. Cationic APs are attracted to the negatively charged bacterial cell surface. In other gram-negative bacteria, modification of lipopolysaccharide or lipooligosaccharide (LOS by the addition of positively charged moieties, such as phosphoethanolamine (PEA, confers AP resistance by means of electrostatic repulsion. H. ducreyi LOS has PEA modifications at two sites, and we identified three genes (lptA, ptdA, and ptdB in H. ducreyi with homology to a family of bacterial PEA transferases. We generated non-polar, unmarked mutants with deletions in one, two, or all three putative PEA transferase genes. The triple mutant was significantly more susceptible to both α- and β-defensins; complementation of all three genes restored parental levels of AP resistance. Deletion of all three PEA transferase genes also resulted in a significant increase in the negativity of the mutant cell surface. Mass spectrometric analysis revealed that LptA was required for PEA modification of lipid A; PtdA and PtdB did not affect PEA modification of LOS. In human inoculation experiments, the triple mutant was as virulent as its parent strain. While this is the first identified mechanism of resistance to α-defensins in H. ducreyi, our in vivo data suggest that resistance to cathelicidin LL-37 may be more important than defensin resistance to H. ducreyi pathogenesis.

  6. Plectasin, a Fungal Defensin, Targets the Bacterial Cell Wall Precursor Lipid II

    DEFF Research Database (Denmark)

    Schneider, Tanja; Kruse, Thomas; Wimmer, Reinhard;

    2010-01-01

    that plectasin, a fungal defensin, acts by directly binding the bacterial cell-wall precursor Lipid II. A wide range of genetic and biochemical approaches identify cell-wall biosynthesis as the pathway targeted by plectasin. In vitro assays for cell-wall synthesis identified Lipid II as the specific cellular...

  7. Defensins: antifungal lessons from eukaryotes

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    Patrícia M. Silva

    2014-03-01

    Full Text Available Over the last years, antimicrobial peptides (AMPs have been the focus of intense research towards the finding of a viable alternative to current antifungal drugs. Defensins are one of the major families of AMPs and the most represented among all eukaryotic groups, providing an important first line of host defense against pathogenic microorganisms. Several of these cysteine-stabilized peptides present a relevant effect against fungi. Defensins are the AMPs with the broader distribution across all eukaryotic kingdoms, namely, Fungi, Plantæ and Animalia, and were recently shown to have an ancestor in a bacterial organism. As a part of the host defense, defensins act as an important vehicle of information between innate and adaptive immune system and have a role in immunomodulation. This multidimensionality represents a powerful host shield, hard for microorganisms to overcome using single approach resistance strategies. Pathogenic fungi resistance to conventional antimycotic drugs is becoming a major problem. Defensins, as other AMPs, have shown to be an effective alternative to the current antimycotic therapies, demonstrating potential as novel therapeutic agents or drug leads. In this review, we summarize the current knowledge on some eukaryotic defensins with antifungal action. An overview of the main targets in the fungal cell and the mechanism of action of these AMPs (namely, the selectivity for some fungal membrane components are presented. Additionally, recent works on antifungal defensins structure, activity and citotoxicity are also reviewed.

  8. Petunia floral defensins with unique prodomains as novel candidates for development of fusarium wilt resistance in transgenic banana plants.

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    Siddhesh B Ghag

    Full Text Available Antimicrobial peptides are a potent group of defense active molecules that have been utilized in developing resistance against a multitude of plant pathogens. Floral defensins constitute a group of cysteine-rich peptides showing potent growth inhibition of pathogenic filamentous fungi especially Fusarium oxysporum in vitro. Full length genes coding for two Petunia floral defensins, PhDef1 and PhDef2 having unique C-terminal 31 and 27 amino acid long predicted prodomains, were overexpressed in transgenic banana plants using embryogenic cells as explants for Agrobacterium-mediated genetic transformation. High level constitutive expression of these defensins in elite banana cv. Rasthali led to significant resistance against infection of Fusarium oxysporum f. sp. cubense as shown by in vitro and ex vivo bioassay studies. Transgenic banana lines expressing either of the two defensins were clearly less chlorotic and had significantly less infestation and discoloration in the vital corm region of the plant as compared to untransformed controls. Transgenic banana plants expressing high level of full-length PhDef1 and PhDef2 were phenotypically normal and no stunting was observed. In conclusion, our results suggest that high-level constitutive expression of floral defensins having distinctive prodomains is an efficient strategy for development of fungal resistance in economically important fruit crops like banana.

  9. The cold-induced defensin TAD1 confers resistance against snow mold and Fusarium head blight in transgenic wheat.

    Science.gov (United States)

    Sasaki, Kentaro; Kuwabara, Chikako; Umeki, Natsuki; Fujioka, Mari; Saburi, Wataru; Matsui, Hirokazu; Abe, Fumitaka; Imai, Ryozo

    2016-06-20

    TAD1 (Triticum aestivum defensin 1) is induced during cold acclimation in winter wheat and encodes a plant defensin with antimicrobial activity. In this study, we demonstrated that recombinant TAD1 protein inhibits hyphal growth of the snow mold fungus, Typhula ishikariensis in vitro. Transgenic wheat plants overexpressing TAD1 were created and tested for resistance against T. ishikariensis. Leaf inoculation assays revealed that overexpression of TAD1 confers resistance against the snow mold. In addition, the TAD1-overexpressors showed resistance against Fusarium graminearum, which causes Fusarium head blight, a devastating disease in wheat and barley. These results indicate that TAD1 is a candidate gene to improve resistance against multiple fungal diseases in cereal crops.

  10. Ectopic expression of Dahlia merckii defensin DmAMP1 improves papaya resistance to Phytophthora palmivora by reducing pathogen vigor.

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    Zhu, Yun J; Agbayani, Ricelle; Moore, Paul H

    2007-06-01

    Phytophthora spp., some of the more important casual agents of plant diseases, are responsible for heavy economic losses worldwide. Plant defensins have been introduced as transgenes into a range of species to increase host resistance to pathogens to which they were originally susceptible. However, the effectiveness and mechanism of interaction of the defensins with Phytophthora spp. have not been clearly characterized in planta. In this study, we expressed the Dahlia merckii defensin, DmAMP1, in papaya (Carica papaya L.), a plant highly susceptible to a root, stem, and fruit rot disease caused by Phytophthora palmivora. Extracts of total leaf proteins from transformed plants inhibited growth of Phytophthora in vitro and discs cut from the leaves of transformed plants inhibited growth of Phytophthora in a bioassay. Results from our greenhouse inoculation experiments demonstrate that expressing the DmAMP1 gene in papaya plants increased resistance against P. palmivora and that this increased resistance was associated with reduced hyphae growth of P. palmivora at the infection sites. The inhibitory effects of DmAMP1 expression in papaya suggest this approach has good potential to impart transgenic resistance against Phytophthora in papaya. PMID:17216480

  11. The Unusual Resistance of Avian Defensin AvBD7 to Proteolytic Enzymes Preserves Its Antibacterial Activity.

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    Bailleul, Geoffrey; Kravtzoff, Amanda; Joulin-Giet, Alix; Lecaille, Fabien; Labas, Valérie; Meudal, Hervé; Loth, Karine; Teixeira-Gomes, Ana-Paula; Gilbert, Florence B; Coquet, Laurent; Jouenne, Thierry; Brömme, Dieter; Schouler, Catherine; Landon, Céline; Lalmanach, Gilles; Lalmanach, Anne-Christine

    2016-01-01

    Defensins are frontline peptides of mucosal immunity in the animal kingdom, including birds. Their resistance to proteolysis and their ensuing ability to maintain antimicrobial potential remains questionable and was therefore investigated. We have shown by bottom-up mass spectrometry analysis of protein extracts that both avian beta-defensins AvBD2 and AvBD7 were ubiquitously distributed along the chicken gut. Cathepsin B was found by immunoblotting in jejunum, ileum, caecum, and caecal tonsils, while cathepsins K, L, and S were merely identified in caecal tonsils. Hydrolysis product of AvBD2 and AvBD7 incubated with a panel of proteases was analysed by RP-HPLC, mass spectrometry and antimicrobial assays. AvBD2 and AvBD7 were resistant to serine proteases and to cathepsins D and H. Conversely cysteine cathepsins B, K, L, and S degraded AvBD2 and abolished its antibacterial activity. Only cathepsin K cleaved AvBD7 and released Ile4-AvBD7, a N-terminal truncated natural peptidoform of AvBD7 that displayed antibacterial activity. Besides the 3-stranded antiparallel beta-sheet typical of beta-defensins, structural analysis of AvBD7 by two-dimensional NMR spectroscopy highlighted the restricted accessibility of the C-terminus embedded by the N-terminal region and gave a formal evidence of a salt bridge (Asp9-Arg12) that could account for proteolysis resistance. The differential susceptibility of avian defensins to proteolysis opens intriguing questions about a distinctive role in the mucosal immunity against pathogen invasion. PMID:27561012

  12. The Unusual Resistance of Avian Defensin AvBD7 to Proteolytic Enzymes Preserves Its Antibacterial Activity

    Science.gov (United States)

    Bailleul, Geoffrey; Kravtzoff, Amanda; Joulin-Giet, Alix; Lecaille, Fabien; Labas, Valérie; Meudal, Hervé; Loth, Karine; Teixeira-Gomes, Ana-Paula; Gilbert, Florence B.; Coquet, Laurent; Jouenne, Thierry; Brömme, Dieter; Schouler, Catherine; Landon, Céline; Lalmanach, Gilles; Lalmanach, Anne-Christine

    2016-01-01

    Defensins are frontline peptides of mucosal immunity in the animal kingdom, including birds. Their resistance to proteolysis and their ensuing ability to maintain antimicrobial potential remains questionable and was therefore investigated. We have shown by bottom-up mass spectrometry analysis of protein extracts that both avian beta-defensins AvBD2 and AvBD7 were ubiquitously distributed along the chicken gut. Cathepsin B was found by immunoblotting in jejunum, ileum, caecum, and caecal tonsils, while cathepsins K, L, and S were merely identified in caecal tonsils. Hydrolysis product of AvBD2 and AvBD7 incubated with a panel of proteases was analysed by RP-HPLC, mass spectrometry and antimicrobial assays. AvBD2 and AvBD7 were resistant to serine proteases and to cathepsins D and H. Conversely cysteine cathepsins B, K, L, and S degraded AvBD2 and abolished its antibacterial activity. Only cathepsin K cleaved AvBD7 and released Ile4-AvBD7, a N-terminal truncated natural peptidoform of AvBD7 that displayed antibacterial activity. Besides the 3-stranded antiparallel beta-sheet typical of beta-defensins, structural analysis of AvBD7 by two-dimensional NMR spectroscopy highlighted the restricted accessibility of the C-terminus embedded by the N-terminal region and gave a formal evidence of a salt bridge (Asp9-Arg12) that could account for proteolysis resistance. The differential susceptibility of avian defensins to proteolysis opens intriguing questions about a distinctive role in the mucosal immunity against pathogen invasion. PMID:27561012

  13. Overexpression of a defensin enhances resistance to a fruit-specific anthracnose fungus in pepper.

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    Hyo-Hyoun Seo

    Full Text Available Functional characterization of a defensin, J1-1, was conducted to evaluate its biotechnological potentiality in transgenic pepper plants against the causal agent of anthracnose disease, Colletotrichum gloeosporioides. To determine antifungal activity, J1-1 recombinant protein was generated and tested for the activity against C. gloeosporioides, resulting in 50% inhibition of fungal growth at a protein concentration of 0.1 mg·mL-1. To develop transgenic pepper plants resistant to anthracnose disease, J1-1 cDNA under the control of 35S promoter was introduced into pepper via Agrobacterium-mediated genetic transformation method. Southern and Northern blot analyses confirmed that a single copy of the transgene in selected transgenic plants was normally expressed and also stably transmitted to subsequent generations. The insertion of T-DNA was further analyzed in three independent homozygous lines using inverse PCR, and confirmed the integration of transgene in non-coding region of genomic DNA. Immunoblot results showed that the level of J1-1 proteins, which was not normally accumulated in unripe fruits, accumulated high in transgenic plants but appeared to differ among transgenic lines. Moreover, the expression of jasmonic acid-biosynthetic genes and pathogenesis-related genes were up-regulated in the transgenic lines, which is co-related with the resistance of J1-1 transgenic plants to anthracnose disease. Consequently, the constitutive expression of J1-1 in transgenic pepper plants provided strong resistance to the anthracnose fungus that was associated with highly reduced lesion formation and fungal colonization. These results implied the significance of the antifungal protein, J1-1, as a useful agronomic trait to control fungal disease.

  14. Antibiotic resistance of bacterial biofilms

    DEFF Research Database (Denmark)

    Hoiby, N.; Bjarnsholt, T.; Givskov, M.;

    2010-01-01

    A biofilm is a structured consortium of bacteria embedded in a self-produced polymer matrix consisting of polysaccharide, protein and DNA. Bacterial biofilms cause chronic infections because they show increased tolerance to antibiotics and disinfectant chemicals as well as resisting phagocytosis...... and other components of the body's defence system. The persistence of, for example, staphylococcal infections related to foreign bodies is due to biofilm formation. Likewise, chronic Pseudomonas aeruginosa lung infection in cystic fibrosis patients is caused by biofilm-growing mucoid strains....... Characteristically, gradients of nutrients and oxygen exist from the top to the bottom of biofilms and these gradients are associated with decreased bacterial metabolic activity and increased doubling times of the bacterial cells; it is these more or less dormant cells that are responsible for some of the tolerance...

  15. 防御素的生物学特性及其抗病基因工程%Biological characteristics of defensin and its disease-resistance genetic engineering

    Institute of Scientific and Technical Information of China (English)

    付蓝宝; 于嘉林; 刘伟华

    2011-01-01

    防御素是一种富含半胱氨酸的小分子多肽,对细菌等微生物具有广谱抗性,且作用机制特殊.迄今为止,国内外在防御素方面进行了大量的研究,已经从各类生物体中分离出不同种类的防御素.并在基因工程和医药领域呈现广泛的应用前景.文章对防御素的分类、生物学特性,包括哺乳动物α-、β-、θ-防御素、昆虫以及植物防御素的分子结构及抗菌活性进行了综述,阐述了防御素的膜作用及与细胞内复合物结合的作用机制.总结和归纳了防御素基因的分离、表达研究进展及动、植物防御素基因在抗病基因工程领域的应用,并对防御素在未来的生物制药和植物抗病基因工程方面的应用前景进行了展望.%Defensin is a kind of cysteine-rich small peptide, which has a broad spectrum of resistance to bacteria with a special resistance mechanism.So far, a large number of studies on defensins have been reported, and the different types of defensins have been isolated from various organisms.A broad prospect of application on defensins has been displayed both in genetic engineering and medicine field.This article reviewed the classification and the biological characteristics of defensins, including mammalian α-, β-, θ-defensins, insect defensins, and plant defensins.The molecular structures,antibacterial activities, and antibacterial mechanisms of these definsins were summarized.The two mechanisms of defensin, including independent membrane mechanism and targeting of intracellular compounds by defensins, are expounded.This paper also summarized the researches on isolation and expression of defensin genes and disease resistance genetic engineering of mammal and plant defensins.A prospect of the future applications of defensin both in biopharmaceutical sciences and plant disease resistance genetic engineering was discussed.

  16. Retransformation of marker-free potato for enhanced resistance against fungal pathogens by pyramiding chitinase and wasabi defensin genes.

    Science.gov (United States)

    Khan, Raham Sher; Darwish, Nader Ahmed; Khattak, Bushra; Ntui, Valentine Otang; Kong, Kynet; Shimomae, Kazuki; Nakamura, Ikuo; Mii, Masahiro

    2014-09-01

    Multi-auto-transformation vector system has been one of the strategies to produce marker-free transgenic plants without using selective chemicals and plant growth regulators and thus facilitating transgene stacking. In the study reported here, retransformation was carried out in marker-free transgenic potato CV. May Queen containing ChiC gene (isolated from Streptomyces griseus strain HUT 6037) with wasabi defensin (WD) gene (isolated from Wasabia japonica) to pyramid the two disease resistant genes. Molecular analyses of the developed shoots confirmed the existence of both the genes of interest (ChiC and WD) in transgenic plants. Co-expression of the genes was confirmed by RT-PCR, northern blot, and western blot analyses. Disease resistance assay of in vitro plants showed that the transgenic lines co-expressing both the ChiC and WD genes had higher resistance against the fungal pathogens, Fusarium oxysporum (Fusarium wilt) and Alternaria solani (early blight) compared to the non-transformed control and the transgenic lines expressing either of the ChiC or WD genes. The disease resistance potential of the transgenic plants could be increased by transgene stacking or multiple transformations. PMID:24802621

  17. Modelling study of dimerization in mammalian defensins

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    Verma Chandra

    2006-12-01

    Full Text Available Abstract Background Defensins are antimicrobial peptides of innate immunity functioning by non-specific binding to anionic phospholipids in bacterial membranes. Their cationicity, amphipathicity and ability to oligomerize are considered key factors for their action. Based on structural information on human β-defensin 2, we examine homologous defensins from various mammalian species for conserved functional physico-chemical characteristics. Results Based on homology greater than 40%, structural models of 8 homologs of HBD-2 were constructed. A conserved pattern of electrostatics and dynamics was observed across 6 of the examined defensins; models backed by energetics suggest that the defensins in these 6 organisms are characterized by dimerization-linked enhanced functional potentials. In contrast, dimerization is not energetically favoured in the sheep, goat and mouse defensins, suggesting that they function efficiently as monomers. Conclusion β-defensin 2 from some mammals may work as monomers while those in others, including humans, work as oligomers. This could potentially be used to design human defensins that may be effective at lower concentrations and hence have therapeutic benefits.

  18. Antifungal defensins and their role in plant defense.

    Science.gov (United States)

    Lacerda, Ariane F; Vasconcelos, Erico A R; Pelegrini, Patrícia Barbosa; Grossi de Sa, Maria F

    2014-01-01

    Since the beginning of the 90s lots of cationic plant, cysteine-rich antimicrobial peptides (AMP) have been studied. However, Broekaert et al. (1995) only coined the term "plant defensin," after comparison of a new class of plant antifungal peptides with known insect defensins. From there, many plant defensins have been reported and studies on this class of peptides encompass its activity toward microorganisms and molecular features of the mechanism of action against bacteria and fungi. Plant defensins also have been tested as biotechnological tools to improve crop production through fungi resistance generation in organisms genetically modified (OGM). Its low effective concentration towards fungi, ranging from 0.1 to 10 μM and its safety to mammals and birds makes them a better choice, in place of chemicals, to control fungi infection on crop fields. Herein, is a review of the history of plant defensins since their discovery at the beginning of 90s, following the advances on its structure conformation and mechanism of action towards microorganisms is reported. This review also points out some important topics, including: (i) the most studied plant defensins and their fungal targets; (ii) the molecular features of plant defensins and their relation with antifungal activity; (iii) the possibility of using plant defensin(s) genes to generate fungi resistant GM crops and biofungicides; and (iv) a brief discussion about the absence of products in the market containing plant antifungal defensins.

  19. Antifungal defensins and their role in plant defense

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    Ariane eLacerda

    2014-04-01

    Full Text Available Since the beginning of the 90’s lots of cationic plant, cysteine-rich antimicrobial peptides (AMP have been studied. However, Broekaert only coined the term plant defensin in 1995, after comparison of a new class of plant antifungal peptides with known insect defensins. From there, many plant defensins have been reported and studies on this class of peptides encompass its activity towards microorganisms and molecular features of the mechanism of action against bacteria and fungi. Plant defensins also have been tested as biotechnological tools to improve crop production through fungi resistance generation in organisms genetically modified (OGM. Its low effective concentration towards fungi, ranging from 0.1 to 10 µM and its safety to mammals and birds makes them a better choice, in place of chemicals, to control fungi infection on crop fields. Herein, is a review of the history of plant defensins since their discovery at the beginning of 90’s, following the advances on its structure conformation and mechanism of action towards microorganisms is reported. This review also points out some important topics, including: (i the most studied plant defensins and their fungal targets; (ii the molecular features of plant defensins and their relation with antifungal activity; (iii the possibility of using plant defensin(s genes to generate fungi resistant GM crops and biofungicides; and (iv a brief discussion about the absence of products in the market containing plant antifungal defensins.

  20. Dielectrophoretic assay of bacterial resistance to antibiotics

    Energy Technology Data Exchange (ETDEWEB)

    Johari, Juliana [School of Engineering, University of Surrey, Guildford, Surrey, GU2 7XH, UK (United Kingdom); Huebner, Yvonne [School of Engineering, University of Surrey, Guildford, Surrey, GU2 7XH, UK (United Kingdom); Hull, Judith C [School of Engineering, University of Surrey, Guildford, Surrey, GU2 7XH, UK (United Kingdom); Dale, Jeremy W [School of Biomedical and Life Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK (United Kingdom); Hughes, Michael P [School of Engineering, University of Surrey, Guildford, Surrey, GU2 7XH, UK (United Kingdom)

    2003-07-21

    The dielectrophoretic collection spectra of antibiotic-sensitive and antibiotic-resistant strains of Staphylococcus epidermidis have been determined. These indicate that in the absence of antibiotic treatment there is a strong similarity between the dielectric properties of sensitive and resistant strains, and that there is a significant difference between the sensitive strains before and after treatment with the antibiotic streptomycin after 24 h exposure. This method offers possibilities for the assessment of bacterial resistance to antibiotics. (note)

  1. Whole blood defensin mRNA expression is a predictive biomarker of docetaxel response in castration-resistant prostate cancer

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    Kohli M

    2015-07-01

    Full Text Available Manish Kohli,1 Charles YF Young,2 Donald J Tindall,2 Debashis Nandy,1 Kyle M McKenzie,3 Graham H Bevan,4 Krishna Vanaja Donkena5 1Department of Oncology, 2Department of Urology, 3Department of Geriatric Medicine, Mayo Clinic, Rochester, MN, 4University of Rochester Medical Center, Rochester, NY, 5Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA Abstract: This study tested the potential of circulating RNA-based signals as predictive biomarkers for docetaxel response in patients with metastatic castration-resistant prostate cancer (CRPC. RNA was analyzed in blood from six CRPC patients by whole-transcriptome sequencing (total RNA-sequencing before and after docetaxel treatment using the Illumina’s HiSeq platform. Targeted RNA capture and sequencing was performed in an independent cohort of ten patients with CRPC matching the discovery cohort to confirm differential expression of the genes. Response to docetaxel was defined on the basis of prostate-specific antigen levels and imaging criteria. Two-way analysis of variance was used to compare differential gene expression in patients classified as responders versus nonresponders before and after docetaxel treatment. Thirty-four genes with two-fold differentially expressed transcripts in responders versus nonresponders were selected from total RNA-sequencing for further validation. Targeted RNA capture and sequencing showed that 13/34 genes were differentially expressed in responders. Alpha defensin genes DEFA1, DEFA1B, and DEFA3 exhibited significantly higher expression in responder patients compared with nonresponder patients before administration of chemotherapy (fold change >2.5. In addition, post-docetaxel treatment significantly increased transcript levels of these defensin genes in responders (fold change >2.8. Our results reveal that patients with higher defensin RNA transcripts in blood respond well to docetaxel therapy. We suggest that monitoring DEFA1, DEFA1B, and DEFA3

  2. Antibiotic resistance in ocular bacterial pathogens

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    S Sharma

    2011-01-01

    Full Text Available Bacterial infections of the eye are common and ophthalmologists are spoilt for choice with a variety of antibiotics available in the market. Antibiotics can be administered in the eye by a number of routes; topical, subconjunctival, subtenon and intraocular. Apart from a gamut of eye drops available, ophthalmologists also have the option of preparing fortified eye drops from parenteral formulations, thereby, achieving high concentrations; often much above the minimum inhibitory concentration (MIC, of antibiotics in ocular tissues during therapy. Antibiotic resistance among ocular pathogens is increasing in parallel with the increase seen over the years in bacteria associated with systemic infections. Although it is believed that the rise in resistant ocular bacterial isolates is linked to the rise in resistant systemic pathogens, recent evidence has correlated the emergence of resistant bacteria in the eye to prior topical antibiotic therapy. One would like to believe that either of these contributes to the emergence of resistance to antibiotics among ocular pathogens. Until recently, ocular pathogens resistant to fluoroquinolones have been minimal but the pattern is currently alarming. The new 8-fluoroquinolone on the scene-besifloxacin, is developed exclusively for ophthalmic use and it is hoped that it will escape the selective pressure for resistance because of lack of systemic use. In addition to development of new antibacterial agents, the strategies to halt or control further development of resistant ocular pathogens should always include judicious use of antibiotics in the treatment of human, animal or plant diseases.

  3. Identification, phylogenetic analysis and expression profile of an anionic insect defensin gene, with antibacterial activity, from bacterial-challenged cotton leafworm, Spodoptera littoralis

    OpenAIRE

    Seufi AlaaEddeen M; Hafez Elsayed E; Galal Fatma H

    2011-01-01

    Abstract Background Defensins are a well known family of cationic antibacterial peptides (AMPs) isolated from fungi, plants, insects, mussels, birds, and various mammals. They are predominantly active against gram (+) bacteria, and a few of them are also active against gram (-) bacteria and fungi. All insect defensins belonging to the invertebrate class have a consensus motif, C-X5-16-C-X3-C-X9-10-C-X4-7-CX1-C. Only seven AMPs have already been found in different lepidopteran species. No repo...

  4. Defensins: natural component of human innate immunity.

    Science.gov (United States)

    Jarczak, Justyna; Kościuczuk, Ewa M; Lisowski, Paweł; Strzałkowska, Nina; Jóźwik, Artur; Horbańczuk, Jarosław; Krzyżewski, Józef; Zwierzchowski, Lech; Bagnicka, Emilia

    2013-09-01

    The widespread use of antibiotics has contributed to a huge increase in the number of resistant bacteria. New classes of drugs are therefore being developed of which defensins are a potential source. Defensins are a group of antimicrobial peptides found in different living organisms, involved in the first line of defense in their innate immune response against pathogens. This review summarizes the results of studies of this family of human antimicrobial peptides (AMPs). There is a special emphasis on describing the entire group and individual peptides, history of their discovery, their functions and expression sites. The results of the recent studies on the use of the biologically active peptides in human medicine are also presented. The pharmaceutical potential of human defensins cannot be ignored, especially considering their strong antimicrobial activity and properties such as low molecular weight, reduced immunogenicity, broad activity spectrum and resistance to proteolysis, but there are still many challenges and questions regarding the possibilities of their practical application.

  5. Bacterial Enzymes and Antibiotic Resistance- Oral Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Maltz, Lauren [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-25

    By using protein crystallography and X-ray diffraction, structures of bacterial enzymes were solved to gain a better understanding of how enzymatic modification acts as an antibacterial resistance mechanism. Aminoglycoside phosphotransferases (APHs) are one of three aminoglycoside modifying enzymes that confer resistance to the aminoglycoside antibiotics via enzymatic modification, rendering many drugs obsolete. Specifically, the APH(2”) family vary in their substrate specificities and also in their preference for the phosphate donor (ADP versus GDP). By solving the structures of members of the APH(2”) family of enzymes, we can see how domain movements are important to their substrate specificity. Our structure of the ternary complex of APH(2”)-IIIa with GDP and kanamycin, when compared to the known structures of APH(2”)-IVa, reveals that there are real physical differences between these two enzymes, a structural finding that explains why the two enzymes differ in their preferences for certain aminoglycosides. Another important group of bacterial resistance enzymes are the Class D β-lactamases. Oxacillinase carbapenemases (OXAs) are part of this enzyme class and have begun to confer resistance to ‘last resort’ drugs, most notably carbapenems. Our structure of OXA-143 shows that the conformational flexibility of a conserved hydrophobic residue in the active site (Val130) serves to control the entry of a transient water molecule responsible for a key step in the enzyme’s mechanism. Our results provide insight into the structural mechanisms of these two different enzymes.

  6. Novel anti-bacterial activities of β-defensin 1 in human platelets: suppression of pathogen growth and signaling of neutrophil extracellular trap formation.

    Directory of Open Access Journals (Sweden)

    Bjoern F Kraemer

    2011-11-01

    Full Text Available Human β-defensins (hBD are antimicrobial peptides that curb microbial activity. Although hBD's are primarily expressed by epithelial cells, we show that human platelets express hBD-1 that has both predicted and novel antibacterial activities. We observed that activated platelets surround Staphylococcus aureus (S. aureus, forcing the pathogens into clusters that have a reduced growth rate compared to S. aureus alone. Given the microbicidal activity of β-defensins, we determined whether hBD family members were present in platelets and found mRNA and protein for hBD-1. We also established that hBD-1 protein resided in extragranular cytoplasmic compartments of platelets. Consistent with this localization pattern, agonists that elicit granular secretion by platelets did not readily induce hBD-1 release. Nevertheless, platelets released hBD-1 when they were stimulated by α-toxin, a S. aureus product that permeabilizes target cells. Platelet-derived hBD-1 significantly impaired the growth of clinical strains of S. aureus. hBD-1 also induced robust neutrophil extracellular trap (NET formation by target polymorphonuclear leukocytes (PMNs, which is a novel antimicrobial function of β-defensins that was not previously identified. Taken together, these data demonstrate that hBD-1 is a previously-unrecognized component of platelets that displays classic antimicrobial activity and, in addition, signals PMNs to extrude DNA lattices that capture and kill bacteria.

  7. Interaction of Defensins with Model Cell Membranes

    Science.gov (United States)

    Sanders, Lori K.; Schmidt, Nathan W.; Yang, Lihua; Mishra, Abhijit; Gordon, Vernita D.; Selsted, Michael E.; Wong, Gerard C. L.

    2009-03-01

    Antimicrobial peptides (AMPs) comprise a key component of innate immunity for a wide range of multicellular organisms. For many AMPs, activity comes from their ability to selectively disrupt and lyse bacterial cell membranes. There are a number of proposed models for this action, but the detailed molecular mechanism of selective membrane permeation remains unclear. Theta defensins are circularized peptides with a high degree of selectivity. We investigate the interaction of model bacterial and eukaryotic cell membranes with theta defensins RTD-1, BTD-7, and compare them to protegrin PG-1, a prototypical AMP, using synchrotron small angle x-ray scattering (SAXS). The relationship between membrane composition and peptide induced changes in membrane curvature and topology is examined. By comparing the membrane phase behavior induced by these different peptides we will discuss the importance of amino acid composition and placement on membrane rearrangement.

  8. Bacterial Gibberellins Induce Systemic Resistance of Plants

    Directory of Open Access Journals (Sweden)

    I. N. FEKLISTOVA

    2014-06-01

    Full Text Available It is generally agreed today that some rhizosphere bacteria can ensure induced systemic resistance to pathogens. In this paper we tested the ability of gibberellins produced by rhizosphere non-pathogenic bacteria Pseudomonas aurantiaca to induce systemic resistance to alternariosis agent – Alternaria brassicicola – in oilseed rape plants.Oilseed rape (Brássica nápus is one of the most promising oil-bearing croppers. It allows improving the supply of population with vegetable oil, animal and poultry industries with high quality vegetable protein. It is used for biofuel production as well.Gibberellin preparation was isolated from liquid culture of strain Pseudomonas aurantiaca grown in 250 mL of M9 medium (48 h, 28 °C under darkroom conditions. Gibberellins were extracted according procedure described by Tien et al. (1979. Gibberellins concentration in the medium was determined by fluorometric method.Elicitor activity of bacterial metabolites – gibberellins – was analyzed in model system of artificial inoculation of oilseed rape germs with phytopathogenic fungi Alternaria brassicicola. The elicitor action efficiency was evaluated on the 15th day of oilseed rape cultivation based on the percentage of leaf surface covered by necrotic lesions.Gibberellins were shown to induce systemic resistance resulted in decreasing of oil seed plants   vulnerability by 52.7%.It is known that under the unfavorable conditions plants synthesis the reactive oxygen intermediates   which activate destructive processes. One of the first organism reactions to stress action is the change of the lipid peroxidation level. It was shown that treatment of the soil with gibberellins resulted in decreasing of the lipid peroxidation level twofold.Gibberellins were shown to have a similar effect on permeability of cell membranes for free nucleotides. The permeability of cell membranes in leaves decreased 2.8-fold at room temperature. We suggest that gibberellins

  9. Bacterial and archaeal resistance to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Confalonieri, F; Sommer, S, E-mail: fabrice.confalonieri@u-psud.fr, E-mail: suzanne.sommer@u-psud.fr [University Paris-Sud, CNRS UMR8621, Institut de Genetique et Microbiologie, Batiments 400-409, Universite Paris-Sud, 91405 Orsay (France)

    2011-01-01

    Organisms living in extreme environments must cope with large fluctuations of temperature, high levels of radiation and/or desiccation, conditions that can induce DNA damage ranging from base modifications to DNA double-strand breaks. The bacterium Deinococcus radiodurans is known for its resistance to extremely high doses of ionizing radiation and for its ability to reconstruct a functional genome from hundreds of radiation-induced chromosomal fragments. Recently, extreme ionizing radiation resistance was also generated by directed evolution of an apparently radiation-sensitive bacterial species, Escherichia coli. Radioresistant organisms are not only found among the Eubacteria but also among the Archaea that represent the third kingdom of life. They present a set of particular features that differentiate them from the Eubacteria and eukaryotes. Moreover, Archaea are often isolated from extreme environments where they live under severe conditions of temperature, pressure, pH, salts or toxic compounds that are lethal for the large majority of living organisms. Thus, Archaea offer the opportunity to understand how cells are able to cope with such harsh conditions. Among them, the halophilic archaeon Halobacterium sp and several Pyrococcus or Thermococcus species, such as Thermococcus gammatolerans, were also shown to display high level of radiation resistance. The dispersion, in the phylogenetic tree, of radioresistant prokaryotes suggests that they have independently acquired radioresistance. Different strategies were selected during evolution including several mechanisms of radiation byproduct detoxification and subtle cellular metabolism modifications to help cells recover from radiation-induced injuries, protection of proteins against oxidation, an efficient DNA repair tool box, an original pathway of DNA double-strand break repair, a condensed nucleoid that may prevent the dispersion of the DNA fragments and specific radiation-induced proteins involved in

  10. Targeting bacterial topoisomerases: how to counter mechanisms of resistance.

    Science.gov (United States)

    Tse-Dinh, Yuk-Ching

    2016-06-01

    DNA gyrase and topoisomerase IV are type IIA bacterial topoisomerases that are targeted by highly effective antibiotics. However, resistance via multiple mechanisms arises to limit the efficacies of these drugs. Continued research on type IIA bacterial topoisomerases has provided novel approaches to counter the most common resistance mechanism for utilization of these proven targets in antibacterial therapy. Bacterial topoisomerase I is being explored as an alternative target that is not expected to show cross-resistance. Dual targeting or combination therapy could be strategies for circumventing the development of resistance to topoisomerase-targeting antibiotics. Bacterial topoisomerases are high-value bactericidal targets that could continue to be exploited for antibacterial therapy, if new tactics to counter resistance can be adopted. PMID:27285067

  11. Bacterial Multidrug Efflux Pumps: Much More Than Antibiotic Resistance Determinants

    OpenAIRE

    Paula Blanco; Sara Hernando-Amado; Jose Antonio Reales-Calderon; Fernando Corona; Felipe Lira; Manuel Alcalde-Rico; Alejandra Bernardini; Maria Blanca Sanchez; Jose Luis Martinez

    2016-01-01

    Bacterial multidrug efflux pumps are antibiotic resistance determinants present in all microorganisms. With few exceptions, they are chromosomally encoded and present a conserved organization both at the genetic and at the protein levels. In addition, most, if not all, strains of a given bacterial species present the same chromosomally-encoded efflux pumps. Altogether this indicates that multidrug efflux pumps are ancient elements encoded in bacterial genomes long before the recent use of ant...

  12. Intravenous antibiotics infusion and bacterial resistence: nursing responsability

    OpenAIRE

    Heloisa Helena Karnas Hoefel; Liana Lautert

    2006-01-01

    The success of antibiotics treatment and development of bacterial resistance depend on many factors. The preparation and management of these factors are associated with nursing care. The aim of this paper is review literature about preparation, management and knowledge of intravenous antibiotics errors analyzing possibilities of influence of bacterial resistance prevention by nurses. Methods: a systematic review was done from LiILACS and M...

  13. Uropathogenic Escherichia coli (UPEC) induced antimicrobial gene expression in the male reproductive tract of rat: evaluation of the potential of Defensin 21 to limit infection.

    Science.gov (United States)

    Biswas, B; Bhushan, S; Rajesh, A; Suraj, S K; Lu, Y; Meinhardt, A; Yenugu, S

    2015-03-01

    Escherichia coli (E. coli) is a common pathogen in epididymitis, which represents a prevalent entity in male reproductive tract infections (RTI). Although current treatment regimens using antibiotics are satisfactory, development of antimicrobial resistance by the pathogen represents a challenge in the management of RTI. Hence, identification of antimicrobial peptides as alternatives to antibiotics has gained importance. We demonstrate that in a rat epididymo-orchitis model induced with uropathogenic E. coli (UPEC) strain MTCC 729, the expression of defensins and defensin-like Spag11 genes are induced in the epididymis and testes. The induction of antimicrobial gene expression is paralleled by phosphorylation of the NF-kB subunit p65 and the inhibitor of NFkB (IkB-alpha), decreased levels of histone deacetylase 1 and increased methylation of Histone 3, indicating the role of classical Toll-like receptor mediated signaling and epigenetic regulation. Recombinant Defensin 21, when administered to UPEC-infected rats, substantially reduced the bacterial load in the epididymis and testis and proved to be more effective than gentamycin. The ability of Defensin 21 to limit RTI provides support that antibacterial proteins of the male reproductive tract may be used as potential alternatives to antibiotics in treatment of this disease.

  14. BLOOD CONTENTS OF DEFENSINS IN PATIENTS WITH PNEUMONIAS CAUSED BY INFLUENZA А/H1N1

    Directory of Open Access Journals (Sweden)

    E. N. Romanova

    2012-01-01

    Full Text Available Abstract. Defensin amounts in severe forms of influenza-associated pneumonia and acute respiratory distresssyndrome is increased to a lesser degree than in pneumonias with milder clinical course. This difference may be determined by selective accumulation of defensins in areas of infectious lesions. Mean content of α-defensins in non-severe pneumonias with influenza А/H1N1 accompanied by normocytosis or leukopenia, is higher than in bacterial pneumonias with leukocytosis. High levels of defensins, along with substantially increased neutrophil counts, associated with normocytosis or leukopenia, reflect a pronounced systemic inflammatory response caused by influenza А/H1N1.

  15. Multiple drug resistance and bacterial infection

    Institute of Scientific and Technical Information of China (English)

    Asad U Khan

    2008-01-01

    Drug resistance is becoming a great problem in developing countries due to excessive use and misuse of antibi-otics.The emergence of new pathogenic strains with resistance developed against most of the antibiotics which may cause,difficult to treat infection.To understand the current scenario in different mode of infection is most important for the clinicians and medical practitioners.This article summarized some common infections and an-tibiotic resistance pattern found among these pathogens.

  16. Construction of a Mammary-specific Expression Vector of Humanα-defensin-1 (HNP-1) Gene

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 IntroductionDefensins, also called human neutrophil peptides(HNP), are small cationic peptides with broad antimicrobial activity~([1]). Human defensins are highly abundant in the cytoplasmic granules of polymorphonuclear neutrophils. Alpha-defensin-1 is an important mediator in either innate immunity or anti-infection. It can be developed to be an ideal new type antibiotic and may provide a better solution for the present situation of extensive antibiotics-resistence. It is difficult to achieve amount of ...

  17. Bacterial Gibberellins Induce Systemic Resistance of Plants

    OpenAIRE

    I. N. FEKLISTOVA; I. A. GRINEVA; T. L. SKAKUN; L. E. SADOVSKAYA

    2014-01-01

    It is generally agreed today that some rhizosphere bacteria can ensure induced systemic resistance to pathogens. In this paper we tested the ability of gibberellins produced by rhizosphere non-pathogenic bacteria Pseudomonas aurantiaca to induce systemic resistance to alternariosis agent – Alternaria brassicicola – in oilseed rape plants.Oilseed rape (Brássica nápus) is one of the most promising oil-bearing croppers. It allows improving the supply of population with vegetable oil, animal and ...

  18. Intravenous antibiotics infusion and bacterial resistence: nursing responsability

    Directory of Open Access Journals (Sweden)

    Heloisa Helena Karnas Hoefel

    2006-12-01

    Full Text Available The success of antibiotics treatment and development of bacterial resistance depend on many factors. The preparation and management of these factors are associated with nursing care. The aim of this paper is review literature about preparation, management and knowledge of intravenous antibiotics errors analyzing possibilities of influence of bacterial resistance prevention by nurses. Methods: a systematic review was done from LiILACS and Medline searching for the word nursing and bacterial resistance, antibiotics control, hospital infections, administration drugs, errors and adverse events. There were chose 58 papers about nursing and/or were basics for international and Brazilian studies. Results: It was described international classifications errors and consequences analyzing their possible influences on antibiotics effects. Based on these knowledge, interventions are recommended to implement safety practice and care.

  19. Bacterial Multidrug Efflux Pumps: Much More Than Antibiotic Resistance Determinants

    Directory of Open Access Journals (Sweden)

    Paula Blanco

    2016-02-01

    Full Text Available Bacterial multidrug efflux pumps are antibiotic resistance determinants present in all microorganisms. With few exceptions, they are chromosomally encoded and present a conserved organization both at the genetic and at the protein levels. In addition, most, if not all, strains of a given bacterial species present the same chromosomally-encoded efflux pumps. Altogether this indicates that multidrug efflux pumps are ancient elements encoded in bacterial genomes long before the recent use of antibiotics for human and animal therapy. In this regard, it is worth mentioning that efflux pumps can extrude a wide range of substrates that include, besides antibiotics, heavy metals, organic pollutants, plant-produced compounds, quorum sensing signals or bacterial metabolites, among others. In the current review, we present information on the different functions that multidrug efflux pumps may have for the bacterial behaviour in different habitats as well as on their regulation by specific signals. Since, in addition to their function in non-clinical ecosystems, multidrug efflux pumps contribute to intrinsic, acquired, and phenotypic resistance of bacterial pathogens, the review also presents information on the search for inhibitors of multidrug efflux pumps, which are currently under development, in the aim of increasing the susceptibility of bacterial pathogens to antibiotics.

  20. Alternatives to overcoming bacterial resistances: State-of-the-art.

    Science.gov (United States)

    Rios, Alessandra C; Moutinho, Carla G; Pinto, Flávio C; Del Fiol, Fernando S; Jozala, Angela; Chaud, Marco V; Vila, Marta M D C; Teixeira, José A; Balcão, Victor M

    2016-10-01

    Worldwide, bacterial resistance to chemical antibiotics has reached such a high level that endangers public health. Presently, the adoption of alternative strategies that promote the elimination of resistant microbial strains from the environment is of utmost importance. This review discusses and analyses several (potential) alternative strategies to current chemical antibiotics. Bacteriophage (or phage) therapy, although not new, makes use of strictly lytic phage particles as an alternative, or a complement, in the antimicrobial treatment of bacterial infections. It is being rediscovered as a safe method, because these biological entities devoid of any metabolic machinery do not possess any affinity whatsoever to eukaryotic cells. Lysin therapy is also recognized as an innovative antimicrobial therapeutic option, since the topical administration of preparations containing purified recombinant lysins with amounts in the order of nanograms, in infections caused by Gram-positive bacteria, demonstrated a high therapeutic potential by causing immediate lysis of the target bacterial cells. Additionally, this therapy exhibits the potential to act synergistically when combined with certain chemical antibiotics already available on the market. Another potential alternative antimicrobial therapy is based on the use of antimicrobial peptides (AMPs), amphiphilic polypeptides that cause disruption of the bacterial membrane and can be used in the treatment of bacterial, fungal and viral infections, in the prevention of biofilm formation, and as antitumoral agents. Interestingly, bacteriocins are a common strategy of bacterial defense against other bacterial agents, eliminating the potential opponents of the former and increasing the number of available nutrients in the environment for their own growth. They can be applied in the food industry as biopreservatives and as probiotics, and also in fighting multi-resistant bacterial strains. The use of antibacterial antibodies

  1. Defensins from insects and plants interact with fungal glucosylceramides

    NARCIS (Netherlands)

    Thevissen, K.; Warnecke, D.C.; François, I.E.J.A.; Leipelt, M.; Heinz, E.; Ott, C.; Zähringer, U.; Thomma, B.P.H.J.; Ferket, K.K.A.; Cammue, B.P.A.

    2004-01-01

    Growth of the yeast species Candida albicans and Pichia pastoris is inhibited by RsAFP2, a plant defensin isolated from radish seed (Raphanus sativus), at micromolar concentrations. In contrast, gcs-deletion mutants of both yeast species are resistant toward RsAFP2. GCS genes encode UDP-glucose:cera

  2. Aedesin: structure and antimicrobial activity against multidrug resistant bacterial strains.

    Directory of Open Access Journals (Sweden)

    Sylvain Godreuil

    Full Text Available Multidrug resistance, which is acquired by both Gram-positive and Gram-negative bacteria, causes infections that are associated with significant morbidity and mortality in many clinical settings around the world. Because of the rapidly increasing incidence of pathogens that have become resistant to all or nearly all available antibiotics, there is a need for a new generation of antimicrobials with a broad therapeutic range for specific applications against infections. Aedesin is a cecropin-like anti-microbial peptide that was recently isolated from dengue virus-infected salivary glands of the Aedes aegypti mosquito. In the present study, we have refined the analysis of its structural characteristics and have determined its antimicrobial effects against a large panel of multidrug resistant bacterial strains, directly isolated from infected patients. Based the results from nuclear magnetic resonance spectroscopy analysis, Aedesin has a helix-bend-helix structure typical for a member of the family of α-helix anti-microbial peptides. Aedesin efficiently killed Gram-negative bacterial strains that display the most worrisome resistance mechanisms encountered in the clinic, including resistance to carbapenems, aminoglycosides, cephalosporins, 4th generation fluoroquinolones, folate inhibitors and monobactams. In contrast, Gram-positive strains were insensitive to the lytic effects of the peptide. The anti-bacterial activity of Aedesin was found to be salt-resistant, indicating that it is active under physiological conditions encountered in body fluids characterized by ionic salt concentrations. In conclusion, because of its strong lytic activity against multidrug resistant Gram-negative bacterial strains displaying all types of clinically relevant resistance mechanisms known today, Aedesin might be an interesting candidate for the development of alternative treatment for infections caused by these types of bacteria.

  3. Test for bacterial resistance build-up against plasma treatment

    International Nuclear Information System (INIS)

    It is well known that the evolution of resistance of microorganisms to a range of different antibiotics presents a major problem in the control of infectious diseases. Accordingly, new bactericidal ‘agents’ are in great demand. Using a cold atmospheric pressure (CAP) plasma dispenser operated with ambient air, a more than five orders of magnitude inactivation or reduction of Methicillin-resistant Staphylococcus aureus (MRSA; resistant against a large number of the tested antibiotics) was obtained in less than 10 s. This makes CAP the most promising candidate for combating nosocomial (hospital-induced) infections. To test for the occurrence and development of bacterial resistance against such plasmas, experiments with Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Enterococcus mundtii) were performed. The aim was to determine quantitative limits for primary (naturally) or secondary (acquired) resistance against the plasma treatment. Our results show that E. coli and E. mundtii possess no primary resistance against the plasma treatment. By generating four generations of bacteria for every strain, where the survivors of the plasma treatment were used for the production of the next generation, a lower limit to secondary resistance was obtained. Our results indicate that CAP technology could contribute to the control of infections in hospitals, in outpatient care and in disaster situations, providing a new, fast and efficient broad-band disinfection technology that is not constrained by bacterial resistance mechanisms. (paper)

  4. [Effect of Three Typical Disinfection Byproducts on Bacterial Antibiotic Resistance].

    Science.gov (United States)

    Lü, Lu; Zhang, Meng-lu; Wang, Chun-ming; Lin, Hui-rong; Yu, Xin

    2015-07-01

    The effect of typical disinfection byproducts (DBPs) on bacterial antibiotic resistance was investigated in this study. chlorodibromomethane (CDBM), iodoacetic acid (IAA) and chloral hydrate (CH) were selected, which belong to trihalomethanes (THMs), haloacetic acids (HAAs) and aldehydes, respectively. After exposure to the selected DBPs, the resistance change of the tested strains to antibiotics was determined. As a result, all of the three DBPs induced Pseudomonas aeruginosa PAO1 to gain increased resistance to the five antibiotics tested, and the DBPs ranked as IAA > CH > CDBM according to their enhancement effects. Multidrug resistance could also be enhanced by treatment with IAA. The same result was observed in Escherichia coli K12, suggesting that the effect of DBPs on antibiotic resistance was a common phenomenon. The mechanism was probably that DBPs stimulated oxidative stress, which induced mutagenesis. And the antibiotic resistance mutation frequency could be increased along with mutagenesis. This study revealed that the acquisition of bacterial antibiotic resistance might be related to DBPs in drinking water systems. Besides the genotoxicological risks, the epidemiological risks of DBPs should not be overlooked.

  5. Major QTL Conferring Resistance to Rice Bacterial Leaf Streak

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Bacterial leaf streak (BLS) is one of the important limiting factors to rice production in southern China and other tropical and sub-tropical areas in Asia. Resistance to BLS was found to be a quantitative trait and no major resistant gene was located in rice until date. In the present study, a new major quantitative trait locus (QTL) conferring resistance to BLS was identified from a highly resistant variety Dular by the employment of Dular/Balilla (DB) and Dular/IR24 (DI) segregation populations and was designated qBLSR-11-1. This QTL was located between the simple sequence repeat (SSR) markers RM120 and RM441 on chromosome 11 and could account for 18.1-21.7% and 36.3% of the variance in DB and DI populations, respectively. The genetic pattern of rice resistance to BLS was discussed.

  6. Newer systems for bacterial resistances to toxic heavy metals.

    OpenAIRE

    Silver, S; Ji, G.

    1994-01-01

    Bacterial plasmids contain specific genes for resistances to toxic heavy metal ions including Ag+, AsO2-, AsO4(3-), Cd2+, Co2+, CrO4(2-), Cu2+, Hg2+, Ni2+, Pb2+, Sb3+, and Zn2+. Recent progress with plasmid copper-resistance systems in Escherichia coli and Pseudomonas syringae show a system of four gene products, an inner membrane protein (PcoD), an outer membrane protein (PcoB), and two periplasmic Cu(2+)-binding proteins (PcoA and PcoC). Synthesis of this system is governed by two regulator...

  7. Screening Rice Cultivars for Resistance to Bacterial Leaf Blight.

    Science.gov (United States)

    Fred, Agaba Kayihura; Kiswara, Gilang; Yi, Gihwan; Kim, Kyung-Min

    2016-05-28

    Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious threats to rice production. In this study, screening of rice for resistance to BLB was carried out at two different times and locations; that is, in a greenhouse during winter and in an open field during summer. The pathogenicity of Xoo race K1 was tested on 32 Korean rice cultivars. Inoculation was conducted at the maximum tillering stage, and the lesion length was measured after 14 days of inoculation. Five cultivars, Hanareum, Namcheon, Samgdeok, Samgang, and Yangjo, were found to be resistant in both the greenhouse and open-field screenings. Expression of the plant defense-related genes JAmyb, OsNPR1, OsPR1a, OsWRKY45, and OsPR10b was observed in resistant and susceptible cultivars by qRT-PCR. Among the five genes tested, only OsPR10b showed coherent expression with the phenotypes. Screening of resistance to Xoo in rice was more accurate when conducted in open fields in the summer cultivation period than in greenhouses in winter. The expression of plant defenserelated genes after bacterial inoculation could give another perspective in elucidating defense mechanisms by using both resistant and susceptible individuals. PMID:26869604

  8. Resistance of Antimicrobial Peptide Gene Transgenic Rice to Bacterial Blight

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; WU Chao; LIU Mei; LIU Xu-ri; Hu Guo-cheng; SI Hua-min; SUN Zong-xiu; LIU Wen-zhen; Fu Ya-ping

    2011-01-01

    Antimierobial peptide is a polypeptide with antimicrobial activity.Antimicrobial peptide genes Np3 and Np5 from Chinese shrimp (Fenneropenaeus Chinensis) were integrated into Oryza sativa L.subsp.japonica cv.Aichi ashahi by Agrobacterium mediated transformation system.PCR analysis showed that the positive ratios of Np3 and Np5 were 36% and 45% in T0 generation,respectively.RT-PCR analysis showed that the antimicrobial peptide genes were expressed in T1 generation,and there was no obvious difference in agronomic traits between transgenic plants and non-transgenic plants.Four Np3 and Np5 transgenic lines in T1 generation were inoculated with ×anthomonas oryzae pv.oryzae strain CR4,and all the four transgenic lines had significantly enhanced resistance to bacterial blight caused by the strain CR4.The Np5 transgenic lines also showed higher resistance to bacterial blight caused by strains JS97-2,Zhe 173 and OS-225.It is suggested that transgenic lines with Np5 gene might possess broad spectrum resistance to rice bacterial blight.

  9. α-Defensins in human innate immunity.

    Science.gov (United States)

    Lehrer, Robert I; Lu, Wuyuan

    2012-01-01

    Defensins are small, multifunctional cationic peptides. They typically contain six conserved cysteines whose three intramolecular disulfides stabilize a largely β-sheet structure. This review of human α-defensins begins by describing their evolution, including their likely relationship to the Big Defensins of invertebrates, and their kinship to the β-defensin peptides of many if not all vertebrates, and the θ-defensins found in certain non-human primates. We provide a short history of the search for leukocyte-derived microbicidal molecules, emphasizing the roles played by luck (good), preconceived notions (mostly bad), and proper timing (essential). The antimicrobial, antiviral, antitoxic, and binding properties of human α-defensins are summarized. The structural features of α-defensins are described extensively and their functional contributions are assessed. The properties of HD6, an enigmatic Paneth cell α-defensin, are contrasted with those of the four myeloid α-defensins (HNP1-4) and of HD5, the other α-defensin of human Paneth cells. The review ends with a decalogue that may assist researchers or students interested in α-defensins and related aspects of neutrophil function.

  10. Defensins: Potential Effectors in Autoimmune Rheumatic Disorders

    Directory of Open Access Journals (Sweden)

    Stefan Vordenbäumen

    2011-08-01

    Full Text Available Defensins are small cationic peptides with antimicrobial properties. They constitute a highly conserved innate immune defense mechanism across species. Based on the arrangement of disulfide-bonds, α- and β-defensins are distinguished in humans. Both types of defensin comprise several distinct molecules that are preferentially expressed at epithelial surfaces and in blood cells. In the last decade, multiple immunomodulatory functions of defensins have been recognized, including chemotactic activity, the promotion of antigen presentation, and modulations of proinflammatory cytokine secretion. These findings suggested a role for defensins not only as a first line of defense, but also as connectors of innate and adaptive immune responses. Recently, increasingly accumulating evidence has indicated that defensins may also be involved in the pathogenesis of autoimmune rheumatic disorders such as systemic lupus erythematosus and rheumatoid arthritis. The current review summarizes the data connecting defensins to autoimmunity.

  11. Nonlinear Stochastic Modelling of Antimicrobial resistance in Bacterial Populations

    DEFF Research Database (Denmark)

    Philipsen, Kirsten Riber

    This thesis applies mathematical modelling and statistical methods to investigate the dynamics and mechanisms of bacterial evolution. More specifically it is concerned with the evolution of antibiotic resistance in bacteria populations, which is an increasing problem for the treatment of infections...... with antibiotics than the non-mutators. In another study a new hypothesis for the long term role of mutator bacteria is tested. This model suggests that mutators can work as "genetic work stations", where multiple mutations occur and subsequently are transmitted to the non-mutator population by conjugation....... Another study in this thesis is concerned with the spread of colonization with resistant bacteria between patients in a hospital and people in the related catchment population. The resistance considered is extended-spectrumbeta-lactamases, and it is the first time a model has been developed for the spread...

  12. Delineation of interfaces on human alpha-defensins critical for human adenovirus and human papillomavirus inhibition.

    Directory of Open Access Journals (Sweden)

    Victoria R Tenge

    2014-09-01

    Full Text Available Human α-defensins are potent anti-microbial peptides with the ability to neutralize bacterial and viral targets. Single alanine mutagenesis has been used to identify determinants of anti-bacterial activity and binding to bacterial proteins such as anthrax lethal factor. Similar analyses of α-defensin interactions with non-enveloped viruses are limited. We used a comprehensive set of human α-defensin 5 (HD5 and human neutrophil peptide 1 (HNP1 alanine scan mutants in a combination of binding and neutralization assays with human adenovirus (AdV and human papillomavirus (HPV. We have identified a core of critical hydrophobic residues that are common determinants for all of the virus-defensin interactions that were analyzed, while specificity in viral recognition is conferred by specific surface-exposed charged residues. The hydrophobic residues serve multiple roles in maintaining the tertiary and quaternary structure of the defensins as well as forming an interface for virus binding. Many of the important solvent-exposed residues of HD5 group together to form a critical surface. However, a single discrete binding face was not identified for HNP1. In lieu of whole AdV, we used a recombinant capsid subunit comprised of penton base and fiber in quantitative binding studies and determined that the anti-viral potency of HD5 was a function of stoichiometry rather than affinity. Our studies support a mechanism in which α-defensins depend on hydrophobic and charge-charge interactions to bind at high copy number to these non-enveloped viruses to neutralize infection and provide insight into properties that guide α-defensin anti-viral activity.

  13. Oral biofilms: a reservoir of transferable, bacterial, antimicrobial resistance.

    Science.gov (United States)

    Roberts, Adam P; Mullany, Peter

    2010-12-01

    Oral microbes are responsible for dental caries and periodontal diseases and have also been implicated in a range of other diseases beyond the oral cavity. These bacteria live primarily as complex, polymicrobial biofilms commonly called dental plaque. Cells growing within a biofilm often exhibit altered phenotypes, such as increased antibiotic resistance. The stable structural properties and close proximity of the bacterial cells within the biofilm appears to be an excellent environment for horizontal gene transfer, which can lead to the spread of antibiotic resistance genes amongst the biofilm inhabitants. This article will present an overview of the different types and amount of resistance to antibiotics that have been found in the human oral microbiota and will discuss the oral inhabitants' role as a reservoir of antimicrobial resistance genes. In addition, data on the genetic support for these resistance genes will be detailed and the evidence for horizontal gene transfer reviewed, demonstrating that the bacteria inhabiting the oral cavity are a reservoir of transferable antibiotic resistance.

  14. Construction of a Mammary-specific Expression Vector of Human α- defensin- 1 ( HNP- 1) Gene

    Institute of Scientific and Technical Information of China (English)

    Yue YANG; Jing-Ping OU YANG; Bao-Hua WANG

    2005-01-01

    @@ 1 Introduction Defensins, also called human neutrophil peptides(HNP), are small cationic peptides with broad antimicrobial activity[1]. Human defensins are highly abundant in the cytoplasmic granules of polymorphonuclear neutrophils. Alpha-defensin-1 is an important mediator in either innate immunity or anti-infection. It can be developed to be an ideal new type antibiotic and may provide a better solution for the present situation of extensive antibiotics-resistence. It is difficult to achieve amount of antimicrobial peptides from nature sources. Transgenic mammary gland bioreactors offer a safe and cost effective source to produce important proteins. The purpose of this study was to construct a mammary-specific expression plasmid containing beta-lactoglobulin (BLG) gene promoter and human α-defensin-1 (HNP-1) gene.

  15. Inducible immune factors of the vector mosquito Anopheles gambiae: biochemical purification of a defensin antibacterial peptide and molecular cloning of preprodefensin cDNA.

    Science.gov (United States)

    Richman, A M; Bulet, P; Hetru, C; Barillas-Mury, C; Hoffmann, J A; Kafalos, F C

    1996-08-01

    Larvae of the mosquito vector of human malaria, Anopheles gambiae, were inoculated with bacteria and extracts were biochemically fractionated by reverse-phase HPLC. Multiple induced polypeptides and antibacterial activities were observed following bacterial infection, including a member of the insect defensin family of antibacterial proteins. A cDNA encoding An. gambiae preprodefensin was isolated using PCR primers based on phylogenetically conserved sequences. The mature peptide is highly conserved, but the signal and propeptide segments are not, relative to corresponding defensin sequences of other insects. Defensin expression is induced in response to bacterial infection, in both adult and larval stages. In contrast, pupae express defensin mRNA constitutively. Defensin expression may prove a valuable molecular marker to monitor the An. gambiae host response to infection by parasitic protozoa of medical importance. PMID:8799739

  16. QTLs for Resistance to Major Rice Diseases Exacerbated by Global Warming: Brown Spot, Bacterial Seedling Rot, and Bacterial Grain Rot.

    Science.gov (United States)

    Mizobuchi, Ritsuko; Fukuoka, Shuichi; Tsushima, Seiya; Yano, Masahiro; Sato, Hiroyuki

    2016-12-01

    In rice (Oryza sativa L.), damage from diseases such as brown spot, caused by Bipolaris oryzae, and bacterial seedling rot and bacterial grain rot, caused by Burkholderia glumae, has increased under global warming because the optimal temperature ranges for growth of these pathogens are relatively high (around 30 °C). Therefore, the need for cultivars carrying genes for resistance to these diseases is increasing to ensure sustainable rice production. In contrast to the situation for other important rice diseases such as blast and bacterial blight, no genes for complete resistance to brown spot, bacterial seedling rot or bacterial grain rot have yet been discovered. Thus, rice breeders have to use partial resistance, which is largely influenced by environmental conditions. Recent progress in molecular genetics and improvement of evaluation methods for disease resistance have facilitated detection of quantitative trait loci (QTLs) associated with resistance. In this review, we summarize the results of worldwide screening for cultivars with resistance to brown spot, bacterial seedling rot and bacterial grain rot and we discuss the identification of QTLs conferring resistance to these diseases in order to provide useful information for rice breeding programs.

  17. QTLs for Resistance to Major Rice Diseases Exacerbated by Global Warming: Brown Spot, Bacterial Seedling Rot, and Bacterial Grain Rot.

    Science.gov (United States)

    Mizobuchi, Ritsuko; Fukuoka, Shuichi; Tsushima, Seiya; Yano, Masahiro; Sato, Hiroyuki

    2016-12-01

    In rice (Oryza sativa L.), damage from diseases such as brown spot, caused by Bipolaris oryzae, and bacterial seedling rot and bacterial grain rot, caused by Burkholderia glumae, has increased under global warming because the optimal temperature ranges for growth of these pathogens are relatively high (around 30 °C). Therefore, the need for cultivars carrying genes for resistance to these diseases is increasing to ensure sustainable rice production. In contrast to the situation for other important rice diseases such as blast and bacterial blight, no genes for complete resistance to brown spot, bacterial seedling rot or bacterial grain rot have yet been discovered. Thus, rice breeders have to use partial resistance, which is largely influenced by environmental conditions. Recent progress in molecular genetics and improvement of evaluation methods for disease resistance have facilitated detection of quantitative trait loci (QTLs) associated with resistance. In this review, we summarize the results of worldwide screening for cultivars with resistance to brown spot, bacterial seedling rot and bacterial grain rot and we discuss the identification of QTLs conferring resistance to these diseases in order to provide useful information for rice breeding programs. PMID:27178300

  18. Mitomycin resistance in mammalian cells expressing the bacterial mitomycin C resistance protein MCRA

    OpenAIRE

    Belcourt, Michael F.; Penketh, Philip G.; Hodnick, William F.; Johnson, David A.; David H Sherman; Rockwell, Sara; Sartorelli, Alan C.

    1999-01-01

    The mitomycin C-resistance gene, mcrA, of Streptomyces lavendulae produces MCRA, a protein that protects this microorganism from its own antibiotic, the antitumor drug mitomycin C. Expression of the bacterial mcrA gene in mammalian Chinese hamster ovary cells causes profound resistance to mitomycin C and to its structurally related analog porfiromycin under aerobic conditions but produces little change in drug sensitivity under hypoxia. The mitomycins are prodrugs that are enzymatically reduc...

  19. Antimicrobial resistance of bacterial strains isolated from avian cellulitis

    Directory of Open Access Journals (Sweden)

    MM Santos

    2014-03-01

    Full Text Available Avian cellulitis is an inflammatory process in the subcutaneous tissue, mainly located in the abdomen and thighs. This problem is commonly observed in poultry at slaughter and it is considered one of the major causes of condemnation of carcasses in Brazil. The aim of this study was to perform the microbial isolation of lesions of avian cellulitis from a processing plant located in the State of Goiás in order to analyze antimicrobial resistance by antibiogram test and to detect resistance genes by polymerase chain reaction. A total of 25 samples of avian cellulitis lesions were analyzed, from which 30 bacterial strains were isolated. There were eleven (44% strains of Escherichia coli, nine (36% strains of Staphylococcus epidermidis, seven (28% strains of Proteus mirabilis and three (12% strains of Manheimiahaemolytica. The antibiogram test showed that all strains were resistant to at least one antimicrobial. The gene of antimicrobial resistance tetB was detected in E. coli, S. epidermidis and P. mirabilis strains, and was the most frequently observed gene. The gene of antimicrobial resistance Sul1 was detected in all bacterial species, while tetA was found in E. coli and S. epidermidis strains, SHV in E. coli strains, S. epidermidis and P. mirabilis,and cat1 in one P. mirabilis strain. The results suggest a potential public health hazard due to the ability of these microorganisms to transmit antimicrobial resistancegenes to other microorganisms present in the intestinal tract of humans and animals, which may affect clinical-medical usage of these drugs.

  20. STUDY OF BACTERIAL RESISTANCE TO ORGANOPHOSPHOROUS PESTICIDES IN IRAN

    Directory of Open Access Journals (Sweden)

    A. Nazarian and M. Mousawi

    2005-07-01

    Full Text Available The broadness application of organophosphorus compounds has abounded the number of its polluted areas. Bioremediation has widely focused on insitu bacterial degradation of organophosphorus residues in the world. Therefore, in this research six numbers of samples from two different sources, soil and water randomly were isolated using different organophosphorus pesticides containing mineral solution without supplementation. More than 100 isolated strains were selected according to their simultaneous optimal growth on mineral medium with organophosphorus and Mac Conkey,s agar. More than 50 percent of them were lost above resistance. The resistant strains were identified by two methods, the biochemical convention and API 20E procedure with positive agreement. The identified strains belonged to Pseudomonas and Flavobacterium species. The maximum tolerant concentrations of different organophosphorus pesticides by these resistant strains were 2.5, 4 and 8 g/L of guthion, methyl parathion and Dimethoate, respectively. The resistance to these pesticides due to organ phosphorous degrading plasmids had the ability to express hydrolytic enzymes. Resistant bacteria lost these plasmids by acridin orange and could translocate to sensitive strains. Thus, certain environmental bacteria could be used as protection tools against antinerve agents.

  1. Antibiotic resistance in prevalent bacterial and protozoan sexually transmitted infections

    Directory of Open Access Journals (Sweden)

    Karl Krupp

    2015-01-01

    Full Text Available The emergence of multi-drug resistant sexually transmitted infections (STIs is causing a treatment crisis across the globe. While cephalosporin-resistant gonorrhea is one of the most pressing issues, extensively antibiotic resistant Chlamydia trachomatis and Mycoplasma hominis are also becoming commonplace. Experts have suggested that the failure of current treatment regimens are "largely inevitable" and have called for entirely new classes of antimicrobial agents. With the exception of several new classes of drugs primarily targeting nosocomial infections, progress has been slow. While pharmaceutical companies continue to introduce new drugs, they are based on decade-old discoveries. While there is disagreement about what constitutes new classes of antibiotics, many experts suggest that the last truly new family of antimicrobials was discovered in 1987. This review summarizes the existing literature on antibiotic resistance in common bacterial and protozoal STIs. It also briefly discusses several of the most promising alternatives to current therapies, and further examines how advances in drug delivery, formulation, concentration, and timing are improving the efficacy of existing treatments. Finally, the paper discusses the current state of pharmaceutical development for multidrug-resistant STI.

  2. How to Measure Export via Bacterial Multidrug Resistance Efflux Pumps

    Science.gov (United States)

    Blair, Jessica M. A.

    2016-01-01

    ABSTRACT Bacterial multidrug resistance (MDR) efflux pumps are an important mechanism of antibiotic resistance and are required for many pathogens to cause infection. They are also being harnessed to improve microbial biotechnological processes, including biofuel production. Therefore, scientists of many specialties must be able to accurately measure efflux activity. However, myriad methodologies have been described and the most appropriate method is not always clear. Within the scientific literature, many methods are misused or data arising are misinterpreted. The methods for measuring efflux activity can be split into two groups, (i) those that directly measure efflux and (ii) those that measure the intracellular accumulation of a substrate, which is then used to infer efflux activity. Here, we review the methods for measuring efflux and explore the most recent advances in this field, including single-cell or cell-free technologies and mass spectrometry, that are being used to provide more detailed information about efflux pump activity. PMID:27381291

  3. How to Measure Export via Bacterial Multidrug Resistance Efflux Pumps.

    Science.gov (United States)

    Blair, Jessica M A; Piddock, Laura J V

    2016-01-01

    Bacterial multidrug resistance (MDR) efflux pumps are an important mechanism of antibiotic resistance and are required for many pathogens to cause infection. They are also being harnessed to improve microbial biotechnological processes, including biofuel production. Therefore, scientists of many specialties must be able to accurately measure efflux activity. However, myriad methodologies have been described and the most appropriate method is not always clear. Within the scientific literature, many methods are misused or data arising are misinterpreted. The methods for measuring efflux activity can be split into two groups, (i) those that directly measure efflux and (ii) those that measure the intracellular accumulation of a substrate, which is then used to infer efflux activity. Here, we review the methods for measuring efflux and explore the most recent advances in this field, including single-cell or cell-free technologies and mass spectrometry, that are being used to provide more detailed information about efflux pump activity. PMID:27381291

  4. Sterilization Resistance of Bacterial Spores Explained with Water Chemistry.

    Science.gov (United States)

    Friedline, Anthony W; Zachariah, Malcolm M; Middaugh, Amy N; Garimella, Ravindranath; Vaishampayan, Parag A; Rice, Charles V

    2015-11-01

    Bacterial spores can survive for long periods without nutrients and in harsh environmental conditions. This survival is influenced by the structure of the spore, the presence of protective compounds, and water retention. These compounds, and the physical state of water in particular, allow some species of bacterial spores to survive sterilization schemes with hydrogen peroxide and UV light. The chemical nature of the spore core and its water has been a subject of some contention and the chemical environment of the water impacts resistance paradigms. Either the spore has a glassy core, where water is immobilized along with other core components, or the core is gel-like with mobile water diffusion. These properties affect the movement of peroxide and radical species, and hence resistance. Deuterium solid-state NMR experiments are useful for examining the nature of the water inside the spore. Previous work in our lab with spores of Bacillus subtilis indicate that, for spores, the core water is in a more immobilized state than expected for the gel-like core theory, suggesting a glassy core environment. Here, we report deuterium solid-state NMR observations of the water within UV- and peroxide-resistant spores from Bacillus pumilus SAFR-032. Variable-temperature NMR experiments indicate no change in the line shape after heating to 50 °C, but an overall decrease in signal after heating to 100 °C. These results show glass-like core dynamics within B. pumilus SAFR-032 that may be the potential source of its known UV-resistance properties. The observed NMR traits can be attributed to the presence of an exosporium containing additional labile deuterons that can aid in the deactivation of sterilizing agents.

  5. Heterologously expressed bacterial and human multidrug resistance proteins confer cadmium resistance to Escherichia coli

    OpenAIRE

    Achard-Joris, M; van Saparoea, HBV; Driessen, AJM; Bourdineaud, JP; Bourdineaud, Jean-Paul

    2005-01-01

    The human MDR1 gene is induced by cadmium exposure although no resistance to this metal is observed in human cells overexpressing hMDR1. To access the role of MDR proteins in cadmium resistance, human MDR1, Lactococcus lactis lmrA, and Oenococcus oeni omrA were expressed in an Escherichia coli tolC mutant strain which proved to be hypersensitive to cadmium. Both the human and bacterial MDR genes conferred cadmium resistance to E. coli up to 0.4 mM concentration. Protection was abolished by 10...

  6. The Fungal Defensin Family Enlarged

    Directory of Open Access Journals (Sweden)

    Jiajia Wu

    2014-08-01

    Full Text Available Fungi are an emerging source of peptide antibiotics. With the availability of a large number of model fungal genome sequences, we can expect that more and more fungal defensin-like peptides (fDLPs will be discovered by sequence similarity search. Here, we report a total of 69 new fDLPs encoded by 63 genes, in which a group of fDLPs derived from dermatophytes are defined as a new family (fDEF8 according to sequence and phylogenetic analyses. In the oleaginous fungus Mortierella alpine, fDLPs have undergone extensive gene expansion. Our work further enlarges the fungal defensin family and will help characterize new peptide antibiotics with therapeutic potential.

  7. Salmonella serovar specific upregulation of porcine defensins 1 and 2 in a jejunal epithelial cell line

    NARCIS (Netherlands)

    Veldhuizen, E.J.A.; Koomen, I; Ultee, A.; van Dijk, A.; Haagsman, H.P.

    2009-01-01

    Defensins are important antimicrobial effector peptides of the innate immune system, which provides protection against bacterial infections in the intestine. Salmonella Choleraesuis and Salmonella Typhimurium are the most commonly isolated serovars in pig, but disease outcome is dependent on the Sal

  8. Performance of resistance gene pyramids to races of rice bacterial blight in Zhejiang Province

    Institute of Scientific and Technical Information of China (English)

    ZHENGKangle; ZHUANGJieyun; WANGHanrong

    1998-01-01

    The effect of gene pyramiding on resistance to bacterial blight (BB) in rice was evahlated among the IR24-based near isogenic lines conraining single resistance gene and gene pyramids containing two, three or lour resistancegenes (see table).

  9. Modulation of Bacterial Multidrug Resistance Efflux Pumps of the Major Facilitator Superfamily

    Directory of Open Access Journals (Sweden)

    Sanath Kumar

    2013-01-01

    Full Text Available Bacterial infections pose a serious public health concern, especially when an infectious disease has a multidrug resistant causative agent. Such multidrug resistant bacteria can compromise the clinical utility of major chemotherapeutic antimicrobial agents. Drug and multidrug resistant bacteria harbor several distinct molecular mechanisms for resistance. Bacterial antimicrobial agent efflux pumps represent a major mechanism of clinical resistance. The major facilitator superfamily (MFS is one of the largest groups of solute transporters to date and includes a significant number of bacterial drug and multidrug efflux pumps. We review recent work on the modulation of multidrug efflux pumps, paying special attention to those transporters belonging primarily to the MFS.

  10. Sustainable control of pea bacterial blight : approaches for durable genetic resistance and biocontrol by endophytic bacteria

    NARCIS (Netherlands)

    Elvira-Recuenco, M.

    2000-01-01

    Key-words: bacterial blight, biological control, biodiversity, endophytic bacteria, L-form, pea, PDRl retrotransposon, Pisum sativum, Pisum abyssinicum, Pseudomonas syringae pv. pisi, race specific resistance, race non-specific resistance, Spanish landraces.Pea bacterial blight (Pseudom

  11. Inheritance of resistance to bacterial streak and hacterial blight in rice

    Institute of Scientific and Technical Information of China (English)

    XUJianlong; WANGHanrong; LINYi; XIYongan

    1998-01-01

    Bacterial streak(BS) caused by Xanthomonas campesiris pv. oryzicola bas become one of the major diseases in southbern rice areas.Up to date, tbere are few reports on the inheritance of resistance to BS and its relationsbip with the resistance to bacterial blight(BB).

  12. Trends in bacterial resistance in a tertiary university hospital over one decade

    OpenAIRE

    Fernando Góngora Rubio; Viviane Decicera Colombo Oliveira; Regina Mara Custódio Rangel; Mara Corrêa Lelles Nogueira; Margarete Teresa Gottardo Almeida

    2013-01-01

    The objective of this study was to investigate bacterial resistance trends, infection sites and the relationship between resistance and admittance to the intensive care unit (ICU). A total of 53,316 bacteria identified between 1999 and 2008 were evaluated. Multidrug resistance was characterized when gram-negative bacilli (GNB) presented resistance to two or more classes of antibiotics. Gram-positive cocci (CPC) were assessed for resistance to penicillin, oxacillin and vancomycin. GNB were the...

  13. Structure-dependent charge density as a determinant of antimicrobial activity of peptide analogues of defensin.

    Science.gov (United States)

    Bai, Yang; Liu, Shouping; Jiang, Ping; Zhou, Lei; Li, Jing; Tang, Charles; Verma, Chandra; Mu, Yuguang; Beuerman, Roger W; Pervushin, Konstantin

    2009-08-01

    Defensins are small (3-5 kDa) cysteine-rich cationic proteins found in both vertebrates and invertebrates constituting the front line of host innate immunity. Despite intensive research, bactericidal and cytotoxic mechanisms of defensins are still largely unknown. Moreover, we recently demonstrated that small peptides derived from defensins are even more potent bactericidal agents with less toxicity toward host cells. In this paper, structures of three C-terminal (R36-K45) analogues of human beta-defensin-3 were studied by 1H NMR spectroscopy and extensive molecular dynamics simulations. Because of indications that these peptides might target the inner bacterial membrane, they were reconstituted in dodecylphosphocholine or dodecylphosphocholine/1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] mixed micelles, and lipid bicelles mimicking the phospholipid-constituted bilayer membrane of mammalian and bacterial cells. The results show that the binding affinity and partitioning into the lipid phase and the ability to dimerize and accrete well-defined structures upon interactions with lipid membranes contribute to compactization of positive charges within peptide oligomers. The peptide charge density, mediated by corresponding three-dimensional structures, was found to directly correlate with the antimicrobial activity. These novel observations may provide a new rationale for the design of improved antimicrobial agents.

  14. Paneth cells, defensins, and the commensal microbiota: a hypothesis on intimate interplay at the intestinal mucosa.

    Science.gov (United States)

    Salzman, Nita H; Underwood, Mark A; Bevins, Charles L

    2007-04-01

    Mucosal surfaces are colonized by a diverse and dynamic microbiota. Much investigation has focused on bacterial colonization of the intestine, home to the vast majority of this microbiota. Experimental evidence has highlighted that these colonizing microbes are essential to host development and homeostasis, but less is known about host factors that may regulate the composition of this ecosystem. While evidence shows that IgA has a role in shaping this microbiota, it is likely that effector molecules of the innate immune system are also involved. One hypothesis is that gene-encoded antimicrobial peptides, key elements of innate immunity throughout nature, have an essential role in this regulation. These effector molecules characteristically have activity against a broad spectrum of bacteria and other microbes. At mucosal surfaces, antimicrobial peptides may affect the numbers and/or composition of the colonizing microbiota. In humans and other mammals, defensins are a predominant class of antimicrobial peptides. In the small intestine, Paneth cells (specialized secretory epithelial cells) produce high quantities of defensins and several other antibiotic peptides and proteins. Data from murine models indicate that Paneth cell defensins play a pivotal role in defense from food and water-borne pathogens in the intestinal lumen. Recent studies in humans provide evidence that reduced Paneth cell defensin expression may be a key pathogenic factor in ileal Crohn's disease, a subgroup of inflammatory bowel disease (IBD), and changes in the colonizing microbiota may mediate this pathogenic mechanism. It is also possible that low levels of Paneth cell defensins, characteristic of normal intestinal development, may predispose premature neonates to necrotizing enterocolitis (NEC) through similar close links with the composition of the intestinal microbiota. Future studies to further define mechanisms by which defensins and other host factors regulate the composition of the

  15. Tagging RAPD markers to a bacterial blight resistance gene in rice

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@The somaclonal mutant HX_3 has shown a broad spectrum resistance to bacterial blight. To study the inheritance of the bacterial blight resistance in HX_3, a cross was made between HX_3 and a susceptible cultivar Longtefu A. The F2 population of 418 plants was inoculated with Chinese bacterial blight strain Zhe 173 (pathotype Ⅳ ). Results showed that the F2 progenies segregated in a ratio of 3R∶ 1S (324 resistant plants and 94 susceptible plants). From the plants tested, 114 individuals (86 resistant and 28 susceptible) were chosen randomly for RAPD analysis. Twelve highly resistant and 12 highly susceptible plants were selected to form a resistant pool and a susceptible pool, respectively.

  16. Application of hordothionins and cecropin B for engineering bacterial disease resistance into plants.

    NARCIS (Netherlands)

    Florack, D.

    1994-01-01

    Bacterial diseases can cause a drastic decrease of yield in certain crops. Breeding for bacterial disease resistance therefore is of utmost necessity. Up to now, traditional plant breeding was the only method to reach this goal. Recent developments in genetic engineering technology however provide n

  17. Application of hordothionins and cecropin B for engineering bacterial disease resistance into plants.

    OpenAIRE

    Florack, D.

    1994-01-01

    Bacterial diseases can cause a drastic decrease of yield in certain crops. Breeding for bacterial disease resistance therefore is of utmost necessity. Up to now, traditional plant breeding was the only method to reach this goal. Recent developments in genetic engineering technology however provide novel ways for the production of disease resistant plants. This thesis describes the results of two research projects that have been undertaken to investigate the potential of such a novel way, name...

  18. Mitomycin resistance in mammalian cells expressing the bacterial mitomycin C resistance protein MCRA.

    Science.gov (United States)

    Belcourt, M F; Penketh, P G; Hodnick, W F; Johnson, D A; Sherman, D H; Rockwell, S; Sartorelli, A C

    1999-08-31

    The mitomycin C-resistance gene, mcrA, of Streptomyces lavendulae produces MCRA, a protein that protects this microorganism from its own antibiotic, the antitumor drug mitomycin C. Expression of the bacterial mcrA gene in mammalian Chinese hamster ovary cells causes profound resistance to mitomycin C and to its structurally related analog porfiromycin under aerobic conditions but produces little change in drug sensitivity under hypoxia. The mitomycins are prodrugs that are enzymatically reduced and activated intracellularly, producing cytotoxic semiquinone anion radical and hydroquinone reduction intermediates. In vitro, MCRA protects DNA from cross-linking by the hydroquinone reduction intermediate of these mitomycins by oxidizing the hydroquinone back to the parent molecule; thus, MCRA acts as a hydroquinone oxidase. These findings suggest potential therapeutic applications for MCRA in the treatment of cancer with the mitomycins and imply that intrinsic or selected mitomycin C resistance in mammalian cells may not be due solely to decreased bioactivation, as has been hypothesized previously, but instead could involve an MCRA-like mechanism. PMID:10468636

  19. Effect of Vibration on Bacterial Growth and Antibiotic Resistance

    Science.gov (United States)

    Juergensmeyer, Elizabeth A.; Juergensmeyer, Margaret A.

    2004-01-01

    The purpose of this research grant was to provide a fundamental, systematic investigation of the effects of oscillatory acceleration on bacterial proliferation and their responses to antibiotics in a liquid medium.

  20. Genetics and Improvement of Bacterial Blight Resistance of Hybrid Rice in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qi

    2009-01-01

    Since 1980s, rice breeding for resistance to bacterial blight has been rapidly progressing in China. The gene Xa4 was mainly used in three-line indica hybrid and two-line hybrid rice. The disease has been 'quiet' for 20 years in China, yet in recent years it has gradually emerged and been prevalent in fields planted with newly released rice varieties in the Changjiang River valley. Under the circumstances, scientists inevitably raised several questions: what causes the resurgence and what should we do next? And/or is resistance breeding still one of the main objectives in rice improvement? Which approach do we take on resistance breeding so that the resistance will be more durable, and the resistance gene will be used more efficiently? A combined strategy involving traditional method, molecular marker-assisted selection, and transgenic technology should bring a new era to the bacterial blight resistance hybrid rice breeding program. This review also briefly discusses and deliberates on issues related to the broadening of bacterial blight resistance, and suitable utilization of resistance genes, alternate planting of available resistance genes; and understands the virulent populations of the bacterial pathogen in China even in Asia.

  1. ß-defensin-2 in breast milk displays a broad antimicrobial activity against pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Joanna Baricelli

    2015-02-01

    Full Text Available OBJECTIVE: To describe the antimicrobial activity of ß-defensin-2 produced in the mammary gland and secreted in human breast milk. METHODS: The peptide production was performed by DNA cloning. ß-defensin-2 levels were quantified in 61 colostrum samples and 39 mature milk samples from healthy donors, by an indirect enzyme-linked immunosorbent assay (ELISA. Using halo inhibition assay, this study assessed activity against seven clinical isolates from diarrheal feces of children between 0 and 2 years of age. The activity of ß-defensin-2 against three opportunistic pathogens that can cause nosocomial infections was determined by microdilution test. RESULTS: The peptide levels were higher in colostrum (n = 61 than in mature milk samples (n = 39, as follows: median and range, 8.52 (2.6-16.3 µg/ml versus 0.97 (0.22-3.78, p < 0.0001; Mann-Whitney test. The recombinant peptide obtained showed high antimicrobial activity against a broad range of pathogenic bacteria. Its antibacterial activity was demonstrated in a disk containing between 1-4 µg, which produced inhibition zones ranging from 18 to 30 mm against three isolates of Salmonella spp. and four of E. coli. ß-defensin-2 showed minimum inhibitory concentrations (MICs of 0.25 µg/mL and 0.5 µg/mL for S. marcescen and P. aeruginosa, respectively, while a higher MIC (4 µg/mL was obtained against an isolated of multidrug-resistant strain of A. baumannii. CONCLUSIONS: To the authors' knowledge, this study is the first to report ß-defensin-2 levels in Latin American women. The production and the activity of ß-defensin-2 in breast milk prove its importance as a defense molecule for intestinal health in pediatric patients.

  2. Induction of bacterial antibiotic resistance by mutagenic halogenated nitrogenous disinfection byproducts

    International Nuclear Information System (INIS)

    Halogenated nitrogenous disinfection byproducts (N-DBPs) raise concerns regarding their mutagenicity and carcinogenicity threatening public health. However, environmental consequence of their mutagenicity has received less attention. In this study, the effect of halogenated N-DBPs on bacterial antibiotic resistance (BAR) was investigated. After exposure to bromoacetamide (BAcAm), trichloroacetonitrile (TCAN) or tribromonitromethane (TBNM), the resistance of Pseudomonas aeruginosa PAO1 to both individual and multiple antibiotics (ciprofloxacin, gentamicin, polymyxin B, rifampin, tetracycline, ciprofloxacin + gentamicin and ciprofloxacin + tetracycline) was increased, which was predominantly ascribed to the overexpression of efflux pumps. The mechanism of this effect was demonstrated to be mutagenesis through sequencing and analyzing antibiotic resistance genes. The same induction phenomena also appeared in Escherichia coli, suggesting this effect may be universal to waterborne pathogens. Therefore, more attention should be given to halogenated N-DBPs, as they could increase not only genotoxicological risks but also epidemiological risks of drinking water. - Highlights: • The halogenated N-DBPs could induce bacterial antibiotic resistance. • Both individual and multiple resistances could be induced. • Efflux mechanism played an important role in the induced antibiotic resistance. • The halogenated N-DBPs induced bacterial antibiotic resistance via mutagenesis. • Effects of N-DBPs on antibiotic resistance may be universal to waterborne pathogens. - Halogenated N-DBPs could increase antibiotic resistance, even multidrug resistance via mutagenesis, contributing to the enrichment of antibiotic resistant bacteria in drinking water

  3. Pilot Screening to Determine Antimicrobial Synergies in a Multidrug-Resistant Bacterial Strain Library

    Science.gov (United States)

    Kim, Si-Hyun; Park, Chulmin; Chun, Hye-Sun; Choi, Jae-Ki; Lee, Hyo-Jin; Cho, Sung-Yeon; Park, Sun Hee; Choi, Su-Mi; Choi, Jung-Hyun; Yoo, Jin-Hong

    2016-01-01

    With the rise in multidrug-resistant (MDR) bacterial infections, there has been increasing interest in combinations of ≥2 antimicrobial agents with synergistic effects. We established an MDR bacterial strain library to screen for in vitro antimicrobial synergy by using a broth microdilution checkerboard method and high-throughput luciferase-based bacterial cell viability assay. In total, 39 MDR bacterial strains, including 23 carbapenem-resistant gram-negative bacteria, 9 vancomycin-intermediate Staphylococcus aureus, and 7 vancomycin-resistant Enterococcus faecalis, were used to screen for potential antimicrobial synergies. Synergies were more frequently identified with combinations of imipenem plus trimethoprim–sulfamethoxazole for carbapenem-resistant Acinetobacter baumannii in the library. To verify this finding, we tested 34 A. baumannii clinical isolates resistant to both imipenem and trimethoprim–sulfamethoxazole by the checkerboard method. The imipenem plus trimethoprim–sulfamethoxazole combination showed synergy in the treatment of 21 (62%) of the clinical isolates. The results indicate that pilot screening for antimicrobial synergy in the MDR bacterial strain library could be valuable in the selection of combination therapeutic regimens to treat MDR bacterial infections. Further studies are warranted to determine whether this screening system can be useful to screen for the combined effects of conventional antimicrobials and new-generation antimicrobials or nonantimicrobials. PMID:26974861

  4. Synergistic effect of interleukin 1 alpha on nontypeable Haemophilus influenzae-induced up-regulation of human beta-defensin 2 in middle ear epithelial cells

    Directory of Open Access Journals (Sweden)

    Park Raekil

    2006-01-01

    Full Text Available Abstract Background We recently showed that beta-defensins have antimicrobial activity against nontypeable Haemophilus influenzae (NTHi and that interleukin 1 alpha (IL-1 alpha up-regulates the transcription of beta-defensin 2 (DEFB4 according to new nomenclature of the Human Genome Organization in human middle ear epithelial cells via a Src-dependent Raf-MEK1/2-ERK signaling pathway. Based on these observations, we investigated if human middle ear epithelial cells could release IL-1 alpha upon exposure to a lysate of NTHi and if this cytokine could have a synergistic effect on beta-defensin 2 up-regulation by the bacterial components. Methods The studies described herein were carried out using epithelial cell lines as well as a murine model of acute otitis media (OM. Human cytokine macroarray analysis was performed to detect the released cytokines in response to NTHi exposure. Real time quantitative PCR was done to compare the induction of IL-1 alpha or beta-defensin 2 mRNAs and to identify the signaling pathways involved. Direct activation of the beta-defensin 2 promoter was monitored using a beta-defensin 2 promoter-Luciferase construct. An IL-1 alpha blocking antibody was used to demonstrate the direct involvement of this cytokine on DEFB4 induction. Results Middle ear epithelial cells released IL-1 alpha when stimulated by NTHi components and this cytokine acted in an autocrine/paracrine synergistic manner with NTHi to up-regulate beta-defensin 2. This synergistic effect of IL-1 alpha on NTHi-induced beta-defensin 2 up-regulation appeared to be mediated by the p38 MAP kinase pathway. Conclusion We demonstrate that IL-1 alpha is secreted by middle ear epithelial cells upon exposure to NTHi components and that it can synergistically act with certain of these molecules to up-regulate beta-defensin 2 via the p38 MAP kinase pathway.

  5. Response to selection for bacterial cold water disease resistance in rainbow trout

    Science.gov (United States)

    Previous studies indicate that resistance to experimental bacterial cold water disease (BCWD) challenge is heritable and thus may be improved through selective breeding. Our objective was to estimate response after one generation of genetic selection for resistance to BCWD in a pedigreed population ...

  6. Antimicrobial activities of chicken β-defensin (4 and 10) peptides against pathogenic bacteria and fungi.

    Science.gov (United States)

    Yacoub, Haitham A; Elazzazy, Ahmed M; Abuzinadah, Osama A H; Al-Hejin, Ahmed M; Mahmoud, Maged M; Harakeh, Steve M

    2015-01-01

    Host Defense Peptides (HDPs) are small cationic peptides found in several organisms. They play a vital role in innate immunity response and immunomodulatory stimulation. This investigation was designed to study the antimicrobial activities of β-defensin peptide-4 (sAvBD-4) and 10 (sAvBD-4) derived from chickens against pathogenic organisms including bacteria and fungi. Ten bacterial strains and three fungal species were used in investigation. The results showed that the sAvBD-10 displayed a higher bactericidal potency against all the tested bacterial strains than that of sAvBD-4. The exhibited bactericidal activity was significant against almost the different bacterial strains at different peptide concentrations except for that of Pseudomonas aeruginosa (P. aeruginosa) and Streptococcus bovis (Str. bovis) strains where a moderate effect was noted. Both peptides were effective in the inactivation of fungal species tested yielding a killing rate of up to 95%. The results revealed that the synthetic peptides were resistant to salt at a concentration of 50 mM NaCl. However, they lost antimicrobial potency when applied in the presence of high salt concentrations. Based on blood hemolysis studies, a little hemolytic effect was showed in the case of both peptides even when applied at high concentrations. The data obtained from this study indicated that synthetic avian peptides exhibit strong antibacterial and antifungal activity. In conclusion, future work and research should be tailored to a better understanding of the mechanisms of action of those peptides and their potential use in the pharmaceutical industry to help reduce the incidence and impact of infectious agent and be marketed as a naturally occurring antibiotic.

  7. Towards allele mining of bacterial wilt disease resistance gene in tomato

    International Nuclear Information System (INIS)

    Tomato (Lycopersicon esculentum Mill.) is the most important vegetable commodity of the Philippines. Bacterial wilt caused by Ralstonia solanacearum is one serious constraint in tomato production particularly during off-season planting. A major locus derived from H7996 that confers resistance to bacterial wilt has been mapped in the tomato genome. To validate the biological function of the resistance locus and generate multiple allele -mimics-, targeted mutation was induced in tomato using gamma ray and ethyl methane sulfonate (EMS) mutagens. Suitable mutagen treatment was established by evaluating a wide range of mutagen doses/concentrations for a) percent seed germination, b) reduction in plant height, and c) loss of resistance. Six hundred Gy and 1.0% EMS were identified to generate large M1 families of H7996. From 10,000 initial seeds treated with either gamma ray or EMS, a total of 3,663 M1 plants were generated. M2 seeds were harvested from all surviving M1 plants. Several DNA markers have been resourced and are being developed specific to the bacterial wilt resistant gene. In the large M2 population, of H7996, both the phenotypic manifestation of bacterial wilt susceptibility and nucleotide changes in the resistance locus will be evaluated. Large M3 families for the different allele series of the bacterial wilt resistance gene will be established for future high throughput TILLING (Targeting Induced Local Lesions in Genomes) analysis in the gene region

  8. Defensive remodeling: How bacterial surface properties and biofilm formation promote resistance to antimicrobial peptides.

    Science.gov (United States)

    Nuri, Reut; Shprung, Tal; Shai, Yechiel

    2015-11-01

    Multidrug resistance bacteria are a major concern worldwide. These pathogens cannot be treated with conventional antibiotics and thus alternative therapeutic agents are needed. Antimicrobial peptides (AMPs) are considered to be good candidates for this purpose. Most AMPs are short and positively charged amphipathic peptides, which are found in all known forms of life. AMPs are known to kill bacteria by binding to the negatively charged bacterial surface, and in most cases cause membrane disruption. Resistance toward AMPs can be developed, by modification of bacterial surface molecules, secretion of protective material and up-regulation or elimination of specific proteins. Because of the general mechanisms of attachment and action of AMPs, bacterial resistance to AMPs often involves biophysical and biochemical changes such as surface rigidity, cell wall thickness, surface charge, as well as membrane and cell wall modification. Here we focus on the biophysical, surface and surrounding changes that bacteria undergo in acquiring resistance to AMPs. In addition we discuss the question of whether bacterial resistance to administered AMPs might compromise our innate immunity to endogenous AMPs. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides.

  9. Effects of antibiotic resistance alleles on bacterial evolutionary responses to viral parasites.

    Science.gov (United States)

    Arias-Sánchez, Flor I; Hall, Alex R

    2016-05-01

    Antibiotic resistance has wide-ranging effects on bacterial phenotypes and evolution. However, the influence of antibiotic resistance on bacterial responses to parasitic viruses remains unclear, despite the ubiquity of such viruses in nature and current interest in therapeutic applications. We experimentally investigated this by exposing various Escherichia coli genotypes, including eight antibiotic-resistant genotypes and a mutator, to different viruses (lytic bacteriophages). Across 960 populations, we measured changes in population density and sensitivity to viruses, and tested whether variation among bacterial genotypes was explained by their relative growth in the absence of parasites, or mutation rate towards phage resistance measured by fluctuation tests for each phage. We found that antibiotic resistance had relatively weak effects on adaptation to phages, although some antibiotic-resistance alleles impeded the evolution of resistance to phages via growth costs. By contrast, a mutator allele, often found in antibiotic-resistant lineages in pathogenic populations, had a relatively large positive effect on phage-resistance evolution and population density under parasitism. This suggests costs of antibiotic resistance may modify the outcome of phage therapy against pathogenic populations previously exposed to antibiotics, but the effects of any co-occurring mutator alleles are likely to be stronger. PMID:27194288

  10. Effects of antibiotic resistance alleles on bacterial evolutionary responses to viral parasites.

    Science.gov (United States)

    Arias-Sánchez, Flor I; Hall, Alex R

    2016-05-01

    Antibiotic resistance has wide-ranging effects on bacterial phenotypes and evolution. However, the influence of antibiotic resistance on bacterial responses to parasitic viruses remains unclear, despite the ubiquity of such viruses in nature and current interest in therapeutic applications. We experimentally investigated this by exposing various Escherichia coli genotypes, including eight antibiotic-resistant genotypes and a mutator, to different viruses (lytic bacteriophages). Across 960 populations, we measured changes in population density and sensitivity to viruses, and tested whether variation among bacterial genotypes was explained by their relative growth in the absence of parasites, or mutation rate towards phage resistance measured by fluctuation tests for each phage. We found that antibiotic resistance had relatively weak effects on adaptation to phages, although some antibiotic-resistance alleles impeded the evolution of resistance to phages via growth costs. By contrast, a mutator allele, often found in antibiotic-resistant lineages in pathogenic populations, had a relatively large positive effect on phage-resistance evolution and population density under parasitism. This suggests costs of antibiotic resistance may modify the outcome of phage therapy against pathogenic populations previously exposed to antibiotics, but the effects of any co-occurring mutator alleles are likely to be stronger.

  11. Phenotypic resistance and the dynamics of bacterial escape from phage control

    DEFF Research Database (Denmark)

    Bull, James J.; Vegge, Christina Skovgaard; Schmerer, Matthew;

    2014-01-01

    The canonical view of phage - bacterial interactions in dense, liquid cultures is that the phage will eliminate most of the sensitive cells; genetic resistance will then ascend to restore high bacterial densities. Yet there are various mechanisms by which bacteria may remain sensitive to phages...... but still attain high densities in their presence - because bacteria enter a transient state of reduced adsorption. Importantly, these mechanisms may be cryptic and inapparent prior to the addition of phage yet result in a rapid rebound of bacterial density after phage are introduced. We describe...... mathematical models of these processes and suggest how different types of this 'phenotypic' resistance may be elucidated. We offer preliminary in vitro studies of a previously characterized E. coli model system and Campylobacter jejuni illustrating apparent phenotypic resistance. As phenotypic resistance may...

  12. Resistance trends among clinical isolates in China reported from CHINET surveillance of bacterial resistance, 2005-2014.

    Science.gov (United States)

    Hu, F-P; Guo, Y; Zhu, D-M; Wang, F; Jiang, X-F; Xu, Y-C; Zhang, X-J; Zhang, C-X; Ji, P; Xie, Y; Kang, M; Wang, C-Q; Wang, A-M; Xu, Y-H; Shen, J-L; Sun, Z-Y; Chen, Z-J; Ni, Y-X; Sun, J-Y; Chu, Y-Z; Tian, S-F; Hu, Z-D; Li, J; Yu, Y-S; Lin, J; Shan, B; Du, Y; Han, Y; Guo, S; Wei, L-H; Wu, L; Zhang, H; Kong, J; Hu, Y-J; Ai, X-M; Zhuo, C; Su, D-H; Yang, Q; Jia, B; Huang, W

    2016-03-01

    With the aim of gathering temporal trends on bacterial epidemiology and resistance from multiple laboratories in China, the CHINET surveillance system was organized in 2005. Antimicrobial susceptibility testing was carried out according to a unified protocol using the Kirby-Bauer method or automated systems. Results were analyzed according to Clinical and Laboratory Standards Institute (CLSI) 2014 definitions. Between 2005 and 2014, the number of bacterial isolates ranged between 22,774 and 84,572 annually. Rates of extended-spectrum β-lactamase production among Escherichia coli isolates were stable, between 51.7 and 55.8%. Resistance of E. coli and Klebsiella pneumoniae to amikacin, ciprofloxacin, piperacillin/tazobactam and cefoperazone/sulbactam decreased with time. Carbapenem resistance among K. pneumoniae isolates increased from 2.4 to 13.4%. Resistance of Pseudomonas aeruginosa strains against all of antimicrobial agents tested including imipenem and meropenem decreased with time. On the contrary, resistance of Acinetobacter baumannii strains to carbapenems increased from 31 to 66.7%. A marked decrease of methicillin resistance from 69% in 2005 to 44.6% in 2014 was observed for Staphylococcus aureus. Carbapenem resistance rates in K. pneumoniae and A. baumannii in China are high. Our results indicate the importance of bacterial surveillance studies.

  13. Bacterial resistance to tetracycline: mechanisms, transfer, and clinical significance

    OpenAIRE

    Speer, B S; Shoemaker, N. B.; Salyers, A A

    1992-01-01

    Tetracycline has been a widely used antibiotic because of its low toxicity and broad spectrum of activity. However, its clinical usefulness has been declining because of the appearance of an increasing number of tetracycline-resistant isolates of clinically important bacteria. Two types of resistance mechanisms predominate: tetracycline efflux and ribosomal protection. A third mechanism of resistance, tetracycline modification, has been identified, but its clinical relevance is still unclear....

  14. Different Lipopolysaccharide Branched-Chain Amino Acids Modulate Porcine Intestinal Endogenous β-Defensin Expression through the Sirt1/ERK/90RSK Pathway.

    Science.gov (United States)

    Ren, Man; Zhang, Shihai; Liu, Xutong; Li, Shenghe; Mao, Xiangbing; Zeng, Xiangfang; Qiao, Shiyan

    2016-05-01

    Nutritional induction of endogenous antimicrobial peptide expression is considered a promising approach to inhibit the outgrowth and infection of pathogenic microbes in mammals. The present study investigated possible regulation of porcine epithelial β-defensins in response to branched-chain amino acids (BCAA) in vivo and in vitro. BCAA treatment increased relative mRNA expression of jejunal and ileal β-defensins in weaned piglets. In IPEC-J2 cells, isoleucine, leucine, and valine could stimulate β-defensin expression, possibly associated with stimulation of ERK1/2 phosphorylation. Inhibition of Sirt1 and ERK completely blocked the activation of ERK and 90RSK protein by isoleucine, simultaneously decreasing defensin expression. BCAA stimulate expression of porcine intestinal epithelial β-defensins with isoleucine the most, potent possibly through activation of the Sirt1/ERK/90RSK signaling pathway. The β-defensins regulation of lipopolysaccharide was related with an ERK-independent pathway. BCAA modulation of endogenous defensin might be a promising approach to enhance disease resistance and intestinal health in young animals and children. PMID:27083206

  15. Primary study on the resistance to bacterial blight (X. oryzae) in Cecropin B gene transgenic rices

    Institute of Scientific and Technical Information of China (English)

    HUAZhihua; HUANGDanian; XUERui; WANGXiaoling; GAOZhenya

    1998-01-01

    Bacterial blight (BB) is one of the major diseases to rice. Antibacterial Cecropin B gene has been cloned and transformed into rice. We studied the resistance to bacterial blight in Cecropin B gene tronsgenic rices.

  16. Bacterial flora and antimicrobial resistance in raw frozen cultured seafood imported to Denmark.

    Science.gov (United States)

    Noor Uddin, Gazi M; Larsen, Marianne Halberg; Guardabassi, Luca; Dalsgaard, Anders

    2013-03-01

    Intensified aquaculture includes the use of antimicrobials for disease control. In contrast to the situation in livestock, Escherichia coli and enterococci are not part of the normal gastrointestinal flora of fish and shrimp and therefore not suitable indicators of antimicrobial resistance in seafood. In this study, the diversity and phenotypic characteristics of the bacterial flora in raw frozen cultured and wild-caught shrimp and fish were evaluated to identify potential indicators of antimicrobial resistance. The bacterial flora cultured on various agar media at different temperatures yielded total viable counts of 4.0 × 10(4) to 3.0 × 10(5) CFU g(-1). Bacterial diversity was indicated by 16S rRNA sequence analysis of 84 isolates representing different colony types; 24 genera and 51 species were identified. Pseudomonas spp. (23% of isolates), Psychrobacter spp. (17%), Serratia spp. (13%), Exiguobacterium spp. (7%), Staphylococcus spp. (6%), and Micrococcus spp. (6%) dominated. Disk susceptibility testing of 39 bacterial isolates to 11 antimicrobials revealed resistance to ampicillin, amoxicillin-clavulanic acid, erythromycin, and third generation cephalosporins. Resistance to third generation cephalosporins was found in Pseudomonas, a genus naturally resistant to most β-lactam antibiotics, and in Staphylococcus hominis. Half of the isolates were susceptible to all antimicrobials tested. Results indicate that identification of a single bacterial resistance indicator naturally present in seafood at point of harvest is unlikely. The bacterial flora found likely represents a processing rather than a raw fish flora because of repeated exposure of raw material to water during processing. Methods and appropriate indicators, such as quantitative PCR of resistance genes, are needed to determine how antimicrobials used in aquaculture affect resistance of bacteria in retailed products.

  17. Strategies to overcome the action of aminoglycoside-modifying enzymes for treating resistant bacterial infections

    OpenAIRE

    Labby, Kristin J.; Garneau-Tsodikova, Sylvie

    2013-01-01

    Shortly after the discovery of the first antibiotics, bacterial resistance began to emerge. Many mechanisms give rise to resistance; the most prevalent mechanism of resistance to the aminoglycoside (AG) family of antibiotics is the action of aminoglycoside-modifying enzymes (AMEs). Since the identification of these modifying enzymes, many efforts have been put forth to prevent their damaging alterations of AGs. These diverse strategies are discussed within this review, including: creating new...

  18. Diversity of Dominant Bacterial Taxa in Activated Sludge Promotes Functional Resistance following Toxic Shock Loading

    KAUST Repository

    Saikaly, Pascal

    2010-12-14

    Examining the relationship between biodiversity and functional stability (resistance and resilience) of activated sludge bacterial communities following disturbance is an important first step towards developing strategies for the design of robust biological wastewater treatment systems. This study investigates the relationship between functional resistance and biodiversity of dominant bacterial taxa by subjecting activated sludge samples, with different levels of biodiversity, to toxic shock loading with cupric sulfate (Cu[II]), 3,5-dichlorophenol (3,5-DCP), or 4-nitrophenol (4-NP). Respirometric batch experiments were performed to determine the functional resistance of activated sludge bacterial community to the three toxicants. Functional resistance was estimated as the 30 min IC50 or the concentration of toxicant that results in a 50% reduction in oxygen utilization rate compared to a referential state represented by a control receiving no toxicant. Biodiversity of dominant bacterial taxa was assessed using polymerase chain reaction-terminal restriction fragment length polymorphism (PCR-T-RFLP) targeting the 16S ribosomal RNA (16S rRNA) gene. Statistical analysis of 30 min IC50 values and PCR-T-RFLP data showed a significant positive correlation (P<0.05) between functional resistance and microbial diversity for each of the three toxicants tested. To our knowledge, this is the first study showing a positive correlation between biodiversity of dominant bacterial taxa in activated sludge and functional resistance. In this system, activated sludge bacterial communities with higher biodiversity are functionally more resistant to disturbance caused by toxic shock loading. © 2010 Springer Science+Business Media, LLC.

  19. [The roles of epigenetics and protein post-translational modifications in bacterial antibiotic resistance].

    Science.gov (United States)

    Xie, Longxiang; Yu, Zhaoxiao; Guo, Siyao; Li, Ping; Abdalla, Abualgasim Elgaili; Xie, Jianping

    2015-08-01

    The increasing antibiotic resistance is now threatening to take us back to a pre-antibiotic era. Bacteria have evolved diverse resistance mechanisms, on which in-depth research could help the development of new strategies to control antibiotic-resistant infections. Epigenetic alterations and protein post-translational modifications (PTMs) play important roles in multiple cellular processes such as metabolism, signal transduction, protein degradation, DNA replication regulation and stress response. Recent studies demonstrated that epigenetics and PTMs also play vital roles in bacterial antibiotic resistance. In this review, we summarize the regulatory roles of epigenetic factors including DNA methylation and regulatory RNAs as well as PTMs such as phosphorylation and succinylation in bacterial antibiotic resistance, which may provide innovative perspectives on selecting antibacterial targets and developing antibiotics. PMID:26266782

  20. Antagonistic Activities of Purple Non-sulfur Bacterial Extracts Against Antibiotic Resistant Vibrio sp.

    OpenAIRE

    Chandrasekaran, R.; Ashok Kumar, G. V.

    2011-01-01

    Solvent extracts of native purple non-sulfur bacterial (PNSB) isolates from the effluents of brackish shrimp culture ponds, near Nagapattinam coast (South India) were evaluated for antibacterial activity by the disc diffusion method. Best results were shown by the chloroform extracts against oxytetracycline resistant Vibrio harveyi and Vibrio fischerii. Among the purple non-sulfur bacterial isolates, Rhodobacter sphaeroides, showed maximum antagonistic activity. The findings suggest that the...

  1. Absence of bacterial resistance to medical-grade manuka honey

    OpenAIRE

    Cooper, R A; Jenkins, L.; Henriques, A. F. M.; Duggan, R. S.; Burton, N. F.

    2010-01-01

    Abstract Clinical use of honey in the topical treatment of wounds has increased in Europe and North America since licensed wound care products became available in 2004 and 2007, respectively. Honey-resistant bacteria have not been isolated from wounds, but there is a need to investigate whether honey has the potential to select for honey resistance. Two cultures of bacteria from reference collections (Staphylococcus aureus NCTC 10017 and Pseudomonas aeruginosa ATCC 27853) and four ...

  2. Molecular mechanisms involved in bacterial speck disease resistance of tomato

    OpenAIRE

    Gu, Y.-Q.

    1998-01-01

    An important recent advance in the field of plant-microbe interactions has been the cloning of genes that confer resistance to specific viruses, bacteria, fungi or nematodes. Disease resistance (R) genes encode proteins with predicted structural motifs consistent with them having roles in signal recognition and transduction. The future challenge is to understand how R gene products specifically perceive defence-eliciting signals from the pathogen and transduce those signals to pathways that l...

  3. Using experimental evolution to explore natural patterns between bacterial motility and resistance to bacteriophages.

    Science.gov (United States)

    Koskella, Britt; Taylor, Tiffany B; Bates, Jennifer; Buckling, Angus

    2011-11-01

    Resistance of bacteria to phages may be gained by alteration of surface proteins to which phages bind, a mechanism that is likely to be costly as these molecules typically have critical functions such as movement or nutrient uptake. To address this potential trade-off, we combine a systematic study of natural bacteria and phage populations with an experimental evolution approach. We compare motility, growth rate and susceptibility to local phages for 80 bacteria isolated from horse chestnut leaves and, contrary to expectation, find no negative association between resistance to phages and bacterial motility or growth rate. However, because correlational patterns (and their absence) are open to numerous interpretations, we test for any causal association between resistance to phages and bacterial motility using experimental evolution of a subset of bacteria in both the presence and absence of naturally associated phages. Again, we find no clear link between the acquisition of resistance and bacterial motility, suggesting that for these natural bacterial populations, phage-mediated selection is unlikely to shape bacterial motility, a key fitness trait for many bacteria in the phyllosphere. The agreement between the observed natural pattern and the experimental evolution results presented here demonstrates the power of this combined approach for testing evolutionary trade-offs.

  4. Trends in bacterial resistance in a tertiary university hospital over one decade

    Directory of Open Access Journals (Sweden)

    Fernando Góngora Rubio

    2013-08-01

    Full Text Available The objective of this study was to investigate bacterial resistance trends, infection sites and the relationship between resistance and admittance to the intensive care unit (ICU. A total of 53,316 bacteria identified between 1999 and 2008 were evaluated. Multidrug resistance was characterized when gram-negative bacilli (GNB presented resistance to two or more classes of antibiotics. Gram-positive cocci (CPC were assessed for resistance to penicillin, oxacillin and vancomycin. GNB were the most common (66.1% isolate. There was a 3.7-fold overall increase in multidrug resistant GNB over the study period; Acinetobacter baumanii and Staphylococcus aureus were the most prevalent. Highest increases were recorded for Kleb siella pneumoniae (14.6-fold and enterococci (73-fold. The resistance rates for GNB and GPC were 36% and 51.7%, respectively. Most multidrug resistant GNB and GPC were recovered from ICU patients (p-value < 0.001. vancomycin-resistant enterococci were isolated during this decade with an increase of 18.7% by 2008. these data confirm the worldwide trend in multidrug bacterial resistance.

  5. Trends in bacterial resistance in a tertiary university hospital over one decade.

    Science.gov (United States)

    Rubio, Fernando Góngora; Oliveira, Viviane Decicera Colombo; Rangel, Regina Mara Custódio; Nogueira, Mara Corrêa Lelles; Almeida, Margarete Teresa Gottardo

    2013-01-01

    The objective of this study was to investigate bacterial resistance trends, infection sites and the relationship between resistance and admittance to the intensive care unit (ICU). A total of 53,316 bacteria identified between 1999 and 2008 were evaluated. Multidrug resistance was characterized when gram-negative bacilli (GNB) presented resistance to two or more classes of antibiotics. Gram-positive cocci (CPC) were assessed for resistance to penicillin, oxacillin and vancomycin. GNB were the most common (66.1%) isolate. There was a 3.7-fold overall increase in multidrug resistant GNB over the study period; Acinetobacter baumanii and Staphylococcus aureus were the most prevalent. Highest increases were recorded for Klebsiella pneumoniae (14.6-fold) and enterococci (73-fold). The resistance rates for GNB and GPC were 36% and 51.7%, respectively. Most multidrug resistant GNB and GPC were recovered from ICU patients (p-value<0.001). Vancomycin-resistant enterococci were isolated during this decade with an increase of 18.7% by 2008. These data confirm the worldwide trend in multidrug bacterial resistance. PMID:23797009

  6. Interferon in resistance to bacterial and protozoan infections

    Science.gov (United States)

    Sonnenfeld, Gerald; Gould, Cheryl L.; Kierszenbaum, Felipe; Degee, Antonie L. W.; Mansfield, John M.

    1986-01-01

    The effects of genetic differences in mouse strains on the modulation of protozoan infections by interferon (IFN) were investigated. In one set of experiments, three different strains of mice were injected with T. cruzi, and their sera were assayed at five time intervals for IFN titer. A greater quantity of IFN was produced by mouse strains that were susceptible to T. cruzi infection than by the more resistant strain. In another set of experiments, spleen cell cultures from inbred strains of mice were challenged with an antigen made from T.b. rhodesiense. The cells from mice resistant to infection, produced greater amounts of IFN-gamma than did cells from the susceptible mice. In a third set of experiments, it was found that mice injected with T.b. rhodesiense before being infected with a diabetogenic virus (EMC-D) were resistant to the effects of the virus and did not produce virus-specific antibody.

  7. PREVALENCE OF BACTERIAL RESISTANCE IN HOSPITALIZED CIRRHOTIC PATIENTS IN SOUTHERN BRAZIL: A NEW CHALLENGE

    Directory of Open Access Journals (Sweden)

    Ane Micheli COSTABEBER

    2016-01-01

    Full Text Available Background & Aims: An increased frequency of infections by multiresistant bacteria has been described in hospitalized patients. The aim of this study was to evaluate the bacterial resistance profile in cirrhotic patients. Methods: This is a retrospective observational study. We assessed the antimicrobial susceptibility of 5,839 bacterial isolates from patients with and without cirrhosis. Regarding the multidrug resistance, we evaluated 4,505 bacterial isolates from 2,180 patients. Results: Two hundred and fifty-one patients had cirrhosis (mean age 57.6 ± 11 years; 61.8% were male, 47.8% of cases associated with hepatitis C virus. Of the isolates of patients with and without cirrhosis, 174/464 (37.5% and 1,783/4,041 (44.1% were multiresistant, respectively (p = 0.007. E. coli was the most common multiresistant bacteria in both groups. Approximately 20% of E. coli and Klebsiella sp. isolates were ESBL-producers and 44% of S. aureus isolates were methicillin-resistant in cirrhotic patients. In cirrhotic patients admitted to the emergency department, hospital ward, and intensive care unit, 28.3%, 50% and 40% had multiresistant isolates, respectively. In patients with and without cirrhosis, 36.2% and 33.5% of isolates were resistant to third-generation cephalosporins, respectively. Conclusions: The empirical treatment of infections in hospitalized patients using broad-spectrum antibiotics should consider the observed pattern of bacterial resistance.

  8. PREVALENCE OF BACTERIAL RESISTANCE IN HOSPITALIZED CIRRHOTIC PATIENTS IN SOUTHERN BRAZIL: A NEW CHALLENGE

    Science.gov (United States)

    COSTABEBER, Ane Micheli; de MATTOS, Angelo Alves; SUKIENNIK, Teresa Cristina Teixeira

    2016-01-01

    Background & Aims: An increased frequency of infections by multiresistant bacteria has been described in hospitalized patients. The aim of this study was to evaluate the bacterial resistance profile in cirrhotic patients. Methods: This is a retrospective observational study. We assessed the antimicrobial susceptibility of 5,839 bacterial isolates from patients with and without cirrhosis. Regarding the multidrug resistance, we evaluated 4,505 bacterial isolates from 2,180 patients. Results: Two hundred and fifty-one patients had cirrhosis (mean age 57.6 ± 11 years; 61.8% were male, 47.8% of cases associated with hepatitis C virus). Of the isolates of patients with and without cirrhosis, 174/464 (37.5%) and 1,783/4,041 (44.1%) were multiresistant, respectively (p = 0.007). E. coli was the most common multiresistant bacteria in both groups. Approximately 20% of E. coli and Klebsiella sp. isolates were ESBL-producers and 44% of S. aureus isolates were methicillin-resistant in cirrhotic patients. In cirrhotic patients admitted to the emergency department, hospital ward, and intensive care unit, 28.3%, 50% and 40% had multiresistant isolates, respectively. In patients with and without cirrhosis, 36.2% and 33.5% of isolates were resistant to third-generation cephalosporins, respectively. Conclusions: The empirical treatment of infections in hospitalized patients using broad-spectrum antibiotics should consider the observed pattern of bacterial resistance. PMID:27253738

  9. A genome-wide screen identifies a single β-defensin gene cluster in the chicken: implications for the origin and evolution of mammalian defensins

    Directory of Open Access Journals (Sweden)

    Xiao Yanjing

    2004-08-01

    Full Text Available Abstract Background Defensins comprise a large family of cationic antimicrobial peptides that are characterized by the presence of a conserved cysteine-rich defensin motif. Based on the spacing pattern of cysteines, these defensins are broadly divided into five groups, namely plant, invertebrate, α-, β-, and θ-defensins, with the last three groups being mostly found in mammalian species. However, the evolutionary relationships among these five groups of defensins remain controversial. Results Following a comprehensive screen, here we report that the chicken genome encodes a total of 13 different β-defensins but with no other groups of defensins being discovered. These chicken β-defensin genes, designated as Gallinacin 1–13, are clustered densely within a 86-Kb distance on the chromosome 3q3.5-q3.7. The deduced peptides vary from 63 to 104 amino acid residues in length sharing the characteristic defensin motif. Based on the tissue expression pattern, 13 β-defensin genes can be divided into two subgroups with Gallinacin 1–7 being predominantly expressed in bone marrow and the respiratory tract and the remaining genes being restricted to liver and the urogenital tract. Comparative analysis of the defensin clusters among chicken, mouse, and human suggested that vertebrate defensins have evolved from a single β-defensin-like gene, which has undergone rapid duplication, diversification, and translocation in various vertebrate lineages during evolution. Conclusions We conclude that the chicken genome encodes only β-defensin sequences and that all mammalian defensins are evolved from a common β-defensin-like ancestor. The α-defensins arose from β-defensins by gene duplication, which may have occurred after the divergence of mammals from other vertebrates, and θ-defensins have arisen from α-defensins specific to the primate lineage. Further analysis of these defensins in different vertebrate lineages will shed light on the mechanisms of

  10. The Impact of Resource Availability on Bacterial Resistance to Phages in Soil

    OpenAIRE

    Pedro Gómez; Jonathan Bennie; Gaston, Kevin J; Angus Buckling

    2015-01-01

    Resource availability can affect the coevolutionary dynamics between host and parasites, shaping communities and hence ecosystem function. A key finding from theoretical and in vitro studies is that host resistance evolves to greater levels with increased resources, but the relevance to natural communities is less clear. We took two complementary approaches to investigate the effect of resource availability on the evolution of bacterial resistance to phages in soil. First, we measured the res...

  11. Insights into the amplification of bacterial resistance to erythromycin in activated sludge.

    Science.gov (United States)

    Guo, Mei-Ting; Yuan, Qing-Bin; Yang, Jian

    2015-10-01

    Wastewater treatment plants are significant reservoirs for antimicrobial resistance. However, little is known about wastewater treatment effects on the variation of antibiotic resistance. The shifts of bacterial resistance to erythromycin, a macrolide widely used in human medicine, on a lab-scale activated sludge system fed with real wastewater was investigated from levels of bacteria, community and genes, in this study. The resistance variation of total heterotrophic bacteria was studied during the biological treatment process, based on culture dependent method. The alterations of bacterial community resistant to erythromycin and nine typical erythromycin resistance genes were explored with molecular approaches, including high-throughput sequencing and quantitative polymerase chain reaction. The results revealed that the total heterotrophs tolerance level to erythromycin concentrations (higher than 32 mg/L) was significantly amplified during the activated sludge treatment, with the prevalence increased from 9.6% to 21.8%. High-throughput sequencing results demonstrated an obvious increase of the total heterotrophic bacterial diversity resistant to erythromycin. Proteobacteria and Bacteroidetes were the two dominant phyla in the influent and effluent of the bioreactor. However, the prevalence of Proteobacteria decreased from 76% to 59% while the total phyla number increased greatly from 18 to 29 through activated sludge treatment. The gene proportions of erm(A), mef(E) and erm(D) were greatly amplified after biological treatment. It is proposed that the transfer of antibiotic resistance genes through the variable mixtures of bacteria in the activated sludge might be the reason for the antibiotic resistance amplification. The amplified risk of antibiotic resistance in wastewater treatment needs to be paid more attention. PMID:25957255

  12. Fluoroquinolone-metal complexes: a route to counteract bacterial resistance?

    Science.gov (United States)

    Feio, Maria J; Sousa, Isabel; Ferreira, Mariana; Cunha-Silva, Luís; Saraiva, Raúl G; Queirós, Carla; Alexandre, José G; Claro, Vasco; Mendes, Adélia; Ortiz, Rosa; Lopes, Sandra; Amaral, Ana Luísa; Lino, João; Fernandes, Patrícia; Silva, Ana João; Moutinho, Lisete; de Castro, Baltazar; Pereira, Eulália; Perelló, Lourdes; Gameiro, Paula

    2014-09-01

    Microbial resistance to antibiotics is one of the biggest public health threats of the modern world. Antibiotic resistance is an area of much clinical relevance and therefore research that has the potential to identify agents that may circumvent it or treat resistant infections is paramount. Solution behavior of various fluoroquinolone (FQ) complexes with copper(II) in the presence and absence of 1,10-phenanthroline (phen) was studied in aqueous solution, by potentiometry and/or spectrophotometry, and are herein described. The results obtained showed that under physiological conditions (micromolar concentration range and pH7.4) only copper(II):FQ:phen ternary complexes are stable. Hence, these complexes were synthesised and characterised by means of UV-visible and IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. In these complexes, the FQ acts as a bidentate ligand that coordinates the metal cation through the carbonyl and carboxyl oxygen atoms and phen coordinates through two N-atoms forming the equatorial plane of a distorted square-pyramidal geometry. The fifth position of the penta-coordinated Cu(II) centre is generally occupied axially by an oxygen atom from a water molecule or from a nitrate ion. Minimum inhibitory concentration (MIC) determinations of the complexes and comparison with free FQ in various E. coli strains indicate that the Cu-complexes are as efficient antimicrobials as the free antibiotic. Moreover, results strongly suggest that the cell intake route of both species is different supporting, therefore, the complexes' suitability as candidates for further biological testing in FQ-resistant microorganisms.

  13. Who Possesses Drug Resistance Genes in the Aquatic Environment? : Sulfamethoxazole (SMX) Resistance Genes among the Bacterial Community in Water Environment of Metro-Manila, Philippines

    OpenAIRE

    Satoru eSuzuki; Mitsuko eOgo; Miller, Todd W.; Akiko eShimizu; Hideshige eTakada; Maria Auxilia eSiringan

    2013-01-01

    Recent evidence has shown that antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are ubiquitous in natural environments, including sites considered pristine. To understand the origin of ARGs and their dynamics, we must first define their actual presence in the natural bacterial assemblage. Here we found varying distribution profiles of sul genes in “colony forming bacterial assemblages” and “natural bacterial assemblages.” Our monitoring for antibiotic contamination r...

  14. Antibiotic exposure can induce various bacterial virulence phenotypes in multidrug-resistant Salmonella enterica serovar Typhimurium

    Science.gov (United States)

    Salmonella is one of the most prevalent bacterial foodborne diseases in the United States and causes an estimated 1 million human cases every year. Multidrug-resistant (MDR) Salmonella has emerged as a public health issue as it has been associated with increased morbidity in humans and mortality in...

  15. Bacterial multidrug resistance mediated by a homologue of the human multidrug transporter P-glycoprotein

    NARCIS (Netherlands)

    Konings, WN; Poelarends, GJ

    2002-01-01

    Most ATP-binding cassette (ABC) multidrug transporters known to date are of eukaryotic origin, such as the P-glycoproteins (Pgps) and multidrug resistance-associated proteins (MRPs). Only one well-characterized ABC multidrug transporter, LmrA, is of bacterial origin. On the basis of its structural a

  16. The Capsule Sensitizes Streptococcus pneumoniae to α-Defensins Human Neutrophil Proteins 1 to 3▿

    OpenAIRE

    Beiter, Katharina; Wartha, Florian; Hurwitz, Robert; Normark, Staffan; Zychlinsky, Arturo; Henriques-Normark, Birgitta

    2008-01-01

    Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide. Its polysaccharide capsule causes resistance to phagocytosis and interferes with the innate immune system's ability to clear infections at an early stage. Nevertheless, we found that encapsulated pneumococci are sensitive to killing by a human neutrophil granule extract. We fractionated the extract by high-performance liquid chromatography and identified α-defensins by mass spectrometry as the proteins responsible...

  17. Epidemiology and antibiotic resistance of bacterial meningitis in Dapaong, northern Togo

    Institute of Scientific and Technical Information of China (English)

    Simplice D Karou; Abago Balaka; Mitiname Bamok; Damhan Tchelougou; Malki Assih; Kokou Anani; Kodjo Agbonoko; Jacques Simpore; Comlan de Souza

    2012-01-01

    Objective:To assess the seasonality of the bacterial meningitis and the antibiotic resistance of incriminated bacteria over the last three years in the northern Togo. Methods: From January 2007 to January 2010, 533 cerebrospinal fluids (CSF) samples were collected from patients suspected of meningitis in the Regional Hospital of Dapaong (northern Togo). After microscopic examination, samples were cultured for bacterial identification and antibiotic susceptibility. Results:The study included 533 patients (306 male and 227 female) aged from 1 day to 55 years [average age (13.00±2.07) years]. Bacterial isolation and identification were attempted for 254/533 (47.65%) samples. The bacterial species identified were:Neisseria meningitidis A (N. meningitidis A) (58.27%), Neisseria meningitidis W135 (N. meningitidis W135) (7.09%), Streptococcus pneumoniae (S. pneumoniae) (26.77%), Haemophilus influenza B (H. influenza B) (6.30%) and Enterobacteriaceae (1.57%). The results indicated that bacterial meningitis occur from November to May with a peak in February for H. influenzae and S. pneumoniae and March for Neisseriaceae. The distribution of positive CSF with regards to the age showed that subjects between 6 and 12 years followed by subjects of 0 to 5 years were most affected with respective frequencies of 67.82% and 56.52% (P20%for both bacterial strains), macrolides (resistance rate> 30%for H. influenzae) quinolones (resistance rate>15%for H. influenzae and N. meningitidis W135). Over three years, the prevalence of S. pneumoniae significantly increased from 8.48%to 73.33%(P<0.001), while the changes in the prevalence of H. influenzae B were not statistically significant: 4.24%, vs. 8.89%, (P= 0.233). Conclusions:Our results indicate that data in African countries differ depending on geographical location in relation to the African meningitis belt. This underlines the importance of epidemiological surveillance of bacterial meningitis.

  18. Combining ability for common bacterial blight resistance in snap and dry bean (Phaseolus vulgaris L.

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    Roberto dos Santos Trindade

    2014-11-01

    Full Text Available Common bacterial blight (CBB, which is caused by Xanthomonas axonopodis pv. phaseoli (Xap, is the main bacterial disease in snap beans and controlling this disease using resistant cultivars is still a challenge. This work aimed to study the combining ability for CBB resistance in Phaseolus vulgaris genotypes. Six parents (two genotypes of CBB-resistant dry bean and four susceptible snap bean accessions were crossed in a complete diallel scheme without reciprocals to estimate the general and specific ability to Xap resistance. CBB resistance was evaluated by the inoculation with two Xap isolates, and its severity was evaluated based on the four following resistance components: area under the disease progress curve; scores in the leaves; latent period and diameter of pod lesion. Differences between the two isolates were observed considering all the disease components. Besides pathogen variability, significant GCA and SCA indicate that additive and non-additive effects are involved in Xap-resistance control for the evaluated genotypes, implying that CBC resistance is a trait with complex inheritance. For breeding purposes, the result demonstrates the need to apply breeding methods that are focused on advanced generations selection.

  19. Defensins promote fusion and lysis of negatively charged membranes.

    OpenAIRE

    Fujii, G; Selsted, M E; Eisenberg, D.

    1993-01-01

    Defensins, a family of cationic peptides isolated from mammalian granulocytes and believed to permeabilize membranes, were tested for their ability to cause fusion and lysis of liposomes. Unlike alpha-helical peptides whose lytic effects have been extensively studied, the defensins consist primarily of beta-sheet. Defensins fuse and lyse negatively charged liposomes but display reduced activity with neutral liposomes. These and other experiments suggest that fusion and lysis is mediated prima...

  20. Bacterial infections in Lilongwe, Malawi: aetiology and antibiotic resistance

    Directory of Open Access Journals (Sweden)

    Makoka Mwai H

    2012-03-01

    Full Text Available Abstract Background Life-threatening infections present major challenges for health systems in Malawi and the developing world because routine microbiologic culture and sensitivity testing are not performed due to lack of capacity. Use of empirical antimicrobial therapy without regular microbiologic surveillance is unable to provide adequate treatment in the face of emerging antimicrobial resistance. This study was conducted to determine antimicrobial susceptibility patterns in order to inform treatment choices and generate hospital-wide baseline data. Methods Culture and susceptibility testing was performed on various specimens from patients presenting with possible infectious diseases at Kamuzu Central Hospital, Lilongwe, Malawi. Results Between July 2006 and December 2007 3104 specimens from 2458 patients were evaluated, with 60.1% from the adult medical service. Common presentations were sepsis, meningitis, pneumonia and abscess. An etiologic agent was detected in 13% of patients. The most common organisms detected from blood cultures were Staphylococcus aureus, Escherichia coli, Salmonella species and Streptococcus pneumoniae, whereas Streptococcus pneumoniae and Cryptococcus neoformans were most frequently detected from cerebrospinal fluid. Haemophilus influenzae was rarely isolated. Resistance to commonly used antibiotics was observed in up to 80% of the isolates while antibiotics that were not commonly in use maintained susceptibility. Conclusions There is widespread resistance to almost all of the antibiotics that are empirically used in Malawi. Antibiotics that have not been widely introduced in Malawi show better laboratory performance. Choices for empirical therapy in Malawi should be revised accordingly. A microbiologic surveillance system should be established and prudent use of antimicrobials promoted to improve patient care.

  1. Pyramiding blast, bacterial blight and brown planthopper resistance genes in rice restorer lines

    Institute of Scientific and Technical Information of China (English)

    JI Zhi-juan; Yang Shu-dong; ZENG Yu-xiang; LIANG Yan; YANG Chang-deng; QIAN Qian

    2016-01-01

    Rice blast, bacterial blight (BB) and brown planthopper (BPH) are the three main pests of rice. This study investigated pyr-amiding genes resistant to blast, BB and BPH to develop restorer lines. Ten new lines with blast, BB and/or BPH resistance genes were developed using marker-assisted selection (MAS) technique and agronomic trait selection (ATS) method. Only HR13 with resistance genes to blast, BB and BPH was obtained. In addition to blast and BB resistance, four lines (HR39, HR41, HR42, HR43) demonstrated moderate resistance to BPH, but MAS for BPH resistance genes were not conducted in developing these four lines. These data suggested that there were unknown elite BPH resistance genes in the Zhongzu 14 donor parent. A more effective defense was demonstrated in the lines withPi1 andPi2 genes although the weather in 2012 was favorable to disease incidence. Blast resistance of the lines with a single resistance gene,Pita, was easily inlfuenced by the weather. Overal, the information obtained through pyramiding multiple resistance genes on developing the restorer lines is helpful for rice resistance breeding.

  2. Heavy metals in liquid pig manure in light of bacterial antimicrobial resistance

    International Nuclear Information System (INIS)

    Heavy metals are regularly found in liquid pig manure, and might interact with bacterial antimicrobial resistance. Concentrations of heavy metals were determined by atomic spectroscopic methods in 305 pig manure samples and were connected to the phenotypic resistance of Escherichia coli (n=613) against 29 antimicrobial drugs. Concentrations of heavy metals (/kg dry matter) were 0.08–5.30 mg cadmium, 1.1–32.0 mg chrome, 22.4–3387.6 mg copper, <2.0–26.7 mg lead, <0.01–0.11 mg mercury, 3.1–97.3 mg nickel and 93.0–8239.0 mg zinc. Associated with the detection of copper and zinc, resistance rates against β-lactams were significantly elevated. By contrast, the presence of mercury was significantly associated with low antimicrobial resistance rates of Escherichia coli against β-lactams, aminoglycosides and other antibiotics. Effects of subinhibitory concentrations of mercury on bacterial resistance against penicillins, cephalosporins, aminoglycosides and doxycycline were also demonstrated in a laboratory trial. Antimicrobial resistance in the porcine microflora might be increased by copper and zinc. By contrast, the occurrence of mercury in the environment might, due to co-toxicity, act counter-selective against antimicrobial resistant strains.

  3. Heavy metals in liquid pig manure in light of bacterial antimicrobial resistance

    Energy Technology Data Exchange (ETDEWEB)

    Hoelzel, Christina S., E-mail: Christina.Hoelzel@wzw.tum.de [Chair of Animal Hygiene, Technische Universitaet Muenchen, Weihenstephaner Berg 3, 85354 Freising (Germany); Mueller, Christa [Institute for Agroecology, Organic Farming and Soil Protection, Bavarian State Research Center for Agriculture (LfL), Lange Point 12, 85354 Freising (Germany); Harms, Katrin S. [Chair of Animal Hygiene, Technische Universitaet Muenchen, Weihenstephaner Berg 3, 85354 Freising (Germany); Mikolajewski, Sabine [Department for Quality Assurance and Analytics, Bavarian State Research Center for Agriculture (LfL), Lange Point 4, 85354 Freising (Germany); Schaefer, Stefanie; Schwaiger, Karin; Bauer, Johann [Chair of Animal Hygiene, Technische Universitaet Muenchen, Weihenstephaner Berg 3, 85354 Freising (Germany)

    2012-02-15

    Heavy metals are regularly found in liquid pig manure, and might interact with bacterial antimicrobial resistance. Concentrations of heavy metals were determined by atomic spectroscopic methods in 305 pig manure samples and were connected to the phenotypic resistance of Escherichia coli (n=613) against 29 antimicrobial drugs. Concentrations of heavy metals (/kg dry matter) were 0.08-5.30 mg cadmium, 1.1-32.0 mg chrome, 22.4-3387.6 mg copper, <2.0-26.7 mg lead, <0.01-0.11 mg mercury, 3.1-97.3 mg nickel and 93.0-8239.0 mg zinc. Associated with the detection of copper and zinc, resistance rates against {beta}-lactams were significantly elevated. By contrast, the presence of mercury was significantly associated with low antimicrobial resistance rates of Escherichia coli against {beta}-lactams, aminoglycosides and other antibiotics. Effects of subinhibitory concentrations of mercury on bacterial resistance against penicillins, cephalosporins, aminoglycosides and doxycycline were also demonstrated in a laboratory trial. Antimicrobial resistance in the porcine microflora might be increased by copper and zinc. By contrast, the occurrence of mercury in the environment might, due to co-toxicity, act counter-selective against antimicrobial resistant strains.

  4. Antagonistic rhizobacteria and jasmonic acid induce resistance against tomato bacterial spot

    Directory of Open Access Journals (Sweden)

    Hélvio Gledson Maciel Ferraz

    2015-12-01

    Full Text Available AbstractTomato bacterial spot on tomato may be caused by four species of Xanthomonas and among them X. gardneri(Xg is the most destructive one, especially in areas irrigated using a center pivot system in Minas Gerais state and the midwest region of Brazil. Due to the ineffectiveness of chemical control and the lack of cultivars with high levels of genetic resistance, this study investigated the potential of three antagonists (Streptomyces setonii (UFV618, Bacillus cereus (UFV592 and Serratia marcescens (UFV252, and the hormone jasmonic acid (JA as a positive control, to reduce bacterial spot symptoms and to potentiate defense enzymes in the leaves of tomato plants infected by Xg. Tomato seeds were microbiolized with each antagonist, and the soil was drenched with these bacteria. The plants were sprayed with JA 48 h before Xginoculation. The final average severity on the tomato plants was reduced by 29.44, 59.26 and 61.33% in the UFV592, UFV618 and JA treatments, respectively. The UFV618 antagonist was as effective as JA in reducing bacterial spot symptoms on tomatoes, which can be explained by the greater activities of defense enzymes that are commonly involved in host resistance against bacterial diseases. These results suggest that JA and the UFV618 antagonist can be used in the integrated management of bacterial spot on tomatoes.

  5. Cultivable Bacterial Microbiota of Northern Bobwhite (Colinus virginianus): A New Reservoir of Antimicrobial Resistance?

    Science.gov (United States)

    Su, Hongwen; McKelvey, Jessica; Rollins, Dale; Zhang, Michael; Brightsmith, Donald J.; Derr, James; Zhang, Shuping

    2014-01-01

    The northern bobwhite (Colinus virginianus) is an ecologically and economically important avian species. At the present time, little is known about the microbial communities associated with these birds. As the first step to create a quail microbiology knowledge base, the current study conducted an inventory of cultivable quail tracheal, crop, cecal, and cloacal microbiota and associated antimicrobial resistance using a combined bacteriology and DNA sequencing approach. A total of 414 morphologically unique bacterial colonies were selected from nonselective aerobic and anaerobic cultures, as well as selective and enrichment cultures. Analysis of the first 500-bp 16S rRNA gene sequences in conjunction with biochemical identifications revealed 190 non-redundant species-level taxonomic units, representing 160 known bacterial species and 30 novel species. The bacterial species were classified into 4 phyla, 14 orders, 37 families, and 59 or more genera. Firmicutes was the most commonly encountered phylum (57%) followed by Actinobacteria (24%), Proteobacteria (17%) and Bacteroidetes (0.02%). Extensive diversity in the species composition of quail microbiota was observed among individual birds and anatomical locations. Quail microbiota harbored several opportunistic pathogens, such as E. coli and Ps. aeruginosa, as well as human commensal organisms, including Neisseria species. Phenotypic characterization of selected bacterial species demonstrated a high prevalence of resistance to the following classes of antimicrobials: phenicol, macrolide, lincosamide, quinolone, and sulphate. Data from the current investigation warrant further investigation on the source, transmission, pathology, and control of antimicrobial resistance in wild quail populations. PMID:24937705

  6. Cultivable bacterial microbiota of northern bobwhite (Colinus virginianus: a new reservoir of antimicrobial resistance?

    Directory of Open Access Journals (Sweden)

    Hongwen Su

    Full Text Available The northern bobwhite (Colinus virginianus is an ecologically and economically important avian species. At the present time, little is known about the microbial communities associated with these birds. As the first step to create a quail microbiology knowledge base, the current study conducted an inventory of cultivable quail tracheal, crop, cecal, and cloacal microbiota and associated antimicrobial resistance using a combined bacteriology and DNA sequencing approach. A total of 414 morphologically unique bacterial colonies were selected from nonselective aerobic and anaerobic cultures, as well as selective and enrichment cultures. Analysis of the first 500-bp 16S rRNA gene sequences in conjunction with biochemical identifications revealed 190 non-redundant species-level taxonomic units, representing 160 known bacterial species and 30 novel species. The bacterial species were classified into 4 phyla, 14 orders, 37 families, and 59 or more genera. Firmicutes was the most commonly encountered phylum (57% followed by Actinobacteria (24%, Proteobacteria (17% and Bacteroidetes (0.02%. Extensive diversity in the species composition of quail microbiota was observed among individual birds and anatomical locations. Quail microbiota harbored several opportunistic pathogens, such as E. coli and Ps. aeruginosa, as well as human commensal organisms, including Neisseria species. Phenotypic characterization of selected bacterial species demonstrated a high prevalence of resistance to the following classes of antimicrobials: phenicol, macrolide, lincosamide, quinolone, and sulphate. Data from the current investigation warrant further investigation on the source, transmission, pathology, and control of antimicrobial resistance in wild quail populations.

  7. Steroidal regulation of uterine resistance to bacterial infection in livestock

    Directory of Open Access Journals (Sweden)

    Lewis Gregory S

    2003-11-01

    Full Text Available Abstract Postpartum uterine infections reduce reproductive efficiency and have significant animal welfare and economic consequences. Postpartum uterine infections are classified as nonspecific, but Arcanobacterium pyogenes and Escherichia coli are usually associated with them in cattle and sheep. Pyometra is the most common type of uterine infection in dairy cattle, and it is detected almost exclusively in cows with active corpora lutea. Luteal progesterone typically down-regulates uterine immune functions and prevents the uterus from resisting infections. Progesterone also can down-regulate uterine eicosanoid synthesis. This seems to be a critical event in the onset of uterine infections, because eicosanoids can up-regulate immune cell functions in vitro. In addition, exogenous prostaglandin F2 alpha stimulates uterine secretion of prostaglandin F2 alpha and enhances immune functions in vivo. Thus, one may hypothesize that eicosanoids can override the negative effects of progesterone and that the up-regulatory effects of exogenous prostaglandin F2 alpha allow the uterus to resolve an infection, regardless of progesterone concentrations. Based on the results of studies to test that hypothesis, cows, sheep, and pigs in various physiological statuses are resistant to intrauterine infusions of Arcanobacterium pyogenes and Escherichia coli, unless progesterone concentrations are increased. In sheep and pigs, exogenous prostaglandin F2 alpha stimulates uterine production of prostaglandin F2 alpha and allows the uterus to resolve Arcanobacterium pyogenes-Escherichia coli-induced infections, even when progesterone is maintained at luteal phase concentrations before and after treatment. Prostaglandin F2 alpha is a proinflammatory molecule that stimulates the production of various proinflammatory cytokines, and it may enhance uterine production of leukotriene B4. Proinflammatory cytokines and leukotriene B4 enhance phagocytosis and lymphocyte functions

  8. Construction of recombinant E. coli Nissle 1917 (EcN) strains for the expression and secretion of defensins.

    Science.gov (United States)

    Seo, Ean-jeong; Weibel, Stephanie; Wehkamp, Jan; Oelschlaeger, Tobias A

    2012-11-01

    The probiotic Escherichia coli strain Nissle 1917 (EcN) is one of the few probiotics licensed as a medication in several countries. Best documented is its effectiveness in keeping patients suffering from ulcerative colitis (UC) in remission. This might be due to its ability to induce the production of human β-defensin 2 (HBD2) in a flagellin-dependent way in intestinal epithelial cells. In contrast to ulcerative colitis, for Crohn's disease (CD) convincing evidence is lacking that EcN might be clinically effective, most likely due to the genetically based inability of sufficient defensin production in CD patients. As a first step in the development of an alternative approach for the treatment of CD patients, EcN strains were constructed which were able to produce human α-defensin 5 (HD5) or β-defensin 2 (HBD2). For that purpose, codon-optimized defensin genes encoding either the proform with the signal sequence of human α-defensin 5 (HD5) or the gene encoding HBD2 with or without the signal sequence were cloned in an expression vector plasmid under the control of the T7 promoter. Synthesis of the encoded defensins was shown by Western blots after induction of expression and lysis of the recombinant EcN strains. Recombinant mature HBD2 with an N-terminal His-tag could be purified by Ni-column chromatography and showed antimicrobial activity against E. coli, Salmonella enterica serovar Typhimurium and Listeria monocytogenes. In a second approach, that part of the HBD2 gene which encodes mature HBD2 was fused with the yebF gene. The resulting fusion protein YebFMHBD2 was secreted from the encoding EcN mutant strain after induction of expression. Presence of YebFMHBD2 in the medium was not the result of leakage from the bacterial cells, as demonstrated in the spent culture supernatant by Western blots specific for β-galactosidase and maltose-binding protein. The dialyzed and concentrated culture supernatant inhibited the growth of E. coli, S. enterica serovar

  9. Bacterial glyphosate resistance conferred by overexpression of an E. coli membrane efflux transporter.

    Science.gov (United States)

    Staub, Jeffrey M; Brand, Leslie; Tran, Minhtien; Kong, Yifei; Rogers, Stephen G

    2012-04-01

    Glyphosate herbicide-resistant crop plants, introduced commercially in 1994, now represent approximately 85% of the land area devoted to transgenic crops. Herbicide resistance in commercial glyphosate-resistant crops is due to expression of a variant form of a bacterial 5-enolpyruvylshikimate-3-phosphate synthase with a significantly decreased binding affinity for glyphosate at the target site of the enzyme. As a result of widespread and recurrent glyphosate use, often as the only herbicide used for weed management, increasing numbers of weedy species have evolved resistance to glyphosate. Weed resistance is most often due to changes in herbicide translocation patterns, presumed to be through the activity of an as yet unidentified membrane transporter in plants. To provide insight into glyphosate resistance mechanisms and identify a potential glyphosate transporter, we screened Escherichia coli genomic DNA for alternate sources of glyphosate resistance genes. Our search identified a single non-target gene that, when overexpressed in E. coli and Pseudomonas, confers high-level glyphosate resistance. The gene, yhhS, encodes a predicted membrane transporter of the major facilitator superfamily involved in drug efflux. We report here that an alternative mode of glyphosate resistance in E. coli is due to reduced accumulation of glyphosate in cells that overexpress this membrane transporter and discuss the implications for potential alternative resistance mechanisms in other organisms such as plants.

  10. Flavonoids from Praxelis clematidea R.M. King and Robinson Modulate Bacterial Drug Resistance

    OpenAIRE

    José Maria Barbosa-Filho; Marcelo Sobral da Silva; Luis Cezar Rodrigues; José Pinto Siqueira-Júnior; Josean Fechine Tavares; João Xavier de Araújo-Júnior; Pedro Gregório Vieira Aquino; Vivyanne dos Santos Falcão-Silva; Gabriela Lemos de Azevedo Maia

    2011-01-01

    Chemical studies of Praxelis clematidea R.M. King & Robinson resulted in the isolation of six flavones: Apigenine, genkwanine, 7,4’-dimethylapigenin, trimethylapigenin,cirsimaritin and tetramethylscutellarein, which were tested for their toxicity against Staphylococcus aureus SA-1199B, a strain possessing the NorA efflux pump. Efflux pumps are integral proteins of the bacterial membrane and are recognized as one of the main causes of bacterial drug resistance, since they expel antibiotics...

  11. Antagonistic Activities of Purple Non-sulfur Bacterial Extracts Against Antibiotic Resistant Vibrio sp.

    Directory of Open Access Journals (Sweden)

    Chandrasekaran, R.

    2011-01-01

    Full Text Available Solvent extracts of native purple non-sulfur bacterial (PNSB isolates from the effluents of brackish shrimp culture ponds, near Nagapattinam coast (South India were evaluated for antibacterial activity by the disc diffusion method. Best results were shown by the chloroform extracts against oxytetracycline resistant Vibrio harveyi and Vibrio fischerii. Among the purple non-sulfur bacterial isolates, Rhodobacter sphaeroides, showed maximum antagonistic activity. The findings suggest that the antagonistic extracts from Rba. sphaeroides could be used as an effective antibiotic in controlling Vibrio spp., in aquaculture systems.

  12. Sulfonamide and tetracycline resistance genes in total- and culturable-bacterial assemblages in South African aquatic environments

    OpenAIRE

    Satoru eSuzuki; Mitsuko eOgo; Tatsuya eKoike; Hideshige eTakada; Brent eNewman

    2015-01-01

    Antibiotic resistant bacteria (ARB) are ubiquitous in the natural environment. The introduction of effluent derived antibiotic resistance genes (ARGs) into aquatic environments is of concern in the spreading of genetic risk. This study showed the prevalence of sulfonamide and tetracycline resistance genes, sul1, sul2, sul3 and tet(M), in the total bacterial assemblage and colony forming bacterial assemblage in river and estuarine water and sewage treatment plants (STP) in South Africa. There ...

  13. Sulfonamide and tetracycline resistance genes in total- and culturable-bacterial assemblages in South African aquatic environments

    OpenAIRE

    Suzuki, Satoru; Ogo, Mitsuko; Koike, Tatsuya; Takada, Hideshige; Newman, Brent

    2015-01-01

    Antibiotic resistant bacteria are ubiquitous in the natural environment. The introduction of effluent derived antibiotic resistance genes (ARGs) into aquatic environments is of concern in the spreading of genetic risk. This study showed the prevalence of sulfonamide and tetracycline resistance genes, sul1, sul2, sul3, and tet(M), in the total bacterial assemblage and colony forming bacterial assemblage in river and estuarine water and sewage treatment plants (STP) in South Africa. There was no ...

  14. Peptide IDR-1018: modulating the immune system and targeting bacterial biofilms to treat antibiotic-resistant bacterial infections.

    Science.gov (United States)

    Mansour, Sarah C; de la Fuente-Núñez, César; Hancock, Robert E W

    2015-05-01

    Host defense (antimicrobial) peptides, produced by all complex organisms, typically contain an abundance of positively charged and hydrophobic amino acid residues. A small synthetic peptide termed innate defense regulator (IDR-)1018 was derived by substantial modification of the bovine neutrophil host defense peptide bactenecin. Here, we review its intriguing properties that include anti-infective, anti-inflammatory, wound healing, and anti-biofilm activities. It was initially developed as an immune modulator with an ability to selectively enhance chemokine production and polarize cellular differentiation while suppressing/balancing the pro-inflammatory response. In this regard, it has demonstrated in vivo activity in murine models including enhancement of wound healing and an ability to protect against Staphylococcus aureus, multidrug resistant Mycobacterium tuberculosis, herpes virus, and inflammatory disorders, including cerebral malaria and neuronal damage in a pre-term birth model. More recently, IDR-1018 was shown, in a broad-spectrum fashion, to selectively target bacterial biofilms, which are adaptively resistant to many antibiotics and represent the most common growth state of bacteria in human infections. Furthermore, IDR-1018 demonstrated synergy with conventional antibiotics to both prevent biofilm formation and treat pre-existing biofilms. These data are consistent with a strong potential as an adjunctive therapy against antibiotic-resistant infections. PMID:25358509

  15. The bacterial DNA repair protein Mfd confers resistance to the host nitrogen immune response.

    Science.gov (United States)

    Guillemet, Elisabeth; Leréec, Alain; Tran, Seav-Ly; Royer, Corinne; Barbosa, Isabelle; Sansonetti, Philippe; Lereclus, Didier; Ramarao, Nalini

    2016-01-01

    Production of reactive nitrogen species (NO) is a key step in the immune response following infections. NO induces lesions to bacterial DNA, thus limiting bacterial growth within hosts. Using two pathogenic bacteria, Bacillus cereus and Shigella flexneri, we show that the DNA-repair protein Mfd (Mutation-Frequency-Decline) is required for bacterial resistance to the host-NO-response. In both species, a mutant deficient for mfd does not survive to NO, produced in vitro or by phagocytic cells. In vivo, the ∆mfd mutant is avirulent and unable to survive the NO-stress. Moreover, NO induces DNA-double-strand-breaks and point mutations in the Δmfd mutant. In overall, these observations demonstrate that NO damages bacterial DNA and that Mfd is required to maintain bacterial genomic integrity. This unexpected discovery reveals that Mfd, a typical housekeeping gene, turns out to be a true virulence factor allowing survival and growth of the pathogen in its host, due to its capacity to protect the bacterium against NO, a key molecule of the innate immune defense. As Mfd is widely conserved in the bacterial kingdom, these data highlight a mechanism that may be used by a large spectrum of bacteria to overcome the host immune response and especially the mutagenic properties of NO. PMID:27435260

  16. Correlation models between environmental factors and bacterial resistance to antimony and copper.

    Directory of Open Access Journals (Sweden)

    Zunji Shi

    Full Text Available Antimony (Sb and copper (Cu are toxic heavy metals that are associated with a wide variety of minerals. Sb(III-oxidizing bacteria that convert the toxic Sb(III to the less toxic Sb(V are potentially useful for environmental Sb bioremediation. A total of 125 culturable Sb(III/Cu(II-resistant bacteria from 11 different types of mining soils were isolated. Four strains identified as Arthrobacter, Acinetobacter and Janibacter exhibited notably high minimum inhibitory concentrations (MICs for Sb(III (>10 mM,making them the most highly Sb(III-resistant bacteria to date. Thirty-six strains were able to oxidize Sb(III, including Pseudomonas-, Comamonas-, Acinetobacter-, Sphingopyxis-, Paracoccus- Aminobacter-, Arthrobacter-, Bacillus-, Janibacter- and Variovorax-like isolates. Canonical correspondence analysis (CCA revealed that the soil concentrations of Sb and Cu were the most obvious environmental factors affecting the culturable bacterial population structures. Stepwise linear regression was used to create two predictive models for the correlation between soil characteristics and the bacterial Sb(III or Cu(II resistance. The concentrations of Sb and Cu in the soil was the significant factors affecting the bacterial Sb(III resistance, whereas the concentrations of S and P in the soil greatly affected the bacterial Cu(II resistance. The two stepwise linear regression models that we derived are as follows: MIC(Sb(III=606.605+0.14533 x C(Sb+0.4128 x C(Cu and MIC((Cu(II=58.3844+0.02119 x C(S+0.00199 x CP [where the MIC(Sb(III and MIC(Cu(II represent the average bacterial MIC for the metal of each soil (μM, and the C(Sb, C(Cu, C(S and C(P represent concentrations for Sb, Cu, S and P (mg/kg in soil, respectively, p<0.01]. The stepwise linear regression models we developed suggest that metals as well as other soil physicochemical parameters can contribute to bacterial resistance to metals.

  17. Plant defensins and their potential use as pest control in agriculture

    International Nuclear Information System (INIS)

    Plants, as all organisms in nature, have elaborate systems of defense against pathogens; which can be physical or chemical and produced in a constitutive and induced way. Among the induced chemical barriers, there is a group of low molecular weight proteins, known as antimicrobial peptides (AMPs). These peptides include defensins, which are peptides with a molecular weight about 5 to 7 KDa, isoelectric point of 9, and length of about 45 to 55 amino acids. Likewise, they have the ability to avoid the growth of phytopathogenic microorganisms, mainly funguses. Moreover, these peptides create resistance to abiotic conditions of stress in plants. This manuscript seeks to make a clear and current description about the recent characteristics and researches related to plant defensins and their most significant uses in pathogens management in crops of economical relevance. It also intends to go deep into the study of such proteins in order to use them as a control strategy, such as production of transgenic plants and microorganisms.

  18. Antimicrobial activity of human β-defensins against lactic acid bacteria.

    Science.gov (United States)

    Wang, Xiao-Fang; Tian, Fei; Cao, Rui-Ming; Li, Jing; Wu, Sheng-Mei; Guo, Xiao-Kui; Chen, Tong-Xin

    2015-01-01

    In this study, we evaluated the antimicrobial activity of human β-defensin-1 (hBD-1), human β-defensin-2 (hBD-2) and human β-defensin-3 (hBD-3) against three internationally common probiotic strains of lactic acid bacterium. Our results indicated that hBD-1, hBD-2 and hBD-3 at the range of 0.08-10 μg/mL do not have obvious antimicrobial activity against these strains. Viability of Bifidobacterium longum JDM301 (B. longum JDM301), Bifidobacterium lactis HN019 (B. lactis HN019) and Lactobacillus rhamnosus GG (LGG) were still very high even at concentration of 10 μg hBD/mL. Then, we explored the mechanism of resistance by using carbonyl cyanide 3-chlorophenylhydrazone (CCCP) to inhibit efflux pumps. In the presence of CCCP, hBD-1, hBD-2 and hBD-3 exhibited enhanced antibacterial effect against B. longum JDM301 and B. lactis HN019, but not against LGG. Efflux pumps in B. longum JDM301 and B. lactis HN019 may partly contribute to their resistance to hBD-1, hBD-2, and hBD-3.

  19. Genetic analysis of the induced mutants of rice resistant to bacterial leaf blight

    International Nuclear Information System (INIS)

    Full text: Seeds of the rice cultivar 'Harebare', which is susceptible to bacterial leaf blight (BLB), were treated with thermal neutrons, gamma-rays, ethyleneimine and ethylmethane-sulfonate. In the M2, plants with better resistance to BLB were identified through inoculation at the seedling and the flag leaf stages with an isolate (T7174) of the Japanese differential race I. Several mutant lines resistant to BLB were selected through tests of the M3 or M4 lines derived from selected resistant M2 plants. The frequency of resistant mutants was significantly higher after the thermal neutron treatment than after treatments with other mutagens. Two mutants, which originated from the neutron treatment, showing a highly quantitative resistance to multiple BLB races were analysed for gene(s) for resistance. The resistance of one of them (M41) to the Japanese races I, II, III, IV, and V was found to be conditioned by a single recessive gene. Three other recessive genes for resistance are known, but their reaction to differential races is different. Therefore, this gene was thought to be new and was tentatively designated as xa-nm(t). The resistance of another mutant (M57) was found to be polygenically inherited. (author)

  20. The drinking water treatment process as a potential source of affecting the bacterial antibiotic resistance.

    Science.gov (United States)

    Bai, Xiaohui; Ma, Xiaolin; Xu, Fengming; Li, Jing; Zhang, Hang; Xiao, Xiang

    2015-11-15

    Two waterworks, with source water derived from the Huangpu or Yangtze River in Shanghai, were investigated, and the effluents were plate-screened for antibiotic-resistant bacteria (ARB) using five antibiotics: ampicillin (AMP), kanamycin (KAN), rifampicin (RFP), chloramphenicol (CM) and streptomycin (STR). The influence of water treatment procedures on the bacterial antibiotic resistance rate and the changes that bacteria underwent when exposed to the five antibiotics at concentration levels ranging from 1 to 100 μg/mL were studied. Multi-drug resistance was also analyzed using drug sensitivity tests. The results indicated that bacteria derived from water treatment plant effluent that used the Huangpu River rather than the Yangtze River as source water exhibited higher antibiotic resistance rates against AMP, STR, RFP and CM but lower antibiotic resistance rates against KAN. When the antibiotic concentration levels ranged from 1 to 10 μg/mL, the antibiotic resistance rates of the bacteria in the water increased as water treatment progressed. Biological activated carbon (BAC) filtration played a key role in increasing the antibiotic resistance rate of bacteria. Chloramine disinfection can enhance antibiotic resistance. Among the isolated ARB, 75% were resistant to multiple antibiotics. Ozone oxidation, BAC filtration and chloramine disinfection can greatly affect the relative abundance of bacteria in the community.

  1. COMPARATIVE RESISTANCE OF BACTERIAL FOODBORNE PATHOGENS TO NON-THERMAL TECHNOLOGIES FOR FOOD PRESERVATION

    Directory of Open Access Journals (Sweden)

    Guillermo eCebrián

    2016-05-01

    Full Text Available In this paper the resistance of bacterial foodborne pathogens to manosonication (MS, pulsed electric fields (PEF, high hydrostatic pressure (HHP and UV-light (UV is reviewed and compared. The influence of different factors on the resistance of bacterial foodborne pathogens to these technologies is also compared and discussed. Only results obtained under harmonized experimental conditions have been considered. This has allowed us to establish meaningful comparisons and draw significant conclusions. Among the six microorganisms here considered, Staphyloccocus aureus is the most resistant foodborne pathogen to MS and HHP and Listeria monocytogenes to UV. The target microorganism of PEF would change depending on the treatment medium pH. Thus, L. monocytogenes is the most PEF resistant microorganism at neutral pH but Gram-negatives (Escherichia coli, Salmonella spp., Cronobacter sakazakii, Campylobacter jejuni would display a similar or even higher resistance at acidic pH. It should be noted that, in acidic products, the baroresistance of some E. coli strains would be comparable to that of S. aureus. The factors affecting the resistance of bacterial foodborne pathogens, as well as the magnitude of the effect, varied depending on the technology considered. Inter- and intra-specific differences in microbial resistance to PEF and HHP are much greater than to MS and UV. Similarly, both the pH and aw of the treatment medium highly condition microbial resistance to PEF and HHP but no to MS or UV. Growth phase also drastically affected bacterial HHP resistance. Regarding UV, the optical properties of the medium are, by far, the most influential factor affecting its lethal efficacy. Finally, increasing treatment temperature leads to a significant increase in lethality of the four technologies, what opens the possibility of the development of combined processes including heat. The appearance of sublethally damaged cells following PEF and HHP treatments could

  2. Comparative Resistance of Bacterial Foodborne Pathogens to Non-thermal Technologies for Food Preservation.

    Science.gov (United States)

    Cebrián, Guillermo; Mañas, Pilar; Condón, Santiago

    2016-01-01

    In this paper the resistance of bacterial foodborne pathogens to manosonication (MS), pulsed electric fields (PEFs), high hydrostatic pressure (HHP), and UV-light (UV) is reviewed and compared. The influence of different factors on the resistance of bacterial foodborne pathogens to these technologies is also compared and discussed. Only results obtained under harmonized experimental conditions have been considered. This has allowed us to establish meaningful comparisons and draw significant conclusions. Among the six microorganisms here considered, Staphyloccocus aureus is the most resistant foodborne pathogen to MS and HHP and Listeria monocytogenes to UV. The target microorganism of PEF would change depending on the treatment medium pH. Thus, L. monocytogenes is the most PEF resistant microorganism at neutral pH but Gram-negatives (Escherichia coli, Salmonella spp., Cronobacter sakazakii, Campylobacter jejuni) would display a similar or even higher resistance at acidic pH. It should be noted that, in acidic products, the baroresistance of some E. coli strains would be comparable to that of S. aureus. The factors affecting the resistance of bacterial foodborne pathogens, as well as the magnitude of the effect, varied depending on the technology considered. Inter- and intra-specific differences in microbial resistance to PEF and HHP are much greater than to MS and UV. Similarly, both the pH and aw of the treatment medium highly condition microbial resistance to PEF and HHP but no to MS or UV. Growth phase also drastically affected bacterial HHP resistance. Regarding UV, the optical properties of the medium are, by far, the most influential factor affecting its lethal efficacy. Finally, increasing treatment temperature leads to a significant increase in lethality of the four technologies, what opens the possibility of the development of combined processes including heat. The appearance of sublethally damaged cells following PEF and HHP treatments could also be

  3. Epidemiology of urinary tract infections, bacterial species and resistances in primary care in France.

    Science.gov (United States)

    Malmartel, A; Ghasarossian, C

    2016-03-01

    General practitioners often have to manage urinary tract infections (UTI) with probabilistic treatments, although bacterial resistances are increasing. Therefore, the French Society of Infectious Diseases published new guidelines in 2014. The aim of this study was to investigate the bacterial epidemiology of UTI in the general population in primary care and analyse risk factors for Escherichia coli resistance to antibiotics. A cross-sectional study was conducted in 12 ambulatory laboratories. Patients over 18 years of age coming for urinalysis were included. Risk factors for UTI were collected using a questionnaire and the laboratory records. Bacteria meeting criteria for UTI were analysed. A positive urinalysis was found in 1119 patients, corresponding to 1125 bacterial isolates. The bacterial species were: E. coli (73 %), Enterococcus spp. (7 %), Klebsiella spp. (6 %), Proteus spp. (4 %), Staphylococcus spp. (3 %) and Pseudomonas spp. (2 %). Regardless of the bacteria, the most common resistance was that to co-trimoxazole: 27 % (95 % confidence interval [CI] = [0.24; 0.30]), followed by ofloxacin resistance: 16 % [0.14; 0.18]. Escherichia coli resistances to co-trimoxazole, ofloxacin, cefixime, nitrofurantoin and fosfomycin were, respectively, 25.5 % [0.23; 0.28], 17 % [0.14; 0.20], 5.6 % [0.04; 0.07], 2.2 % [0.01; 0.03] and 1.2 % [0.005; 0.02]. Independent risk factors for E. coli resistance to ofloxacin were age over 85 years (odds ratio [OR] = 3.08; [1.61; 5.87]) and a history of UTI in the last 6 months (OR = 2.34; [1.54; 3.52]). Our findings support the guidelines recommending fluoroquinolone sparing. The scarcity of E. coli resistance to fosfomycin justifies its use as a first-line treatment in acute cystitis. These results should be reassessed in a few years to identify changes in the bacterial epidemiology of UTI. PMID:26740324

  4. Defensin γ-thionin from Capsicum chinense has immunomodulatory effects on bovine mammary epithelial cells during Staphylococcus aureus internalization.

    Science.gov (United States)

    Díaz-Murillo, Violeta; Medina-Estrada, Ivan; López-Meza, Joel E; Ochoa-Zarzosa, Alejandra

    2016-04-01

    β-Defensins are members of the antimicrobial peptide superfamily that are produced in various species from different kingdoms, including plants. Plant defensins exhibit primarily antifungal activities, unlike those from animals that exhibit a broad-spectrum antimicrobial action. Recently, immunomodulatory roles of mammal β-defensins have been observed to regulate inflammation and activate the immune system. Similar roles for plant β-defensins remain unknown. In addition, the regulation of the immune system by mammalian β-defensins has been studied in humans and mice models, particularly in immune cells, but few studies have investigated these peptides in epithelial cells, which are in intimate contact with pathogens. The aim of this work was to evaluate the effect of the chemically synthesized β-defensin γ-thionin from Capsicum chinense on the innate immune response of bovine mammary epithelial cells (bMECs) infected with Staphylococcus aureus, the primary pathogen responsible for bovine mastitis, which is capable of living within bMECs. Our results indicate that γ-thionin at 0.1 μg/ml was able to reduce the internalization of S. aureus into bMECs (∼50%), and it also modulates the innate immune response of these cells by inducing the mRNA expression (∼5-fold) and membrane abundance (∼3-fold) of Toll-like receptor 2 (TLR2), as well as by inducing genes coding for the pro-inflammatory cytokines TNF-α and IL-1β (∼14 and 8-fold, respectively) before and after the bacterial infection. γ-Thionin also induces the expression of the mRNA of anti-inflammatory cytokine IL-10 (∼12-fold). Interestingly, the reduction in bacterial internalization coincides with the production of other antimicrobial products by bMECs, such as NO before infection, and the secretion into the medium of the endogenous antimicrobial peptide DEFB1 after infection. The results from this work support the potential use of β-defensins from plants as immunomodulators of the mammalian

  5. Improvement of Resistance to Bacterial Blight by Marker-Assisted Selection in a Wide Compatibility Restorer Line of Hybrid Rice

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiu-hua; LUO Yan-chang; LIU Qiao-quan; WANG Shou-hai; WU Hsin-kan; LI Cheng-quan; WANG Zong-yang; WU Shuang; GU Ming-hong; WANG De-zheng; DU Shi-yun

    2004-01-01

    4183 is a promising wide compatibility restorer line with good grain quality. Its hybrid rice Shuangyou 4183 (Shuangjiu A/4183) was registered in Anhui Province in 2003. However, the line and its hybrid rice are susceptible to bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo). R4183 carrying Xa21 was developed to improve bacterial blight resistance of 4183 through introducing the broad-spectrum resistance gene Xa21 by marker-aided selection. R4183 had similar level of bacterial blight resistance to IRBB21, the resistant donor, while maintained the wide compatibility, restoring ability and other good economic traits of the recurrent parent 4183. Critical issues on improvement of bacterial blight resistance of hybrid rice and breeding strategies were also discussed.

  6. Therapeutic potential of antifungal plant and insect defensins

    NARCIS (Netherlands)

    Thevissen, K.; Kristensen, H.H.; Thomma, B.P.H.J.; Cammue, B.P.A.; François, I.E.J.A.

    2007-01-01

    To defend themselves against invading fungal pathogens, plants and insects largely depend on the production of a wide array of antifungal molecules, including antimicrobial peptides such as defensins. Interestingly, plant and insect defensins display antimicrobial activity not only against plant and

  7. The Defensins Consist of Two Independent, Convergent Protein Superfamilies.

    Science.gov (United States)

    Shafee, Thomas M A; Lay, Fung T; Hulett, Mark D; Anderson, Marilyn A

    2016-09-01

    The defensin and defensin-like proteins are an extensive group of small, cationic, disulfide-rich proteins found in animals, plants, and fungi and mostly perform roles in host defense. The term defensin was originally used for small mammalian proteins found in neutrophils and was subsequently applied to insect proteins and plant γ-thionins based on their perceived sequence and structural similarity. Defensins are often described as ancient innate immunity molecules and classified as a single superfamily and both sequence alignments and phylogenies have been constructed. Here, we present evidence that the defensins have not all evolved from a single ancestor. Instead, they consist of two analogous superfamilies, and extensive convergent evolution is the source of their similarities. Evidence of common origin necessarily gets weaker for distantly related genes, as is the case for defensins, which are both divergent and small. We show that similarities that have been used as evidence for common origin are all expected by chance in short, constrained, disulfide-rich proteins. Differences in tertiary structure, secondary structure order, and disulfide bond connectivity indicate convergence as the likely source of the similarity. We refer to the two evolutionarily independent groups as the cis-defensins and trans-defensins based on the orientation of the most conserved pair of disulfides. PMID:27297472

  8. Enteric defensins are essential regulators of intestinal microbial ecology

    NARCIS (Netherlands)

    Salzman, Nita H.; Hung, Kuiechun; Haribhai, Dipica; Chu, Hiutung; Karlsson-Sjoeberg, Jenny; Amir, Elad; Teggatz, Paul; Barman, Melissa; Hayward, Michael; Eastwood, Daniel; Stoel, Maaike; Zhou, Yanjiao; Sodergren, Erica; Weinstock, George M.; Bevins, Charles L.; Williams, Calvin B.; Bos, Nicolaas A.

    2010-01-01

    Antimicrobial peptides are important effectors of innate immunity throughout the plant and animal kingdoms. In the mammalian small intestine, Paneth cell alpha-defensins are antimicrobial peptides that contribute to host defense against enteric pathogens. To determine if alpha-defensins also govern

  9. Plant Defensins NaD1 and NaD2 Induce Different Stress Response Pathways in Fungi.

    Science.gov (United States)

    Dracatos, Peter M; Payne, Jennifer; Di Pietro, Antonio; Anderson, Marilyn A; Plummer, Kim M

    2016-01-01

    Nicotiana alata defensins 1 and 2 (NaD1 and NaD2) are plant defensins from the ornamental tobacco that have antifungal activity against a variety of fungal pathogens. Some plant defensins interact with fungal cell wall O-glycosylated proteins. Therefore, we investigated if this was the case for NaD1 and NaD2, by assessing the sensitivity of the three Aspergillus nidulans (An) O-mannosyltransferase (pmt) knockout (KO) mutants (An∆pmtA, An∆pmtB, and An∆pmtC). An∆pmtA was resistant to both defensins, while An∆pmtC was resistant to NaD2 only, suggesting NaD1 and NaD2 are unlikely to have a general interaction with O-linked side chains. Further evidence of this difference in the antifungal mechanism was provided by the dissimilarity of the NaD1 and NaD2 sensitivities of the Fusarium oxysporum f. sp. lycopersici (Fol) signalling knockout mutants from the cell wall integrity (CWI) and high osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathways. HOG pathway mutants were sensitive to both NaD1 and NaD2, while CWI pathway mutants only displayed sensitivity to NaD2. PMID:27598152

  10. MinION nanopore sequencing identifies the position and structure of a bacterial antibiotic resistance island.

    Science.gov (United States)

    Ashton, Philip M; Nair, Satheesh; Dallman, Tim; Rubino, Salvatore; Rabsch, Wolfgang; Mwaigwisya, Solomon; Wain, John; O'Grady, Justin

    2015-03-01

    Short-read, high-throughput sequencing technology cannot identify the chromosomal position of repetitive insertion sequences that typically flank horizontally acquired genes such as bacterial virulence genes and antibiotic resistance genes. The MinION nanopore sequencer can produce long sequencing reads on a device similar in size to a USB memory stick. Here we apply a MinION sequencer to resolve the structure and chromosomal insertion site of a composite antibiotic resistance island in Salmonella Typhi Haplotype 58. Nanopore sequencing data from a single 18-h run was used to create a scaffold for an assembly generated from short-read Illumina data. Our results demonstrate the potential of the MinION device in clinical laboratories to fully characterize the epidemic spread of bacterial pathogens. PMID:25485618

  11. Bottlenecks in the transmission of antibiotic resistance from natural ecosystems to human bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Jose L Martinez

    2012-01-01

    Full Text Available It is generally accepted that resistance genes acquired by human pathogens trough horizontal gene transfer have been originated in environmental, non pathogenic bacteria. As the consequence, there exists an increasing concern on the role that natural, non-clinical ecosystems, may play on the evolution of resistance. Recent studies have shown that the variability of determinants that can provide antibiotic resistance upon their expression in a heterologous host is much larger than what is actually found in human pathogens. Along the review, the role that different processes as founder effect, ecological connectivity, fitness costs or second-order selection may have on the establishment of a specific resistance determinant in the population of bacterial pathogens is analysed.

  12. Benchmarking of methods for identification of antimicrobial resistance genes in bacterial whole genome data

    DEFF Research Database (Denmark)

    Clausen, Philip T. L. C.; Zankari, Ea; Aarestrup, Frank Møller;

    2016-01-01

    was compared with the observed phenotypes for all isolates. To challenge further the sensitivity of the in silico methods, the datasets were also down-sampled to 1% of the reads and reanalysed. The best results were obtained by identification of resistance genes by mapping directly against the raw reads......Next generation sequencing (NGS) may be an alternative to phenotypic susceptibility testing for surveillance and clinical diagnosis. However, current bioinformatics methods may be associated with false positives and negatives. In this study, a novel mapping method was developed and benchmarked...... to two different methods in current use for identification of antibiotic resistance genes in bacterial WGS data. A novel method, KmerResistance, which examines the co-occurrence of k-mers between the WGS data and a database of resistance genes, was developed. The performance of this method was compared...

  13. Hybrid Rice Resistant to Bacterial Leaf Blight Developed By Marker Assisted Selection

    Institute of Scientific and Technical Information of China (English)

    CAO Li-yong; ZHUANG Jie-yun; YUAN Shou-jiang; ZHAN Xiao-deng; ZHENG Kang-le; CHENG Shi-hua

    2003-01-01

    Through recurrént backcrossing in combination with molecular marker-assisted selection (MAS), restorer lines R8006 and R1176 carrying Xa-21 , a gene having broad-spectrum resistance to rice bacterial leaf blight, were selected. By crossing the two lines to CMS line Zhong 9A, two new hybrid rice combinations, Zhongyou 6 and Zhongyou 1176 were developed. The hybrids showed high resistance to diseases, good grain quality and high yielding potential in national and provincial adaptability and yield trials.

  14. An efficient system for intracellular delivery of beta-lactam antibiotics to overcome bacterial resistance

    OpenAIRE

    Nadia Abed; Fatouma Saïd-Hassane; Fatima Zouhiri; Julie Mougin; Valérie Nicolas; Didier Desmaële; Ruxandra Gref; Patrick Couvreur

    2015-01-01

    The “Golden era” of antibiotics is definitely an old story and this is especially true for intracellular bacterial infections. The poor intracellular bioavailability of antibiotics reduces the efficency of many treatments and thereby promotes resistances. Therefore, the development of nanodevices coupled with antibiotics that are capable of targeting and releasing the drug into the infected-cells appears to be a promising solution to circumvent these complications. Here, we took advantage of ...

  15. Insights in Nanoparticle-Bacterium Interactions: New Frontiers to Bypass Bacterial Resistance to Antibiotics.

    Science.gov (United States)

    Diab, Roudayna; Khameneh, Bahman; Joubert, Olivier; Duval, Raphael

    2015-01-01

    Nanotechnology has been revealed as a fundamental approach for antibiotics delivery. In this paper, recent findings demonstrating the superiority of nanocarried-antibiotics over "naked" ones and the ways by which nanoparticles can help to overwhelm bacterial drug resistance are reviewed. The second part of this paper sheds light on nanoparticle-bacterium interaction patterns. Finally, key factors affecting the effectiveness of nanoparticles interactions with bacteria are discussed.

  16. Housefly Larva Vermicomposting Efficiently Attenuates Antibiotic Resistance Genes in Swine Manure, with Concomitant Bacterial Population Changes

    OpenAIRE

    Wang, Hang; Li, Hongyi; Gilbert, Jack A.; Li, Haibo; Wu, Longhua; Liu, Meng; Wang, Liling; Zhou, Qiansheng; Yuan, Junxiang; Zhang, Zhijian

    2015-01-01

    Manure from swine treated with antimicrobials as feed additives is a major source for the expansion of the antibiotic resistance gene (ARG) reservoir in the environment. Vermicomposting via housefly larvae (Musca domestica) can be efficiently used to treat manure and regenerate biofertilizer, but few studies have investigated its effect on ARG attenuation. Here, we tracked the abundances of 9 ARGs and the composition and structure of the bacterial communities in manure samples across 6 days o...

  17. Transcriptional responses of resistant and susceptible fish clones to the bacterial pathogen Flavobacterium psychrophilum.

    Directory of Open Access Journals (Sweden)

    Christelle Langevin

    Full Text Available Flavobacterium psychrophilum is a bacterial species that represents one of the most important pathogens for aquaculture worldwide, especially for salmonids. To gain insights into the genetic basis of the natural resistance to F. psychrophilum, we selected homozygous clones of rainbow trout with contrasted susceptibility to the infection. We compared the transcriptional response to the bacteria in the pronephros of a susceptible and a resistant line by micro-array analysis five days after infection. While the basal transcriptome of healthy fish was significantly different in the resistant and susceptible lines, the transcriptome modifications induced by the bacteria involved essentially the same genes and pathways. The response to F. psychrophilum involved antimicrobial peptides, complement, and a number of enzymes and chemokines. The matrix metalloproteases mmp9 and mmp13 were among the most highly induced genes in both genetic backgrounds. Key genes of both pro- and anti-inflammatory response such as IL1 and IL10, were up-regulated with a greater magnitude in susceptible animals where the bacterial load was also much higher. While higher resistance to F. psychrophilum does not seem to be based on extensive differences in the orientation of the immune response, several genes including complement C3 showed stronger induction in the resistant fish. They may be important for the variation of susceptibility to the infection.

  18. Transgenic Rice Plants Harboring Genomic DNA from Zizania latifolia Confer Bacterial Blight Resistance

    Institute of Scientific and Technical Information of China (English)

    SHEN Wei-wei; SONG Cheng-li; CHEN Jie; Fu Ya-ping; Wu Jian-li; JIANG Shao-mei

    2011-01-01

    Based on the sequence of a resistance gene analog FZ14 derived from Zizania latifolia (Griseb.),a pair of specific PCR primers FZ14P1/FZ14P2 was designed to isolate candidate disease resistance gene.The pooled-PCR approach was adopted using the primer pair to screen a genomic transformation-competent artificial chromosome (TAC) library derived from Z.latifolia.A positive TAC clone (ZR1) was obtained and confirmed by sequence analysis.The results indicated that ZR1 consisted of conserved motifs similar to P-loop (kinase 1a),kinase 2,kinase 3a and GLPL (Gly-Leu-Pro-Leu),suggesting that it could be a portion of NBS-LRR type of resistance gene.Using Agrobacterium-mediated transformation of Nipponbare mature embryo,a total of 48 independent transgenic T0 plants were obtained.Among them,36 plants were highly resistant to the virulent bacterial blight strain P×O71.The results indicate that ZR1 contains at least one functional bacterial blight resistance gene.

  19. Heterologously expressed bacterial and human multidrug resistance proteins confer cadmium resistance to Escherichia coli

    NARCIS (Netherlands)

    Achard-Joris, M; van Saparoea, HBV; Driessen, AJM; Bourdineaud, JP; Bourdineaud, Jean-Paul

    2005-01-01

    The human MDR1 gene is induced by cadmium exposure although no resistance to this metal is observed in human cells overexpressing hMDR1. To access the role of MDR proteins in cadmium resistance, human MDR1, Lactococcus lactis lmrA, and Oenococcus oeni omrA were expressed in an Escherichia coli tolC

  20. Antimicrobial Photodynamic Therapy: Study of Bacterial Recovery Viability and Potential Development of Resistance after Treatment

    Science.gov (United States)

    Tavares, Anabela; Carvalho, Carla M. B.; Faustino, Maria A.; Neves, Maria G. P. M. S.; Tomé, João P. C.; Tomé, Augusto C.; Cavaleiro, José A. S.; Cunha, Ângela; Gomes, Newton C. M.; Alves, Eliana; Almeida, Adelaide

    2010-01-01

    Antimicrobial photodynamic therapy (aPDT) has emerged in the clinical field as a potential alternative to antibiotics to treat microbial infections. No cases of microbial viability recovery or any resistance mechanisms against it are yet known. 5,10,15-tris(1-Methylpyridinium-4-yl)-20-(pentafluorophenyl)-porphyrin triiodide (Tri-Py+-Me-PF) was used as photosensitizer. Vibrio fischeri and recombinant Escherichia coli were the studied bacteria. To determine the bacterial recovery after treatment, Tri-Py+-Me-PF (5.0 μM) was added to bacterial suspensions and the samples were irradiated with white light (40 W m−2) for 270 minutes. Then, the samples were protected from light, aliquots collected at different intervals and the bioluminescence measured. To assess the development of resistance after treatment, bacterial suspensions were exposed to white light (25 minutes), in presence of 5.0 μM of Tri-Py+-Me-PF (99.99% of inactivation) and plated. After the first irradiation period, surviving colonies were collected from the plate and resuspended in PBS. Then, an identical protocol was used and repeated ten times for each bacterium. The results suggest that aPDT using Tri-Py+-Me-PF represents a promising approach to efficiently destroy bacteria since after a single treatment these microorganisms do not recover their viability and after ten generations of partially photosensitized cells neither of the bacteria develop resistance to the photodynamic process. PMID:20161973

  1. Cloning of a big defensin gene and its response to Vibrio parahaemolyticus challenge in the noble scallop Chlamys nobilis (Bivalve: Pectinidae).

    Science.gov (United States)

    Yang, Jianqing; Luo, Jiafu; Zheng, Huaiping; Lu, Yeqing; Zhang, Hongkuan

    2016-09-01

    The noble scallop Chlamys nobilis has been an important marine cultured bivalve in the Southern Sea of China for decades. However, large-scale mortality events often occurred during the scallop' cultivation. As one of AMPs (antimicrobial peptides), big defensin is an important component of the innate immunity against pathogenic microorganisms in invertebrates. In order to investigate whether the big defensin can play a role in the immune defense against pathogenic microorganisms in noble scallop, a big defensin gene from the hemocytes of Chlamys nobilis (CnBD) was cloned, and the mRNA level was measured after an acute Vibrio parahaemolyticus challenge of 36 h. The CnBD cDNA contains an open reading frame (ORF) of 381 bp encoding a peptide of 126 amino acids residues. The deduce amino acid sequence of CnBD shows a high similarity with that from Argopecten irradians and displays common features of big defensin, indicating that CnBD is a new member of the big defensin family. Compared with the control group, the relative mRNA level of CnBD was significantly up-regulated at 3, 24 and 36 h. The present result indicated that CnBD played an immune role against bacterial infection in noble scallop. PMID:27474446

  2. Appraising Contemporary Strategies to Combat Multidrug Resistant Gram-Negative Bacterial Infections–Proceedings and Data From the Gram-Negative Resistance Summit

    OpenAIRE

    Kollef, Marin H; Golan, Yoav; Micek, Scott T.; Shorr, Andrew F.; Marcos I. Restrepo

    2011-01-01

    The emerging problem of antibiotic resistance, especially among Gram-negative bacteria (GNB), has become a serious threat to global public health. Very few new antibacterial classes with activity against antibiotic-resistant GNB have been brought to market. Renewed and growing attention to the development of novel compounds targeting antibiotic-resistant GNB, as well as a better understanding of strategies aimed at preventing the spread of resistant bacterial strains and preserving the effica...

  3. Lucifensins, the Insect Defensins of Biomedical Importance: The Story behind Maggot Therapy.

    Science.gov (United States)

    Ceřovský, Václav; Bém, Robert

    2014-01-01

    Defensins are the most widespread antimicrobial peptides characterised in insects. These cyclic peptides, 4-6 kDa in size, are folded into α-helical/β-sheet mixed structures and have a common conserved motif of three intramolecular disulfide bridges with a Cys1-Cys4, Cys2-Cys5 and Cys3-Cys6 connectivity. They have the ability to kill especially Gram-positive bacteria and some fungi, but Gram-negative bacteria are more resistant against them. Among them are the medicinally important compounds lucifensin and lucifensin II, which have recently been identified in the medicinal larvae of the blowflies Lucilia sericata and Lucilia cuprina, respectively. These defensins contribute to wound healing during a procedure known as maggot debridement therapy (MDT) which is routinely used at hospitals worldwide. Here we discuss the decades-long story of the effort to isolate and characterise these two defensins from the bodies of medicinal larvae or from their secretions/excretions. Furthermore, our previous studies showed that the free-range larvae of L. sericata acutely eliminated most of the Gram-positive strains of bacteria and some Gram-negative strains in patients with infected diabetic foot ulcers, but MDT was ineffective during the healing of wounds infected with Pseudomonas sp. and Acinetobacter sp. The bactericidal role of lucifensins secreted into the infected wound by larvae during MDT and its ability to enhance host immunity by functioning as immunomodulator is also discussed.

  4. Lucifensins, the Insect Defensins of Biomedical Importance: The Story behind Maggot Therapy

    Directory of Open Access Journals (Sweden)

    Václav Čeřovský

    2014-02-01

    Full Text Available Defensins are the most widespread antimicrobial peptides characterised in insects. These cyclic peptides, 4–6 kDa in size, are folded into α-helical/β-sheet mixed structures and have a common conserved motif of three intramolecular disulfide bridges with a Cys1-Cys4, Cys2-Cys5 and Cys3-Cys6 connectivity. They have the ability to kill especially Gram-positive bacteria and some fungi, but Gram-negative bacteria are more resistant against them. Among them are the medicinally important compounds lucifensin and lucifensin II, which have recently been identified in the medicinal larvae of the blowflies Lucilia sericata and Lucilia cuprina, respectively. These defensins contribute to wound healing during a procedure known as maggot debridement therapy (MDT which is routinely used at hospitals worldwide. Here we discuss the decades-long story of the effort to isolate and characterise these two defensins from the bodies of medicinal larvae or from their secretions/excretions. Furthermore, our previous studies showed that the free-range larvae of L. sericata acutely eliminated most of the Gram-positive strains of bacteria and some Gram-negative strains in patients with infected diabetic foot ulcers, but MDT was ineffective during the healing of wounds infected with Pseudomonas sp. and Acinetobacter sp. The bactericidal role of lucifensins secreted into the infected wound by larvae during MDT and its ability to enhance host immunity by functioning as immunomodulator is also discussed.

  5. Structural Studies of Bacterial Enzymes and their Relation to Antibiotic Resistance Mechanisms - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Maltz, Lauren [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    By using protein crystallography and X-ray diffraction, structures of bacterial enzymes were solved to gain a better understanding of how enzymatic modification acts as an antibacterial resistance mechanism. Aminoglycoside phosphotransferases (APHs) are one of three aminoglycoside modifying enzymes that confer resistance to the aminoglycoside antibiotics via enzymatic modification, rendering many drugs obsolete. Specifically, the APH(2”) family vary in their substrate specificities and also in their preference for the phosphate donor (ADP versus GDP). By solving the structures of members of the APH(2”) family of enzymes, we can see how domain movements are important to their substrate specificity. Our structure of the ternary complex of APH(2”)-IIIa with GDP and kanamycin, when compared to the known structures of APH(2”)-IVa, reveals that there are real physical differences between these two enzymes, a structural finding that explains why the two enzymes differ in their preferences for certain aminoglycosides. Another important group of bacterial resistance enzymes are the Class D β- lactamases. Oxacillinase carbapenemases (OXAs) are part of this enzyme class and have begun to confer resistance to ‘last resort’ drugs, most notably carbapenems. Our structure of OXA-143 shows that the conformational flexibility of a conserved hydrophobic residue in the active site (Val130) serves to control the entry of a transient water molecule responsible for a key step in the enzyme’s mechanism. Our results provide insight into the structural mechanisms of these two different enzymes

  6. Development of the variety for resistance against bacterial leaf-blight in rice with thermal neutrons

    International Nuclear Information System (INIS)

    In search for the development of genes for resistance against bacterial leaf-blight in rice, thermal neutrons generated from the Research Reactor at the Kyoto University have been applied to the breeding. In this paper, the developmental outcome is described, and a potential application of thermal neutrons for breeding the variety of resistance against bacterial leaf-blight in rice is reviewed. When thermal neutrons were delivered to the rice, the ratio of absorbed doses by B-10, which is contained in a small quantity in the plant, was found to be larger than expected. This implies characteristic effects of thermal neutrons on the plant. When boric acid was incorporated into the plant before irradiation, the effect of thermal neutrons per irradiation time was considered to become great. The frequency of mutations for resistance was significantly higher by thermal neutron, as compared with that induced by other mutagens, such as gamma radiation, ethylene-imine, ethyl-methane-sulfonate, and nitroso-methyl-urea. Genetic analysis of mutants for resistance revealed recessive genes and polygenes. Finally, the application of thermal neutrons and other radiations would contribute greatly to a resolution of serious pollution problems in global food and environment. (N.K.)

  7. Quantitative analysis of resistance in cotton to three new isolates of the bacterial blight pathogen.

    Science.gov (United States)

    Wallace, T P; El-Zik, K M

    1990-04-01

    Genetic variability for virulence of the bacterial blight pathogen [Xanthomonas campestris pv malvacearum (Smith) Dye] on cotton (Gossypium hirsutum L.) has been shown by the identification of 19 races of the pathogen based on disease reactions of a set of ten host differentials. This study was conducted to determine the inheritance of host resistance to three recently identified isolates of X. campestris pv malvacearum, which are virulent on the entire set of differentials. True leaves of Tamcot CAMD-E, LEBOCAS-3-80, Stoneville 825, and their f1, F2, and backcross progenies were wound-inoculated in the field with separate bacterial suspensions of the virulent HV3, HV7, and Sudan isolates of the pathogen. LEBOCAS-3-80 was replaced with S295, a new immune cultivar, for a greenhouse study in which both cotyledons and true leaves were inoculated. Disease reactions were rated on a scale of 1-10, and genetic models were proposed utilizing generation means analysis. Dominance, when significant, was in the direction of resistance in all but one cross-isolate combination. Digenic interaction components indicated a duplicate type. Narrow-sense heritability for resistance ranged from 0.59 to 0.68; therefore, primarily additive-genetic variability among the selected cutlivars was detected, indicating that breeding for improved resistance to these isolates is a practical goal.

  8. Constitutive presence of antibiotic resistance genes within the bacterial community of a large subalpine lake.

    Science.gov (United States)

    Di Cesare, Andrea; Eckert, Ester M; Teruggi, Alessia; Fontaneto, Diego; Bertoni, Roberto; Callieri, Cristiana; Corno, Gianluca

    2015-08-01

    The fate of antibiotic resistance genes (ARGs) in environmental microbial communities is of primary concern as prodromal of a potential transfer to pathogenic bacteria. Although of diverse origin, the persistence of ARGs in aquatic environments is highly influenced by anthropic activities, allowing potential control actions in well-studied environments. However, knowledge of abundance and space-time distribution of ARGs in ecosystems is still scarce. Using quantitative real-time PCR, we investigated the presence and the abundance of twelve ARGs (against tetracyclines, β-lactams, aminoglycosides, quinolones and sulphonamides) at different sampling sites, depths and seasons, in Lake Maggiore, a large subalpine lake, and in the area of its watershed. We then evaluated the correlation between each ARG and a number of ecological parameters in the water column in the deepest part of the lake. Our results suggest the constitutive presence of at least four ARGs within the bacterial community with a high proportion of bacteria potentially resistant to tetracyclines and sulphonamides. The presence of these ARGs was independent of the total bacterial density and temperature. The dynamics of tet(A) and sulII genes were, however, positively correlated with dissolved oxygen and negatively to chlorophyll a, suggesting that the resistant microbes inhabit specific niches. These observations indicate that the lake is a reservoir of antibiotic resistances, highlighting the need of a deeper understanding of the sources of ARGs and the factors allowing their persistence in waters. PMID:26118321

  9. Multidrug resistance phenotypes are widespread over different bacterial taxonomic groups thriving in surface water.

    Science.gov (United States)

    Narciso-da-Rocha, Carlos; Manaia, Célia M

    2016-09-01

    The environment is the original and most ancient source of the antibiotic resistance determinants that threat the human health nowadays. In the environment, water is a privileged habitat and mode of dissemination of bacteria of different origins. Freshwater bodies that cross urban areas are supposed to hold a complex mixture of both human/animal origin and strictly environmental bacteria. In this study, we were interested in unveiling the bacterial diversity in urban river transects and, simultaneously, investigate the occurrence of antibiotic resistant bacteria, in particular the multidrug resistant (MDR). With this aim, water and sediments of two rivers were sampled from an urban transect and the bacterial diversity was assessed based on 16S rRNA gene-based community analysis and, simultaneously, total heterotrophic bacteria were isolated in the presence and in the absence of antibiotics. The three predominant phyla were Proteobacteria, Bacteroidetes and Actinobacteria, in water, or Acidobacteria, in sediments. MDR bacteria were observed to belong to the predominant phyla observed in water, mostly of the classes Gamma- and Betaproteobacteria (Proteobacteria) and Sphingobacteriia and Flavobacteriia (Bacteroidetes) and belonged to genera of ubiquitous (Pseudomonas, Acinetobacter, Stenotrophomonas) or mainly environmental (Chitinophaga, Chryseobacterium) bacteria. The observation that MDR bacteria are widespread in the environment and over distinct phylogenetic lineages has two relevant implications: i) the potential of environmental bacteria as source or facilitators for antibiotic resistance acquisition; ii) the need to complement culture-independent methods with culture-based approaches in order to identify major sources of MDR profiles. PMID:27131885

  10. Increased expression and levels of human β defensins (hBD2 and hBD4 in adults with dental caries

    Directory of Open Access Journals (Sweden)

    Girolamo Jose Barrera

    2013-09-01

    Full Text Available Introduction: Defensins are small anti-microbial peptides produced by epithelial cells. These peptides have a broad range of actions against microorganisms, including Gram-positive and Gram-negative bacteria.Human defensins are classifi ed into two subfamilies, the α-, and β- defensins, which differ in their distribution of disulphide bonds between the six conserved cysteine residues. Defensins are found in salivaand others compartments of the body. Human β defensins 2 (hBD2, beta defensins 4 (hBD4 and alpha defensins 4 (hNP4 in saliva may contributes to vulnerability or resistance to caries. This study aimed to determine a possible correlation between caries and levels of defensins measuring the expression in gingival tissue and concentrations in saliva samples.Methods: Oral examinations were performed on 100 adults of both genders (18-30 years old, and unstimulated whole saliva was collected for immunoassays of the three peptides and for the salivary pH, buffercapacity, protein, and peroxidase activity. mRNA levels of defensins in gingival sample were assessed by semi-quantitative RT-PCR technique.Results: The median salivary levels of hBD2 and hBD4 were 1.88 μg/ml and 0.86 μg/ml respectively for the caries-free group (n=44 and 7.26 μ/ml (hBD2 and 4.25 μg/ml (hBD4 for all subjects with evidenceof caries (n=56. There was no difference in the levels of hNP4, salivary pH, and proteins between groups, however the peroxidase activity and buffer capacity (interval 6.0-5.0 were reduced in caries group. Transcriptional levels of hBD2 and hBD4 did correlate with caries experience, the mRNA expression of hBD2 and hBD4 were signifi cantly higher in patients with caries than in patients with no-caries (p < 0.01.Conclusion: We conclude that high salivary levels and expression of beta defensins, low peroxidase activity and buffer capacity may represent a biological response of oral tissue to caries. Our observation couldlead to new ways to prevent

  11. A Scorpion Defensin BmKDfsin4 Inhibits Hepatitis B Virus Replication in Vitro

    Directory of Open Access Journals (Sweden)

    Zhengyang Zeng

    2016-04-01

    Full Text Available Hepatitis B virus (HBV infection is a major worldwide health problem which can cause acute and chronic hepatitis and can significantly increase the risk of liver cirrhosis and primary hepatocellular carcinoma (HCC. Nowadays, clinical therapies of HBV infection still mainly rely on nucleotide analogs and interferons, the usage of which is limited by drug-resistant mutation or side effects. Defensins had been reported to effectively inhibit the proliferation of bacteria, fungi, parasites and viruses. Here, we screened the anti-HBV activity of 25 scorpion-derived peptides most recently characterized by our group. Through evaluating anti-HBV activity and cytotoxicity, we found that BmKDfsin4, a scorpion defensin with antibacterial and Kv1.3-blocking activities, has a comparable high inhibitory rate of both HBeAg and HBsAg in HepG2.2.15 culture medium and low cytotoxicity to HepG2.2.15. Then, our experimental results further showed that BmKDfsin4 can dose-dependently decrease the production of HBV DNA and HBV viral proteins in both culture medium and cell lysate. Interestingly, BmKDfsin4 exerted high serum stability. Together, this study indicates that the scorpion defensin BmKDfsin4 also has inhibitory activity against HBV replication along with its antibacterial and potassium ion channel Kv1.3-blocking activities, which shows that BmKDfsin4 is a uniquely multifunctional defensin molecule. Our work also provides a good molecule material which will be used to investigate the link or relationship of its antiviral, antibacterial and ion channel–modulating activities in the future.

  12. Overexpression of BSR1 confers broad-spectrum resistance against two bacterial diseases and two major fungal diseases in rice.

    Science.gov (United States)

    Maeda, Satoru; Hayashi, Nagao; Sasaya, Takahide; Mori, Masaki

    2016-06-01

    Broad-spectrum disease resistance against two or more types of pathogen species is desirable for crop improvement. In rice, Xanthomonas oryzae pv. oryzae (Xoo), the causal bacteria of rice leaf blight, and Magnaporthe oryzae, the fungal pathogen causing rice blast, are two of the most devastating pathogens. We identified the rice BROAD-SPECTRUM RESISTANCE 1 (BSR1) gene for a BIK1-like receptor-like cytoplasmic kinase using the FOX hunting system, and demonstrated that BSR1-overexpressing (OX) rice showed strong resistance to the bacterial pathogen, Xoo and the fungal pathogen, M. oryzae. Here, we report that BSR1-OX rice showed extended resistance against two other different races of Xoo, and to at least one other race of M. oryzae. In addition, the rice showed resistance to another bacterial species, Burkholderia glumae, which causes bacterial seedling rot and bacterial grain rot, and to Cochliobolus miyabeanus, another fungal species causing brown spot. Furthermore, BSR1-OX rice showed slight resistance to rice stripe disease, a major viral disease caused by rice stripe virus. Thus, we demonstrated that BSR1-OX rice shows remarkable broad-spectrum resistance to at least two major bacterial species and two major fungal species, and slight resistance to one viral pathogen. PMID:27436950

  13. High prevalence of multidrug resistance in bacterial uropathogens from Kathmandu, Nepal

    Directory of Open Access Journals (Sweden)

    Baral Pankaj

    2012-01-01

    Full Text Available Abstract Background Urinary Tract Infection (UTI is one of the most common infectious diseases and people of all age-groups and geographical locations are affected. The impact of disease is even worst in low-resource developing countries due to unaware of the UTIs caused by multidrug-resistant (MDR pathogens and the possibility of transfer of MDR traits between them. The present study aimed to determine the prevalence of MDR bacterial isolates from UTI patients, the antibiotic resistance pattern and the conjugational transfer of multidrug resistance phenotypes in Escherichia coli (E. coli. Results Two hundred and nineteen bacterial isolates were recovered from 710 urine samples at Kathmandu Model hospital during the study period. All samples and isolates were investigated by standard laboratory procedures. Among the significant bacterial growth (30.8%, 219 isolates, 41.1% isolates were MDR. The most prevailing organism, E. coli (81.3%, 178 isolates was 38.2% MDR, whereas second most common organism, Citrobacter spp. (5%, 11 isolates was found 72.7% MDR. Extended-spectrum β-lactamase (ESBL production was detected in 55.2% of a subset of MDR E. coli isolates. Among the 29 MDR E. coli isolates, plasmids of size ranging 2-51 kb were obtained with different 15 profiles. The most common plasmid of size 32 kb was detected in all of the plasmid-harbored E. coli strains. The majority of E. coli isolates investigated for the multidrug resistance transfer were able to transfer plasmid-mediated MDR phenotypes along with ESBL pattern with a frequency ranging from 0.3 × 10-7 to 1.5 × 10-7 to an E. coli HB101 recipient strain by conjugation. Most of the donor and recipient strain showed high levels of minimum inhibitory concentration (MIC values for commonly-used antibiotics. Conclusions The high prevalence of multidrug resistance in bacterial uropathogens was observed. Particularly, resistance patterns were alarmingly higher for amoxycillin, co

  14. Induction of bacterial antibiotic resistance by mutagenic halogenated nitrogenous disinfection byproducts.

    Science.gov (United States)

    Lv, Lu; Yu, Xin; Xu, Qian; Ye, Chengsong

    2015-10-01

    Halogenated nitrogenous disinfection byproducts (N-DBPs) raise concerns regarding their mutagenicity and carcinogenicity threatening public health. However, environmental consequence of their mutagenicity has received less attention. In this study, the effect of halogenated N-DBPs on bacterial antibiotic resistance (BAR) was investigated. After exposure to bromoacetamide (BAcAm), trichloroacetonitrile (TCAN) or tribromonitromethane (TBNM), the resistance of Pseudomonas aeruginosa PAO1 to both individual and multiple antibiotics (ciprofloxacin, gentamicin, polymyxin B, rifampin, tetracycline, ciprofloxacin + gentamicin and ciprofloxacin + tetracycline) was increased, which was predominantly ascribed to the overexpression of efflux pumps. The mechanism of this effect was demonstrated to be mutagenesis through sequencing and analyzing antibiotic resistance genes. The same induction phenomena also appeared in Escherichia coli, suggesting this effect may be universal to waterborne pathogens. Therefore, more attention should be given to halogenated N-DBPs, as they could increase not only genotoxicological risks but also epidemiological risks of drinking water.

  15. The diversity of membrane transporters encoded in bacterial arsenic-resistance operons

    Directory of Open Access Journals (Sweden)

    Yiren Yang

    2015-05-01

    Full Text Available Transporter-facilitated arsenite extrusion is the major pathway of arsenic resistance within bacteria. So far only two types of membrane-bound transporter proteins, ArsB and ArsY (ACR3, have been well studied, although the arsenic transporters in bacteria display considerable diversity. Utilizing accumulated genome sequence data, we searched arsenic resistance (ars operons in about 2,500 bacterial strains and located over 700 membrane-bound transporters which are encoded in these operons. Sequence analysis revealed at least five distinct transporter families, with ArsY being the most dominant, followed by ArsB, ArsP (a recently reported permease family, Major Facilitator protein Superfamily (MFS and Major Intrinsic Protein (MIP. In addition, other types of transporters encoded in the ars operons were found, but in much lower frequencies. The diversity and evolutionary relationships of these transporters with regard to arsenic resistance will be discussed.

  16. Survival and evolution of a large multidrug resistance plasmid in new clinical bacterial hosts

    DEFF Research Database (Denmark)

    Porse, Andreas; Schønning, Kristian; Munck, Christian;

    2016-01-01

    and population sequencing to show that the long-term persistence and molecular integrity of the plasmid is highly influenced by multiple factors within a 25 kb plasmid region constituting a host-dependent burden. In the E. coli hosts investigated here, improved plasmid stability readily evolves via IS......Large conjugative plasmids are important drivers of bacterial evolution and contribute significantly to the dissemination of antibiotic resistance. Although plasmid borne multidrug resistance is recognized as one of the main challenges in modern medicine, the adaptive forces shaping the evolution...... of these plasmids within pathogenic hosts are poorly understood. Here we study plasmid-host adaptations following transfer of a 73 kb conjugative multidrug resistance plasmid to naïve clinical isolates of Klebsiella pneumoniae and Escherichia coli We use experimental evolution, mathematical modelling...

  17. Resistance to Bacterial Leaf Blight in a Somaclonal Rice Mutant HX-3 at Cellular Level

    Institute of Scientific and Technical Information of China (English)

    GAO Dong-ying; ZHOU Yi-hong; HUANG Xue-qing; SUN Li-hua; LIU Ai-min

    2004-01-01

    The interaction between rice host and its pathogen Xanthomonas oryzae pv. oryzae (Xoo) at cellular level was studied by using a resistant somaclonal mutant HX-3 and its susceptable donor Minghui 63. After inoculation with Xoo strain Zhe 173 (Chinese pathotype Ⅳ), the activity of superoxide dismutase (SOD) and peroxidase (POD) in the callus of Minghui 63 was increased dramatically, and the active oxygen(O2 - .) was produced at a higher rate; Meanwhile, the callus grew slowly with the reduction of protein content. Compared to the activity of SOD and POD, the production rate of O2-. and the fresh weight in HX-3 callus varied little after the inoculation. It could be proposed that there were great differences between the resistance of HX-3 and Mighui 63 at cellular level. There was no difference detected concerning resistance to bacterial leaf blight in HX-3 between the plant and the callus.

  18. Survival and evolution of a large multidrug resistance plasmid in new clinical bacterial hosts

    DEFF Research Database (Denmark)

    Porse, Andreas; Schønning, Kristian; Munck, Christian;

    2016-01-01

    Large conjugative plasmids are important drivers of bacterial evolution and contribute significantly to the dissemination of antibiotic resistance. Although plasmid borne multidrug resistance is recognized as one of the main challenges in modern medicine, the adaptive forces shaping the evolution...... sequencing to show that the long-term persistence and molecular integrity of the plasmid is highly influenced by multiple factors within a 25 kb plasmid region constituting a host-dependent burden. In the E. coli hosts investigated here, improved plasmid stability readily evolves via IS26 mediated deletions...... consistently followed by all evolved E. coli lineages exposes a trade-off between horizontal and vertical transmission that may ultimately limit the dissemination potential of clinical multidrug resistance plasmids in these hosts....

  19. Seed defensins of barnyard grass Echinochloa crusgalli (L.) Beauv.

    Science.gov (United States)

    Odintsova, Tatyana I; Rogozhin, Eugene A; Baranov, Yurij; Musolyamov, Alexander Kh; Yalpani, Nasser; Egorov, Tsezi A; Grishin, Eugene V

    2008-01-01

    From the annual weed barnyard grass Echinochloa crusgalli (L.) Beauv., two novel defensins Ec-AMP-D1 and Ec-AMP-D2 that differ by a single amino acid substitution were isolated by a combination of different chromatographic procedures. Both defensins were active against several phytopathogenic fungi and the oomycete Phytophthora infestans at micromolar concentrations. The Ec-AMP-D1 showed higher activity against the oomycete than Ec-AMP-D2. The comparison of the amino acid sequences of the antifungal E. crusgalli defensins with those of earlier characterized T. kiharae defensins [T.I. Odintsova, Ts.A. Egorov, A.Kh. Musolyamov, M.S. Odintsova, V.A. Pukhalsky, E.V. Grishin, Seed defensins from T. kiharae and related species: genome localization of defensin-encoding genes, Biochimie, 89 (2007) 605-612.] that were devoid of substantial antifungal activity point to the C-terminal region of the molecule as the main determinant of the antifungal activity of E. crusgalli defensins.

  20. Antibiotics, Antibiotic Resistance Genes, and Bacterial Community Composition in Fresh Water Aquaculture Environment in China.

    Science.gov (United States)

    Xiong, Wenguang; Sun, Yongxue; Zhang, Tong; Ding, Xueyao; Li, Yafei; Wang, Mianzhi; Zeng, Zhenling

    2015-08-01

    Environmental antibiotic resistance has drawn increasing attention due to its great threat to human health. In this study, we investigated concentrations of antibiotics (tetracyclines, sulfonamides and (fluoro)quinolones) and abundances of antibiotic resistance genes (ARGs), including tetracycline resistance genes, sulfonamide resistance genes, and plasmid-mediated quinolone resistance genes, and analyzed bacterial community composition in aquaculture environment in Guangdong, China. The concentrations of sulfametoxydiazine, sulfamethazine, sulfamethoxazole, oxytetracycline, chlorotetracycline, doxycycline, ciprofloxacin, norfloxacin, and enrofloxacin were as high as 446 μg kg(-1) and 98.6 ng L(-1) in sediment and water samples, respectively. The relative abundances (ARG copies/16S ribosomal RNA (rRNA) gene copies) of ARGs (sul1, sul2, sul3, tetM, tetO, tetW, tetS, tetQ, tetX, tetB/P, qepA, oqxA, oqxB, aac(6')-Ib, and qnrS) were as high as 2.8 × 10(-2). The dominant phyla were Proteobacteria, Bacteroidetes, and Firmicutes in sediment samples and Proteobacteria, Actinobacteria and Bacteroidetes in water samples. The genera associated with pathogens were also observed, such as Acinetobacter, Arcobacter, and Clostridium. This study comprehensively investigated antibiotics, ARGs, and bacterial community composition in aquaculture environment in China. The results indicated that fish ponds are reservoirs of ARGs and the presence of potential resistant and pathogen-associated taxonomic groups in fish ponds might imply the potential risk to human health.

  1. Aerobic bacterial profile and antibiotic resistance in patients with diabetic foot infections

    Directory of Open Access Journals (Sweden)

    Michele Cezimbra Perim

    2015-10-01

    Full Text Available ABSTRACTINTRODUCTION: This study aimed to determine the frequencies of bacterial isolates cultured from diabetic foot infections and assess their resistance and susceptibility to commonly used antibiotics.METHODS: This prospective study included 41 patients with diabetic foot lesions. Bacteria were isolated from foot lesions, and their antibiotic susceptibility pattern was determined using the Kirby-Bauer disk diffusion method and/or broth method [minimum inhibitory concentration (MIC].RESULTS: The most common location of ulceration was the toe (54%, followed by the plantar surface (27% and dorsal portion (19%. A total of 89 bacterial isolates were obtained from 30 patients. The infections were predominantly due to Gram-positive bacteria and polymicrobial bacteremia. The most commonly isolated Gram-positive bacteria were Staphylococcus aureus, followed by Staphylococcus saprophyticus, Staphylococcus epidermidis, Streptococcus agalactiae, and Streptococcus pneumoniae. The most commonly isolated Gram-negative bacteria were Proteus spp. and Enterobacterspp., followed by Escherichia coli, Pseudomonasspp., and Citrobacterspp. Nine cases of methicillin-resistant Staphylococcus aureus (MRSA had cefoxitin resistance, and among these MRSA isolates, 3 were resistant to vancomycin with the MIC technique. The antibiotic imipenem was the most effective against both Gram-positive and Gram-negative bacteria, and gentamicin was effective against Gram-negative bacteria.CONCLUSIONS: The present study confirmed the high prevalence of multidrug-resistant pathogens in diabetic foot ulcers. It is necessary to evaluate the different microorganisms infecting the wound and to know the antibiotic susceptibility patterns of the isolates from the infected wound. This knowledge is crucial for planning treatment with the appropriate antibiotics, reducing resistance patterns, and minimizing healthcare costs.

  2. Isolation and Characterization of Nickel Uptake by Nickel Resistant Bacterial Isolate (NiRBI)

    Institute of Scientific and Technical Information of China (English)

    JAGDISH S PATEL; PRERNA C PATEL; KIRAN KALIA

    2006-01-01

    Bioremediation technology has gained importance because microbes could be the convenient source of bio-absorption/bioaccumulation of metals from effluent streams. Methods The nickel-resistant bacterial isolates (NiRBI)were selected from various bacterial isolates from industrial effluent and grown in nutrient broth containing different concentrations of nickel sulfate (0.3-3.0 mmol/L) and their capability of accumulating metal from the medium. Results Well-defined growth of NiRBI was observed in the medium containing up to 2.5 mmol/L of nickel. The isolate was identified using 16S rRNA and closely related to Pseudomonas fragi. Maximum accumulation of nickel (0.59 mg/g dry weight of bacterial cells) was observed when NiRBI was grown in media containing 2 mmol/L of nickel. The protein profile of the NiRBI cellular extract by SDS-PAGE showed two metal stress-induced proteins of molecular weight 48 KD and 18 KD with a simultaneous down regulation of four proteins of 46.7 KD, 42.2 KD, 19.7 KD, and 4.0 KD. Conclusion 48 KD and 18 KD proteins play a role in metal resistance mechanism by NiRBI.

  3. Antibiotic resistance genes occurrence and bacterial community composition in the Liuxi River

    Directory of Open Access Journals (Sweden)

    Wenguang eXiong

    2014-12-01

    Full Text Available Antibiotic resistance genes (ARGs in the environment have paid great concern due to their health risk. We investigated antibiotics concentrations (tetracyclines, sulfonamides and fluoroquinolones, ARGs abundances (tetracycline, sulfonamide and plasmid-mediated quinolone resistance (PMQR genes, and bacterial community composition in sediment and water samples in the Liuxi River, China. Antibiotics concentrations were determined by ultra-performance liquid chromatography-electrospray tandem mass spectrometry. ARGs abundances were quantified by a culture-independent method. Bacterial community composition was analyzed by metagenomic approach based on Ion Torrent Personal Genome Machine platform. Antibiotics concentrations were at the levels of 1.19 to 622 ug kg-1 in sediment samples and below the limit of detection to 127 ng L-1 in water samples. Relative abundances (ARGs copies/16S rRNA gene copies of detected ARGs were at the range of 10-5 to 10-2. The dominant phyla were Proteobacteria, Bacteroidetes and Verrucomicrobia in sediment samples, and were Proteobacteria, Actinobacteria and Bacteroidetes in water samples. The results indicated that the river environment was contaminated by antibiotics and may be as a reservoir of ARGs. This study provided quantitative data on antibiotics, ARGs and bacterial community composition in the Liuxi River, a geographical location different from the reported studies.

  4. Conjunctival bacterial flora and antibiotic resistance pattern in patients undergoing cataract surgery

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    Arantes Tiago Eugênio Faria e

    2006-01-01

    Full Text Available PURPOSE: To evaluate the conjunctival bacterial flora and its antibiotic resistance pattern in eyes of patients undergoing cataract surgery. METHODS: From August to October 2004, 50 patients undergoing cataract surgery in the "Fundação Altino Ventura", Recife, Brazil, were prospectively evaluated. Conjunctival material was obtained on the day of surgery, before the application of topical anesthetic, antibiotic or povidone-iodine. The collected material was inoculated and bacterioscopic analysis was carried out. In the cases where there was bacterial growth, antibiotic susceptibility tests and cultures, for isolation and identification of the bacteria, were performed. RESULTS: Of the 50 eyes, 43 (86.0% had positive cultures. The coagulase-negative Staphylococcus (CNS, found in 27 (54.0% eyes, was the most frequent organism. More than 90% of the isolates of this bacterium were susceptible to cephalotin, vancomycin, chloramphenicol, ofloxacin and gatifloxacin; 70 to 90% were susceptible to gentamicin, cefotaxime, oxacillin and ciprofloxacin; and less than 70% were sensible to neomycin. Four (10.5% of the bacterial isolates were resistant to four or more antibiotics, two of them were CNS. CONCLUSION: The most frequent bacterium in the conjunctival flora is the coagulase-negative Staphylococcus. The isolates of this organism showed low susceptibility rate to neomycin, and high susceptibility rates to cephalotin, vancomycin, chloramphenicol, ofloxacin and gatifloxacin.

  5. Pipecolic acid enhances resistance to bacterial infection and primes salicylic acid and nicotine accumulation in tobacco.

    Science.gov (United States)

    Vogel-Adghough, Drissia; Stahl, Elia; Návarová, Hana; Zeier, Juergen

    2013-11-01

    Distinct amino acid metabolic pathways constitute integral parts of the plant immune system. We have recently identified pipecolic acid (Pip), a lysine-derived non-protein amino acid, as a critical regulator of systemic acquired resistance (SAR) and basal immunity to bacterial infection in Arabidopsis thaliana. In Arabidopsis, Pip acts as an endogenous mediator of defense amplification and priming. For instance, Pip conditions plants for effective biosynthesis of the phenolic defense signal salicylic acid (SA), accumulation of the phytoalexin camalexin, and expression of defense-related genes. Here, we show that tobacco plants respond to leaf infection by the compatible bacterial pathogen Pseudomonas syringae pv tabaci (Pstb) with a significant accumulation of several amino acids, including Lys, branched-chain, aromatic, and amide group amino acids. Moreover, Pstb strongly triggers, alongside the biosynthesis of SA and increases in the defensive alkaloid nicotine, the production of the Lys catabolites Pip and α-aminoadipic acid. Exogenous application of Pip to tobacco plants provides significant protection to infection by adapted Pstb or by non-adapted, hypersensitive cell death-inducing P. syringae pv maculicola. Pip thereby primes tobacco for rapid and strong accumulation of SA and nicotine following bacterial infection. Thus, our study indicates that the role of Pip as an amplifier of immune responses is conserved between members of the rosid and asterid groups of eudicot plants and suggests a broad practical applicability for Pip as a natural enhancer of plant disease resistance.

  6. Rainbow trout (Oncorhynchus mykiss) resistance to columnaris disease is heritable and favorably correlated with bacterial cold water disease resistance.

    Science.gov (United States)

    Evenhuis, J P; Leeds, T D; Marancik, D P; LaPatra, S E; Wiens, G D

    2015-04-01

    Columnaris disease (CD), caused by Flavobacterium columnare, is an emerging disease affecting rainbow trout aquaculture. Objectives of this study were to 1) estimate heritability of CD resistance in a rainbow trout line (ARS-Fp-R) previously selected 4 generations for improved bacterial cold water disease (BCWD) resistance; 2) estimate genetic correlations among CD resistance, BCWD resistance, and growth to market BW; and 3) compare CD resistance among the ARS-Fp-R, ARS-Fp-S (selected 1 generation for increased BCWD susceptibility), and ARS-Fp-C (selection control) lines. Heritability of CD resistance was estimated using data from a waterborne challenge of 44 full-sib ARS-Fp-R families produced using a paternal half-sib mating design, and genetic correlations were estimated using these data and 5 generations of BCWD resistance, 9-mo BW (approximately 0.5 kg), and 12-mo BW (approximately 1.0 kg) data from 405 ARS-Fp-R full-sib families. The CD and BCWD challenges were initiated at approximately 52 and 84 d posthatch, or approximately 650 and 1,050 degree days (°C × d), respectively. Survival of ARS-Fp-R families ranged from 0 to 48% following CD challenge and heritability estimates were similar between CD (0.17 ± 0.09) and BCWD (0.18 ± 0.03) resistance, and the genetic correlation between these 2 traits was favorable (0.35 ± 0.25). Genetic correlations were small and antagonistic (-0.15 ± 0.08 to -0.19 ± 0.24) between the 2 resistance traits and 9- and 12-mo BW. Two challenges were conducted in consecutive years to compare CD resistance among ARS-Fp-R, ARS-Fp-C, and ARS-Fp-S families. In the first challenge, ARS-Fp-R families (83% survival) had greater CD resistance than ARS-Fp-C (73.5%; P = 0.02) and ARS-Fp-S (68%; P < 0.001) families, which did not differ (P = 0.16). In the second challenge, using an approximately 2.5-fold greater challenge dose, ARS-Fp-R families exhibited greater CD resistance (56% survival) than ARS-Fp-S (38% survival; P = 0.02) families

  7. Hidden Selection of Bacterial Resistance to Fluoroquinolones In Vivo: The Case of Legionella pneumophila and Humans

    Science.gov (United States)

    Shadoud, Lubana; Almahmoud, Iyad; Jarraud, Sophie; Etienne, Jérôme; Larrat, Sylvie; Schwebel, Carole; Timsit, Jean-François; Schneider, Dominique; Maurin, Max

    2015-01-01

    Background Infectious diseases are the leading cause of human morbidity and mortality worldwide. One dramatic issue is the emergence of microbial resistance to antibiotics which is a major public health concern. Surprisingly however, such in vivo adaptive ability has not been reported yet for many intracellular human bacterial pathogens such as Legionella pneumophila. Methods We examined 82 unrelated patients with Legionnaire's disease from which 139 respiratory specimens were sampled during hospitalization and antibiotic therapy. We both developed a real time PCR assay and used deep-sequencing approaches to detect antibiotic resistance mutations in L. pneumophila and follow their selection and fate in these samples. Findings We identified the in vivo selection of fluoroquinolone resistance mutations in L. pneumophila in two infected patients treated with these antibiotics. By investigating the mutational dynamics in patients, we showed that antibiotic resistance occurred during hospitalization most likely after fluoroquinolone treatment. Interpretation In vivo selection of antibiotic resistances in L. pneumophila may be associated with treatment failures and poor prognosis. This hidden resistance must be carefully considered in the therapeutic management of legionellosis patients and in the control of the gradual loss of effectiveness of antibiotics. PMID:26501115

  8. Impact on Bacterial Resistance of Therapeutically Nonequivalent Generics: The Case of Piperacillin-Tazobactam

    Science.gov (United States)

    Rodriguez, Carlos A.; Agudelo, Maria; Aguilar, Yudy A.; Zuluaga, Andres F.

    2016-01-01

    Previous studies have demonstrated that pharmaceutical equivalence and pharmacokinetic equivalence of generic antibiotics are necessary but not sufficient conditions to guarantee therapeutic equivalence (better called pharmacodynamic equivalence). In addition, there is scientific evidence suggesting a direct link between pharmacodynamic nonequivalence of generic vancomycin and promotion of resistance in Staphylococcus aureus. To find out if even subtle deviations from the expected pharmacodynamic behavior with respect to the innovator could favor resistance, we studied a generic product of piperacillin-tazobactam characterized by pharmaceutical and pharmacokinetic equivalence but a faulty fit of Hill’s Emax sigmoid model that could be interpreted as pharmacodynamic nonequivalence. We determined the impact in vivo of this generic product on the resistance of a mixed Escherichia coli population composed of ∼99% susceptible cells (ATCC 35218 strain) and a ∼1% isogenic resistant subpopulation that overproduces TEM-1 β-lactamase. After only 24 hours of treatment in the neutropenic murine thigh infection model, the generic amplified the resistant subpopulation up to 20-times compared with the innovator, following an inverted-U dose-response relationship. These findings highlight the critical role of therapeutic nonequivalence of generic antibiotics as a key factor contributing to the global problem of bacterial resistance. PMID:27191163

  9. Practical survey on antibiotic-resistant bacterial communities in livestock manure and manure-amended soil.

    Science.gov (United States)

    Yang, Qingxiang; Wang, Ruifei; Ren, Siwei; Szoboszlay, Marton; Moe, Luke A

    2016-01-01

    Through livestock manure fertilization, antibiotics, antibiotic-resistant bacteria and genes are transferred to agricultural soils, resulting in a high prevalence of antibiotic-resistant bacteria in the soil. It is not clear, however, whether a correlation exists between resistant bacterial populations in manure and manure-amended soil. In this work, we demonstrate that the prevalence of cephalexin-, amoxicillin-, kanamycin- and gentamicin-resistant bacteria as well as bacteria simultaneously resistant to all four antibiotics was much higher in manure-amended soils than in manure-free soil. 454-pyrosequencing indicated that the ARB and multiple antibiotic-resistant bacteria (MARB) in swine or chicken manure and manure-amended soil were mainly distributed among Sphingobacterium, Myroides, Enterococcus, Comamonas and unclassified Flavobacteriaceae. The genus Sphingobacterium was highly prevalent among ARB from swine manure and manure-amended soil, and was also the most dominant genus among MARB from chicken manure and manure-amended soil. Other dominant genera among ARB or MARB populations in manure samples, including Myroides, Enterococcus and Comamonas, could not be detected or were detected at very low relative abundance in manure-amended soil. The present study suggests the possibility of transfer of ARBs from livestock manures to soils and persistence of ARB in these environments. PMID:26513264

  10. Broad-spectrum antimicrobial activity of human intestinal defensin 5.

    OpenAIRE

    Porter, E M; van Dam, E; Valore, E V; Ganz, T

    1997-01-01

    Defensins are antibiotic peptides expressed in human and animal myeloid and epithelial cells. Due to the limited availability of natural peptides, the properties of human epithelial defensins have not been studied. We assayed the microbicidal activity of recombinant human intestinal defensin 5 (rHD-5) in the presence of salt (O to 150 mM NaCl) with varied pH (pH 5.5 to pH 8.5) and trypsin (25 and 250 microg/ml). rHD-5 exhibits microbicidal activity against Listeria monocytogenes, Escherichia ...

  11. Proteomics as a tool for studying bacterial virulence and antimicrobial resistance

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    Francisco José Pérez -Llarena

    2016-03-01

    Full Text Available Proteomic studies have improved our understanding of the microbial world. The most recent advances in this field have helped us to explore aspects beyond genomics. For example, by studying proteins and their regulation, researchers now understand how some pathogenic bacteria have adapted to the lethal actions of antibiotics. Proteomics has also advanced our knowledge of mechanisms of bacterial virulence and some important aspects of how bacteria interact with human cells and, thus, of the pathogenesis of infectious diseases. This review article addresses these issues in some of the most important human pathogens. It also reports some applications of MALDI-TOF mass spectrometry that may be important for the diagnosis of bacterial resistance in clinical laboratories in the future. The reported advances will enable new diagnostic and therapeutic strategies to be developed in the fight against some of the most lethal bacteria affecting humans.

  12. Comparative Resistance of AH26 and a New Sealer Prototype to a Bacterial Challenge

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    Derek Duggan

    2012-01-01

    Full Text Available Objective. This study compared the leakage resistance of a New Sealer Prototype (NSP with a traditional sealer (AH 26 in Resilon-filled roots subjected to a bacterial challenge. Study Design. 41 roots were instrumented to ISO size 50 apically. Group 1 (=20 contained Resilon and AH 26 sealer and roots in group 2 (=21 contained Resilon and NSP. Roots were embedded in a dual-chamber model with the upper chamber containing Streptococcus mutans inoculum. Evidence of bacterial penetration was observed for 1 month. Fisher's Test was used to analyze the data. Results. 8 of 20 roots (40% in the AH 26 group demonstrated leakage whereas 3 of 21 roots (14% in the NSP group leaked. The difference in leakage rates was not statistically significant (=0.053. Conclusion. The traditional sealer (AH 26 demonstrated increased leakage rates compared to the New Sealer Prototype (NSP, but the difference did not reach statistical significance in this study.

  13. Big defensins, a diverse family of antimicrobial peptides that follows different patterns of expression in hemocytes of the oyster Crassostrea gigas.

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    Rafael D Rosa

    Full Text Available BACKGROUND: Big defensin is an antimicrobial peptide composed of a highly hydrophobic N-terminal region and a cationic C-terminal region containing six cysteine residues involved in three internal disulfide bridges. While big defensin sequences have been reported in various mollusk species, few studies have been devoted to their sequence diversity, gene organization and their expression in response to microbial infections. FINDINGS: Using the high-throughput Digital Gene Expression approach, we have identified in Crassostrea gigas oysters several sequences coding for big defensins induced in response to a Vibrio infection. We showed that the oyster big defensin family is composed of three members (named Cg-BigDef1, Cg-BigDef2 and Cg-BigDef3 that are encoded by distinct genomic sequences. All Cg-BigDefs contain a hydrophobic N-terminal domain and a cationic C-terminal domain that resembles vertebrate β-defensins. Both domains are encoded by separate exons. We found that big defensins form a group predominantly present in mollusks and closer to vertebrate defensins than to invertebrate and fungi CSαβ-containing defensins. Moreover, we showed that Cg-BigDefs are expressed in oyster hemocytes only and follow different patterns of gene expression. While Cg-BigDef3 is non-regulated, both Cg-BigDef1 and Cg-BigDef2 transcripts are strongly induced in response to bacterial challenge. Induction was dependent on pathogen associated molecular patterns but not damage-dependent. The inducibility of Cg-BigDef1 was confirmed by HPLC and mass spectrometry, since ions with a molecular mass compatible with mature Cg-BigDef1 (10.7 kDa were present in immune-challenged oysters only. From our biochemical data, native Cg-BigDef1 would result from the elimination of a prepropeptide sequence and the cyclization of the resulting N-terminal glutamine residue into a pyroglutamic acid. CONCLUSIONS: We provide here the first report showing that big defensins form a family

  14. Gene Expression Variability Underlies Adaptive Resistance in Phenotypically Heterogeneous Bacterial Populations.

    Science.gov (United States)

    Erickson, Keesha E; Otoupal, Peter B; Chatterjee, Anushree

    2015-11-13

    The root cause of the antibiotic resistance crisis is the ability of bacteria to evolve resistance to a multitude of antibiotics and other environmental toxins. The regulation of adaptation is difficult to pinpoint due to extensive phenotypic heterogeneity arising during evolution. Here, we investigate the mechanisms underlying general bacterial adaptation by evolving wild-type Escherichia coli populations to dissimilar chemical toxins. We demonstrate the presence of extensive inter- and intrapopulation phenotypic heterogeneity across adapted populations in multiple traits, including minimum inhibitory concentration, growth rate, and lag time. To search for a common response across the heterogeneous adapted populations, we measured gene expression in three stress-response networks: the mar regulon, the general stress response, and the SOS response. While few genes were differentially expressed, clustering revealed that interpopulation gene expression variability in adapted populations was distinct from that of unadapted populations. Notably, we observed both increases and decreases in gene expression variability upon adaptation. Sequencing select genes revealed that the observed gene expression trends are not necessarily attributable to genetic changes. To further explore the connection between gene expression variability and adaptation, we propagated single-gene knockout and CRISPR (clustered regularly interspaced short palindromic repeats) interference strains and quantified impact on adaptation to antibiotics. We identified significant correlations that suggest genes with low expression variability have greater impact on adaptation. This study provides evidence that gene expression variability can be used as an indicator of bacterial adaptive resistance, even in the face of the pervasive phenotypic heterogeneity underlying adaptation. PMID:27623410

  15. Effects of Biochar Amendment on Tomato Bacterial Wilt Resistance and Soil Microbial Amount and Activity

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    Yang Lu

    2016-01-01

    Full Text Available Bacterial wilt is a serious soilborne disease of Solanaceae crops which is caused by Ralstonia solanacearum. The important role of biochar in enhancing disease resistance in plants has been verified; however, the underlying mechanism remains not fully understood. In this study, two different biochars, made from peanut shell (BC1 and wheat straw (BC2, were added to Ralstonia solanacearum-infected soil to explore the interrelation among biochar, tomato bacterial wilt, and soil microbial properties. The results showed that both BC1 and BC2 treatments significantly reduced the disease index of bacterial wilt by 28.6% and 65.7%, respectively. The populations of R. solanacearum in soil were also significantly decreased by biochar application. Ralstonia solanacearum infection significantly reduced the densities of soil bacteria and actinomycetes and increased the ratio of soil fungi/bacteria in the soil. By contrast, BC1 and BC2 addition to pathogen-infected soil significantly increased the densities of soil bacteria and actinomycetes but decreased the density of fungi and the ratios of soil fungi/bacteria and fungi/actinomycetes. Biochar treatments also increased soil neutral phosphatase and urease activity. Furthermore, higher metabolic capabilities of microorganisms by biochar application were found at 96 and 144 h in Biolog EcoPlates. These results suggest that both peanut and wheat biochar amendments were effective in inhibiting tomato bacterial wilt caused by R. solanacearum. The results suggest a relationship between the disease resistance of the plants and the changes in soil microbial population densities and activity.

  16. New insights in the bacterial spore resistance to extreme terrestrial and extraterrestrial factors

    Science.gov (United States)

    Moeller, Ralf; Horneck, Gerda; Reitz, Guenther

    Based on their unique resistance to various space parameters, Bacillus endospores are one of the model systems used for astrobiological studies. The extremely high resistance of bacterial endospores to environmental stress factors has intrigued researchers since long time and many characteristic spore features, especially those involved in the protection of spore DNA, have already been uncovered. The disclosure of the complete genomic sequence of Bacillus subtilis 168, one of the often used astrobiological model system, and the rapid development of tran-scriptional microarray techniques have opened new opportunities of gaining further insights in the enigma of spore resistance. Spores of B. subtilis were exposed to various extreme ter-restrial and extraterrestrial stressors to reach a better understanding of the DNA protection and repair strategies, which them to cope with the induced DNA damage. Following physical stress factors of environmental importance -either on Earth or in space -were selected for this thesis: (i) mono-and polychromatic UV radiation, (ii) ionizing radiation, (iii) exposure to ultrahigh vacuum; and (iv) high shock pressures simulating meteorite impacts. To reach a most comprehensive understanding of spore resistance to those harsh terrestrial or simulated extraterrestrial conditions, a standardized experimental protocol of the preparation and ana-lyzing methods was established including the determination of the following spore responses: (i) survival, (ii) induced mutations, (iii) DNA damage, (iv) role of different repair pathways by use of a set of repair deficient mutants, and (v) transcriptional responses during spore germi-nation by use of genome-wide transcriptome analyses and confirmation by RT-PCR. From this comprehensive set of data on spore resistance to a variety of environmental stress parameters a model of a "built-in" transcriptional program of bacterial spores in response to DNA damaging treatments to ensure DNA restoration

  17. Enhanced Disease Susceptibility1 Mediates Pathogen Resistance and Virulence Function of a Bacterial Effector in Soybean.

    Science.gov (United States)

    Wang, Jialin; Shine, M B; Gao, Qing-Ming; Navarre, Duroy; Jiang, Wei; Liu, Chunyan; Chen, Qingshan; Hu, Guohua; Kachroo, Aardra

    2014-05-28

    Enhanced disease susceptibility1 (EDS1) and phytoalexin deficient4 (PAD4) are well-known regulators of both basal and resistance (R) protein-mediated plant defense. We identified two EDS1-like (GmEDS1a/GmEDS1b) proteins and one PAD4-like (GmPAD4) protein that are required for resistance signaling in soybean (Glycine max). Consistent with their significant structural conservation to Arabidopsis (Arabidopsis thaliana) counterparts, constitutive expression of GmEDS1 or GmPAD4 complemented the pathogen resistance defects of Arabidopsis eds1 and pad4 mutants, respectively. Interestingly, however, the GmEDS1 and GmPAD4 did not complement pathogen-inducible salicylic acid accumulation in the eds1/pad4 mutants. Furthermore, the GmEDS1a/GmEDS1b proteins were unable to complement the turnip crinkle virus coat protein-mediated activation of the Arabidopsis R protein Hypersensitive reaction to Turnip crinkle virus (HRT), even though both interacted with HRT. Silencing GmEDS1a/GmEDS1b or GmPAD4 reduced basal and pathogen-inducible salicylic acid accumulation and enhanced soybean susceptibility to virulent pathogens. The GmEDS1a/GmEDS1b and GmPAD4 genes were also required for Resistance to Pseudomonas syringae pv glycinea2 (Rpg2)-mediated resistance to Pseudomonas syringae. Notably, the GmEDS1a/GmEDS1b proteins interacted with the cognate bacterial effector AvrA1 and were required for its virulence function in rpg2 plants. Together, these results show that despite significant structural similarities, conserved defense signaling components from diverse plants can differ in their functionalities. In addition, we demonstrate a role for GmEDS1 in regulating the virulence function of a bacterial effector.

  18. Evidence of major genes affecting bacterial cold water disease resistance in rainbow trout using Bayesian methods of complex segregation analysis

    Science.gov (United States)

    Bacterial cold water disease (BCWD) causes significant economic loss in salmonid aquaculture. We previously detected genetic variation for BCWD resistance in our rainbow trout population, and a family-based selection program to improve resistance was initiated at the NCCCWA in 2005. The main objec...

  19. Evidence of major genes affecting resistance to bacterial cold water disease in rainbow trout using Bayesian methods of segregation analysis

    Science.gov (United States)

    Bacterial cold water disease (BCWD) causes significant economic loss in salmonid aquaculture. We previously detected genetic variation for BCWD resistance in our rainbow trout population, and a family-based selection program to improve resistance was initiated at the National Center for Cool and Col...

  20. Synergistic and Additive Effect of Oregano Essential Oil and Biological Silver Nanoparticles against Multidrug-Resistant Bacterial Strains

    OpenAIRE

    Scandorieiro, Sara; de Camargo, Larissa C.; Lancheros, Cesar A. C.; Yamada-Ogatta, Sueli F.; Celso V Nakamura; de Oliveira, Admilton G.; Andrade, Célia G.T. de J.; Duran, Nelson; Nakazato, Gerson; Renata K. T. Kobayashi

    2016-01-01

    Bacterial resistance to conventional antibiotics has become a clinical and public health problem, making therapeutic decisions more challenging. Plant compounds and nanodrugs have been proposed as potential antimicrobial alternatives. Studies have shown that oregano (Origanum vulgare) essential oil (OEO) and silver nanoparticles have potent antibacterial activity, also against multidrug-resistant strains; however, the strong organoleptic characteristics of OEO and the development of resistanc...

  1. Bacterial Flora from Healthy Clarias gariepinus and their Antimicrobial Resistance Pattern

    Directory of Open Access Journals (Sweden)

    M.O. Efuntoye

    2012-06-01

    Full Text Available The antibiotic resistance of bacteria isolated from Clarias gariepinus from 3 farms in Ago-Iwoye, Nigeria was investigated. Morphological and biochemical characteristics of isolates revealed that majority of the bacteria belonged to the family Enterobacteriaceae. Staphylococcus aureus and Pseudomonas aeruginosa were also recovered. E. coli strains were highly resistant to ampicillin, chloramphenicol and oxytetracycline (82.4%. Majority of the Pseudomonas aeruginosa were resistant to ampicillin (63.6%, amoxycillin (54.5%, nalidixic acid (63.6% and oxytetracycline (72.7%, whereas most of the Salmonella spp. were resistant to erythromycin (85.7%, gentamycin (71.4%, amoxicillin (57.1%, chloramphenicol (57.1% and sulphamethoxazole (57.1%. All isolates were highly sensitive to ciprofloxacin, novobiocin and ofloxacin. While the presence of potentially pathogenic bacterial species as observed in the study may not present a serious human health hazard because of heat treatment accorded fish before consumption, the presence of antibiotic resistant strains should not be ignored because of the potential for horizontal gene transfer in the food chain.

  2. Novel bacterial metabolite merochlorin A demonstrates in vitro activity against multi-drug resistant methicillin-resistant Staphylococcus aureus.

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    George Sakoulas

    Full Text Available BACKGROUND: We evaluated the in vitro activity of a merochlorin A, a novel compound with a unique carbon skeleton, against a spectrum of clinically relevant bacterial pathogens and against previously characterized clinical and laboratory Staphylococcus aureus isolates with resistance to numerous antibiotics. METHODS: Merochlorin A was isolated and purified from a marine-derived actinomycete strain CNH189. Susceptibility testing for merochlorin A was performed against previously characterized human pathogens using broth microdilution and agar dilution methods. Cytotoxicity was assayed in tissue culture assays at 24 and 72 hours against human HeLa and mouse sarcoma L929 cell lines. RESULTS: The structure of as new antibiotic, merochlorin A, was assigned by comprehensive spectroscopic analysis. Merochlorin A demonstrated in vitro activity against Gram-positive bacteria, including Clostridium dificile, but not against Gram negative bacteria. In S. aureus, susceptibility was not affected by ribosomal mutations conferring linezolid resistance, mutations in dlt or mprF conferring resistance to daptomycin, accessory gene regulator knockout mutations, or the development of the vancomycin-intermediate resistant phenotype. Merochlorin A demonstrated rapid bactericidal activity against MRSA. Activity was lost in the presence of 20% serum. CONCLUSIONS: The unique meroterpenoid, merochlorin A demonstrated excellent in vitro activity against S. aureus and C. dificile and did not show cross-resistance to contemporary antibiotics against Gram positive organisms. The activity was, however, markedly reduced in 20% human serum. Future directions for this compound may include evaluation for topical use, coating biomedical devices, or the pursuit of chemically modified derivatives of this compound that retain activity in the presence of serum.

  3. Retrocyclins neutralize bacterial toxins by potentiating their unfolding.

    Science.gov (United States)

    Kudryashova, Elena; Seveau, Stephanie; Lu, Wuyuan; Kudryashov, Dmitri S

    2015-04-15

    Defensins are a class of immune peptides with a broad range of activities against bacterial, fungal and viral pathogens. Besides exerting direct anti-microbial activity via dis-organization of bacterial membranes, defensins are also able to neutralize various unrelated bacterial toxins. Recently, we have demonstrated that in the case of human α- and β-defensins, this later ability is achieved through exploiting toxins' marginal thermodynamic stability, i.e. defensins act as molecular anti-chaperones unfolding toxin molecules and exposing their hydrophobic regions and thus promoting toxin precipitation and inactivation [Kudryashova et al. (2014) Immunity 41, 709-721]. Retrocyclins (RCs) are humanized synthetic θ-defensin peptides that possess unique cyclic structure, differentiating them from α- and β-defensins. Importantly, RCs are more potent against some bacterial and viral pathogens and more stable than their linear counterparts. However, the mechanism of bacterial toxin inactivation by RCs is not known. In the present study, we demonstrate that RCs facilitate unfolding of bacterial toxins. Using differential scanning fluorimetry (DSF), limited proteolysis and collisional quenching of internal tryptophan fluorescence, we show that hydrophobic regions of toxins normally buried in the molecule interior become more exposed to solvents and accessible to proteolytic cleavage in the presence of RCs. The RC-induced unfolding of toxins led to their precipitation and abrogated activity. Toxin inactivation by RCs was strongly diminished under reducing conditions, but preserved at physiological salt and serum concentrations. Therefore, despite significant structural diversity, α-, β- and θ-defensins employ similar mechanisms of toxin inactivation, which may be shared by anti-microbial peptides from other families.

  4. Focal Targeting of the Bacterial Envelope by Antimicrobial Peptides

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    Rafi eRashid

    2016-06-01

    Full Text Available Antimicrobial peptides (AMPs are utilized by both eukaryotic and prokaryotic organisms. AMPs such as the human beta defensins, human neutrophil peptides, human cathelicidin, and many bacterial bacteriocins are cationic and capable of binding to anionic regions of the bacterial surface. Cationic AMPs (CAMPs target anionic lipids (e.g. phosphatidylglycerol (PG and cardiolipins (CL in the cell membrane and anionic components (e.g. lipopolysaccharide (LPS and lipoteichoic acid (LTA of the cell envelope. Bacteria have evolved mechanisms to modify these same targets in order to resist CAMP killing, e.g. lysinylation of PG to yield cationic lysyl-PG and alanylation of LTA. Since CAMPs offer a promising therapeutic alternative to conventional antibiotics, which are becoming less effective due to rapidly emerging antibiotic resistance, there is a strong need to improve our understanding about the AMP mechanism of action. Recent literature suggests that AMPs often interact with the bacterial cell envelope at discrete foci. Here we review recent AMP literature, with an emphasis on focal interactions with bacteria, including (1 CAMP disruption mechanisms, (2 delocalization of membrane proteins and lipids by CAMPs, and (3 CAMP sensing systems and resistance mechanisms. We conclude with new approaches for studying the bacterial membrane, e.g., lipidomics, high resolution imaging and non-detergent-based membrane domain extraction.

  5. Focal Targeting of the Bacterial Envelope by Antimicrobial Peptides.

    Science.gov (United States)

    Rashid, Rafi; Veleba, Mark; Kline, Kimberly A

    2016-01-01

    Antimicrobial peptides (AMPs) are utilized by both eukaryotic and prokaryotic organisms. AMPs such as the human beta defensins, human neutrophil peptides, human cathelicidin, and many bacterial bacteriocins are cationic and capable of binding to anionic regions of the bacterial surface. Cationic AMPs (CAMPs) target anionic lipids [e.g., phosphatidylglycerol (PG) and cardiolipins (CL)] in the cell membrane and anionic components [e.g., lipopolysaccharide (LPS) and lipoteichoic acid (LTA)] of the cell envelope. Bacteria have evolved mechanisms to modify these same targets in order to resist CAMP killing, e.g., lysinylation of PG to yield cationic lysyl-PG and alanylation of LTA. Since CAMPs offer a promising therapeutic alternative to conventional antibiotics, which are becoming less effective due to rapidly emerging antibiotic resistance, there is a strong need to improve our understanding about the AMP mechanism of action. Recent literature suggests that AMPs often interact with the bacterial cell envelope at discrete foci. Here we review recent AMP literature, with an emphasis on focal interactions with bacteria, including (1) CAMP disruption mechanisms, (2) delocalization of membrane proteins and lipids by CAMPs, and (3) CAMP sensing systems and resistance mechanisms. We conclude with new approaches for studying the bacterial membrane, e.g., lipidomics, high resolution imaging, and non-detergent-based membrane domain extraction. PMID:27376064

  6. Antimicrobial activity of human α-defensin 6 analogs: insights into the physico-chemical reasons behind weak bactericidal activity of HD6 in vitro.

    Science.gov (United States)

    Mathew, Basil; Nagaraj, Ramakrishnan

    2015-11-01

    Human α-defensin 6 (HD6), unlike other mammalian defensins, does not exhibit bactericidal activity, particularly against aerobic bacteria. Monomeric HD6 has a tertiary structure similar to other α-defensins in the crystalline state. However, the physico-chemical reasons behind the lack of antibacterial activity of HD6 are yet to be established unequivocally. In this study, we have investigated the antimicrobial activity of HD6 analogs. A linear analog of HD6, in which the distribution of arginine residues was similar to active α-defensins, shows broad-spectrum antimicrobial activity, indicating that atypical distribution of arginine residues contributes to the inactivity of HD6. Peptides spanning the N-terminal cationic segment were active against a wide range of organisms. Antimicrobial potency of these shorter analogs was further enhanced when myristic acid was conjugated at the N-terminus. Cytoplasmic localization of the analogs without fatty acylation was observed to be necessary for bacterial killing, while they exhibited fungicidal activity by permeabilizing Candida albicans membranes. Myristoylated analogs and the linear full-length arginine analog exhibited activity by permeabilizing bacterial and fungal membranes. Our study provides insights into the lack of bactericidal activity of HD6 against aerobic bacteria. PMID:26400692

  7. Characterization and functions of beta defensins in the epididymis

    Institute of Scientific and Technical Information of China (English)

    Susan H. Hall; Suresh Yenugu; Yashwanth Radhakrishnan; Maria Christina W. Avellar; Peter Petrusz; Frank S. French

    2007-01-01

    The epididymal β-defensins have evolved by repeated gene duplication and divergence to encode a family of proteins that provide direct protection against pathogens and also support the male reproductive tract in its primary function. Male tract defensins also facilitate recovery from pathogen attack. The β-defensins possess ancient conserved sequence and structural features widespread in multi-cellular organisms, suggesting fundamental roles in species survival. Primate SPAG11, the functional fusion of two ancestrally independent β-defensin genes, produces a large family of alternatively spliced transcripts that are expressed according to tissue-specific and species-specific constraints. The complexity of SPAG11 varies in different branches of mammalian evolution. Interactions of human SPAG11D with host proteins indicate involvement in multiple signaling pathways.

  8. Prevalence of antibacterial resistant bacterial contaminants from mobile phones of hospital inpatients

    Directory of Open Access Journals (Sweden)

    B. Vinod Kumar

    2014-10-01

    Full Text Available Mobile phones contaminated with bacteria may act as fomites. Antibiotic resistant bacterial contamination of mobile phones of inpatients was studied. One hundred and six samples were collected from mobile phones of patients admitted in various hospitals in Jazan province of Saudi Arabia. Eighty-nine (83.9% out of 106 mobile phones were found to be contaminated with bacteria. Fifty-two (49.0% coagulase-negative Staphylococcus, 12 (11.3% Staphylococcus aureus, 7 (6.6% Enterobacter cloacae, 3 (2.83% Pseudomonas stutzeri, 3 (2.83% Sphingomonas paucimobilis, 2 (1.8% Enterococcus faecalis and 10 (9.4% aerobic spore bearers were isolated. All the isolated bacteria were found to be resistant to various antibiotics. Hence, regular disinfection of mobile phones of hospital inpatients is advised.

  9. Production of bacterial blight resistant lines from somatic hybridization between Oryza sativa L. and Oryza meyeriana L.

    Institute of Scientific and Technical Information of China (English)

    严成其; 钱凯先; 薛刚平; 吴忠长; 陈跃磊; 颜秋生; 张雪琴; 吴平

    2004-01-01

    Novel bacterial blight (BB) resistance gene(s) for rice was (were) introduced into a cultivated japonica rice variety Oryza sativa (cv. 8411), via somatic hybridization using the wild rice Oryza meyeriana as the donor of the resistance gene(s). Twenty-nine progenies of somatically hybridized plants were obtained. Seven somatically hybridized plants and their parents were used for AFLP (amplified fragment length polymorphism) analysis using 8 primer pairs. Results confirmed that these plants were somatic hybrids containing the characteristic bands of both parents. The morphology of the regenerated rice showed characters of both O.sativa and O.meyeriana. Two somatic hybrids showed highest BB resistance and the other 8 plants showed moderate resistance. The new germplasms with highest resistance have been used in the rice breeding program for the improvement of bacterial blight resistance.

  10. Production of bacterial blight resistant lines from somatic hybridization between Oryza sativa L.and Oryza meyeriana L.

    Institute of Scientific and Technical Information of China (English)

    严成其; 钱凯先; 薛刚平; 吴忠长; 陈跃磊; 颜秋生; 张雪琴; 吴平

    2004-01-01

    Novel bacterial blight (BB) resistance gene(s) for rice was (were) introduced into a cultivated japonica rice variety Oryza sativa (cv. 8411), via somatic hybridization using the wild rice Oryza meyeriana as the donor of the resistance gene(s). Twenty-nine progenies of somatically hybridized plants were obtained. Seven somatically hybridized plants and their parents were used for AFLP (amplified fragment length polymorphism) analysis using 8 primer pairs. Results confirmed that these plants were somatic hybrids containing the characteristic bands of both parents. The morphology of the regenerated rice showed characters of both O. sativa and O. meyeriana. Two somatic hybrids showed highest BB resistance and the other 8 plants showed moderate resistance. The new germplasms with highest resistance have been used in the rice bfeeding program for the improvement of bacterial blight resistance.

  11. Interactions of Antibiotics and Methanolic Crude Extracts of Afzelia Africana (Smith. Against Drug Resistance Bacterial Isolates

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    Anthony Okoh

    2011-07-01

    Full Text Available Infection due to multidrug resistance pathogens is difficult to manage due to bacterial virulence factors and because of a relatively limited choice of antimicrobial agents. Thus, it is imperative to discover fresh antimicrobials or new practices that are effective for the treatment of infectious diseases caused by drug-resistant microorganisms. The objective of this experiment is to investigate for synergistic outcomes when crude methanolic extract of the stem bark of Afzelia africana and antibiotics were combined against a panel of antibiotic resistant bacterial strains that have been implicated in infections. Standard microbiological protocols were used to determine the minimum inhibitory concentrations (MICs of the extract and antibiotics, as well as to investigate the effect of combinations of the methanolic extract of A. africana stem bark and selected antibiotics using the time-kill assay method. The extract of Afzelia africana exhibited antibacterial activities against both Gram-negative and Gram-positive bacteria made up of environmental and standard strains at a screening concentration of 5 mg/mL. The MICs of the crude extracts and the antibiotics varied between 1 μg/mL and 5.0 mg/mL. Overall, synergistic response constituted about 63.79% of all manner of combinations of extract and antibiotics against all test organisms; antagonism was not detected among the 176 tests carried out. The extract from A. africana stem bark showed potentials of synergy in combination with antibiotics against strains of pathogenic bacteria. The detection of synergy between the extract and antibiotics demonstrates the potential of this plant as a source of antibiotic resistance modulating compounds.

  12. Reduced Paneth cell α-defensins in ileal Crohn's disease

    OpenAIRE

    Wehkamp, Jan; Salzman, Nita H.; Porter, Edith; Nuding, Sabine; Weichenthal, Michael; Petras, Robert E; Shen, Bo; Schaeffeler, Elke; Schwab, Matthias; Linzmeier, Rose; Feathers, Ryan W.; Chu, Hiutung; Lima, Heriberto; Fellermann, Klaus; Ganz, Tomas

    2005-01-01

    The pathogenesis of Crohn′s disease (CD), an idiopathic inflammatory bowel disease, is attributed, in part, to intestinal bacteria that may initiate and perpetuate mucosal inflammation in genetically susceptible individuals. Paneth cells (PC) are the major source of antimicrobial peptides in the small intestine, including human α-defensins HD5 and HD6. We tested the hypothesis that reduced expression of PC α-defensins compromises mucosal host defenses and predisposes patients to CD of the ile...

  13. Antibiotic Resistance Pattern Of Bacterial Pathogens Isolated From Poultry Manure Used To Fertilize Fish Ponds In New Bussa, Nigeria

    Directory of Open Access Journals (Sweden)

    Funso Omojowo

    2013-02-01

    Full Text Available This study was carried out to isolate and identify antibiotic resistant bacteria from poultry manure usually used for pond fertilization. Poultry manure from 120 Chickens in National Institute for Freshwater Fisheries Research (NIFFR integrated fish farms, New-Bussa, Nigeria was collected. Five bacterial pathogens; Salmonella typhi, Escherichia coli, Shigella dysenteriae, Staphylococcus aureus and Aeromonas hydrophila were isolated. Antibiotic susceptibility testing carried out using the disk diffusion technique. Antibiotics used were; ofloxacin, amoxicillin, tetracycline, ampicillin, erythromycin, gentamicin, nalidixic acid and chloramphenicol. All the isolated organisms were 100% sensitive to ofloxacin. The multiple resistance pattern revealed that 100% were resistant to tetracycline, 84.34% resistant to ampicillin, 76.68% resistant to amoxicillin, 66% resistant to chloramphenicol, 66% resistant to gentamicin, 29% resistant to erythromycin, 28.34% resistant to nalidixic acid. The risk posed by untreated poultry manure used in fish pond fertilization and the public health implications of these results were discussed.

  14. Transgenic resistance confers effective field level control of bacterial spot disease in tomato.

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    Diana M Horvath

    Full Text Available We investigated whether lines of transgenic tomato (Solanum lycopersicum expressing the Bs2 resistance gene from pepper, a close relative of tomato, demonstrate improved resistance to bacterial spot disease caused by Xanthomonas species in replicated multi-year field trials under commercial type growing conditions. We report that the presence of the Bs2 gene in the highly susceptible VF 36 background reduced disease to extremely low levels, and VF 36-Bs2 plants displayed the lowest disease severity amongst all tomato varieties tested, including commercial and breeding lines with host resistance. Yields of marketable fruit from transgenic lines were typically 2.5 times that of the non-transformed parent line, but varied between 1.5 and 11.5 fold depending on weather conditions and disease pressure. Trials were conducted without application of any copper-based bactericides, presently in wide use despite negative impacts on the environment. This is the first demonstration of effective field resistance in a transgenic genotype based on a plant R gene and provides an opportunity for control of a devastating pathogen while eliminating ineffective copper pesticides.

  15.   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.

  16. Early-onset sepsis in a neonatal intensive care unit in Beni Suef, Egypt: bacterial isolates and antibiotic resistance pattern

    OpenAIRE

    Fahmey, Sameh Samir

    2013-01-01

    Purpose To identify the frequency of bacterial isolates in early-onset neonatal sepsis (EONS) and their antimicrobial resistance pattern. Methods A retrospective study of EONS was conducted at the Beni Suef University Hospital from September 2008 to September 2012. A case of EONS was defined as an infant who had clinical signs of infection or who was born to a mother with risk factors for infection, and in whom blood culture obtained within 72 hours of life grew a bacterial pathogen. Results ...

  17. Resistance Induction and Enhanced Tuber Production by Pre-inoculation with Bacterial Strains in Potato Plants against Phytophthora infestans

    OpenAIRE

    Kim, Hyo-Jeong; Jeun, Yong-Chull

    2006-01-01

    Efficacy of resistance induction by the bacterial isolates Pseudomonas putida (TRL2-3), Micrococcus luteus (TRK2-2) and Flexibacteraceae bacterium (MRL412), which were isolated from the rhizosphere of plants growing in Jeju Mountain, were tested in a greenhouse. The disease severity caused by Phytophthora infestans was effectively reduced in the potato plants pre-inoculated with bacterial isolates compared with those of the untreated control plants growing in a greenhouse. In order to estimat...

  18. Cloning of a peroxidase gene from cassava with potential as a molecular marker for resistance to bacterial blight

    OpenAIRE

    Luiz Filipe Pereira; Goodwin, Paul H.; Larry Erickson

    2003-01-01

    Cassava bacterial blight (CBB), caused by Xanthomonas axonopodis pv. manihotis, is considered one of the most important bacterial diseases of cassava (Manihot esculenta Crantz). In order to characterize the cassava genes involved in resistance to this disease, a genomic clone of a cationic peroxidase gene, MEPX1, was isolated by PCR from cassava cultivar MCOL 22. The DNA sequence of MEPX1 showed high homology with other plant peroxidase genes and contained a large intron typical of peroxidase...

  19. Metagenomic analysis of bacterial community composition and antibiotic resistance genes in a wastewater treatment plant and its receiving surface water.

    Science.gov (United States)

    Tang, Junying; Bu, Yuanqing; Zhang, Xu-Xiang; Huang, Kailong; He, Xiwei; Ye, Lin; Shan, Zhengjun; Ren, Hongqiang

    2016-10-01

    The presence of pathogenic bacteria and the dissemination of antibiotic resistance genes (ARGs) may pose big risks to the rivers that receive the effluent from municipal wastewater treatment plants (WWTPs). In this study, we investigated the changes of bacterial community and ARGs along treatment processes of one WWTP, and examined the effects of the effluent discharge on the bacterial community and ARGs in the receiving river. Pyrosequencing was applied to reveal bacterial community composition including potential bacterial pathogen, and Illumina high-throughput sequencing was used for profiling ARGs. The results showed that the WWTP had good removal efficiency on potential pathogenic bacteria (especially Arcobacter butzleri) and ARGs. Moreover, the bacterial communities of downstream and upstream of the river showed no significant difference. However, the increase in the abundance of potential pathogens and ARGs at effluent outfall was observed, indicating that WWTP effluent might contribute to the dissemination of potential pathogenic bacteria and ARGs in the receiving river.

  20. Combining ability of Phaseolus vulgaris L. for resistance to common bacterial blight

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    Rosana Rodrigues

    1999-12-01

    Full Text Available Many diseases limit dry bean and snap bean yields. Common bacterial blight (CBB, caused by Xanthomonas axonopodis pv. phaseoli, is one of the most serious bacterial diseases in dry bean and snap bean that cause crop losses. Since there is no satisfactory chemical control, the use of resistant cultivars is an important control measure. Genetic studies of resistance are important for choosing appropriate breeding methods. Combining ability was determined for disease resistance in three snap bean genotypes (Alessa, Hab 52 and Hab 198 and two dry bean genotypes (Bac-6 and A-794. Plants were inoculated with highly pathogenic isolate CNF 15, using a razor blade procedure in leaves and needle punctures in pods. They were evaluated 7 days after inoculation. Leaves were evaluated on a 1 to 5 scale and pods by lesion diameter. Diallel analysis was conducted using Griffing's model. General combining ability (GCA was significant for both leaf and pod infection, whereas specific combining ability (SCA was significant for disease reaction in pods. Bac-6 and A-794 were considered superior genotypes for leaf resistance. Nonadditive effects were predominant in pod reactions, and Alessa x Bac-6, Alessa x A-794 and Hab 52 x Bac-6 were the best combinations.Entre as várias doenças que causam problemas às culturas do feijão-de-vagem e do feijão comum, uma das mais importantes é o crestamento bacteriano comum (CBB, causado pela bactéria Xanthomonas axonopodis pv. phaseoli, que pode ocasionar grandes perdas na produção. O controle químico não é eficiente, e entre as medidas de controle recomendadas, destaca-se a resistência genética. Estudos genéticos da resistência são básicos para a definição dos métodos de melhoramento a serem adotados para cada caso. Avaliou-se a capacidade de combinação de três genótipos de feijão-de-vagem (Alessa, Hab 52, Hab 198 e dois de feijão comum (Bac-6 e A-794 quanto à resistência ao CBB, em folhas e vagens. A

  1. Conformational landscape and pathway of disulfide bond reduction of human alpha defensin

    NARCIS (Netherlands)

    Snijder, Joost; Van De Waterbeemd, Michiel; Glover, Matthew S.; Shi, Liuqing; Clemmer, David E.; Heck, Albert J R

    2015-01-01

    Human alpha defensins are a class of antimicrobial peptides with additional antiviral activity. Such antimicrobial peptides constitute a major part of mammalian innate immunity. Alpha defensins contain six cysteines, which form three well defined disulfide bridges under oxidizing conditions. Residue

  2. Does the appearance of drug resistance during therapy alter bacterial susceptibility to opsonophagocytosis?

    Science.gov (United States)

    Gemmell, C G

    1996-01-01

    Coagulase-negative staphylococci (CNS) are common causes of infection in patients undergoing chronic ambulatory peritoneal dialysis (CAPD). Their ability to survive intracellularly within peritoneal macrophages and to persist within the peritoneum during antibiotic therapy has led to the development of drug resistance during treatment. Strains of Staphylococcus epidermidis (SE) and Staphytococcus haemolyticus (SH) have been isolated from patients with CAPD during treatment with ciprofloxacin. The respective MIC values pre-and post-therapy were SE-0.25 and 128 mg/L and SH-0.50 and 64 mg/L. The susceptibility of each isolate to opsonophagocytosis was measured in vitro using isolated polymorphonuclear leucocytes (PMN) derived from fresh human blood donations. The bacteria were radiolabelled during growth, opsonised in either 1 or 10% serum and their uptake measured No differences were seen between the pre- and post therapy isolates when using 10% serum as opsonic source (18 vs. 21%); with 1% serum the corresponding values were lower (5 and 8% respectively). Similarly their ability to generate a respiratory burst as measured by chemiluminescence (CL) in the phagocytic cells was not diminished in the strains which had developed resistance to ciprofloxacin. The mean CL response to the strains isolated at outset of therapy ranged from 0.35-0.45 cpsc, and to the resistant strains following therapy from 0.36-0.50 cpsc. It is clear from the present investigation that although the bacterial strain became at least 10 times more resistant to ciprofloxacin during therapy, no change in their susceptibility to phagocytosis occurred refuting the idea that the emergence of drug resistant strains during therapy results in "super-bugs" of greater virulence.

  3. Application of Targeted Molecular and Material Property Optimization to Bacterial Attachment-Resistant (Meth)acrylate Polymers.

    Science.gov (United States)

    Adlington, Kevin; Nguyen, Nam T; Eaves, Elizabeth; Yang, Jing; Chang, Chien-Yi; Li, Jianing; Gower, Alexandra L; Stimpson, Amy; Anderson, Daniel G; Langer, Robert; Davies, Martyn C; Hook, Andrew L; Williams, Paul; Alexander, Morgan R; Irvine, Derek J

    2016-09-12

    Developing medical devices that resist bacterial attachment and subsequent biofilm formation is highly desirable. In this paper, we report the optimization of the molecular structure and thus material properties of a range of (meth)acrylate copolymers which contain monomers reported to deliver bacterial resistance to surfaces. This optimization allows such monomers to be employed within novel coatings to reduce bacterial attachment to silicone urinary catheters. We show that the flexibility of copolymers can be tuned to match that of the silicone catheter substrate, by copolymerizing these polymers with a lower Tg monomer such that it passes the flexing fatigue tests as coatings upon catheters, that the homopolymers failed. Furthermore, the Tg values of the copolymers are shown to be readily estimated by the Fox equation. The bacterial resistance performance of these copolymers were typically found to be better than the neat silicone or a commercial silver containing hydrogel surface, when the monomer feed contained only 25 v% of the "hit" monomer. The method of initiation (either photo or thermal) was shown not to affect the bacterial resistance of the copolymers. Optimized synthesis conditions to ensure that the correct copolymer composition and to prevent the onset of gelation are detailed. PMID:27461341

  4. Identification of molecular markers linked to rice bacterial blight resistance genes from Oryza meyeriana

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    Jing WANG,Chen CHENG,Yanru ZHOU,Yong YANG,Qiong MEI,Junmin LI,Ye CHENG,Chengqi YAN,Jianping CHEN

    2015-09-01

    Full Text Available Y73 is a progeny of asymmetric somatic hybridization between Oryza sativa cv. Dalixiang and the wild rice species Oryza meyeriana. Inoculation with a range of strains of Xanthomonas oryzae pv. oryzae showed that Y73 had inherited a high level of resistance to rice bacterial blight (BB from its wild parent. An F2 population of 7125 individuals was constructed from the cross between Y73 and a BB-susceptible cultivar IR24. After testing 615 SSR and STS markers covering the 12 rice chromosomes, 186 markers were selected that showed polymorphism between Y73 and IR24. Molecular markers linked to the BB resistance genes in Y73 were scanned using the F2 population and the polymorphic markers. The SSR marker RM128 on chromosome 1, the STS marker R03D159 on chromosome 3 and the STS marker R05D104 on chromosome 5 were found to be linked to the rice BB resistance genes in Y73.

  5. Mechanism of bacterial membrane poration by Antimicrobial Peptides

    Science.gov (United States)

    Arora, Ankita; Mishra, Abhijit

    2015-03-01

    Bacterial resistance to conventional antibiotics is a major health concern. Antimicrobial peptides (AMPs), an important component of mammalian immune system, are thought to utilize non-specific interactions to target common features on the outer membranes of pathogens; hence development of resistance to such AMPs may be less pronounced. Most AMPs are amphiphilic and cationic in nature. Most AMPs form pores in the bacterial membranes causing them to lyse, however, the exact mechanism is unknown. Here, we study the AMP CHRG01 (KSSTRGRKSSRRKK), derived from human β defensin 3 (hBD3) with all Cysteine residues substituted with Serine. Circular Dichorism studies indicate that CHRG01 shows helicity and there is change in helicity as it interacts with the lipid membrane. The AMP was effective against different species of bacteria. Leakage of cellular components from bacterial cells observed by SEM and AFM indicates AMP action by pore formation. Confocal microscopy studies on giant vesicles incubated with AMP confirm poration. The effect of this AMP on model bacterial membranes is characterized using Small Angle X-ray scattering and Fluorescence spectroscopy to elucidate the mechanism behind antimicrobial activity.

  6. In vitro inhibitory potentials of crude plant extracts on multidrug resistant bacterial species from infected human wounds

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    Yetunde A Ekanola

    2013-01-01

    Full Text Available Background: Scientific data on usage of plants to promote wound healing is exclusively scare in Nigeria. AIM: The aim of this study was to determine in vitro inhibitory potentials of crude extracts of garlic (Allium sativum and ginger (Zingiber officinale on multiple antibiotic resistant bacteria isolated from deep and superficial human wounds. Materials and Methods: Using agar disc- and modified agar well-diffusion methods, 87 wound-borne bacterial strains, Staphylococcus aureus, Proteus mirabilis and Pseudomonas aeruginosa were screened for in vitro susceptibility to 15 commonly-available antibiotic discs, 18 antibiotic drugs and three plant extracts. Results: Staph. aureus strains exhibited 52.5-97.4% resistance to antibiotic (discs, with multiple antibiotic resistance (MAR of 25.0 -100%. Between 39.1 and 95.7% of Proteus mirabilis strains resisted the antibiotics (discs, while MAR was 37.5-100%. Resistance rates displayed by Ps. aeruginosa strains were 61.5-100% with MAR of 50.0-100%. Overall antibiotic resistance patterns of respective bacterial species recorded for the antibiotic drugs were Staph. aureus (11.1-83.3%, Pr. mirabilis (16.7-77.8% and Ps. aeruginosa (16.7-50.0% and the most-resisted antibiotic drugs were axacef (55.3-82.6%, septrin (84.2-92.3%, primpex (78.3-84.6%, mediphenicol (63.2-73.1% and augmentin 1 (43.2-76.9%. All the multidrug resistant wound-borne bacterial strains exhibited minimal to moderate susceptibility towards crude extracts of garlic (17.4-34.6% and ginger (57.7-60.8%. Conclusion: Human wound-borne bacterial strains, which were multi-resistant to commonly available antibiotics (discs/drugs were minimally or moderately susceptible to crude extracts of garlic (Allium sativum and ginger (Zingiber officinale, which can be of clinical importance as herbal therapy in wound dressings or other forms of wound treatments.

  7. Bacterial Etiology and Antibiotic Resistance Profile of Community-Acquired Urinary Tract Infections in a Cameroonian City

    Science.gov (United States)

    Gonsu, Hortense Kamga; Koulla-Shiro, Sinata

    2016-01-01

    Introduction. Community-acquired urinary tract infections (CAUTIs) are usually treated empirically. Geographical variations in etiologic agents and their antibiotic sensitivity patterns are common. Knowledge of antibiotic resistance trends is important for improving evidence-based recommendations for empirical treatment of UTIs. Our aim was to determine the major bacterial etiologies of CAUTIs and their antibiotic resistance patterns in a cosmopolitan area of Cameroon for comparison with prescription practices of local physicians. Methods. We performed a cross-sectional descriptive study at two main hospitals in Yaoundé, collecting a clean-catch mid-stream urine sample from 92 patients having a clinical diagnosis of UTI. The empirical antibiotherapy was noted, and identification of bacterial species was done on CLED agar; antibiotic susceptibility testing was performed using the Kirby-Bauer disc diffusion method. Results. A total of 55 patients had samples positive for a UTI. Ciprofloxacin and amoxicillin/clavulanic acid were the most empirically prescribed antibiotics (30.9% and 23.6%, resp.); bacterial isolates showed high prevalence of resistance to both compounds. Escherichia coli (50.9%) was the most common pathogen, followed by Klebsiella pneumoniae (16.4%). Prevalence of resistance for ciprofloxacin was higher compared to newer quinolones. Conclusions. E. coli and K. pneumoniae were the predominant bacterial etiologies; the prevalence of resistance to commonly prescribed antibiotics was high. PMID:27667998

  8. Bacterial Etiology and Antibiotic Resistance Profile of Community-Acquired Urinary Tract Infections in a Cameroonian City.

    Science.gov (United States)

    Nzalie, Rolf Nyah-Tuku; Gonsu, Hortense Kamga; Koulla-Shiro, Sinata

    2016-01-01

    Introduction. Community-acquired urinary tract infections (CAUTIs) are usually treated empirically. Geographical variations in etiologic agents and their antibiotic sensitivity patterns are common. Knowledge of antibiotic resistance trends is important for improving evidence-based recommendations for empirical treatment of UTIs. Our aim was to determine the major bacterial etiologies of CAUTIs and their antibiotic resistance patterns in a cosmopolitan area of Cameroon for comparison with prescription practices of local physicians. Methods. We performed a cross-sectional descriptive study at two main hospitals in Yaoundé, collecting a clean-catch mid-stream urine sample from 92 patients having a clinical diagnosis of UTI. The empirical antibiotherapy was noted, and identification of bacterial species was done on CLED agar; antibiotic susceptibility testing was performed using the Kirby-Bauer disc diffusion method. Results. A total of 55 patients had samples positive for a UTI. Ciprofloxacin and amoxicillin/clavulanic acid were the most empirically prescribed antibiotics (30.9% and 23.6%, resp.); bacterial isolates showed high prevalence of resistance to both compounds. Escherichia coli (50.9%) was the most common pathogen, followed by Klebsiella pneumoniae (16.4%). Prevalence of resistance for ciprofloxacin was higher compared to newer quinolones. Conclusions. E. coli and K. pneumoniae were the predominant bacterial etiologies; the prevalence of resistance to commonly prescribed antibiotics was high. PMID:27667998

  9. Characterization of copper-resistant bacteria and bacterial communities from copper-polluted agricultural soils of central Chile

    Directory of Open Access Journals (Sweden)

    Altimira Fabiola

    2012-09-01

    Full Text Available Abstract Background Copper mining has led to Cu pollution in agricultural soils. In this report, the effects of Cu pollution on bacterial communities of agricultural soils from Valparaiso region, central Chile, were studied. Denaturing gradient gel electrophoresis (DGGE of the 16S rRNA genes was used for the characterization of bacterial communities from Cu-polluted and non-polluted soils. Cu-resistant bacterial strains were isolated from Cu-polluted soils and characterized. Results DGGE showed a similar high number of bands and banding pattern of the bacterial communities from Cu-polluted and non-polluted soils. The presence of copA genes encoding the multi-copper oxidase that confers Cu-resistance in bacteria was detected by PCR in metagenomic DNA from the three Cu-polluted soils, but not in the non-polluted soil. The number of Cu-tolerant heterotrophic cultivable bacteria was significantly higher in Cu-polluted soils than in the non-polluted soil. Ninety two Cu-resistant bacterial strains were isolated from three Cu-polluted agricultural soils. Five isolated strains showed high resistance to copper (MIC ranged from 3.1 to 4.7 mM and also resistance to other heavy metals. 16S rRNA gene sequence analyses indicate that these isolates belong to the genera Sphingomonas, Stenotrophomonas and Arthrobacter. The Sphingomonas sp. strains O12, A32 and A55 and Stenotrophomonas sp. C21 possess plasmids containing the Cu-resistance copA genes. Arthrobacter sp. O4 possesses the copA gene, but plasmids were not detected in this strain. The amino acid sequences of CopA from Sphingomonas isolates (O12, A32 and A55, Stenotrophomonas strain (C21 and Arthrobacter strain (O4 are closely related to CopA from Sphingomonas, Stenotrophomonas and Arthrobacter strains, respectively. Conclusions This study suggests that bacterial communities of agricultural soils from central Chile exposed to long-term Cu-pollution have been adapted by acquiring Cu genetic determinants

  10. Airway β-Defensin-1 Protein Is Elevated in COPD and Severe Asthma

    Directory of Open Access Journals (Sweden)

    Katherine J. Baines

    2015-01-01

    Full Text Available Background. Innate immune antimicrobial peptides, including β-defensin-1, promote the chemotaxis and activation of several immune cells. The role of β-defensin-1 in asthma and chronic obstructive pulmonary disease (COPD remains unclear. Methods. Induced sputum was collected from healthy controls and individuals with asthma or COPD. β-defensin-1 protein in sputum supernatant was quantified by ELISA. Biomarker potential was examined using receiver operating characteristic curves. β-defensin-1 release from primary bronchial epithelial cells (pBECs was investigated in culture with and without cigarette smoke extract (CSE. Results. Airway β-defensin-1 protein was elevated in COPD participants compared to asthma participants and healthy controls. Inflammatory phenotype had no effect on β-defensin-1 levels in asthma or COPD. β-defensin-1 protein was significantly higher in severe asthma compared to controlled and uncontrolled asthma. β-defensin-1 protein could predict the presence of COPD from both healthy controls and asthma patients. Exposure of pBECs to CSE decreased β-defensin-1 production in healthy controls; however in pBECs from COPD participants the level of β-defensin-1 remanied unchanged. Conclusions. Elevated β-defensin-1 protein is a feature of COPD and severe asthma regardless of inflammatory phenotype. β-defensin-1 production is dysregulated in the epithelium of patients with COPD and may be an effective biomarker and potential therapeutic target.

  11. Plasma alpha-defensin is associated with cardiovascular morbidity and mortality in type 1 diabetic patients

    DEFF Research Database (Denmark)

    Joseph, G.; Tarnow, L.; Astrup, A.S.;

    2008-01-01

    CONTEXT: alpha-Defensins are antimicrobial peptides of the innate immune system. In addition, experimental evidence suggests that alpha-defensins are proatherogenic. OBJECTIVE: The objective of the study was to examine the predictive value of plasma alpha-defensin as a clinical marker...

  12. Microarray Analysis of the Transcriptome for Bacterial Wilt Resistance in Pepper (Capsicum annuum L.

    Directory of Open Access Journals (Sweden)

    Jihyun HWANG

    2011-11-01

    Full Text Available Ralstonia solanacearum causes one of the most common soil-borne vascular diseases of diverse plant species, including many solanaceous crops such as tomato and pepper. The resulting disease, bacterial wilt (BW, is devastating and difficult to control using conventional approaches. The aim of this study was to investigate the differentially expressed genes in pepper root systems in response to infection by R. solanacearum. DNA microarray (Capsicum annuum 135K Microarray v3.0 Gene Expression platform analyses were performed using a susceptible genotype, ‘Chilbok’, and a resistant genotype, ‘KC350’, at 3 time points (1, 3, and 6 days post inoculation. It has been identified 115 resistance-specific genes (R-response genes and 109 susceptibility-specific genes (S-response gene, which were up-regulated in 1 genotype, but down-regulated in the other genotype. Gene Ontology (GO analysis for functional categorization indicated that many R-response genes were related to genes that function in xyloglucan biosynthesis and cell wall organization, while S-response genes were involved in the response to stress and cell death. The expression of genes encoding xyloglucan endotransglycosylase/hydrolase (XTH and β-galactosidase were verified by real-time RT-PCR at an early time point of R. solanacearum infection. The results supported the idea that rapidly induced XTH expression in ‘KC350’ may play an important role in the restructuring and reinforcement of the cell wall and restrict bacterial movement in xylem vessels. In addition, induced expression of β-galactosidase in R. solanacearum-infected ‘Chilbok’ implied that degradation of the cell wall structure in vascular tissues by β-galactosidase might be an important factor facilitating R. solanacearum invasion of and movement in susceptible host plants.

  13. Bacteriophage therapy for membrane biofouling in membrane bioreactors and antibiotic-resistant bacterial biofilms.

    Science.gov (United States)

    Bhattacharjee, Ananda Shankar; Choi, Jeongdong; Motlagh, Amir Mohaghegh; Mukherji, Sachiyo T; Goel, Ramesh

    2015-08-01

    To demonstrate elimination of bacterial biofilm on membranes to represent wastewater treatment as well as biofilm formed by antibiotic-resistant bacterial (ARB) to signify medical application, an antibiotic-resistant bacterium and its lytic bacteriophage were isolated from a full-scale wastewater treatment plant. Based on gram staining and complete 16 S rDNA sequencing, the isolated bacterium showed a more than 99% homology with Delftia tsuruhatensis, a gram-negative bacterium belonging to β-proteobacteria. The Delftia lytic phage's draft genome revealed the phage to be an N4-like phage with 59.7% G + C content. No transfer RNAs were detected for the phage suggesting that the phage is highly adapted to its host Delftia tsuruhatensis ARB-1 with regard to codon usage, and does not require additional tRNAs of its own. The gene annotation of the Delftia lytic phage found three different components of RNA polymerase (RNAP) in the genome, which is a typical characteristic of N4-like phages. The lytic phage specific to D. tsuruhatensis ARB-1 could successfully remove the biofilm formed by it on a glass slide. The water flux through the membrane of a prototype lab-scale membrane bioreactor decreased from 47 L/h m(2) to ∼15 L/h m(2) over 4 days due to a biofilm formed by D. tsuruhatensis ARB-1. However, the flux increased to 70% of the original after the lytic phage application. Overall, this research demonstrated phage therapy's great potential to solve the problem of membrane biofouling, as well as the problems posed by pathogenic biofilms in external wounds and on medical instruments.

  14. Aminomethyl spectinomycins as therapeutics for drug-resistant respiratory tract and sexually transmitted bacterial infections.

    Science.gov (United States)

    Bruhn, David F; Waidyarachchi, Samanthi L; Madhura, Dora B; Shcherbakov, Dimitri; Zheng, Zhong; Liu, Jiuyu; Abdelrahman, Yasser M; Singh, Aman P; Duscha, Stefan; Rathi, Chetan; Lee, Robin B; Belland, Robert J; Meibohm, Bernd; Rosch, Jason W; Böttger, Erik C; Lee, Richard E

    2015-05-20

    The antibiotic spectinomycin is a potent inhibitor of bacterial protein synthesis with a unique mechanism of action and an excellent safety index, but it lacks antibacterial activity against most clinically important pathogens. A series of N-benzyl-substituted 3'-(R)-3'-aminomethyl-3'-hydroxy spectinomycins was developed on the basis of a computational analysis of the aminomethyl spectinomycin binding site and structure-guided synthesis. These compounds had ribosomal inhibition values comparable to spectinomycin but showed increased potency against the common respiratory tract pathogens Streptococcus pneumoniae, Haemophilus influenzae, Legionella pneumophila, and Moraxella catarrhalis, as well as the sexually transmitted bacteria Neisseria gonorrhoeae and Chlamydia trachomatis. Non-ribosome-binding 3'-(S) isomers of the lead compounds demonstrated weak inhibitory activity in in vitro protein translation assays and poor antibacterial activity, indicating that the antibacterial activity of the series remains on target against the ribosome. Compounds also demonstrated no mammalian cytotoxicity, improved microsomal stability, and favorable pharmacokinetic properties in rats. The lead compound from the series exhibited excellent chemical stability superior to spectinomycin; no interaction with a panel of human receptors and drug metabolism enzymes, suggesting low potential for adverse reactions or drug-drug interactions in vivo; activity in vitro against a panel of penicillin-, macrolide-, and cephalosporin-resistant S. pneumoniae clinical isolates; and the ability to cure mice of fatal pneumococcal pneumonia and sepsis at a dose of 5 mg/kg. Together, these studies indicate that N-benzyl aminomethyl spectinomycins are suitable for further development to treat drug-resistant respiratory tract and sexually transmitted bacterial infections. PMID:25995221

  15. Resistance of a novel root canal sealer to bacterial ingress in vitro.

    Science.gov (United States)

    Padachey, N; Patel, V; Santerre, P; Cvitkovitch, D; Lawrence, H P; Friedman, S

    2000-11-01

    A dentin-bonding root canal sealer (ZUT) has been developed, consisting of an experimental glass ionomer cement (KT-308) and an antimicrobial silver-containing zeolite (0.2% by weight). This in vitro study evaluated the ability of ZUT used with or without gutta-percha, to resist bacterial ingress of Enterococcus faecalis over a period of 90 days. Canals of 80 single-rooted teeth were prepared with apical patency and filled as follows (n = 10): KT-308 alone; KT-308 with a single gutta-percha cone (SCGP); ZUT alone; ZUT with SCGP; AH26 alone; AH26 with SCGP; positive control-no root canal filling; and negative control-no root canal filling, with the apices of this group sealed with C&B Metabond cement. Teeth were coated with nail polish except for the apical 2 mm, and each tooth was sealed in a 4-ml glass vial, with an 18-gauge needle inserted through the vial cover and bonded into the pulp chamber with C&B Metabond cement. After sterilization with 2.5 Mrad gamma-radiation, Brain Heart Infusion broth with phenol red was injected into each vial. An inoculum of E. faecalis was pipetted through the needle into the pulp chamber every 5 days, and the broth was monitored daily for color change and turbidity. When change occurred, the broth was cultured for growth of E. faecalis. Kaplan-Meier survival analysis and the log-rank test revealed no significant differences among the three sealers used. The presence of gutta-percha, however, significantly improved resistance to bacterial ingress through obturated root canals (X, p < 0.05). Under the conditions of this study, the hypothesized advantage of ZUT (0.2% zeolite) was not demonstrated. PMID:11469295

  16. Anti-Legionella dumoffii Activity of Galleria mellonella Defensin and Apolipophorin III

    Directory of Open Access Journals (Sweden)

    Małgorzata Cytryńska

    2012-12-01

    Full Text Available The gram-negative bacterium Legionella dumoffii is, beside Legionella pneumophila, an etiological agent of Legionnaires’ disease, an atypical form of pneumonia. The aim of this study was to determine the antimicrobial activity of Galleria mellonella defense polypeptides against L. dumoffii. The extract of immune hemolymph, containing a mixture of defense peptides and proteins, exhibited a dose-dependent bactericidal effect on L. dumoffii. The bacterium appeared sensitive to a main component of the hemolymph extract, apolipophorin III, as well as to a defense peptide, Galleria defensin, used at the concentrations 0.4 mg/mL and 40 μg/mL, respectively. L. dumoffii cells cultured in the presence of choline were more susceptible to both defense factors analyzed. A transmission electron microscopy study of bacterial cells demonstrated that Galleria defensin and apolipophorin III induced irreversible cell wall damage and strong intracellular alterations, i.e., increased vacuolization, cytoplasm condensation and the appearance of electron-white spaces in electron micrographs. Our findings suggest that insects, such as G. mellonella, with their great diversity of antimicrobial factors, can serve as a rich source of compounds for the testing of Legionella susceptibility to defense-related peptides and proteins.

  17. Anti-Legionella dumoffii Activity of Galleria mellonella Defensin and Apolipophorin III

    Science.gov (United States)

    Palusińska-Szysz, Marta; Zdybicka-Barabas, Agnieszka; Pawlikowska-Pawlęga, Bożena; Mak, Pawel; Cytryńska, Małgorzata

    2012-01-01

    The gram-negative bacterium Legionella dumoffii is, beside Legionella pneumophila, an etiological agent of Legionnaires’ disease, an atypical form of pneumonia. The aim of this study was to determine the antimicrobial activity of Galleria mellonella defense polypeptides against L. dumoffii. The extract of immune hemolymph, containing a mixture of defense peptides and proteins, exhibited a dose-dependent bactericidal effect on L. dumoffii. The bacterium appeared sensitive to a main component of the hemolymph extract, apolipophorin III, as well as to a defense peptide, Galleria defensin, used at the concentrations 0.4 mg/mL and 40 μg/mL, respectively. L. dumoffii cells cultured in the presence of choline were more susceptible to both defense factors analyzed. A transmission electron microscopy study of bacterial cells demonstrated that Galleria defensin and apolipophorin III induced irreversible cell wall damage and strong intracellular alterations, i.e., increased vacuolization, cytoplasm condensation and the appearance of electron-white spaces in electron micrographs. Our findings suggest that insects, such as G. mellonella, with their great diversity of antimicrobial factors, can serve as a rich source of compounds for the testing of Legionella susceptibility to defense-related peptides and proteins. PMID:23235329

  18. Housefly Larva Vermicomposting Efficiently Attenuates Antibiotic Resistance Genes in Swine Manure, with Concomitant Bacterial Population Changes.

    Science.gov (United States)

    Wang, Hang; Li, Hongyi; Gilbert, Jack A; Li, Haibo; Wu, Longhua; Liu, Meng; Wang, Liling; Zhou, Qiansheng; Yuan, Junxiang; Zhang, Zhijian

    2015-11-01

    Manure from swine treated with antimicrobials as feed additives is a major source for the expansion of the antibiotic resistance gene (ARG) reservoir in the environment. Vermicomposting via housefly larvae (Musca domestica) can be efficiently used to treat manure and regenerate biofertilizer, but few studies have investigated its effect on ARG attenuation. Here, we tracked the abundances of 9 ARGs and the composition and structure of the bacterial communities in manure samples across 6 days of full-scale manure vermicomposting. On day 6, the abundances of genes encoding tetracycline resistance [tet(M), tet(O), tet(Q), and tet(W)] were reduced (P < 0.05), while those of genes encoding sulfonamide resistance (sul1 and sul2) were increased (P < 0.05) when normalized to 16S rRNA. The abundances of tetracycline resistance genes were correlated (P < 0.05) with the changing concentrations of tetracyclines in the manure. The overall diversity and richness of the bacteria significantly decreased during vermicomposting, accompanied by a 100 times increase in the relative abundance of Flavobacteriaceae spp. Variations in the abundances of ARGs were correlated with the changing microbial community structure and the relative abundances of the family Ruminococcaceae, class Bacilli, or phylum Proteobacteria. Vermicomposting, as a waste management practice, can reduce the overall abundance of ARGs. More research is warranted to assess the use of this waste management practice as a measure to attenuate the dissemination of antimicrobial residues and ARGs from livestock production before vermicompost can be safely used as biofertilizer in agroecosystems.

  19. Overexpression of the Eggplant (Solanum melongena) NAC Family Transcription Factor SmNAC Suppresses Resistance to Bacterial Wilt

    OpenAIRE

    Na, Chen; Shuanghua, Wu; Jinglong, Fu; Bihao, Cao; Jianjun, Lei; Changming, Chen; Jin, Jiang

    2016-01-01

    Bacterial wilt (BW) is a serious disease that affects eggplant (Solanum melongena) production. Although resistance to this disease has been reported, the underlying mechanism is unknown. In this study, we identified a NAC family transcription factor (SmNAC) from eggplant and characterized its expression, its localization at the tissue and subcellular levels, and its role in BW resistance. To this end, transgenic eggplant lines were generated in which the expression of SmNAC was constitutively...

  20. Gamma radiation-induced mutant of NSIC RC144 with broad-spectrum resistance to bacterial blight

    International Nuclear Information System (INIS)

    Mutant lines derived from gamma radiation-treated commercial variety NSIC RC144 were produced and screened for novel resistance to bacterial blight, one of the most serious diseases of rice. Preliminary screening of a bulk M2 population through induced method using race 3 of the pathogen Xanthomonas oryzae pv. oryzae (Xoo) resulted in the selection of 89 resistant plants. Subsequent repeated bacterial blight screenings and generation advance for five seasons resulted in the selection of two highly resistant M7 sister lines whose origin can be traced to a single M2 plant. DNA fingerprinting using 63 genome-wide simple sequence repeat (SSR) markers revealed an identical pattern in these lines. Using the same set of markers, they also exhibited 98% similarity to wild type NSIC RC144 indicating that the resistance is due to mutation and not due to genetic admixture or seed impurity. Two seasons of bacterial blight screening using 14 local isolates representing ten races of Xoo revealed an identical reaction pattern in these lines. The reaction pattern was observed to be unique compared to known patterns in four IRBB isolines (IRBB 4, 5, 7 and 21) with strong resistant reaction to bacterial blight suggesting possible novel resistance. The susceptible reaction in F1 testcrosses using Xoo race 6 and the segregation patterns in two F2 populations that fit with the expected 3 susceptible: 1 resistant ratio (P = 0.4, ns) suggest a single-gene recessive mutation in these lines. These mutants are now being used as resistance donor in the breeding program while further molecular characterization to map and characterize the mutated gene is being pursued

  1. Influence of the Diversity of Bacterial Isolates from Drinking Water on Resistance of Biofilms to Disinfection ▿

    OpenAIRE

    Simões, Lúcia C; Simões, M; Vieira, M. J.

    2010-01-01

    Single- and multispecies biofilms formed by six drinking water-isolated bacterial species were used to assess their susceptibilities to sodium hypochlorite (SHC). In general, multispecies biofilms were more resistant to inactivation and removal than single biofilms. Total biofilm inactivation was achieved only for Acinetobacter calcoaceticus single-species biofilms and for those multispecies biofilms without A. calcoaceticus. Biofilms with all bacteria had the highest resistance t...

  2. The evolution of bacterial resistance against bacteriophages in the horse chestnut phyllosphere is general across both space and time.

    Science.gov (United States)

    Koskella, Britt; Parr, Nicole

    2015-08-19

    Insight to the spatial and temporal scales of coevolution is key to predicting the outcome of host-parasite interactions and spread of disease. For bacteria infecting long-lived hosts, selection to overcome host defences is just one factor shaping the course of evolution; populations will also be competing with other microbial species and will themselves be facing infection by bacteriophage viruses. Here, we examine the temporal and spatial patterns of bacterial adaptation against natural phage populations from within leaves of horse chestnut trees. Using a time-shift experiment with both sympatric and allopatric phages from either contemporary or earlier points in the season, we demonstrate that bacterial resistance is higher against phages from the past, regardless of spatial sympatry or how much earlier in the season phages were collected. Similarly, we show that future bacterial hosts are more resistant to both sympatric and allopatric phages than contemporary bacterial hosts. Together, our results suggest the evolution of relatively general bacterial resistance against phages in nature and are contrasting to previously observed patterns of phage adaptation to bacteria from the same tree hosts over the same time frame, indicating a potential asymmetry in coevolutionary dynamics.

  3. Enhanced Biofilm Formation and Increased Resistance to Antimicrobial Agents and Bacterial Invasion Are Caused by Synergistic Interactions in Multispecies Biofilms

    DEFF Research Database (Denmark)

    Burmølle, Mette; Webb, J.S.; Rao, D.;

    2006-01-01

    Most biofilms in their natural environments are likely to consist of consortia of species that influence each other in synergistic and antagonistic manners. However, few reports specifically address interactions within multispecies biofilms. In this study, 17 epiphytic bacterial strains, isolated...... specific interactions. In summary, our data strongly indicate that synergistic effects promote biofilm biomass and resistance of the biofilm to antimicrobial agents and bacterial invasion in multispecies biofilms.......Most biofilms in their natural environments are likely to consist of consortia of species that influence each other in synergistic and antagonistic manners. However, few reports specifically address interactions within multispecies biofilms. In this study, 17 epiphytic bacterial strains, isolated......-species biofilms resisted invasion to a greater extent than did the biofilms formed by the single species. Replacement of each strain by its cell-free culture supernatant suggested that synergy was dependent both on species-specific physical interactions between cells and on extracellular secreted factors or less...

  4. Assessment of anaerobic bacterial diversity and its effects on anaerobic system stability and the occurrence of antibiotic resistance genes.

    Science.gov (United States)

    Aydin, Sevcan; Ince, Bahar; Ince, Orhan

    2016-05-01

    This study evaluated the link between anaerobic bacterial diversity and, the biodegradation of antibiotic combinations and assessed how amending antibiotic combination and increasing concentration of antibiotics in a stepwise fashion influences the development of resistance genes in anaerobic reactors. The biodegradation, sorption and occurrence of the known antibiotic resistance genes (ARGs) of erythromycin and tetracycline were investigated using the processes of UV-HPLC and qPCR analysis respectively. Ion Torrent sequencing was used to detect microbial community changes in response to the addition of antibiotics. The overall results indicated that changes in the structure of a microbial community lead to changes in biodegradation capacity, sorption of antibiotics combinations and occurrence of ARGs. The enhanced biodegradation efficiency appeared to generate variations in the structure of the bacterial community. The results suggested that controlling the ultimate Gram-negative bacterial community, especially Acinetobacter-related populations, may promote the successful biodegradation of antibiotic combinations and reduce the occurrence of ARGs. PMID:26897411

  5. Bioremediation potential of a highly mercury resistant bacterial strain Sphingobium SA2 isolated from contaminated soil.

    Science.gov (United States)

    Mahbub, Khandaker Rayhan; Krishnan, Kannan; Megharaj, Mallavarapu; Naidu, Ravi

    2016-02-01

    A mercury resistant bacterial strain, SA2, was isolated from soil contaminated with mercury. The 16S rRNA gene sequence of this isolate showed 99% sequence similarity to the genera Sphingobium and Sphingomonas of α-proteobacteria group. However, the isolate formed a distinct phyletic line with the genus Sphingobium suggesting the strain belongs to Sphingobium sp. Toxicity studies indicated resistance to high levels of mercury with estimated EC50 values 4.5 mg L(-1) and 44.15 mg L(-1) and MIC values 5.1 mg L(-1) and 48.48 mg L(-1) in minimal and rich media, respectively. The strain SA2 was able to volatilize mercury by producing mercuric reductase enzyme which makes it potential candidate for remediating mercury. ICP-QQQ-MS analysis of Hg supplemented culture solutions confirmed that almost 79% mercury in the culture suspension was volatilized in 6 h. A very small amount of mercury was observed to accumulate in cell pellets which was also evident according to ESEM-EDX analysis. The mercuric reductase gene merA was amplified and sequenced. The deduced amino acid sequence demonstrated sequence homology with α-proteobacteria and Ascomycota group.

  6. The Terminal Oxidase Cytochrome bd Promotes Sulfide-resistant Bacterial Respiration and Growth.

    Science.gov (United States)

    Forte, Elena; Borisov, Vitaliy B; Falabella, Micol; Colaço, Henrique G; Tinajero-Trejo, Mariana; Poole, Robert K; Vicente, João B; Sarti, Paolo; Giuffrè, Alessandro

    2016-01-01

    Hydrogen sulfide (H2S) impairs mitochondrial respiration by potently inhibiting the heme-copper cytochrome c oxidase. Since many prokaryotes, including Escherichia (E.) coli, generate H2S and encounter high H2S levels particularly in the human gut, herein we tested whether bacteria can sustain sulfide-resistant O2-dependent respiration. E. coli has three respiratory oxidases, the cyanide-sensitive heme-copper bo3 enzyme and two bd oxidases much less sensitive to cyanide. Working on the isolated enzymes, we found that, whereas the bo3 oxidase is inhibited by sulfide with half-maximal inhibitory concentration IC50 = 1.1 ± 0.1 μM, under identical experimental conditions both bd oxidases are insensitive to sulfide up to 58 μM. In E. coli respiratory mutants, both O2-consumption and aerobic growth proved to be severely impaired by sulfide when respiration was sustained by the bo3 oxidase alone, but unaffected by ≤200 μM sulfide when either bd enzyme acted as the only terminal oxidase. Accordingly, wild-type E. coli showed sulfide-insensitive respiration and growth under conditions favouring the expression of bd oxidases. In all tested conditions, cyanide mimicked the functional effect of sulfide on bacterial respiration. We conclude that bd oxidases promote sulfide-resistant O2-consumption and growth in E. coli and possibly other bacteria. The impact of this discovery is discussed. PMID:27030302

  7. Housefly Larva Vermicomposting Efficiently Attenuates Antibiotic Resistance Genes in Swine Manure, with Concomitant Bacterial Population Changes.

    Science.gov (United States)

    Wang, Hang; Li, Hongyi; Gilbert, Jack A; Li, Haibo; Wu, Longhua; Liu, Meng; Wang, Liling; Zhou, Qiansheng; Yuan, Junxiang; Zhang, Zhijian

    2015-11-01

    Manure from swine treated with antimicrobials as feed additives is a major source for the expansion of the antibiotic resistance gene (ARG) reservoir in the environment. Vermicomposting via housefly larvae (Musca domestica) can be efficiently used to treat manure and regenerate biofertilizer, but few studies have investigated its effect on ARG attenuation. Here, we tracked the abundances of 9 ARGs and the composition and structure of the bacterial communities in manure samples across 6 days of full-scale manure vermicomposting. On day 6, the abundances of genes encoding tetracycline resistance [tet(M), tet(O), tet(Q), and tet(W)] were reduced (P vermicomposting, accompanied by a 100 times increase in the relative abundance of Flavobacteriaceae spp. Variations in the abundances of ARGs were correlated with the changing microbial community structure and the relative abundances of the family Ruminococcaceae, class Bacilli, or phylum Proteobacteria. Vermicomposting, as a waste management practice, can reduce the overall abundance of ARGs. More research is warranted to assess the use of this waste management practice as a measure to attenuate the dissemination of antimicrobial residues and ARGs from livestock production before vermicompost can be safely used as biofertilizer in agroecosystems. PMID:26296728

  8. Nucleotide diversity analysis of three major bacterial blight resistance genes in rice.

    Directory of Open Access Journals (Sweden)

    Waikhom Bimolata

    Full Text Available Nucleotide sequence polymorphisms among R gene alleles influence the process of co-evolutionary interaction between host and pathogen by shaping the response of host plants towards invading pathogens. Here, we present the DNA sequence polymorphisms and diversities present among natural alleles of three rice bacterial blight resistance genes, Xa21, Xa26 and xa5. The diversity was examined across different wild relatives and cultivars of Oryza species. Functional significance of selected alleles was evaluated through semi-quantitative reverse transcription polymerase chain reaction and real time PCR. The greatest nucleotide diversity and singleton variable sites (SVS were present in Xa26 (π = 0.01958; SVS = 182 followed by xa5 and Xa21 alleles. The highest frequency of single nucleotide polymorphisms were observed in Xa21 alleles and least in xa5. Transition bias was observed in all the genes and 'G' to 'A' transitions were more favored than other form of transitions. Neutrality tests failed to show the presence of selection at these loci, though negative Tajima's D values indicate the presence of a rare form of polymorphisms. At the interspecies level, O. nivara exhibited more diversity than O. sativa. We have also identified two nearly identical resistant alleles of xa5 and two sequentially identical alleles of Xa21. The alleles of xa5 showed basal levels of expression while Xa21 alleles were functionally not expressed.

  9. Resistance and resilience responses of a range of soil eukaryote and bacterial taxa to fungicide application.

    Science.gov (United States)

    Howell, Christopher C; Hilton, Sally; Semple, Kirk T; Bending, Gary D

    2014-10-01

    The application of plant protection products has the potential to significantly affect soil microbial community structure and function. However, the extent to which soil microbial communities from different trophic levels exhibit resistance and resilience to such compounds remains poorly understood. The resistance and resilience responses of a range of microbial communities (bacteria, fungi, archaea, pseudomonads, and nematodes) to different concentrations of the strobilurin fungicide, azoxystrobin were studied. A significant concentration-dependent decrease, and subsequent recovery in soil dehydrogenase activity was recorded, but no significant impact on total microbial biomass was observed. Impacts on specific microbial communities were studied using small subunit (SSU) rRNA terminal restriction fragment length polymorphism (T-RFLP) profiling using soil DNA and RNA. The application of azoxystrobin significantly affected fungal and nematode community structure and diversity but had no impact on other communities. Community impacts were more pronounced in the RNA-derived T-RFLP profiles than in the DNA-derived profiles. qPCR confirmed that azoxystrobin application significantly reduced fungal, but not bacterial, SSU rRNA gene copy number. Azoxystrobin application reduced the prevalence of ascomycete fungi, but increased the relative abundance of zygomycetes. Azoxystrobin amendment also reduced the relative abundance of nematodes in the order Enoplia, but stimulated a large increase in the relative abundance of nematodes from the order Araeolaimida.

  10. Bacterial Contamination and Antibiotic Resistance of Staphylococcus Aureus Isolated from Automated Teller Machine

    Directory of Open Access Journals (Sweden)

    Moshtaghi, H. (PhD

    2015-05-01

    Full Text Available Background and Objective: Automated Teller Machine (ATMs is likely to be contaminated with various microorganisms specially pathogen germs. This may be due to their exposure to dust and their vast dermal contact with multiple users. This study investigated the bacterial contamination on the keyboard of ATMs and drug resistance of the bacteria isolated from them. Material and Methods: the keyboards of 50 ATMs in Shahrekord city, Iran, were examined from October 2012 to February 2013. The sterile swab sticks moistened with Triptose soy broth were used for sampling. The bacteriological tests used were culture, biochemical test and agar disk diffusion method for antibiogram. Results: All the samples were found to be contaminated with Coagulase negative staphylococci (57.54%, Bacillus species (21.92%, Staphylococcus aureus (19.18% and coliform bacteria (1.36%. The resistance of Staphylococcus aureus was 92.8% to penicillin, 85.7% to amoxicilin، 71.4% to ampicillin, 57.1% to nytrofuran, 50% to tetracycline, 42.8% to erythromycin, 42.8% to gentamycin, 14.2 % to ciprofloxacin, 7.1% to trimethoprim and sulfamtuksazul. All species were susceptible to, ofloxacine, chloramphenicol, clindamycin, tobramycin, vancomycin and cefotaxime. Conclusion: given the presence of pathogens on ATMs and their role in transferring the contamination, we recommend considering personal hygiene and periodically disinfecting the keyboards to reduce contamination

  11. EXPRESSION OF BACTERIAL PROTEIN-A IN TOBACCO LEADS TO ENHANCED RESISTANCE TO STRESS CONDITIONS

    Directory of Open Access Journals (Sweden)

    Chaitali Roy

    2014-08-01

    Full Text Available Tobacco is the most commonly used plant for expression of transgenes from a variety of organisms because it can be easily grown and transformed, it provides abundant amounts of fresh tissue and has a well-established cell culture system. As bacterial enzymes can be synthesized in tobacco, here we explore the possibility of in planta expression of staphylococcal protein-A(PA which is an antibody, an important group among biopharmaceuticals. In our study we have shown that the tobacco plants harboring PA gene could combat the crown gall infection and also effective in resisting abiotic stress conditions. Transgenic plants when subjected to interact with wild variety of Agrobacterium shows its enhanced capability to resist the gall formation. And when transgenic tobacco plants were grown in presence of 200mM NaCl and/or MG(Methylglyoxal solution, shows their increased tolerance towards salinity stress and high MG stress. So far transgenic tobacco plants are concerned, improvements in the expression of recombinant proteins and their recovery from tobacco may also enhance production and commercial use of this protein.

  12. Influence of silver additions to type 316 stainless steels on bacterial inhibition, mechanical properties, and corrosion resistance

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Tseng, I-Sheng; Møller, Per;

    2010-01-01

    techniques. The microstructure of these 316 stainless steels was examined, and the influences of silver additions to 316 stainless steels on bacterial inhibition, mechanical properties, and corrosion resistance were investigated. This study suggested that silver-bearing 316 stainless steels could be used in...

  13. Yeast cell wall extract induces disease resistance against bacterial and fungal pathogens in Arabidopsis thaliana and Brassica crop.

    Directory of Open Access Journals (Sweden)

    Mari Narusaka

    Full Text Available Housaku Monogatari (HM is a plant activator prepared from a yeast cell wall extract. We examined the efficacy of HM application and observed that HM treatment increased the resistance of Arabidopsis thaliana and Brassica rapa leaves to bacterial and fungal infections. HM reduced the severity of bacterial leaf spot and anthracnose on A. thaliana and Brassica crop leaves with protective effects. In addition, gene expression analysis of A. thaliana plants after treatment with HM indicated increased expression of several plant defense-related genes. HM treatment appears to induce early activation of jasmonate/ethylene and late activation of salicylic acid (SA pathways. Analysis using signaling mutants revealed that HM required SA accumulation and SA signaling to facilitate resistance to the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Colletotrichum higginsianum. In addition, HM-induced resistance conferred chitin-independent disease resistance to bacterial pathogens in A. thaliana. These results suggest that HM contains multiple microbe-associated molecular patterns that activate defense responses in plants. These findings suggest that the application of HM is a useful tool that may facilitate new disease control methods.

  14. Assessment of Relationship Between Bacterial Stripe Resistance And Leaf Protein Bands In Rice (Oryza sativa L.) Varieties.

    Science.gov (United States)

    Talei, D.; Fotokian, M. H.

    2008-01-01

    Bacterial stripe as a new rice disease in Iran is more frequent nowadays. The objective of this study was to assessment of resistance in rice varieties together with evaluating of zymogram bands resulted from SDS PAGE electrophoresis of leaf proteins. For this purpose, 30 lines were tested in a randomized complete block design with three replications. The analysis of variance showed that there was significant difference between genotypes for resistance. Mean compare based on field results revealed that Domsiyah had the lowest resistance while Nemat and 7162 demonstrated the highest resistance. Laboratory results showed that there were significant difference between protein bands resulted from sensitive and resistance verities. Twenty bands were observed through SDS PAGE electrophoresis of leaf proteins. The 9th and 12th bands were found in sensitive varieties while were not in resistance genotypes. According to the results of this study, 7162 variety can be considered as the sources of resistance in breeding programs. Meanwhile attending to existence of 9th and 12th bands in sensitive varieties, resistance against bacterial stripe of rice maybe influenced by absence of these proteins.

  15. [PK/PD Modeling as a Tool for Predicting Bacterial Resistance to Antibiotics: Alternative Analyses of Experimental Data].

    Science.gov (United States)

    Golikova, M V; Strukova, E N; Portnoy, Y A; Firsov, A A

    2015-01-01

    Postexposure number of mutants (NM) is a conventional endpoint in bacterial resistance studies using in vitro dynamic models that simulate antibiotic pharmacokinetics. To compare NM with a recently introduced integral parameter AUBC(M), the area under the time course of resistance mutants, the enrichment of resistant Staphylococcus aureus was studied in vitro by simulation of mono(daptomycin, doxycycline) and combined treatments (daptomycin + rifampicin, rifampicin + linezolid). Differences in the time courses of resistant S. aureus could be reflected by AUBC(M) but not N(M). Moreover, unlike AUBC(M), N(M) did not reflect the pronounced differences in the time courses of S. aureus mutants resistant to 2x, 4x, 8x and 16xMIC of doxycycline and rifampicin. The findings suggested that AUBC(M) was a more appropriate endpoint of the amplification of resistant mutants than N(M).

  16. Frequency of bacterial isolates and pattern of antimicrobial resistance in patients with hematological malignancies: A snapshot from tertiary cancer center

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    M Sengar

    2015-01-01

    Full Text Available BACKGROUND: Infections are the most important cause of mortality in patients with high-risk febrile neutropenia. Emergence of multi-drug resistant organisms (MDROs has become a major challenge for hemato-oncologists. Knowledge of the prevalent organisms and their antimicrobial sensitivity can help deciding the empirical therapy at individual centers and allows timely measures to reduce the risk of antimicrobial resistance. AIMS: To evaluate the frequency of bacterial isolates from all the samples and the pattern of bacterial bloodstream infections and incidence of MDROs. SETTINGS AND DESIGN: This is a retrospective analysis from a tertiary care cancer center. MATERIALS AND METHODS: From January to June 2014 information on all the samples received in Department of Microbiology was collected retrospectively. The data from samples collected from patients with hematological cancers were analyzed for types of bacterial isolates and antimicrobial sensitivity. RESULTS: A total of 739 isolates were identified with 67.9% of isolates being Gram-negative. The predominant Gram-negative organisms were Escherichia coli, Psuedomonas spp. and Klebsiella spp. Among the bacterial bloodstream infections, 66% were Gram-negative isolates. MDROs constituted 22% of all isolates in blood cultures. Incidence of resistant Gram-positive organisms was low in the present dataset (methicillin resistant Staphylococcus aureus and vancomycin-resistant enterococci-1.3%. CONCLUSIONS: The analysis reconfirms the Gram-negative organisms as the predominant pathogens in bacteremia seen in patients with hematological cancers. The high frequency of multi-drug resistance in the dataset calls for the need of emergency measures to curtail further development and propagation of resistant organisms.

  17. Purification and characterization of a scorpion defensin, a 4kDa antibacterial peptide presenting structural similarities with insect defensins and scorpion toxins.

    Science.gov (United States)

    Cociancich, S; Goyffon, M; Bontems, F; Bulet, P; Bouet, F; Menez, A; Hoffmann, J

    1993-07-15

    Insect defensins are a group of inducible small-sized antibacterial peptides with three intramolecular disulfide bridges. NMR studies have recently shown that they share striking structural similarities with scorpion toxins. We have investigated in a scorpion species, Leiurus quinquestriatus, the potential presence of antibacterial molecules and report the isolation and structural characterization of a novel insect defensin homologue, which we refer to as scorpion defensin. This peptide shows a remarkably high degree of sequence homology with a defensin recently characterized in a species belonging to the ancient insect order of the Odonata with which it defines a novel ancient subclass of defensins. The scorpion defensin has in common with the scorpion toxins a consensus sequence Cys-[...]-Cys-Xaa-Xaa-Xaa-Cys-[...]-Gly-Xaa-Cys-[...]-Cys-Xaa-Cys present in all scorpion toxins characterized so far. PMID:8333834

  18. Defensins couple dysbiosis to primary immunodeficiency in Crohn's disease

    Institute of Scientific and Technical Information of China (English)

    Mathias Chamaillard; Rodrigue Dessein

    2011-01-01

    Antimicrobial peptides, including defensins, are essential effectors in host defence and in the maintenance of immune homeostasis. Clinical studies have linked the defective expression of both α- and β-defensin to the reduced killing of certain microorganisms by the intestinal mucosa of patients suffering from ileal and colonic Crohn's disease (CD), respectively. Only recently have the events leading to defective expression of defensins in CD been further elucidated, and are discussed herein.These events may account for CD-associated alterations in the microbiome and may subsequently precipitate the development of granulomatous inflammatory lesions in genetically-predisposed patients. We also address how these discoveries may pave the way for the development of a molecular medicine aimed at restoring gut barrier function in CD.

  19. Atmospheric pressure resistive barrier air plasma jet induced bacterial inactivation in aqueous environment

    Science.gov (United States)

    Thiyagarajan, Magesh; Sarani, Abdollah; Gonzales, Xavier

    2013-03-01

    An atmospheric pressure resistive barrier air plasma jet is designed to inactivate bacteria in aqueous media in direct and indirect exposure modes of treatment. The resistive barrier plasma jet is designed to operate at both dc and standard 50-60 Hz low frequency ac power input and the ambient air at 50% humidity level was used as the operating gas. The voltage-current characteristics of the plasma jet were analyzed and the operating frequency of the discharge was measured to be 20 kHz and the plasma power was measured to be 26 W. The plasma jet rotational temperatures (Trot) are obtained from the optical emission spectra, from the N2C-B(2+) transitions by matching the experimental spectrum results with the Spectra Air (SPECAIR) simulation spectra. The reactive oxygen and nitrogen species were measured using optical emission spectroscopy and gas analyzers, for direct and indirect treatment modes. The nitric oxides (NO) were observed to be the predominant long lived reactive nitrogen species produced by the plasma. Three different bacteria including Staphylococcus aureus (Gram-positive), Escherichia coli (Gram-negative), and Neisseria meningitidis (Gram-negative) were suspended in an aqueous media and treated by the resistive barrier air plasma jet in direct and indirect exposure modes. The results show that a near complete bacterial inactivation was achieved within 120 s for both direct and indirect plasma treatment of S. aureus and E. coli bacteria. Conversely, a partial inactivation of N. meningitidis was observed by 120 s direct plasma exposure and insignificant inactivation was observed for the indirect plasma exposure treatment. Plasma induced shifts in N. meningitidis gene expression was analyzed using pilC gene expression as a representative gene and the results showed a reduction in the expression of the pilC gene compared to untreated samples suggesting that the observed protection against NO may be regulated by other genes.

  20. Determination of physiological, taxonomic, and molecular characteristics of a cultivable arsenic-resistant bacterial community.

    Science.gov (United States)

    Cordi, A; Pagnout, C; Devin, S; Poirel, J; Billard, P; Dollard, M A; Bauda, P

    2015-09-01

    A collection of 219 bacterial arsenic-resistant isolates was constituted from neutral arsenic mine drainage sediments. Isolates were grown aerobically or anaerobically during 21 days on solid DR2A medium using agar or gelan gum as gelling agent, with 7 mM As(III) or 20 mM As(V) as selective pressure. Interestingly, the sum of the different incubation conditions used (arsenic form, gelling agent, oxygen pressure) results in an overall increase of the isolate diversity. Isolated strains mainly belonged to Proteobacteria (63%), Actinobacteria (25%), and Bacteroidetes (10%). The most representative genera were Pseudomonas (20%), Acinetobacter (8%), and Serratia (15%) among the Proteobacteria; Rhodococcus (13%) and Microbacterium (5%) among Actinobacteria; and Flavobacterium (13%) among the Bacteroidetes. Isolates were screened for the presence of arsenic-related genes (arsB, ACR3(1), ACR3(2), aioA, arsM, and arrA). In this way, 106 ACR3(1)-, 74 arsB-, 22 aioA-, 14 ACR3(2)-, and one arsM-positive PCR products were obtained and sequenced. Analysis of isolate sensitivity toward metalloids (arsenite, arsenate, and antimonite) revealed correlations between taxonomy, sensitivity, and genotype. Antimonite sensitivity correlated with the presence of ACR3(1) mainly present in Bacteroidetes and Actinobacteria, and arsenite or antimonite resistance correlated with arsB gene presence. The presence of either aioA gene or several different arsenite carrier genes did not ensure a high level of arsenic resistance in the tested conditions.

  1. Sulfonamide and tetracycline resistance genes in total- and culturable-bacterial assemblages in South African aquatic environments

    Science.gov (United States)

    Suzuki, Satoru; Ogo, Mitsuko; Koike, Tatsuya; Takada, Hideshige; Newman, Brent

    2015-01-01

    Antibiotic resistant bacteria are ubiquitous in the natural environment. The introduction of effluent derived antibiotic resistance genes (ARGs) into aquatic environments is of concern in the spreading of genetic risk. This study showed the prevalence of sulfonamide and tetracycline resistance genes, sul1, sul2, sul3, and tet(M), in the total bacterial assemblage and colony forming bacterial assemblage in river and estuarine water and sewage treatment plants (STP) in South Africa. There was no correlation between antibiotic concentrations and ARGs, suggesting the targeted ARGs are spread in a wide area without connection to selection pressure. Among sul genes, sul1 and sul2 were major genes in the total (over 10-2 copies/16S) and colony forming bacteria assemblages (∼10-1 copies/16S). In urban waters, the sul3 gene was mostly not detectable in total and culturable assemblages, suggesting sul3 is not abundant. tet(M) was found in natural assemblages with 10-3 copies/16S level in STP, but was not detected in colony forming bacteria, suggesting the non-culturable (yet-to-be cultured) bacterial community in urban surface waters and STP effluent possess the tet(M) gene. Sulfamethoxazole (SMX) resistant (SMXr) and oxytetracycline (OTC) resistant (OTCr) bacterial communities in urban waters possessed not only sul1 and sul2 but also sul3 and tet(M) genes. These genes are widely distributed in SMXr and OTCr bacteria. In conclusion, urban river and estuarine water and STP effluent in the Durban area were highly contaminated with ARGs, and the yet-to-be cultured bacterial community may act as a non-visible ARG reservoir in certain situations. PMID:26300864

  2. Sulfonamide and tetracycline resistance genes in total- and culturable-bacterial assemblages in South African aquatic environments

    Directory of Open Access Journals (Sweden)

    Satoru eSuzuki

    2015-08-01

    Full Text Available Antibiotic resistant bacteria (ARB are ubiquitous in the natural environment. The introduction of effluent derived antibiotic resistance genes (ARGs into aquatic environments is of concern in the spreading of genetic risk. This study showed the prevalence of sulfonamide and tetracycline resistance genes, sul1, sul2, sul3 and tet(M, in the total bacterial assemblage and colony forming bacterial assemblage in river and estuarine water and sewage treatment plants (STP in South Africa. There was no correlation between antibiotic concentrations and ARGs, suggesting the targeted ARGs are spread in a wide area without connection to selection pressure. Among sul genes, sul1 and sul2 were major genes in the total (over 10-2 copies/16S and colony forming bacteria assemblages (approx 10-1 copies/16S. In urban waters, the sul3 gene was mostly not detectable in total and culturable assemblages, suggesting sul3 is not abundant. tet(M was found in natural assemblages with 10-3 copies/16S level in STP, but was not detected in colony forming bacteria, suggesting the non-culturable (yet-to-be cultured bacterial community in urban surface waters and STP effluent possess the tet(M gene. Sulfamethoxazole resistant (SMXr and oxytetracycline resistant (OTCr bacterial communities in urban waters possessed not only sul1 and sul2 but also sul3 and tet(M genes. These genes are widely distributed in SMXr and OTCr bacteria. In conclusion, urban river and estuarine water and STP effluent in the Durban area were highly contaminated with ARGs, and the yet-to-be cultured bacterial community may act as a non-visible ARG reservoir in certain situations.

  3. Design and activity of a cyclic mini-β-defensin analog: a novel antimicrobial tool

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    Scudiero O

    2015-10-01

    suggest that this novel peptide may be added to the arsenal of tools available to combat antibiotic-resistant infectious diseases, particularly because of its potential for encapsulation in a nanomedicine vector. Keywords: antimicrobial activity, cyclic mini-peptide, human beta-defensin

  4. Genetic parameters and selection for resistance to bacterial spot in recombinant F6 lines of Capsicum annuum

    Directory of Open Access Journals (Sweden)

    Messias Gonzaga Pereira

    2009-01-01

    Full Text Available This study aimed to advance generations and select superior sweet pepper genotypes with resistance tobacterial spot, using the breeding method Single Seed Descent (SSD based on the segregating population derived from thecross between Capsicum annuum L. UENF 1421 (susceptible, non-pungent and UENF 1381 (resistant, pungent. Thesegregating F3 generation was grown in pots in a greenhouse until the F5 generation. The F6 generation was grown in fieldconditions. The reaction to bacterial spot was evaluated by inoculation with isolate ENA 4135 of Xanthomonas campestris pv.vesicatoria, based on a score scale and by calculating the area under the disease progress curve (AUDPC. The presence orabsence of capsaicin was also assessed. Eighteen F6 lines were bacterial leaf spot-resistant. Since no capsaicin was detectedin the F6 lines 032, 316, 399, 434, and 517, these will be used in the next steps of the sweet pepper breeding program.

  5. Transcriptional responses of Italian ryegrass during interaction with Xanthomonas translucens pv. graminis reveal novel candidate genes for bacterial wilt resistance

    DEFF Research Database (Denmark)

    Wichmann, Fabienne; Asp, Torben; Widmer, Franko;

    2011-01-01

    Xanthomonas translucens pv. graminis (Xtg) causes bacterial wilt, a severe disease of forage grasses such as Italian ryegrass (Lolium multiflorum Lam.). In order to gain a more detailed understanding of the genetic control of resistance mechanisms and to provide prerequisites for marker assisted...... selection, the partial transcriptomes of two Italian ryegrass genotypes, one resistant and one susceptible to bacterial wilt were compared at four time points after Xtg infection. A cDNA microarray developed from a perennial ryegrass (Lolium perenne) expressed sequence tag set consisting of 9,990 unique...... genes was used for transcriptome analysis in Italian ryegrass. An average of 4,487 (45%) of the perennial ryegrass sequences spotted on the cDNA microarray were detected by cross-hybridisation to Italian ryegrass. Transcriptome analyses of the resistant versus the susceptible genotype revealed...

  6. Frequency of Bacterial Contamination and Antibiotic Resistance Patterns in Devices and in Personnel of Endoscopy and Colonoscopy Units

    Directory of Open Access Journals (Sweden)

    Torabi, P. (BSc

    2014-06-01

    Full Text Available Background and Objective: This study was aimed to determine the extent of bacterial contamination and drug resistance patterns of isolates colonized in colonoscope and endoscope and in relevant personnel. Material and Methods: A total of 107 samples were obtained from staff of endoscopy and colonoscopy units (SEU and SCU and gastroenterological imaging equipment. For isolation and identification of the bacteria, swab culture method and biochemical identification test were used, respectively. Antimicrobial resistance profiles, multi-drug resistance (MDR patterns and phenetic relatedness of these isolates were also analyzed according to standard methods. Results: Most frequent pathogenic bacteria among the SEU and gastroenterological imaging related equipments were included S. aureus (20.8 % and 0 %; Enterococcus spp. (0 % and 5.4%; Pseudomonas spp. (0% and 13.5 %, and Clostridium difficile (0% and 12.5%. Analysis of resistance phenotypes showed a high frequency of MDR phenotypes among the SEU (82.1%, and also in endoscopes, colonoscopes, and other equipments (20%, 50% and 100%, respectively. Phylotyping of S. epidermidis isolates showed the role of staff in transmission of resistance strains to medical equipments and also circulation of strains with identical resistance phenotype among the studied samples. Conclusion: High frequency of pathogenic bacteria in colonoscopes, endoscopes and in the staff of endoscopy & colonoscopy units, and also contamination of these instruments with MDR pathogens emphasize the need for proper disinfection of endoscopes and colonoscopes and also instruction of staff in these units. Key words: Bacterial Contamination; Endoscope; Colonoscope; Antimicrobial Resistance; Gastrointestinal Disease.

  7. Resistance to ketolide antibiotics by coordinated expression of rRNA methyltransferases in a bacterial producer of natural ketolides.

    Science.gov (United States)

    Almutairi, Mashal M; Park, Sung Ryeol; Rose, Simon; Hansen, Douglas A; Vázquez-Laslop, Nora; Douthwaite, Stephen; Sherman, David H; Mankin, Alexander S

    2015-10-20

    Ketolides are promising new antimicrobials effective against a broad range of Gram-positive pathogens, in part because of the low propensity of these drugs to trigger the expression of resistance genes. A natural ketolide pikromycin and a related compound methymycin are produced by Streptomyces venezuelae strain ATCC 15439. The producer avoids the inhibitory effects of its own antibiotics by expressing two paralogous rRNA methylase genes pikR1 and pikR2 with seemingly redundant functions. We show here that the PikR1 and PikR2 enzymes mono- and dimethylate, respectively, the N6 amino group in 23S rRNA nucleotide A2058. PikR1 monomethylase is constitutively expressed; it confers low resistance at low fitness cost and is required for ketolide-induced activation of pikR2 to attain high-level resistance. The regulatory mechanism controlling pikR2 expression has been evolutionary optimized for preferential activation by ketolide antibiotics. The resistance genes and the induction mechanism remain fully functional when transferred to heterologous bacterial hosts. The anticipated wide use of ketolide antibiotics could promote horizontal transfer of these highly efficient resistance genes to pathogens. Taken together, these findings emphasized the need for surveillance of pikR1/pikR2-based bacterial resistance and the preemptive development of drugs that can remain effective against the ketolide-specific resistance mechanism.

  8. Enteric bacterial pathogens in children with diarrhea in Niger: diversity and antimicrobial resistance.

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    Céline Langendorf

    Full Text Available Although rotavirus is the leading cause of severe diarrhea among children in sub-Saharan Africa, better knowledge of circulating enteric pathogenic bacteria and their antimicrobial resistance is crucial for prevention and treatment strategies.As a part of rotavirus gastroenteritis surveillance in Maradi, Niger, we performed stool culture on a sub-population of children under 5 with moderate-to-severe diarrhea between April 2010 and March 2012. Campylobacter, Shigella and Salmonella were sought with conventional culture and biochemical methods. Shigella and Salmonella were serotyped by slide agglutination. Enteropathogenic Escherichia coli (EPEC were screened by slide agglutination with EPEC O-typing antisera and confirmed by detection of virulence genes. Antimicrobial susceptibility was determined by disk diffusion. We enrolled 4020 children, including 230 with bloody diarrhea. At least one pathogenic bacterium was found in 28.0% of children with watery diarrhea and 42.2% with bloody diarrhea. Mixed infections were found in 10.3% of children. EPEC, Salmonella and Campylobacter spp. were similarly frequent in children with watery diarrhea (11.1%, 9.2% and 11.4% respectively and Shigella spp. were the most frequent among children with bloody diarrhea (22.1%. The most frequent Shigella serogroup was S. flexneri (69/122, 56.5%. The most frequent Salmonella serotypes were Typhimurimum (71/355, 20.0%, Enteritidis (56/355, 15.8% and Corvallis (46/355, 13.0%. The majority of putative EPEC isolates was confirmed to be EPEC (90/111, 81.1%. More than half of all Enterobacteriaceae were resistant to amoxicillin and co-trimoxazole. Around 13% (46/360 Salmonella exhibited an extended-spectrum beta-lactamase phenotype.This study provides updated information on enteric bacteria diversity and antibiotic resistance in the Sahel region, where such data are scarce. Whether they are or not the causative agent of diarrhea, bacterial infections and their antibiotic

  9. PREVALENCE AND ANTIBIOTIC RESISTANCE OF FOOD BORNE BACTERIAL CONTAMINATION IN SOME EGYPTIAN FOOD food

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    Samy Selim

    2015-09-01

    Full Text Available This study was undertaken to investigate the prevalence and antibiotic resistance of food borne bacterial contamination in some Egyptian food. Total viable bacteria and total coliform bacteriawere isolated from different sources of food; carbohydrates (bread, flour and basbousa, vegetables (outer and inner tissues of potato and outer and inner tissues of cucumber and proteins (mincedmeat, cheese and milk. The study resulted in maximum value of total viable bacteria found in outer tissue of potato 68X104±1.0, while the minimum value found in inner tissues of potato andcucumber. The study resulted in total coliform was maximum value in minced meat 6.4X103±0.3. Basbousa and inner tissue of potato and cucumber were free from coliforms. The ability of isolatesto producing proteolytic enzymes was tested, we found that 326 isolate (63.92% from all isolates had this ability, thus we selected most 2 potent proteolytic isolates. The two isolates were identifiedas Bacillus cereus and Escherichia coli. The identification confirmed by microlog 34.20 system and 16SrRNA for two isolates and the same result was founded. Sensitivity tested for the most potentproteolytic species to 12 of the most commonly used antibiotics in the Egyptian pharmacy. The results showed that all species were sensitive to most of antibiotics, except B. cereus which was strongly susceptible to azteronam and ceftazidim. The data showed that raw meat, cooked food products, and raw milk were most commonly contaminated with foodborne pathogens and many pathogens were resistant to different antibiotics. The study provided useful information for assessment of the possible risk posed to consumers, which has significant public health impact.

  10. Bacterial resistance to antibiotics in acne vulgaris: An in vitro study

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    Hassanzadeh Parvin

    2008-01-01

    Full Text Available Background: Acne vulgaris is one of the most common skin disorders in youth especially during the puberty. Objective: This in vitro study was performed to determine the antibiotic resistance and sensitivity in acne vulgaris. Materials and Methods: Samples were collected from normal skin and nodulocystic and pustular skin lesions of one hundred youngsters (64 girls, 36 boys among college students in the age range of 18-24 years old. The specimens were cultured individually on blood agar and Muller-Hinton media. The cultures were then incubated under both aerobic and anaerobic conditions for 2 to 7 days. Bacteria were identified and their resistance to common antibiotics was evaluated according to the standard procedures. Results: In aerobic culture of pustular and nodulocystic skin lesions, Staphylococcus aureus was present in 41% of subjects, Staphylococcus epidermidis in 53% and Micrococcus spp in 45% of subjucts. In anaerobic bacterial culture of pustular and nodulocystic skin lesions, Staphylococcus aureus was present in 39%, Propionibacterium acne in 33% and Staphylococcus epidermidis in 21% of subjects. The results of present study revealed that clindamycin and erythromycin were the least effective antibiotics for Propionibacterium acne while tetracycline was the least effective for Staphylococcus aureus in vitro . A synergic effect of benzoyl peroxide, erythromycin or clindamycin was noticed. Rifampin was the most effective antibiotic in vitro . Conclusion: Our results showed that rifampin was the most sensitive antibiotic in vitro for acne vulgaris. To achieve a better treatment, a combination of rifampin with other antibiotics may be more efficient. We suggest in vivo studies for better evaluation and treatment of acne patients with rifampin.

  11. Endotoxin, capsule, and bacterial attachment contribute to Neisseria meningitidis resistance to the human antimicrobial peptide LL-37.

    Science.gov (United States)

    Jones, Allison; Geörg, Miriam; Maudsdotter, Lisa; Jonsson, Ann-Beth

    2009-06-01

    Pathogenic bacteria have evolved numerous mechanisms to evade the human immune system and have developed widespread resistance to traditional antibiotics. We studied the human pathogen Neisseria meningitidis and present evidence of novel mechanisms of resistance to the human antimicrobial peptide LL-37. We found that bacteria attached to host epithelial cells are resistant to 10 microM LL-37 whereas bacteria in solution or attached to plastic are killed, indicating that the cell microenvironment protects bacteria. The bacterial endotoxin lipooligosaccharide and the polysaccharide capsule contribute to LL-37 resistance, probably by preventing LL-37 from reaching the bacterial membrane, as more LL-37 reaches the bacterial membrane on both lipooligosaccharide-deficient and capsule-deficient mutants whereas both mutants are also more susceptible to LL-37 killing than the wild-type strain. N. meningitidis bacteria respond to sublethal doses of LL-37 and upregulate two of their capsule genes, siaC and siaD, which further results in upregulation of capsule biosynthesis.

  12. Overexpression of the Eggplant (Solanum melongena) NAC Family Transcription Factor SmNAC Suppresses Resistance to Bacterial Wilt.

    Science.gov (United States)

    Na, Chen; Shuanghua, Wu; Jinglong, Fu; Bihao, Cao; Jianjun, Lei; Changming, Chen; Jin, Jiang

    2016-01-01

    Bacterial wilt (BW) is a serious disease that affects eggplant (Solanum melongena) production. Although resistance to this disease has been reported, the underlying mechanism is unknown. In this study, we identified a NAC family transcription factor (SmNAC) from eggplant and characterized its expression, its localization at the tissue and subcellular levels, and its role in BW resistance. To this end, transgenic eggplant lines were generated in which the expression of SmNAC was constitutively up regulated or suppressed using RNAi. The results indicated that overexpression of SmNAC decreases resistance to BW. Moreover, SmNAC overexpression resulted in the reduced accumulation of the plant immune signaling molecule salicylic acid (SA) and reduced expression of ICS1 (a gene that encode isochorismate synthase 1, which is involved in SA biosynthesis). We propose that reduced SA content results in increased bacterial wilt susceptibility in the transgenic lines. Our results provide important new insights into the regulatory mechanisms of bacterial wilt resistance in eggplant. PMID:27528282

  13. Drug resistance of bacterial dental biofilm and the potential use of natural compounds as alternative for prevention and treatment.

    Science.gov (United States)

    Kouidhi, Bochra; Al Qurashi, Yasir Mohammed A; Chaieb, Kamel

    2015-03-01

    Oral diseases, such as dental caries and periodontal disease are directly linked with the ability of bacteria to form biofilm. The development of dental caries involves acidogenic and aciduric Gram-positive bacteria colonizing the supragingival biofilm (Streptococcus, Lactobacillus and Actinomycetes). Periodontal diseases have been linked to anaerobic Gram-negative bacteria forming a subgingival plaque (Porphyromonas gingivalis, Actinobacillus, Prevotella and Fusobacterium). Cells embedded in biofilm are up to 1000-fold more resistant to antibiotics compared to their planctonic ones. Several mechanisms have been proposed to explain biofilms drug resistance. Given the increased bacterial resistance to antibiotics currently used in dentistry, a great importance is given to natural compounds for the prevention of oral bacterial growth, adhesion and colonization. Over the past decade, interest in drugs derived from medicinal plants has markedly increased. It has been well documented that medicinal plants and natural compounds confer considerable antibacterial activity against various microorganisms including cariogenic and periodontal pathogens. This paper provides a review of the literature focusing on the studies on (i) biofilm in the oral cavity, (ii) drug resistance of bacterial biofilm and (iii) the potential use of plant extracts, essential oils and natural compounds as biofilm preventive agents in dentistry, involving their origin and their mechanism of biofilm inhibition.

  14. The inflammasomes: Molecular effectors of host resistance against bacterial, viral, parasitic and fungal infections

    Directory of Open Access Journals (Sweden)

    Alexander eSkeldon

    2011-02-01

    Full Text Available The inflammasomes are large multi-protein complexes scaffolded by cytosolic pattern recognition receptors (PRRs that form an important part of the innate immune system. They are activated following the recognition of microbial-associated molecular patterns (MAMPs or host-derived danger signals (danger-associated molecular patterns or DAMPs by PRRs. This recognition results in the recruitment and activation of the pro-inflammatory protease caspase-1, which cleaves its preferred substrates pro-interleukin-1β (IL-1β and pro-IL-18 into their mature biologically active cytokine forms. Through processing of a number of other cellular substrates, caspase-1 is also required for the release of alarmins and the induction and execution of an inflammatory form of cell death termed pyroptosis. A growing spectrum of inflammasomes have been identified in the host defence against a variety of pathogens. Reciprocally, pathogens have evolved effector strategies to antagonize the inflammasome pathway. In this review we discuss recent developments in the understanding of inflammasome-mediated recognition of bacterial, viral, parasitic and fungal infections and the beneficial or detrimental effects of inflammasome signalling in host resistance.

  15. Cell resistant zwitterionic polyelectrolyte coating promotes bacterial attachment: an adhesion contradiction.

    Science.gov (United States)

    Martinez, Jessica S; Kelly, Kristopher D; Ghoussoub, Yara E; Delgado, Jose D; Keller Iii, Thomas C S; Schlenoff, Joseph B

    2016-04-22

    Polymers of various architectures with zwitterionic functionality have recently been shown to effectively suppress nonspecific fouling of surfaces by proteins and prokaryotic (bacteria) or eukaryotic (mammalian) cells as well as other microorganisms and environmental contaminants. In this work, zwitterionic copolymers were used to make thin coatings on substrates with the layer-by-layer method. Polyelectrolyte multilayers, PEMUs, were built with [poly(allylamine hydrochloride)], PAH, and copolymers of acrylic acid and either the AEDAPS zwitterionic group 3-[2-(acrylamido)-ethyldimethyl ammonio] propane sulfonate (PAA-co-AEDAPS), or benzophenone (PAABp). Benzophenone allowed the PEMU to be toughened by photocrosslinking post-deposition. The attachment of two mammalian cell lines, rat aortic smooth muscle (A7r5) and mouse fibroblasts (3T3), and the biofilm-forming Gram-negative bacteria Escherichia coli was studied on PEMUs terminated with PAA-co-AEDAPS. Consistent with earlier studies, it is shown that PAH/PAA-co-AEDAPS PEMUs resist the adhesion of mammalian cells, but, contrary to our initial hypothesis, are bacterial adhesive and significantly so after maximizing the surface presentation of PAA-co-AEDAPS. This unexpected contrast in the adhesive behavior of prokaryotic and eukaryotic cells is explained by differences in adhesion mechanisms as well as different responses to the topology and morphology of the multilayer surface. PMID:26872345

  16. Metabolite profiles of rice cultivars containing bacterial blight-resistant genes are distinctive from susceptible rice

    Institute of Scientific and Technical Information of China (English)

    Jiao Wu; Haichuan Yu; Haofu Dai; Wenli Mei; Xin Huang; Shuifang Zhu; Ming Peng

    2012-01-01

    The metabolic changes of bacterial blight-resistant line C418/Xa23 generated by molecular marker-assisted selection (n =12),transgenic variety C418-Xa21 generated by using the Agrobacterium-mediated system (n =12),and progenitor cultivar C418 (n =12) were monitored using gas chromatography/mass spectrometry.The validation,discrimination,and establishment of correlative relationships between metabolite signals were performed by cluster analysis,principal component analysis,and partial least squares-discriminant analysis.Significant and unintended changes were observed in 154 components in C418/Xa23 and 48 components in C418-Xa21 compared with C418 (P < 0.05,Fold change > 2.0).The most significant decreases detected (P< 0.001) in both C418/Xa23 and C418-Xa21 were in three amino acids: glycine,tyrosine,and alanine,and four identified metabolites: malic acid,ferulic acid,succinic acid,and glycerol.Linoleic acid was increased specifically in C418/Xa23 which was derived from traditional breeding.This line,possessing a distinctive metabolite profile as a positive control,shows more differences vs.the parental than the transgenic line.Only succinic acid that falls outside the boundaries of natural variability between the two non-transgenic varieties C418 and C418/Xa23 should be further investigated with respect to safety or nutritional impact.

  17. An efficient system for intracellular delivery of beta-lactam antibiotics to overcome bacterial resistance.

    Science.gov (United States)

    Abed, Nadia; Saïd-Hassane, Fatouma; Zouhiri, Fatima; Mougin, Julie; Nicolas, Valérie; Desmaële, Didier; Gref, Ruxandra; Couvreur, Patrick

    2015-01-01

    The "Golden era" of antibiotics is definitely an old story and this is especially true for intracellular bacterial infections. The poor intracellular bioavailability of antibiotics reduces the efficency of many treatments and thereby promotes resistances. Therefore, the development of nanodevices coupled with antibiotics that are capable of targeting and releasing the drug into the infected-cells appears to be a promising solution to circumvent these complications. Here, we took advantage of two natural terpenes (farnesyl and geranyl) to design nanodevices for an efficient intracellular delivery of penicillin G. The covalent linkage between the terpene moieties and the antibiotic leads to formation of prodrugs that self-assemble to form nanoparticles with a high drug payload between 55-63%. Futhermore, the addition of an environmentally-sensitive bond between the antibiotic and the terpene led to an efficient antibacterial activity against the intracellular pathogen Staphylococcus aureus with reduced intracellular replication of about 99.9% compared to untreated infected cells. Using HPLC analysis, we demonstrated and quantified the intracellular release of PenG when this sensitive-bond (SB) was present on the prodrug, showing the success of this technology to deliver antibiotics directly into cells.

  18. Bacterial Profile of Blood Stream Infection and Antibiotic Resistance Pattern of Isolates.

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    Usha Arora, Pushpa Devi

    2007-10-01

    Full Text Available Blood samples from 2542 clinically diagnosed cases of septicemia were processed. Out of these 946(76.55% were from Pediatric Department and rest from other Departments. Growth was obtained in509(20.02% cases . Candida spp were isolated from 23 (4.57 cases Out of 486 bacterial isolates 52.67% were gram positive bacteria whereas 47.33% were gram negative bacilli . Staph aureus 133 (27.37%wasthe predominant organisms followed by CONS 98 (20.1%. Amongst gram negative organismsEnterobacter 69 (14.19 % was the most predominant followed by Esch coli 45 (9.27 % Pseudomonas 37(7.62 % and Acinetobacter spp 34 (6.69 %. Amongst gram positive organisms maximum resistancewas seen with ampicillin (74.61% and erythromycin (69.67 %. Most of the gram negative bacilli wereMDR (71%. Maximum resistance was observed with ampicillin (86.1% cephalexin (68.07% andpiperacillin (57.71%. Most successful drugs were amikacin,gentamicin and cefotaxime. 34.35% of theisolates were ESBL producers.

  19. Epidemiology and burden of multidrug-resistant bacterial infection in a developing country

    Science.gov (United States)

    Lim, Cherry; Takahashi, Emi; Hongsuwan, Maliwan; Wuthiekanun, Vanaporn; Thamlikitkul, Visanu; Hinjoy, Soawapak; Day, Nicholas PJ; Peacock, Sharon J; Limmathurotsakul, Direk

    2016-01-01

    Little is known about the excess mortality caused by multidrug-resistant (MDR) bacterial infection in low- and middle-income countries (LMICs). We retrospectively obtained microbiology laboratory and hospital databases of nine public hospitals in northeast Thailand from 2004 to 2010, and linked these with the national death registry to obtain the 30-day mortality outcome. The 30-day mortality in those with MDR community-acquired bacteraemia, healthcare-associated bacteraemia, and hospital-acquired bacteraemia were 35% (549/1555), 49% (247/500), and 53% (640/1198), respectively. We estimate that 19,122 of 45,209 (43%) deaths in patients with hospital-acquired infection due to MDR bacteria in Thailand in 2010 represented excess mortality caused by MDR. We demonstrate that national statistics on the epidemiology and burden of MDR in LMICs could be improved by integrating information from readily available databases. The prevalence and mortality attributable to MDR in Thailand are high. This is likely to reflect the situation in other LMICs. DOI: http://dx.doi.org/10.7554/eLife.18082.001 PMID:27599374

  20. Differential and coordinated expression of defensins and cytokines by gingival epithelial cells and dendritic cells in response to oral bacteria

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    Clark Edward A

    2010-07-01

    Full Text Available Abstract Background Epithelial cells and dendritic cells (DCs both initiate and contribute to innate immune responses to bacteria. However, much less is known about the coordinated regulation of innate immune responses between GECs and immune cells, particularly DCs in the oral cavity. The present study was conducted to investigate whether their responses are coordinated and are bacteria-specific in the oral cavity. Results The β-defensin antimicrobial peptides hBD1, hBD2 and hBD3 were expressed by immature DCs as well as gingival epithelial cells (GECs. HBD1, hBD2 and hBD3 are upregulated in DCs while hBD2 and hBD3 are upregulated in GECs in response to bacterial stimulation. Responses of both cell types were bacteria-specific, as demonstrated by distinctive profiles of hBDs mRNA expression and secreted cytokines and chemokines in response to cell wall preparations of various bacteria of different pathogenicity: Fusobacterium nucleatum, Actinomyces naeslundii and Porphyromonas gingivalis. The regulation of expression of hBD2, IL-8, CXCL2/GROβ and CCL-20/MIP3α by GECs was greatly enhanced by conditioned medium from bacterially activated DCs. This enhancement was primarily mediated via IL-1β, since induction was largely attenuated by IL-1 receptor antagonist. In addition, the defensins influence DCs by eliciting differential cytokine and chemokine secretion. HBD2 significantly induced IL-6, while hBD3 induced MCP-1 to approximately the same extent as LPS, suggesting a unique role in immune responses. Conclusions The results suggest that cytokines, chemokines and β-defensins are involved in interaction of these two cell types, and the responses are bacteria-specific. Differential and coordinated regulation between GECs and DCs may be important in regulation of innate immune homeostasis and response to pathogens in the oral cavity.

  1. Who possesses drug resistance genes in the aquatic environment?: sulfamethoxazole (SMX) resistance genes among the bacterial community in water environment of Metro-Manila, Philippines

    Science.gov (United States)

    Suzuki, Satoru; Ogo, Mitsuko; Miller, Todd W.; Shimizu, Akiko; Takada, Hideshige; Siringan, Maria Auxilia T.

    2013-01-01

    Recent evidence has shown that antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are ubiquitous in natural environments, including sites considered pristine. To understand the origin of ARGs and their dynamics, we must first define their actual presence in the natural bacterial assemblage. Here we found varying distribution profiles of sul genes in “colony forming bacterial assemblages” and “natural bacterial assemblages.” Our monitoring for antibiotic contamination revealed that sulfamethoxazole (SMX) is a major contaminant in aquatic environments of Metro-Manila, which would have been derived from human and animal use, and subsequently decreased through the process of outflow from source to the sea. The SMX-resistant bacterial rate evaluated by the colony forming unit showed 10 to 86% of the total colony numbers showed higher rates from freshwater sites compared to marine sites. When sul genes were quantified by qPCR, colony-forming bacteria conveyed sul1 and sul2 genes in freshwater and seawater (10−5–10−2 copy/16S) but not sul3. Among the natural bacterial assemblage, all sul1, sul2, and sul3 were detected (10−5–10−3 copy/16S), whereas all sul genes were at an almost non-detectable level in the freshwater assemblage. This study suggests that sul1 and sul2 are main sul genes in culturable bacteria, whereas sul3 is conveyed by non-culturable bacteria in the sea. As a result marine bacteria possess sul1, sul2 and sul3 genes in the marine environment. PMID:23641240

  2. Who Possesses Drug Resistance Genes in the Aquatic Environment? : Sulfamethoxazole (SMX Resistance Genes among the Bacterial Community in Water Environment of Metro-Manila, Philippines

    Directory of Open Access Journals (Sweden)

    Satoru eSuzuki

    2013-04-01

    Full Text Available Recent evidence has shown that antibiotic resistant bacteria (ARB and antibiotic resistance genes (ARG are ubiquitous in natural environments, including sites considered pristine. To understand the origin of ARGs and their dynamics, we must first define their actual presence in the natural bacterial assemblage. Here we found varying distribution profiles of sul genes in colony forming bacterial assemblages and natural bacterial assemblages. Our monitoring for antibiotic contamination revealed that sulfamethoxazole (SMX is a major contaminant in aquatic environments of Metro-Manila, which would have been derived from human and animal use, and subsequently decreased through the process of outflow from source to the sea. The SMX-resistant bacterial rate evaluated by the colony forming unit showed 10 to 86 % of the total colony numbers showed higher rates from freshwater sites compared to marine sites. When sul genes were quantified by qPCR, colony-forming bacteria conveyed sul1 and sul2 genes in freshwater and seawater (10-5-10-2 copy/16S but not sul3. Among the natural bacterial assemblage, all sul1, sul2 and sul3 were detected (10-5-10-3 copy/16S, whereas all sul genes were at an almost non-detectable level in the freshwater assemblage. This study suggests that sul1 and sul2 are main sul genes in culturable bacteria, whereas sul3 is conveyed by non-culturable bacteria in the sea. As a result marine bacteria possess sul1, sul2 and sul3 genes in the marine environment.

  3. Prevalence of antimicrobial resistance among bacterial pathogens isolated from cattle in different European countries: 2002–2004

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    Stärk Katharina

    2008-07-01

    Full Text Available Abstract Background The project "Antibiotic resistance in bacteria of animal origin – II" (ARBAO-II was funded by the European Union (FAIR5-QLK2-2002-01146 for the period 2003–2005, with the aim to establish a continuous monitoring of antimicrobial susceptibility among veterinary laboratories in European countries based on validated and harmonised methodologies. Available summary data of the susceptibility testing of the bacterial pathogens from the different laboratories were collected. Method Antimicrobial susceptibility data for several bovine pathogens were obtained over a three year period (2002–2004. Each year the participating laboratories were requested to fill in excel-file templates with national summary data on the occurrence of antimicrobial resistance from different bacterial species. A proficiency test (EQAS – external quality assurance system for antimicrobial susceptibility testing was conducted each year to test the accuracy of antimicrobial susceptibility testing in the participating laboratories. The data from this testing demonstrated that for the species included in the EQAS the results are comparable between countries. Results Data from 25,241 isolates were collected from 13 European countries. For Staphylococcus aureus from bovine mastitis major differences were apparent in the occurrence of resistance between countries and between the different antimicrobial agents tested. The highest frequency of resistance was observed for penicillin. For Mannheimia haemolytica resistance to ampicillin, tetracycline and trimethoprim/sulphonamide were observed in France, the Netherlands and Portugal. All isolates of Pasteurella multocida isolated in Finland and most of those from Denmark, England (and Wales, Italy and Sweden were susceptible to the majority of the antimicrobials. Streptococcus dysgalactiae and Streptococcus uberis isolates from Sweden were fully susceptible. For the other countries some resistance was observed to

  4. Transfer of bacterial blight resistance from Oryza meyeriana to O.Sativa L.by asymmetric somatic hybridization

    Institute of Scientific and Technical Information of China (English)

    ZHU Yongsheng; CHEN Baotang; YU Shunwu; ZHANG Duanpin; ZHANG Xueqin; YAN Qiusheng

    2004-01-01

    Asymmetric somatic hybrid plants were produced between cultivated rice (Oryza sativa L.) and wild species [O. Meyeriana (Zoll. etMor, exSteud.)] with high resistance to rice bacterial blight. X-ray-irradiated protoplasts of the wild species were used as donor and chemically fused with iodoacetamide-inactivated protoplasts of rice cv. 02428to produce hybrids. Seventy-two plants were regenerated from 623 calli based on metabolic complementation. The morphological characters of the plants closely resembled that of the rice. Simple sequence repeats were employed to identify their hybridity. Cytological analysis of root-tips revealed that their chromosome number varied in the range of 27-38. The somatic hybrids were inoculated with strains of Xanthamonas oryzae pv. Oryzae at adult growth stage and demonstrated the resistance to bacterial blight introgression from the O. Meyeriana.

  5. Cloning of a peroxidase gene from cassava with potential as a molecular marker for resistance to bacterial blight

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    Pereira Luiz Filipe

    2003-01-01

    Full Text Available Cassava bacterial blight (CBB, caused by Xanthomonas axonopodis pv. manihotis, is considered one of the most important bacterial diseases of cassava (Manihot esculenta Crantz. In order to characterize the cassava genes involved in resistance to this disease, a genomic clone of a cationic peroxidase gene, MEPX1, was isolated by PCR from cassava cultivar MCOL 22. The DNA sequence of MEPX1 showed high homology with other plant peroxidase genes and contained a large intron typical of peroxidase genes. The predicted translation product showed a heme-ligand motif, also a characteristic of peroxidases, as well as phosphorylation, myristoylation and glycosylation sites. The amino acid sequence had 75 % homology with two Arabidopsis thaliana peroxidases. A Southern blot of 17 cassava cultivars, probed with MEPX1, showed multiple hybridization bands. Polymorphisms between cultivars generally reflected geographic origin, but there was also an association with resistance to CBB, indicating that MEPX1 could be a potentially useful marker for this trait.

  6. Role of acute-phase proteins in interleukin-1-induced nonspecific resistance to bacterial infections in mice.

    OpenAIRE

    Vogels, M.T.E.; L. Cantoni; Carelli, M.; Sironi, M; Ghezzi, P; van der Meer, J. W M

    1993-01-01

    Treatment with a single low dose (80 to 800 ng) of interleukin-1 (IL-1) 24 h before a lethal bacterial challenge of granulocytopenic and normal mice enhances nonspecific resistance. Since IL-1 induces secretion of acute-phase proteins, liver proteins which possess several detoxifying effects, we investigated the role of these proteins in the IL-1-induced protection. Inhibition of liver protein synthesis with D-galactosamine (GALN) completely inhibited the IL-1-induced synthesis of acute-phase...

  7. Comparative analysis of bacterial community and antibiotic-resistant strains in different developmental stages of the housefly (Musca domestica).

    Science.gov (United States)

    Wei, Ting; Hu, Jun; Miyanaga, Kazuhiko; Tanji, Yasunori

    2013-02-01

    The housefly (Musca domestica) is an important host for a variety of bacteria, including some pathogenic and antibiotic-resistant strains. To further investigate the relationship between the housefly and the bacteria it harbors, it is necessary to understand the fate of microorganisms during the larval metamorphosis. The major bacterial communities in three developmental stages of the housefly (maggot, pupa, and adult fly) were investigated by a culture-independent method, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis of 16S rRNA genes. The bacteria that were identified using DGGE analysis spanned phyla Proteobacteria, Firmicutes, and Bacteroidetes. Changes in the predominant genera were observed during the housefly development. Bacteroides, Koukoulia, and Schineria were detected in maggots, Neisseria in pupae, and Macrococcus, Lactococcus, and Kurthia in adult flies. Antibiotic-resistant bacteria were screened using a selective medium and tested for antibiotic susceptibility. Most resistant isolates from maggots and pupae were classified as Proteus spp., while those from adult flies were much more diverse and spanned 12 genera. Among 20 tested strains across the three stages, 18 were resistant to at least two antibiotics. Overall, we demonstrated that there are changes in the major bacterial communities and antibiotic-resistant strains as the housefly develops. PMID:22526786

  8. Comparative analysis of bacterial community and antibiotic-resistant strains in different developmental stages of the housefly (Musca domestica).

    Science.gov (United States)

    Wei, Ting; Hu, Jun; Miyanaga, Kazuhiko; Tanji, Yasunori

    2013-02-01

    The housefly (Musca domestica) is an important host for a variety of bacteria, including some pathogenic and antibiotic-resistant strains. To further investigate the relationship between the housefly and the bacteria it harbors, it is necessary to understand the fate of microorganisms during the larval metamorphosis. The major bacterial communities in three developmental stages of the housefly (maggot, pupa, and adult fly) were investigated by a culture-independent method, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis of 16S rRNA genes. The bacteria that were identified using DGGE analysis spanned phyla Proteobacteria, Firmicutes, and Bacteroidetes. Changes in the predominant genera were observed during the housefly development. Bacteroides, Koukoulia, and Schineria were detected in maggots, Neisseria in pupae, and Macrococcus, Lactococcus, and Kurthia in adult flies. Antibiotic-resistant bacteria were screened using a selective medium and tested for antibiotic susceptibility. Most resistant isolates from maggots and pupae were classified as Proteus spp., while those from adult flies were much more diverse and spanned 12 genera. Among 20 tested strains across the three stages, 18 were resistant to at least two antibiotics. Overall, we demonstrated that there are changes in the major bacterial communities and antibiotic-resistant strains as the housefly develops.

  9. Risk Factors and Scoring System for Predicting Bacterial Resistance to Cefepime as Used Empirically in Haematology Wards

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    Hicham El Maaroufi

    2015-01-01

    Full Text Available Objectives. Bacterial resistance is of growing concern in haematology wards. As the inappropriate administration of empirical antibacterial may alter survival, we studied risk factors for resistance to our usual empirical first-line antibacterial therapy, cefepime. Methods. We retrospectively studied 103 first episodes of bacteraemia recorded in our haematology department over 2.5 years. Risk factors for cefepime-resistance were identified by multivariate logistic regression with backward selection (P<0.05. A scoring system for predicting cefepime-resistance was built on independent factor, with an internal validation by the bootstrap resampling technique. Results. 38 (37% episodes were due to Gram-negative bacteria. Fifty (49% were due to bacteria resistant to cefepime. Cefepime resistance was significantly associated with a decreased survival at day 30 (P<0.05. Three risk factors were independently associated with cefepime-resistance: acute lymphoblastic leukaemia; ≥18 days since hospital admission; and receipt of any β-lactam in the last month. Patients with ≥2 of these risk factors had a probability of 86% (CI 95%, 25 to 100% to carry a cefepime-resistant strain. Conclusion. Using our scoring system should reduce the indication of very broad antibacterial regimens in the empirical, first-line treatment of febrile hematology patients in more than 80% of the cases.

  10. Sludge as a potential important source of antibiotic resistance genes in both the bacterial and bacteriophage fractions.

    Science.gov (United States)

    Calero-Cáceres, William; Melgarejo, Ana; Colomer-Lluch, Marta; Stoll, Claudia; Lucena, Francisco; Jofre, Juan; Muniesa, Maite

    2014-07-01

    The emergence and prevalence of antibiotic resistance genes (ARGs) in the environment is a serious global health concern. ARGs found in bacteria can become mobilized in bacteriophage particles in the environment. Sludge derived from secondary treatment in wastewater treatment plants (WWTPs) constitutes a concentrated pool of bacteria and phages that are removed during the treatment process. This study evaluates the prevalence of ARGs in the bacterial and phage fractions of anaerobic digested sludge; five ARGs (blaTEM, blaCTX-M, qnrA, qnrS, and sul1) are quantified by qPCR. Comparison between the wastewater and sludge revealed a shift in the prevalence of ARGs (blaTEM and sul1 became more prevalent in sludge), suggesting there is a change in the bacterial and phage populations from wastewater to those selected during the secondary treatment and the later anaerobic mesophilic digestion of the sludge. ARGs densities were higher in the bacterial than in the phage fraction, with high densities in both fractions; particularly for blaTEM and sul1 (5 and 8 log10 gene copies (GC)/g, respectively, in bacterial DNA; 5.5 and 4.4 log10 GC/g, respectively, in phage DNA). These results question the potential agricultural uses of treated sludge, as it could contribute to the spread of ARGs in the environment and have an impact on the bacterial communities of the receiving ecosystem.

  11. Exploring the Medicinal Potential of the Fruit Bodies of Oyster Mushroom, Pleurotus ostreatus (Agaricomycetes), against Multidrug-Resistant Bacterial Isolates.

    Science.gov (United States)

    Skariyachan, Sinosh; Prasanna, Apoorva; Manjunath, Sirisha P; Karanth, Soujanya S; Nazre, Ambika

    2016-01-01

    Bacterial resistance to present-generation antibiotics is increasing drastically, which has become a major public health concern. The present study focuses on demonstrating the antimicrobial potential of fruit bodies of the culinary/medicinal oyster mushroom Pleurotus ostreatus against clinical pathogens. Five bacterial isolates were collected from Sagar Hospital in Bangalore, India. The collected strains were grown on selective and differential media and antibiotic susceptibility testing was applied using 48 antibiotics by disc diffusion assay. The antibacterial efficiency of the mushroom extract against clinical pathogens, which were found to be multidrug resistant (MDR) to most of the tested antibiotics, was studied. The yield of cultivated mushrooms was evident at moist, cooler, and humid conditions. The clinical isolates of Staphylococcus aureus, Salmonella typhi, Acinetobacter sp., Proteus mirabilis, and Proteus spp. were found to be MDR to β-lactam, fluoroquinolones, sulfonamides, third- and fourth-generation cephalosporins, aminoglycosides, macrolides, tetracyclines, and carbapenems. The methanolic extracts of mushroom fruit bodies were found to be more effective than present-generation antibiotics against methicillin- and vancomycin- resistant S. aureus, S. typhi, Acinetobacter sp., and P. mirabilis at a concentration ranging from 50 to 100 µg/disc or 50 to 100 µL/well. The current study suggests that the methanolic extract of P. ostreatus can be used as a promising antibacterial agent against MDR bacterial pathogens. PMID:27481158

  12. TaCPK2-A, a calcium-dependent protein kinase gene that is required for wheat powdery mildew resistance enhances bacterial blight resistance in transgenic rice.

    Science.gov (United States)

    Geng, Shuaifeng; Li, Aili; Tang, Lichuan; Yin, Lingjie; Wu, Liang; Lei, Cailin; Guo, Xiuping; Zhang, Xin; Jiang, Guanghuai; Zhai, Wenxue; Wei, Yuming; Zheng, Youliang; Lan, Xiujin; Mao, Long

    2013-08-01

    Calcium-dependent protein kinases (CPKs) are important Ca2+ signalling components involved in complex immune and stress signalling networks; but the knowledge of CPK gene functions in the hexaploid wheat is limited. Previously, TaCPK2 was shown to be inducible by powdery mildew (Blumeria graminis tritici, Bgt) infection in wheat. Here, its functions in disease resistance are characterized further. This study shows the presence of defence-response and cold-response cis-elements on the promoters of the A subgenome homoeologue (TaCPK2-A) and D subgenome homoeologue (TaCPK2-D), respectively. Their expression patterns were then confirmed by quantitative real-time PCR (qRT-PCR) using genome-specific primers, where TaCPK2-A was induced by Bgt treatment while TaCPK2-D mainly responded to cold treatment. Downregulation of TaCPK2-A by virus-induced gene silencing (VIGS) causes loss of resistance to Bgt in resistant wheat lines, indicating that TaCPK2-A is required for powdery mildew resistance. Furthermore, overexpression of TaCPK2-A in rice enhanced bacterial blight (Xanthomonas oryzae pv. oryzae, Xoo) resistance. qRT-PCR analysis showed that overexpression of TaCPK2-A in rice promoted the expression of OsWRKY45-1, a transcription factor involved in both fungal and bacterial resistance by regulating jasmonic acid and salicylic acid signalling genes. The opposite effect was found in wheat TaCPK2-A VIGS plants, where the homologue of OsWRKY45-1 was significantly repressed. These data suggest that modulation of WRKY45-1 and associated defence-response genes by CPK2 genes may be the common mechanism for multiple disease resistance in grass species, which may have undergone subfunctionalization in promoters before the formation of hexaploid wheat. PMID:23918959

  13. Association mapping of common bacterial blight resistance QTL in Ontario bean breeding populations

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    Navabi Alireza

    2011-03-01

    Full Text Available Abstract Background Common bacterial blight (CBB, incited by Xanthomonas axonopodis pv. phaseoli (Xap, is a major yield-limiting factor of common bean (Phaseolus vulgaris L. production around the world. Host resistance is practically the most effective and environmentally-sound approach to control CBB. Unlike conventional QTL discovery strategies, in which bi-parental populations (F2, RIL, or DH need to be developed, association mapping-based strategies can use plant breeding populations to synchronize QTL discovery and cultivar development. Results A population of 469 dry bean lines of different market classes representing plant materials routinely developed in a bean breeding program were used. Of them, 395 lines were evaluated for CBB resistance at 14 and 21 DAI (Days After Inoculation in the summer of 2009 in an artificially inoculated CBB nursery in south-western Ontario. All lines were genotyped using 132 SNPs (Single Nucleotide Polymorphisms evenly distributed across the genome. Of the 132 SNPs, 26 SNPs had more than 20% missing data, 12 SNPs were monomorphic, and 17 SNPs had a MAF (Minor Allelic Frequency of less than 0.20, therefore only 75 SNPs were used for association study, based on one SNP per locus. The best possible population structure was to assign 36% and 64% of the lines into Andean and Mesoamerican subgroups, respectively. Kinship analysis also revealed complex familial relationships among all lines, which corresponds with the known pedigree history. MLM (Mixed Linear Model analysis, including population structure and kinship, was used to discover marker-trait associations. Eighteen and 22 markers were significantly associated with CBB rating at 14 and 21 DAI, respectively. Fourteen markers were significant for both dates and the markers UBC420, SU91, g321, g471, and g796 were highly significant (p ≤ 0.001. Furthermore, 12 significant SNP markers were co-localized with or close to the CBB-QTLs identified previously in bi

  14. Defending the fort: a role for defensin-2 in limiting Rickettsia montanensis infection of Dermacentor variabilis.

    Science.gov (United States)

    Pelc, R S; McClure, J C; Sears, K T; Chung, A; Rahman, M S; Ceraul, S M

    2014-08-01

    The importance of tick defensins is evidenced by their expression in a wide variety of tick tissues and prevalence across many tick genera. To date, the functional and biological significance of defensin-2 as a rickettsiastatic or rickettsiacidal antimicrobial peptide has not been addressed. In a previous study, defensin-2 transcription was shown to increase in Dermacentor variabilis ticks challenged with Rickettsia montanensis. In the present study, the hypothesis that defensin-2 is functional as a rickettsiastatic and/or rickettsiacidal antimicrobial peptide is tested. We show that defensin-2 plays a role in reducing burden after acquisition of Rickettsia montanensis through capillary feeding. Moreover, defensin-2 is shown to associate with R. montanensis in vitro and in vivo, causing cytoplasmic leakiness.

  15. Exposure of the grass shrimp, Palaemonetes pugio, to antimicrobial compounds affects associated Vibrio bacterial density and development of antibiotic resistance.

    Science.gov (United States)

    DeLorenzo, M E; Brooker, J; Chung, K W; Kelly, M; Martinez, J; Moore, J G; Thomas, M

    2016-04-01

    Antimicrobial compounds are widespread, emerging contaminants in the aquatic environment and may threaten ecosystem and human health. This study characterized effects of antimicrobial compounds common to human and veterinary medicine, aquaculture, and consumer personal care products [erythromycin (ERY), sulfamethoxazole (SMX), oxytetracycline (OTC), and triclosan (TCS)] in the grass shrimp Palaemonetes pugio. The effects of antimicrobial treatments on grass shrimp mortality and lipid peroxidation activity were measured. The effects of antimicrobial treatments on the bacterial community of the shrimp were then assessed by measuring Vibrio density and testing bacterial isolates for antibiotic resistance. TCS (0.33 mg/L) increased shrimp mortality by 37% and increased lipid peroxidation activity by 63%. A mixture of 0.33 mg/L TCS and 60 mg/L SMX caused a 47% increase in shrimp mortality and an 88% increase in lipid peroxidation activity. Exposure to SMX (30 mg/L or 60 mg/L) alone and to a mixture of SMX/ERY/OTC did not significantly affect shrimp survival or lipid peroxidation activity. Shrimp exposure to 0.33 mg/L TCS increased Vibrio density 350% as compared to the control whereas SMX, the SMX/TCS mixture, and the mixture of SMX/ERY/OTC decreased Vibrio density 78-94%. Increased Vibrio antibiotic resistance was observed for all shrimp antimicrobial treatments except for the mixture of SMX/ERY/OTC. Approximately 87% of grass shrimp Vibrio isolates displayed resistance to TCS in the control treatment suggesting a high level of TCS resistance in environmental Vibrio populations. The presence of TCS in coastal waters may preferentially increase the resistance and abundance of pathogenic bacteria. These results indicate the need for further study into the potential interactions between antimicrobials, aquatic organisms, and associated bacterial communities.

  16. Bacterial profile and patterns of antimicrobial drug resistance in intra-abdominal infections: Current experience in a teaching hospital

    Directory of Open Access Journals (Sweden)

    Neetu Shree

    2013-01-01

    Full Text Available Context: Bacterial isolates from intra-abdominal infections, in particular, peritonitis and their unpredictable antimicrobial resistance patterns, continue to be a matter of concern not only globally but regionally too. Aim: An attempt in the present study was made to study the patterns of drug resistance in bacterial isolates, especially gram negative bacilli in intra-abdominal infections (IAI in our hospital. Materials and Methods: From 100 cases of peritonitis, identification of isolates was done as per recommended methods. Antimicrobial susceptibility and extended-spectrum beta-lactamase (ESBL testing were performed following the CLSI guidelines. Results: A total of 133 clinical isolates were obtained, of which 108 were aerobes and 22 anaerobes. Fungal isolates were recovered in only three cases. Escherichia coli (47/108 emerged as the most predominant pathogen followed by Klebsiella spp. (27/108, while Bacteroides fragilis emerged as the predominant anaerobe (12/22. Among coliforms, 61.7% E. coli and 74.1% Klebsiella spp. were ESBL positive. A high level of resistance was observed for beta lactams, ciprofloxacin, amikacin, and ertapenem. Ertapenem resistance (30-41% seen in coliforms, appears as an important issue. Imipenem, tigecycline, and colistin were the most consistently active agents tested against ESBL producers. Conclusion: Drug resistance continues to be a major concern in isolates from intra-abdominal infections. Treatment with appropriate antibiotics preceded by antimicrobial resistance testing aided by early diagnosis, adequate surgical management, and knowledge of antibiotic - resistant organisms appears effective in reducing morbidity and mortality in IAI cases.

  17. Expression of an evolved engineered variant of a bacterial glycine oxidase leads to glyphosate resistance in alfalfa.

    Science.gov (United States)

    Nicolia, A; Ferradini, N; Molla, G; Biagetti, E; Pollegioni, L; Veronesi, F; Rosellini, D

    2014-08-20

    The main strategy for resistance to the herbicide glyphosate in plants is the overexpression of an herbicide insensitive, bacterial 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). A glyphosate resistance strategy based on the ability to degrade the herbicide can be useful to reduce glyphosate phytotoxicity to the crops. Here we present the characterization of glyphosate resistance in transgenic alfalfa (Medicago sativa L.) expressing a plant-optimized variant of glycine oxidase (GO) from Bacillus subtilis, evolved in vitro by a protein engineering approach to efficiently degrade glyphosate. Two constructs were used, one with (GO(TP+)) and one without (GO(TP-)) the pea rbcS plastid transit peptide. Molecular and biochemical analyses confirmed the stable integration of the transgene and the correct localization of the plastid-imported GO protein. Transgenic alfalfa plants were tested for glyphosate resistance both in vitro and in vivo. Two GO(TP+) lines showed moderate resistance to the herbicide in both conditions. Optimization of expression of this GO variant may allow to attain sufficient field resistance to glyphosate herbicides, thus providing a resistance strategy based on herbicide degradation.

  18. Root-associated bacterial endophytes from Ralstonia solanacearum resistant and susceptible tomato cultivars and their pathogen antagonistic effects

    Directory of Open Access Journals (Sweden)

    Reshmi eUpreti

    2015-04-01

    Full Text Available This study was undertaken to assess if the root-associated native bacterial endophytes in tomato have any bearing in governing the host resistance to the wilt pathogen Ralstonia solanacearum. Internal colonization of roots by bacterial endophytes was confirmed through confocal imaging after SYTO-9 staining. Endophytes were isolated from surface-sterilized roots of 4-week old seedlings of known wilt resistant (R tomato cultivar Arka Abha and susceptible (S cv. Arka Vikas on nutrient agar after plating the tissue homogenate. Arka Abha displayed more diversity with nine distinct organisms while Arka Vikas showed five species with two common organisms (Pseudomonas oleovorans and Agrobacterium tumefaciens. Screening for general indicators of biocontrol potential showed more isolates from Arka Abha positive for siderophore, HCN and antibiotic biosynthesis than from Arka Vikas. Direct challenge against the pathogen indicated strong antagonism by three Arka Abha isolates (P. oleovorans, Pantoea ananatis and Enterobacter cloacae and moderate activity by three others, while just one isolate from Arka Vikas (P. oleovorans showed strong antagonism. Validation for the presence of bacterial endophytes on three R cultivars (Arka Alok, Arka Ananya, Arka Samrat showed 8-9 antagonistic bacteria in them in comparison with four species in the three S cultivars (Arka Ashish, Arka Meghali, Arka Saurabhav. Altogether 34 isolates belonging to five classes, 16 genera and 27 species with 23 of them exhibiting pathogen antagonism were isolated from the four R cultivars against 17 isolates under three classes, seven genera and 13 species from the four S cultivars with eight isolates displaying antagonistic effects. The prevalence of higher endophytic bacterial diversity and more antagonistic organisms associated with the seedling roots of resistant cultivars over susceptible genotypes suggest a possible role by the root-associated endophytes in natural defense against the

  19. Bacterial flora and antibiotic resistance from eggs of green turtles Chelonia mydas: an indication of polluted effluents.

    Science.gov (United States)

    Al-Bahry, Saif; Mahmoud, Ibrahim; Elshafie, Abdulkader; Al-Harthy, Asila; Al-Ghafri, Sabha; Al-Amri, Issa; Alkindi, Abdulaziz

    2009-05-01

    Sea turtles migrate to various habitats where they can be exposed to different pollutants. Bacteria were collected from turtle eggs and their resistance to antibiotics was used as pollutant bio-indicators of contaminated effluents. Eggs were collected randomly from turtles when they were laying their eggs. A total of 90 eggs were collected and placed into sterile plastic bags (3 eggs/turtle) during June-December of 2003. The bacteria located in the eggshell, albumen and yolk were examined, and 42% of the eggs were contaminated with 10 genera of bacteria. Pseudomonas spp. were the most frequent isolates. The albumen was found to be the part of the egg to be the least contaminated by bacterial infection. Bacterial isolates tested with 14 antibiotics showed variations in resistance. Resistance to ampicillin was the highest. The presence of antibiotic resistant bacteria in eggs indicates that the green turtle populations were subjected to polluted effluents during some of their migratory routes and feeding habitats. Scanning electron microscopy revealed that Salmonella typhimurium penetrated all eggshell layers.

  20. Bacterial flora and antibiotic resistance from eggs of green turtles Chelonia mydas: An indication of polluted effluents

    International Nuclear Information System (INIS)

    Sea turtles migrate to various habitats where they can be exposed to different pollutants. Bacteria were collected from turtle eggs and their resistance to antibiotics was used as pollutant bio-indicators of contaminated effluents. Eggs were collected randomly from turtles when they were laying their eggs. A total of 90 eggs were collected and placed into sterile plastic bags (3 eggs/turtle) during June-December of 2003. The bacteria located in the eggshell, albumen and yolk were examined, and 42% of the eggs were contaminated with 10 genera of bacteria. Pseudomonas spp. were the most frequent isolates. The albumen was found to be the part of the egg to be the least contaminated by bacterial infection. Bacterial isolates tested with 14 antibiotics showed variations in resistance. Resistance to ampicillin was the highest. The presence of antibiotic resistant bacteria in eggs indicates that the green turtle populations were subjected to polluted effluents during some of their migratory routes and feeding habitats. Scanning electron microscopy revealed that Salmonella typhimurium penetrated all eggshell layers.

  1. Expression and antimicrobial function of beta-defensin 1 in the lower urinary tract.

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    Brian Becknell

    Full Text Available Beta defensins (BDs are cationic peptides with antimicrobial activity that defend epithelial surfaces including the skin, gastrointestinal, and respiratory tracts. However, BD expression and function in the urinary tract are incompletely characterized. The purpose of this study was to describe Beta Defensin-1 (BD-1 expression in the lower urinary tract, regulation by cystitis, and antimicrobial activity toward uropathogenic Escherichia coli (UPEC in vivo. Human DEFB1 and orthologous mouse Defb1 mRNA are detectable in bladder and ureter homogenates, and human BD-1 protein localizes to the urothelium. To determine the relevance of BD-1 to lower urinary tract defense in vivo, we evaluated clearance of UPEC by Defb1 knockout (Defb1(-/- mice. At 6, 18, and 48 hours following transurethral UPEC inoculation, no significant differences were observed in bacterial burden in bladders or kidneys of Defb1(-/- and wild type C57BL/6 mice. In wild type mice, bladder Defb1 mRNA levels decreased as early as two hours post-infection and reached a nadir by six hours. RT-PCR profiling of BDs identified expression of Defb3 and Defb14 mRNA in murine bladder and ureter, which encode for mBD-3 and mBD-14 protein, respectively. MBD-14 protein expression was observed in bladder urothelium following UPEC infection, and both mBD-3 and mBD-14 displayed dose-dependent bactericidal activity toward UPEC in vitro. Thus, whereas mBD-1 deficiency does not alter bladder UPEC burden in vivo, we have identified mBD-3 and mBD-14 as potential mediators of mucosal immunity in the lower urinary tract.

  2. Identification and molecular characterization of defensin gene from the ant Formica aquilonia.

    Science.gov (United States)

    Viljakainen, L; Pamilo, P

    2005-08-01

    The effectors of the insect immune system are antimicrobial peptides. With the aim of studying the evolution of immune system genes, we identified a gene encoding the antimicrobial peptide defensin from a social insect, the wood ant Formica aquilonia. In this article we report the identification and characterization of this gene. We also compare the ant defensin gene structure to that previously obtained from two other hymenopteran species, the honeybee, Apis mellifera, and the bumblebee, Bombus ignitus. The ant defensin gene structure differs from both of these bee defensins with respect to the number and length of introns and exons. PMID:16033427

  3. Molecular and Functional Analysis of Human β-Defensin 3 Action at Melanocortin Receptors

    OpenAIRE

    Nix, Matthew A.; Kaelin, Christopher B.; Ta, Tina; Weis, Allison; Morton, Gregory J.; Barsh, Gregory S.; Millhauser, Glenn L.

    2013-01-01

    The β-defensins are a class of small, cationic proteins first recognized as antimicrobial components of the innate and adaptive immune system. More recently, one of the major β-defensins produced in skin, β-defensin 3, has been discovered to function as a melanocortin receptor ligand in vivo and in vitro, but its biophysical and pharmacological basis of action has been enigmatic. Here we report functional and biochemical studies focused on human β-defensin 3 (HBD3) and melanocortin receptors ...

  4. Resistance to ketolide antibiotics by coordinated expression of rRNA methyltransferases in a bacterial producer of natural ketolides

    DEFF Research Database (Denmark)

    Almutairi, Mashal M; Park, Sung Ryeol; Rose, Simon;

    2015-01-01

    activation by ketolide antibiotics. The resistance genes and the induction mechanism remain fully functional when transferred to heterologous bacterial hosts. The anticipated wide use of ketolide antibiotics could promote horizontal transfer of these highly efficient resistance genes to pathogens. Taken......Ketolides are promising new antimicrobials effective against a broad range of Gram-positive pathogens, in part because of the low propensity of these drugs to trigger the expression of resistance genes. A natural ketolide pikromycin and a related compound methymycin are produced by Streptomyces...... venezuelae strain ATCC 15439. The producer avoids the inhibitory effects of its own antibiotics by expressing two paralogous rRNA methylase genes pikR1 and pikR2 with seemingly redundant functions. We show here that the PikR1 and PikR2 enzymes mono- and dimethylate, respectively, the N6 amino group in 23S r...

  5. Breeding Rice Restorer Lines with High Resistance to Bacterial Blight by Using Molecular Marker-Assisted Selection

    Institute of Scientific and Technical Information of China (English)

    DENG Qi-ming; WANG Shi-quan; ZHENG Ai-ping; ZHANG Hong-yu; LI Ping

    2006-01-01

    Two bacterial blight (BB) resistance genes, Xa21 and Xa4, from IRBB24 were introduced into hybrid rice restorer line Mianhui 725, which is highly susceptible to BB, by using hybridization and molecular marker-assisted selection technology. Four homologous restorer lines were obtained through testing the R target genes with molecular markers and analyzing parental genetic background. Inoculation of the four lines and their hybrids with the specific strains of Xanthomonas oryzae pv. oryzae, P1, P6 and seven representative strains of Chinese pathotype, C Ⅰ -CⅦ, showed that all of the four lines and their hybrids were highly resistant and presented broad resistance-spectrum to BB. The hybrids of G46A / R207-2 displayed good agronomic characters and high yield potential, and R207-2 was named Shuhui 207.

  6. Modification of β-Defensin-2 by Dicarbonyls Methylglyoxal and Glyoxal Inhibits Antibacterial and Chemotactic Function In Vitro.

    Directory of Open Access Journals (Sweden)

    Janna G Kiselar

    Full Text Available Beta-defensins (hBDs provide antimicrobial and chemotactic defense against bacterial, viral and fungal infections. Human β-defensin-2 (hBD-2 acts against gram-negative bacteria and chemoattracts immature dendritic cells, thus regulating innate and adaptive immunity. Immunosuppression due to hyperglycemia underlies chronic infection in Type 2 diabetes. Hyperglycemia also elevates production of dicarbonyls methylgloxal (MGO and glyoxal (GO.The effect of dicarbonyl on defensin peptide structure was tested by exposing recombinant hBD-2 (rhBD-2 to MGO or GO with subsequent analysis by MALDI-TOF MS and LC/MS/MS. Antimicrobial function of untreated rhBD-2 vs. rhBD-2 exposed to dicarbonyl against strains of both gram-negative and gram-positive bacteria in culture was determined by radial diffusion assay. The effect of dicarbonyl on rhBD-2 chemotactic function was determined by chemotaxis assay in CEM-SS cells.MGO or GO in vitro irreversibly adducts to the rhBD-2 peptide, and significantly reduces antimicrobial and chemotactic functions. Adducts derive from two arginine residues, Arg22 and Arg23 near the C-terminus, and the N-terminal glycine (Gly1. We show by radial diffusion testing on gram-negative E. coli and P. aeruginosa, and gram-positive S. aureus, and a chemotaxis assay for CEM-SS cells, that antimicrobial activity and chemotactic function of rhBD-2 are significantly reduced by MGO.Dicarbonyl modification of cationic antimicrobial peptides represents a potential link between hyperglycemia and the clinical manifestation of increased susceptibility to infection, protracted wound healing, and chronic inflammation in undiagnosed and uncontrolled Type 2 diabetes.

  7. A locked nucleic acid (LNA-based real-time PCR assay for the rapid detection of multiple bacterial antibiotic resistance genes directly from positive blood culture.

    Directory of Open Access Journals (Sweden)

    Lingxiang Zhu

    Full Text Available Bacterial strains resistant to various antibiotic drugs are frequently encountered in clinical infections, and the rapid identification of drug-resistant strains is highly essential for clinical treatment. We developed a locked nucleic acid (LNA-based quantitative real-time PCR (LNA-qPCR method for the rapid detection of 13 antibiotic resistance genes and successfully used it to distinguish drug-resistant bacterial strains from positive blood culture samples. A sequence-specific primer-probe set was designed, and the specificity of the assays was assessed using 27 ATCC bacterial strains and 77 negative blood culture samples. No cross-reaction was identified among bacterial strains and in negative samples, indicating 100% specificity. The sensitivity of the assays was determined by spiking each bacterial strain into negative blood samples, and the detection limit was 1-10 colony forming units (CFU per reaction. The LNA-qPCR assays were first applied to 72 clinical bacterial isolates for the identification of known drug resistance genes, and the results were verified by the direct sequencing of PCR products. Finally, the LNA-qPCR assays were used for the detection in 47 positive blood culture samples, 19 of which (40.4% were positive for antibiotic resistance genes, showing 91.5% consistency with phenotypic susceptibility results. In conclusion, LNA-qPCR is a reliable method for the rapid detection of bacterial antibiotic resistance genes and can be used as a supplement to phenotypic susceptibility testing for the early detection of antimicrobial resistance to allow the selection of appropriate antimicrobial treatment and to prevent the spread of resistant isolates.

  8. Antimicrobial-Resistant Bacterial Populations and Antimicrobial Resistance Genes Obtained from Environments Impacted by Livestock and Municipal Waste.

    Directory of Open Access Journals (Sweden)

    Getahun E Agga

    Full Text Available This study compared the populations of antimicrobial-resistant bacteria and the repertoire of antimicrobial resistance genes in four environments: effluent of three municipal wastewater treatment facilities, three cattle feedlot runoff catchment ponds, three swine waste lagoons, and two "low impact" environments (an urban lake and a relict prairie. Multiple liquid and solid samples were collected from each environment. The prevalences and concentrations of antimicrobial-resistant (AMR Gram-negative (Escherichia coli and Salmonella enterica and Gram-positive (enterococci bacteria were determined from individual samples (n = 174. The prevalences of 84 antimicrobial resistance genes in metagenomic DNA isolated from samples pooled (n = 44 by collection date, location, and sample type were determined. The prevalences and concentrations of AMR E. coli and Salmonella were similar among the livestock and municipal sample sources. The levels of erythromycin-resistant enterococci were significantly higher in liquid samples from cattle catchment ponds and swine waste lagoons than in liquid samples from municipal wastewater treatment facilities, but solid samples from these environments did not differ significantly. Similarly, trimethoprim/sulfamethoxazole-resistant E. coli concentrations were significantly higher in swine liquid than in municipal liquid samples, but there was no difference in solid samples. Multivariate analysis of the distribution of antimicrobial resistance genes using principal coordinate analysis showed distinct clustering of samples with livestock (cattle and swine, low impact environment and municipal samples forming three separate clusters. The numbers of class A beta-lactamase, class C beta-lactamase, and fluoroquinolone resistance genes detected were significantly higher (P < 0.05 in municipal samples than in cattle runoff or swine lagoon samples. In conclusion, we report that AMR is a very widespread phenomenon and that similar

  9. Prevalence of antibiotic resistance genes and bacterial community composition in a river influenced by a wastewater treatment plant.

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    Elisabet Marti

    Full Text Available Antibiotic resistance represents a global health problem, requiring better understanding of the ecology of antibiotic resistance genes (ARGs, their selection and their spread in the environment. Antibiotics are constantly released to the environment through wastewater treatment plant (WWTP effluents. We investigated, therefore, the effect of these discharges on the prevalence of ARGs and bacterial community composition in biofilm and sediment samples of a receiving river. We used culture-independent approaches such as quantitative PCR to determine the prevalence of eleven ARGs and 16S rRNA gene-based pyrosequencing to examine the composition of bacterial communities. Concentration of antibiotics in WWTP influent and effluent were also determined. ARGs such as qnrS, bla TEM, bla CTX-M, bla SHV, erm(B, sul(I, sul(II, tet(O and tet(W were detected in all biofilm and sediment samples analyzed. Moreover, we observed a significant increase in the relative abundance of ARGs in biofilm samples collected downstream of the WWTP discharge. We also found significant differences with respect to community structure and composition between upstream and downstream samples. Therefore, our results indicate that WWTP discharges may contribute to the spread of ARGs into the environment and may also impact on the bacterial communities of the receiving river.

  10. The two-component signal transduction system YvcPQ regulates the bacterial resistance to bacitracin in Bacillus thuringiensis.

    Science.gov (United States)

    Zhang, Shumeng; Li, Xinfeng; Wang, Xun; Li, Zhou; He, Jin

    2016-10-01

    YvcPQ is one of the two-component signal transduction systems that respond to specific stimuli and enable cells to adjust multiple cellular functions. It consists of a histidine kinase YvcQ and a response regulator YvcP. In this study, through searching the consensus sequence recognized by YvcP, we found four YvcP-binding motifs in the promoter regions of genes yvcR (BMB171_C4100), BMB171_C4385, kapD (BMB171_C4525) and BMB171_C4835 in Bacillus thuringiensis BMB171 which is a representative of Bacillus cereus group, and confirmed that these genes are regulated by YvcP. We compared the sequence of yvcPQ and its downstream genes in genus Bacillus, and found two different kinds of yvc locus, one was the yvcPQ-RS in B. subtilis species and the other was the yvcPQ-R-S1S2 in B. cereus group. Furthermore, we found that YvcP activates the transcription of yvcS1S2 (downstream of yvcR) to promote bacterial resistance to bacitracin and deletion of either yvcPQ operon or yvcS1S2 operon renders the bacterial cells more sensitive to bacitracin. This study enriched our understanding of both the YvcPQ's function and the mechanism of bacterial resistance to bacitracin.

  11. The population genetics of drug resistance evolution in natural populations of viral, bacterial and eukaryotic pathogens.

    Science.gov (United States)

    Wilson, Benjamin A; Garud, Nandita R; Feder, Alison F; Assaf, Zoe J; Pennings, Pleuni S

    2016-01-01

    Drug resistance is a costly consequence of pathogen evolution and a major concern in public health. In this review, we show how population genetics can be used to study the evolution of drug resistance and also how drug resistance evolution is informative as an evolutionary model system. We highlight five examples from diverse organisms with particular focus on: (i) identifying drug resistance loci in the malaria parasite Plasmodium falciparum using the genomic signatures of selective sweeps, (ii) determining the role of epistasis in drug resistance evolution in influenza, (iii) quantifying the role of standing genetic variation in the evolution of drug resistance in HIV, (iv) using drug resistance mutations to study clonal interference dynamics in tuberculosis and (v) analysing the population structure of the core and accessory genome of Staphylococcus aureus to understand the spread of methicillin resistance. Throughout this review, we discuss the uses of sequence data and population genetic theory in studying the evolution of drug resistance.

  12. Copper amendment of agricultural soil selects for bacterial antibiotic resistance in the field

    DEFF Research Database (Denmark)

    Berg, J.; Tom-Petersen, A.; Nybroe, O.

    2005-01-01

    Aims: The objective of this study was to determine whether Cu-amendment of field plots affects the frequency of Cu resistance, and antibiotic resistance patterns in indigenous soil bacteria. Methods and Results: Soil bacteria were isolated from untreated and Cu-amended field plots. Cu......-amendment significantly increased the frequency of Cu-resistant isolates. A panel of isolates were characterized by Gram-reaction, amplified ribosomal DNA restriction analysis and resistance profiling against seven antibiotics. More than 95% of the Cu-resistant isolates were Gram-negative. Cu-resistant Gram......-negative isolates had significantly higher incidence of resistance to ampicillin, sulphanilamide and multiple (greater than or equal to3) antibiotics than Cu-sensitive Gram-negative isolates. Furthermore, Cu-resistant Gram-negative isolates from Cu-contaminated plots had significantly higher incidence of resistance...

  13. Occurrence of Antibiotic Resistance Genes and Bacterial Markers in a Tropical River Receiving Hospital and Urban Wastewaters.

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    Naresh Devarajan

    Full Text Available The occurrence of emerging biological contaminants including antibiotic resistance genes (ARGs and Faecal Indicator Bacteria (FIB is still little investigated in developing countries under tropical conditions. In this study, the total bacterial load, the abundance of FIB (E. coli and Enterococcus spp. (ENT, Pseudomonas spp. and ARGs (blaTEM, blaCTX-M, blaSHV, blaNDM and aadA were quantified using quantitative PCR in the total DNA extracted from the sediments recovered from hospital outlet pipes (HOP and the Cauvery River Basin (CRB, Tiruchirappalli, Tamil Nadu, India. The abundance of bacterial marker genes were 120, 104 and 89 fold higher for the E. coli, Enterococcus spp. and Pseudomonas spp., respectively at HOP when compared with CRB. The ARGs aadA and blaTEM were most frequently detected in higher concentration than other ARGs at all the sampling sites. The ARGs blaSHV and blaNDM were identified in CRB sediments contaminated by hospital and urban wastewaters. The ARGs abundance strongly correlated (r ≥ 0.36, p < 0.05, n = 45 with total bacterial load and E. coli in the sediments, indicating a common origin and extant source of contamination. Tropical aquatic ecosystems receiving wastewaters can act as reservoir of ARGs, which could potentially be transferred to susceptible bacterial pathogens at these sites.

  14. Variable effects of oxytetracycline on antibiotic resistance gene abundance and the bacterial community during aerobic composting of cow manure.

    Science.gov (United States)

    Qian, Xun; Sun, Wei; Gu, Jie; Wang, Xiao-Juan; Sun, Jia-Jun; Yin, Ya-Nan; Duan, Man-Li

    2016-09-01

    Livestock manure is often subjected to aerobic composting but little is known about the variation in antibiotic resistance genes (ARGs) during the composting process under different concentrations of antibiotics. This study compared the effects of three concentrations of oxytetracycline (OTC; 10, 60, and 200mg/kg) on ARGs and the succession of the bacterial community during composting. Very similar trends were observed in the relative abundances (RAs) of each ARG among the OTC treatments and the control during composting. After composting, the RAs of tetC, tetX, sul1, sul2, and intI1 increased 2-43 times, whereas those of tetQ, tetM, and tetW declined by 44-99%. OTC addition significantly increased the absolute abundances and RAs of tetC and intI1, while 200mg/kg OTC also enhanced those of tetM, tetQ, and drfA7. The bacterial community could be grouped according to the composting time under different treatments. The highest concentration of OTC had a more persistent effect on the bacterial community. In the present study, the succession of the bacterial community appeared to have a greater influence on the variation of ARGs during composting than the presence of antibiotics. Aerobic composting was not effective in reducing most of the ARGs, and thus the compost product should be considered as an important reservoir for ARGs. PMID:27179201

  15. Plant Ribosomal Proteins, RPL12 and RPL19, Play a Role in Nonhost Disease Resistance against Bacterial Pathogens.

    Science.gov (United States)

    Nagaraj, Satish; Senthil-Kumar, Muthappa; Ramu, Vemanna S; Wang, Keri; Mysore, Kirankumar S

    2015-01-01

    Characterizing the molecular mechanism involved in nonhost disease resistance is important to understand the adaptations of plant-pathogen interactions. In this study, virus-induced gene silencing (VIGS)-based forward genetics screen was utilized to identify genes involved in nonhost resistance in Nicotiana benthamiana. Genes encoding ribosomal proteins, RPL12 and RPL19, were identified in the screening. These genes when silenced in N. benthamiana caused a delay in nonhost bacteria induced hypersensitive response (HR) with concurrent increase in nonhost bacterial multiplication. Arabidopsis mutants of AtRPL12 and AtRPL19 also compromised nonhost resistance. The studies on NbRPL12 and NbRPL19 double silenced plants suggested that both RPL12 and RPL19 act in the same pathway to confer nonhost resistance. Our work suggests a role for RPL12 and RPL19 in nonhost disease resistance in N. benthamiana and Arabidopsis. In addition, we show that these genes also play a minor role in basal resistance against virulent pathogens. PMID:26779226

  16. A new gene, developed through mutagenesis with thermal neutrons, for resistance of rice to bacterial leaf blight

    International Nuclear Information System (INIS)

    Dry seed lots of a rice variety, Harebare, susceptible to bacterial leaf blight (BLB), were treated with thermal neutrons with and without pre-treatment of the seeds by boron-enrichment, gamma-rays and nitroso-methyl-urea (NMU). The selections were made on M2-M3 materials by inoculation of Japanese BLB race III, with the result that several BLB resistant mutants to race III and the other differential races could be obtained. Mutagenic efficiency of thermal neutrons to the seeds without boron-enrichment for induction of BLB resistant mutants was found to be significantly higher than that of the other mutagens. Four mutant lines of all the selected ones were analyzed for genes for BLB resistance through cross tests between the mutants and the original variety. Harebare, indicating that the resistance in the mutants was conditioned by single recessive gene(s). The mutant designated 86M95 was especially noted for its gene conferring complete (or durable) resistance to multiple BLB races. The 86M95 mutant or the gene may be of practical value for breeding of rice for BLB resistance. (author)

  17. Selection on an antimicrobial peptide defensin in ants.

    Science.gov (United States)

    Viljakainen, Lumi; Pamilo, Pekka

    2008-12-01

    Ants live in crowded nests with interacting individuals, which makes them particularly prone to infectious diseases. The question is, how do ants cope with the increased risk of pathogen transmission due to sociality? We have studied the molecular evolution of defensin, a gene encoding an antimicrobial protein, in ants. Defensin sequences from several ant species were analyzed with maximum likelihood models of codon substitution to infer selection. Positive selection was detected in the mature region of defensin, whereas the signal and pro regions seem to be evolving neutrally. We also found a significantly higher rate of nonsynonymous substitutions in some phylogenetic lineages, as well as dN/dS >1, suggesting varying selection pressures in different lineages. Earlier studies on the molecular evolution of insect antimicrobial peptide genes have focused on termites and dipteran species, and detected positive selection only in duplicated termicin genes in termites. These findings, together with our present results, provide an indication that the immune systems of social insects (ants and termites) and dipteran insects may have responded differently to the selection pressure caused by microbial pathogens. PMID:18956133

  18. Antimicrobial-Resistant Bacterial Populations and Antimicrobial Resistance Genes Obtained from Environments Impacted by Livestock and Municipal Waste.

    Science.gov (United States)

    Agga, Getahun E; Arthur, Terrance M; Durso, Lisa M; Harhay, Dayna M; Schmidt, John W

    2015-01-01

    This study compared the populations of antimicrobial-resistant bacteria and the repertoire of antimicrobial resistance genes in four environments: effluent of three municipal wastewater treatment facilities, three cattle feedlot runoff catchment ponds, three swine waste lagoons, and two "low impact" environments (an urban lake and a relict prairie). Multiple liquid and solid samples were collected from each environment. The prevalences and concentrations of antimicrobial-resistant (AMR) Gram-negative (Escherichia coli and Salmonella enterica) and Gram-positive (enterococci) bacteria were determined from individual samples (n = 174). The prevalences of 84 antimicrobial resistance genes in metagenomic DNA isolated from samples pooled (n = 44) by collection date, location, and sample type were determined. The prevalences and concentrations of AMR E. coli and Salmonella were similar among the livestock and municipal sample sources. The levels of erythromycin-resistant enterococci were significantly higher in liquid samples from cattle catchment ponds and swine waste lagoons than in liquid samples from municipal wastewater treatment facilities, but solid samples from these environments did not differ significantly. Similarly, trimethoprim/sulfamethoxazole-resistant E. coli concentrations were significantly higher in swine liquid than in municipal liquid samples, but there was no difference in solid samples. Multivariate analysis of the distribution of antimicrobial resistance genes using principal coordinate analysis showed distinct clustering of samples with livestock (cattle and swine), low impact environment and municipal samples forming three separate clusters. The numbers of class A beta-lactamase, class C beta-lactamase, and fluoroquinolone resistance genes detected were significantly higher (P waste streams, but a higher diversity of antimicrobial resistance genes are present in treated human waste discharged from municipal wastewater treatment plants than in

  19. Characterization of different plasmid-borne dihydropteroate synthases mediating bacterial resistance to sulfonamides.

    OpenAIRE

    Swedberg, G; Sköld, O

    1980-01-01

    Plasmid-borne resistance to sulfonamides was studied in both newly isolated and earlier characterized R plasmids. Two different classes of drug-resistant dihydropteroate synthases were found to be responsible for most cases of plasmid-mediated sulfonamide resistance. The plasmid-coded enzymes could be completely separated from their chromosomal counterpart and also showed differences in heat stability and molecular size. The resistant and chromosomal enzymes could bind the normal substrate, p...

  20. Ciprofloxacin Affects Host Cells by Suppressing Expression of the Endogenous Antimicrobial Peptides Cathelicidins and Beta-Defensin-3 in Colon Epithelia

    Directory of Open Access Journals (Sweden)

    Protim Sarker

    2014-07-01

    Full Text Available Antibiotics exert several effects on host cells including regulation of immune components. Antimicrobial peptides (AMPs, e.g., cathelicidins and defensins display multiple functions in innate immunity. In colonic mucosa, cathelicidins are induced by butyrate, a bacterial fermentation product. Here, we investigated the effect of antibiotics on butyrate-induced expression of cathelicidins and beta-defensins in colon epithelial cells. Real-time PCR analysis revealed that ciprofloxacin and clindamycin reduce butyrate-induced transcription of the human cathelicidin LL-37 in the colonic epithelial cell line HT-29. Suppression of LL-37 peptide/protein by ciprofloxacin was confirmed by Western blot analysis. Immunohistochemical analysis demonstrated that ciprofloxacin suppresses the rabbit cathelicidin CAP-18 in rectal epithelia of healthy and butyrate-treated Shigella-infected rabbits. Ciprofloxacin also down-regulated butyrate-induced transcription of the human beta-defensin-3 in HT-29 cells. Microarray analysis of HT-29 cells revealed upregulation by butyrate with subsequent down-regulation by ciprofloxacin of additional genes encoding immune factors. Dephosphorylation of histone H3, an epigenetic event provided a possible mechanism of the suppressive effect of ciprofloxacin. Furthermore, LL-37 peptide inhibited Clostridium difficile growth in vitro. In conclusion, ciprofloxacin and clindamycin exert immunomodulatory function by down-regulating AMPs and other immune components in colonic epithelial cells. Suppression of AMPs may contribute to the overgrowth of C. difficile, causing antibiotic-associated diarrhea.

  1. Inducible expression of p50 from TMV for increased resistance to bacterial crown gall disease in tobacco.

    Science.gov (United States)

    Niemeyer, Julia; Ruhe, Jonas; Machens, Fabian; Stahl, Dietmar J; Hehl, Reinhard

    2014-01-01

    The dominant tobacco mosaic virus (TMV) resistance gene N induces a hypersensitive response upon TMV infection and protects tobacco against systemic spread of the virus. It has been proposed to change disease resistance specificity by reprogramming the expression of resistance genes or their corresponding avirulence genes. To reprogramme the resistance response of N towards bacterial pathogens, the helicase domain (p50) of the TMV replicase, the avirulence gene of N, was linked to synthetic promoters 4D and 2S2D harbouring elicitor-responsive cis-elements. These promoter::p50 constructs induce local necrotic lesions on NN tobacco plants in an Agrobacterium tumefaciens infiltration assay. A tobacco genotype void of N (nn) was transformed with the promoter::p50 constructs and subsequently crossed to NN plants. Nn F1 offspring selected for the T-DNA develop normally under sterile conditions. After transfer to soil, some of the F1 plants expressing the 2S2D::p50 constructs develop spontaneous necrosis. Transgenic Nn F1 plants with 4D::p50 and 2S2D::p50 expressing constructs upregulate p50 transcription and induce local necrotic lesions in an A. tumefaciens infiltration assay. When leaves and stems of Nn F1 offspring harbouring promoter::p50 constructs are infected with oncogenic A. tumefaciens C58, transgenic lines harbouring the 2S2D::p50 construct induce necrosis and completely lack tumor development. These results demonstrate a successful reprogramming of the viral N gene response against bacterial crown gall disease and highlight the importance of achieving tight regulation of avirulence gene expression and the control of necrosis in the presence of the corresponding resistance gene. PMID:23955710

  2. Breeding of R8012, a Rice Restorer Line Resistant to Blast and Bacterial Blight Through Marker-Assisted Selection

    Institute of Scientific and Technical Information of China (English)

    ZHAN Xiao-deng; ZHOU Hai-peng; CHAI Rong-yao; ZHUANG Jie-yun; CHENG Shi-hua; CAO Li-yong

    2012-01-01

    Genetic improvement Is one of the most effective strategies to prevent rlce from blast and bacterial blight (BB)diseases,the two most prevalent diseases jeopardizing rice production.Rice hybrids with dural resistance to blast and BB are needed for sustainable production of food.An incomplete diallels design resulted in 25 crosses between five blast and five BB resistant germplasrn accesslons.Only one pair of parents,DH146 × TM487,showed polymorphism for all the markers to Identify one blast resistance gene P125 and three BB resistance genes,Xa21,xa13 and xa5,thus it was used in the marker-assisted selection (MAS).F2 individuals of DH148 × TM487 were genotyped using flanking markers of RM3330and sequence tagged site (STS) marker SAT for P125.The resistant F2 plants with P125 were used for pyramiding BB resistance genes Xa21,xa13 and xa5 identified by the markers pTA248,RM264 and RM153,respectively In subsequent generations.Finally,after selection for agronomic traits and restoration ability among 12 pyramided lines,we acquired an elite restorer line,R8012 including all four target genes (P125+Xa21+xa13+xa5).Hybrid Zhong 9A/R8012 derived from the selected line showed stronger resistance to blast and BB,and higher grain yield than the commercial checks uniformally in experimental plots,2007 state-wide yield trial and 2008 nation-wide yield trial.This study provides a paradigmatic example to show that MAS is a practically feasible tool in effectively pyramiding multiple resistance genes.The resultant restoring line and its hybrid would play an important role in securing rice production in China.

  3. Construction of the recombinant broad-host-range plasmids providing their bacterial hosts arsenic resistance and arsenite oxidation ability.

    Science.gov (United States)

    Drewniak, Lukasz; Ciezkowska, Martyna; Radlinska, Monika; Sklodowska, Aleksandra

    2015-02-20

    The plasmid pSinA of Sinorhizobium sp. M14 was used as a source of functional phenotypic modules, encoding proteins involved in arsenite oxidation and arsenic resistance, to obtain recombinant broad-host-range plasmids providing their bacterial hosts arsenic resistance and arsenite oxidative ability. An arsenite oxidation module was cloned into pBBR1MCS-2 vector yielding plasmid vector pAIO1, while an arsenic resistance module was cloned into pCM62 vector yielding plasmid pARS1. Both plasmid constructs were introduced (separately and together) into the cells of phylogenetically distant (representing Alpha-, Beta-, and Gammaproteobacteria) and physiologically diversified (unable to oxidize arsenite and susceptible/resistant to arsenite and arsenate) bacteria. Functional analysis of the modified strains showed that: (i) the plasmid pARS1 can be used for the construction of strains with an increased resistance to arsenite [up to 20mM of As(III), (ii) the presence of the plasmid pAIO1 in bacteria previously unable to oxidize As(III) to As(V), contributes to the acquisition of arsenite oxidation abilities by these cells, (iii) the highest arsenite utilization rate are observed in the culture of strains harbouring both the plasmids pAIO1 and pARS1, (iv) the strains harbouring the plasmid pAIO1 were able to grow on arsenic-contaminated mine waters (∼ 3.0 mg As L(-1)) without any supplementation. PMID:25617684

  4. C/EBPβ Promotes Immunity to Oral Candidiasis through Regulation of β-Defensins.

    Science.gov (United States)

    Simpson-Abelson, Michelle R; Childs, Erin E; Ferreira, M Carolina; Bishu, Shrinivas; Conti, Heather R; Gaffen, Sarah L

    2015-01-01

    Humans or mice subjected to immunosuppression, such as corticosteroids or anti-cytokine biologic therapies, are susceptible to mucosal infections by the commensal fungus Candida albicans. Recently it has become evident that the Th17/IL-17 axis is essential for immunity to candidiasis, but the downstream events that control immunity to this fungus are poorly understood. The CCAAT/Enhancer Binding Protein-β (C/EBPβ) transcription factor is important for signaling by multiple inflammatory stimuli, including IL-17. C/EBPβ is regulated in a variety of ways by IL-17, and controls several downstream IL-17 target genes. However, the role of C/EBPβ in vivo is poorly understood, in part because C/EBPβ-deficient mice are challenging to breed and work with. In this study, we sought to understand the role of C/EBPβ in the context of an IL-17-dependent immune response, using C. albicans infection as a model system. Confirming prior findings, we found that C/EBPβ is required for immunity to systemic candidiasis. In contrast, C/EBPβ(-/-) mice were resistant to oropharyngeal candidiasis (OPC), in a manner indistinguishable from immunocompetent WT mice. However, C/EBPβ(-/-) mice experienced more severe OPC than WT mice in the context of cortisone-induced immunosuppression. Expression of the antimicrobial peptide β-defensin (BD)-3 correlated strongly with susceptibility in C/EBPβ(-/-) mice, but no other IL-17-dependent genes were associated with susceptibility. Therefore, C/EBPβ contributes to immunity to mucosal candidiasis during cortisone immunosuppression in a manner linked to β-defensin 3 expression, but is apparently dispensable for the IL-17-dependent response.

  5. Bacterial cellulose produced by a new acid-resistant strain of Gluconacetobacter genus.

    Science.gov (United States)

    Castro, Cristina; Zuluaga, Robin; Álvarez, Catalina; Putaux, Jean-Luc; Caro, Gloria; Rojas, Orlando J; Mondragon, Iñaki; Gañán, Piedad

    2012-08-01

    A bacterial strain isolated from the fermentation of Colombian homemade vinegar, Gluconacetobacter medellensis, was investigated as a new source of bacterial cellulose (BC). The BC produced from substrate media consisting of various carbon sources at different pH and incubation times was quantified. Hestrin-Schramm (HS) medium modified with glucose led to the highest BC yields followed by sucrose and fructose. Interestingly, the microorganisms are highly tolerant to low pH: an optimum yield of 4.5 g/L was achieved at pH 3.5, which is generally too low for other bacterial species to function. The cellulose microfibrils produced by the new strain were characterized by scanning and transmission electron microscopy, infrared spectroscopy X-ray diffraction and elemental analysis. The morphological, structural and chemical characteristics of the cellulose produced are similar to those expected for BC.

  6. Characterization of defensin gene from abalone Haliotis discus hannai and its deduced protein

    Institute of Scientific and Technical Information of China (English)

    HONG Xuguang; SUN Xiuqin; ZHENG Minggang; QU Lingyun; ZAN Jindong; ZHANG Jinxing

    2008-01-01

    Defensin is one of preserved ancient host defensive materials formed in biological evolution. As a regulator and effector molecule, it is very important in animals' acquired immune system. This paper reports the defensin gene from the mixed liver and kidney cDNA library of abalone Haliotis discus hannai Ino. Sequence analysis shows that the gene sequence of full-length cDNA encodes 42 mature peptides (including six Cys), molecular weight of 4 323 Da, and pI of 8.02. Amino acid sequence homology analysis shows that the peptides are highly similar (70% in common) to other insects defensin. Because of a typical insect-defensin structural character of mature peptide in the secondary structure, the polypeptide named Haliotis discus defensin (hd-def), a novel of antimicrobial peptides, belongs to insects defensin subfamily. The RT-PCR result of Haliotis discus defensin shows that the gene can be expressed only in the hepatopancreas by Gram-negative and positive bacteria stimulation, which is ascribed to inducible expression. Therefore, it is revealed that the Haliotis discus defensin gene expression was related to the antibacterial infection of Haliotis discus hannai Ino.

  7. Alpha-defensin DEFA1A3 gene copy number elevation in Danish Crohn's disease patients

    DEFF Research Database (Denmark)

    Jespersgaard, Cathrine; Fode, Peder; Dybdahl, Marianne;

    2011-01-01

    BACKGROUND AND PURPOSE OF STUDY: Extensive copy number variation is observed for the DEFA1A3 gene encoding alpha-defensins 1-3. The objective of this study was to determine the involvement of alpha-defensins in colonic tissue from Crohn's disease (CD) patients and the possible genetic association...

  8. Evaluation of beta defensin 2 production by chicken heterophils using direct MALDI mass spectrometry

    Science.gov (United States)

    Beta defensins (BD) are cysteine rich, cationic antimicrobial peptides (AMP) produced mainly by epithelial and myeloid cells such as neutrophils. In birds, the equivalent of neutrophils, heterophils produce avian beta defensins (AvBD) of which AvBD2 is the major isoform. Heterophils recognize patho...

  9. Resistance and resilience of removal efficiency and bacterial community structure of gas biofilters exposed to repeated shock loads.

    Science.gov (United States)

    Cabrol, Léa; Malhautier, Luc; Poly, Franck; Roux, Xavier Le; Lepeuple, Anne-Sophie; Fanlo, Jean-Louis

    2012-11-01

    Since full-scale biofilters are often operated under fluctuating conditions, it is critical to understand their response to transient states. Four pilot-scale biofilters treating a composting gas mixture and undergoing repeated substrate pulses of increasing intensity were studied. A systematic approach was proposed to quantify the resistance and resilience capacity of their removal efficiency, which enabled to distinguish between recalcitrant (ammonia, DMDS, ketones) and easily degradable (esters and aldehyde) compounds. The threshold of disturbing shock intensity and the influence of disturbance history depended on the contaminant considered. The spatial and temporal distribution of the bacterial community structure in response to the perturbation regime was analysed by Denaturing Gradient Gel Electrophoresis (DGGE). Even if the substrate-pulses acted as a driving force for some community characteristics (community stratification), the structure-function relationships were trickier to evidence: the distributions of resistance and composition were only partially coupled, with contradictory results depending on the contaminant considered.

  10. Bottlenecks in the Transferability of Antibiotic Resistance from Natural Ecosystems to Human Bacterial Pathogens

    OpenAIRE

    Martínez, José L.

    2012-01-01

    It is generally accepted that resistance genes acquired by human pathogens through horizontal gene transfer originated in environmental, non-pathogenic bacteria. As a consequence, there is increasing concern on the roles that natural, non-clinical ecosystems, may play in the evolution of resistance. Recent studies have shown that the variability of determinants that can provide antibiotic resistance on their expression in a heterologous host is much larger than what is actually found in human...

  11. Bottlenecks in the transmission of antibiotic resistance from natural ecosystems to human bacterial pathogens

    OpenAIRE

    Martinez, Jose L.

    2012-01-01

    It is generally accepted that resistance genes acquired by human pathogens trough horizontal gene transfer have been originated in environmental, non pathogenic bacteria. As the consequence, there exists an increasing concern on the role that natural, non-clinical ecosystems, may play on the evolution of resistance. Recent studies have shown that the variability of determinants that can provide antibiotic resistance upon their expression in a heterologous host is much larger than what is actu...

  12. Multidrug resistance mediated by a bacterial homolog of the human multidrug transporter MDR1.

    OpenAIRE

    van Veen, Hendrik W.; Venema, Koen; Bolhuis, Henk; Oussenko, Irina; Kok, Jan; Poolman, Bert; Driessen, Arnold J. M.; Konings, Wil N.

    1996-01-01

    Resistance of Lactococcus lactis to cytotoxic compounds shares features with the multidrug resistance phenotype of mammalian tumor cells. Here, we report the gene cloning and functional characterization in Escherichia coli of LmrA, a lactococcal structural and functional homolog of the human multidrug resistance P-glycoprotein MDR1. LmrA is a 590-aa polypeptide that has a putative topology of six alpha-helical transmembrane segments in the N-terminal hydrophobic domain, followed by a hydrophi...

  13. Production of putrescine-capped stable silver nanoparticle: its characterization and antibacterial activity against multidrug-resistant bacterial strains

    Science.gov (United States)

    Saha, Saswati; Gupta, Bhaskar; Gupta, Kamala; Chaudhuri, Mahua Ghosh

    2016-04-01

    Integration of biology with nanotechnology is now becoming attention-grabbing area of research. The antimicrobial potency of silver has been eminent from antiquity. Due to the recent desire for the enhancement of antibacterial efficacy of silver, various synthesis methods of silver in their nano dimensions are being practiced using a range of capping material. The present work highlights a facile biomimetic approach for production of silver nanoparticle being capped and stabilized by putrescine, possessing a diameter of 10-25 ± 1.5 nm. The synthesized nanoparticles have been analyzed spectrally and analytically. Morphological studies are carried out by high-resolution transmission electron microscopy and crystallinity by selected area electron diffraction patterns. Moreover, the elemental composition of the capped nanoparticles was confirmed by energy-dispersive X-ray spectroscopy analysis. A comparative study (zone of inhibition and minimum inhibitory concentration) regarding the interactions and antibacterial potentiality of the capped silver nanoparticles with respect to the bare ones reveal the efficiency of the capped one over the bare one. The bacterial kinetic study was executed to monitor the interference of nanoparticles with bacterial growth rate. The results also highlight the efficacy of putrescine-capped silver nanoparticles as effective growth inhibitors against multi-drug resistant human pathogenic bacterial strains, which may, thus, potentially be applicable as an effective antibacterial control system to fight diseases.

  14. The role of silicon in enhancing resistance to bacterial blight of hydroponic- and soil-cultured rice.

    Science.gov (United States)

    Song, Alin; Xue, Gaofeng; Cui, Peiyuan; Fan, Fenliang; Liu, Hongfang; Yin, Chang; Sun, Wanchun; Liang, Yongchao

    2016-04-19

    Here we report for the first time that bacterial blight of rice can be alleviated by silicon (Si) added. In both inoculated and uninoculated plants, shoot dry weight was significantly higher in the +Si plants than in the -Si plants. A soil-cultured trial showed that disease severity was 24.3% lower in the Si-amended plants than in the non-Si-amended plants. Plants that were switched from -Si to +Si nutrient solution and simultaneously inoculated with Xoo also exhibited the same high resistance to bacterial blight as the plants that were treated continuously with Si, with control efficiencies of 52.8 and 62.9%, respectively. Moreover, total concentrations of soluble phenolics and lignin in rice leaves were significantly higher in the +Si plants than in the -Si plants. Polyphenoloxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities in rice leaves were observed to be higher in the +Si plants than in the -Si plants. The expression levels of Os03g0109600, Prla, Rcht2 and Lox2osPil, were also higher in +Si plants than in -Si plants post-inoculation during the experimental time. Addition of Si resulted in increased Pal transcription, and inhibited CatA and Os03g0126000 expression in the earlier and later stages of bacterial inoculation, respectively.

  15. The role of silicon in enhancing resistance to bacterial blight of hydroponic- and soil-cultured rice.

    Science.gov (United States)

    Song, Alin; Xue, Gaofeng; Cui, Peiyuan; Fan, Fenliang; Liu, Hongfang; Yin, Chang; Sun, Wanchun; Liang, Yongchao

    2016-01-01

    Here we report for the first time that bacterial blight of rice can be alleviated by silicon (Si) added. In both inoculated and uninoculated plants, shoot dry weight was significantly higher in the +Si plants than in the -Si plants. A soil-cultured trial showed that disease severity was 24.3% lower in the Si-amended plants than in the non-Si-amended plants. Plants that were switched from -Si to +Si nutrient solution and simultaneously inoculated with Xoo also exhibited the same high resistance to bacterial blight as the plants that were treated continuously with Si, with control efficiencies of 52.8 and 62.9%, respectively. Moreover, total concentrations of soluble phenolics and lignin in rice leaves were significantly higher in the +Si plants than in the -Si plants. Polyphenoloxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities in rice leaves were observed to be higher in the +Si plants than in the -Si plants. The expression levels of Os03g0109600, Prla, Rcht2 and Lox2osPil, were also higher in +Si plants than in -Si plants post-inoculation during the experimental time. Addition of Si resulted in increased Pal transcription, and inhibited CatA and Os03g0126000 expression in the earlier and later stages of bacterial inoculation, respectively. PMID:27091552

  16. The role of silicon in enhancing resistance to bacterial blight of hydroponic- and soil-cultured rice

    Science.gov (United States)

    Song, Alin; Xue, Gaofeng; Cui, Peiyuan; Fan, Fenliang; Liu, Hongfang; Yin, Chang; Sun, Wanchun; Liang, Yongchao

    2016-01-01

    Here we report for the first time that bacterial blight of rice can be alleviated by silicon (Si) added. In both inoculated and uninoculated plants, shoot dry weight was significantly higher in the +Si plants than in the −Si plants. A soil-cultured trial showed that disease severity was 24.3% lower in the Si-amended plants than in the non-Si-amended plants. Plants that were switched from −Si to +Si nutrient solution and simultaneously inoculated with Xoo also exhibited the same high resistance to bacterial blight as the plants that were treated continuously with Si, with control efficiencies of 52.8 and 62.9%, respectively. Moreover, total concentrations of soluble phenolics and lignin in rice leaves were significantly higher in the +Si plants than in the −Si plants. Polyphenoloxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities in rice leaves were observed to be higher in the +Si plants than in the −Si plants. The expression levels of Os03g0109600, Prla, Rcht2 and Lox2osPil, were also higher in +Si plants than in −Si plants post-inoculation during the experimental time. Addition of Si resulted in increased Pal transcription, and inhibited CatA and Os03g0126000 expression in the earlier and later stages of bacterial inoculation, respectively. PMID:27091552

  17. Preliminary field evaluation of rainbow trout selectively bred for increased resistance to bacterial cold water disease

    Science.gov (United States)

    Bacterial cold water disease (BCWD) is one of the most frequent causes of elevated mortality in juvenile salmonids, and the development of effective control strategies is a priority. We previously reported results of a selective breeding program designed to increase rainbow trout survival following ...

  18. Field evaluation of rainbow trout selectively bred for resistance to bacterial cold water disease

    Science.gov (United States)

    Bacterial cold water disease (BCWD) is a frequent cause of elevated mortality in rainbow trout and the development of effective control strategies is a priority within the U.S. Since 2005, the NCCCWA has implemented a selective breeding program and has created three genetic lines of outbred rainbow...

  19. Identification of markers associated with bacterial blight resistance loci in cowpea (Vigna unguiculata (L.) Walp.)

    NARCIS (Netherlands)

    Agbicodo, A.C.M.E.; Fatokun, C.A.; Bandyopadhyay, R.; Wydra, K.; Diop, N.N.; Muchero, W.; Ehlers, J.D.; Roberts, P.A.; Close, T.J.; Visser, R.G.F.; Linden, van der C.G.

    2010-01-01

    Cowpea bacterial blight (CoBB), caused by Xanthomonas axonopodis pv. vignicola (Xav), is a worldwide major disease of cowpea [Vigna unguiculata (L.) Walp.]. Among different strategies to control the disease including cultural practices, intercropping, application of chemicals, and sowing pathogen-fr

  20. BACTERIAL EPIDEMIOLOGY AND ANTIMICROBIAL RESISTANCE IN THE SURGERY WARDS OF A LARGE TEACHING HOSPITAL IN SOUTHERN ITALY

    Directory of Open Access Journals (Sweden)

    Silvano Esposito

    2015-05-01

    Full Text Available Objectives: Surgical infections represent an increasingly important problem for the National Health System. In this study we retrospectively evaluated the bacterial epidemiology and antimicrobial susceptibility of the microorganisms concerned as well as the utilization of antibiotics in the General and Emergency Surgery wards of a large teaching hospital in southern Italy in the period 2011-2013. Methods: Data concerning bacterial isolates and antimicrobial susceptibility were retrieved from the Vitek II database. The pharmacy provided data about the consumption of antibiotics in the above reported wards. Chi-square or Fisher’s exact test were used to analyze categorical variables. Results: In all, 94 Gram-negative were isolated in 2011, 77 in 2012, and 125 in 2013, Escherichia coli, Acinetobacter baumannii and Pseudomonas aeruginosa always being the most frequently isolated microorganisms. In the same years, there were respectively 105, 93, and 165 Gram-positive isolated, Enterococcus faecalis, Staphylococcus epidermidis and Staphylococcus aureus being the most commonly found. No significant variation in the antibiotic susceptibility pattern was observed, either among Gram-negative or among Gram-positive pathogens; carbapenems (especially meropenem consumption remained stable over time. Conclusions: Our results show no significant increase in antimicrobial resistance over the period in question, and a higher rate of both MRSA isolates and resistance to carbapenems in A. baumannii compared with other European data.

  1. "ETIOLOGY AND ANTIBACTERIAL RESISTANCE OF BACTERIAL URINARY TRACT INFECTIONS IN CHILDREN’S MEDICAL CENTER, TEHRAN, IRAN"

    Directory of Open Access Journals (Sweden)

    M. Haghi-Ashteiani

    2007-06-01

    Full Text Available Urinary tract infection (UTI is a common bacterial illness in children. Knowledge of the antimicrobial resistance patterns of common uropathogens in children according to local epidemiology is essential for providing clinically appropriate, cost effective therapy for UTI. The aim of this study was to determine the distribution of urinary tract infections in a referral hospital, Children’s Medical Center, and determination of in vitro susceptibility of these organisms to antimicrobial agents. Of the 1231 bacterial isolates the most frequent isolates were Escherichia coli (38.66%, Klebsiella spp. (22.25%, Coagulase-negative staphylococci (10.1%, Pseudomonas spp. (8.7%, enterococci (8.28%, Enterobacter spp. (4.1%, staphylococcus aureus (3.24%, and proteus mirabilis (2.9%. Among Enterobacteriaceae, 79.80% of E. coli were amikacin-sensitive. Of Gram-positive cocci, 66.66% of staphylococcus aureus were vancomycin-sensitive. Our data show the original distribution of uropathogens from UTIs in children referred to Children’s Medical Center in Tehran and the emergence of multidrug resistant strains.

  2. Identification, cloning and functional characterization of novel beta-defensins in the rat (Rattus norvegicus

    Directory of Open Access Journals (Sweden)

    French Frank S

    2006-02-01

    Full Text Available Abstract Background beta-defensins are small cationic peptides that exhibit broad spectrum antimicrobial properties. The majority of beta-defensins identified in humans are predominantly expressed in the male reproductive tract and have roles in non-immunological processes such as sperm maturation and capacitation. Characterization of novel defensins in the male reproductive tract can lead to increased understanding of their dual roles in immunity and sperm maturation. Methods In silico rat genomic analyses were used to identify novel beta-defensins related to human defensins 118–123. RNAs isolated from male reproductive tract tissues of rat were reverse transcribed and PCR amplified using gene specific primers for defensins. PCR products were sequenced to confirm their identity. RT-PCR analysis was performed to analyze the tissue distribution, developmental expression and androgen regulation of these defensins. Recombinant defensins were tested against E. coli in a colony forming unit assay to analyze their antimicrobial activities. Results Novel beta-defensins, Defb21, Defb24, Defb27, Defb30 and Defb36 were identified in the rat male reproductive tract. Defb30 and Defb36 were the most restricted in expression, whereas the others were expressed in a variety of tissues including the female reproductive tract. Early onset of defensin expression was observed in the epididymides of 10–60 day old rats. Defb21-Defb36 expression in castrated rats was down regulated and maintained at normal levels in testosterone supplemented animals. DEFB24 and DEFB30 proteins showed potent dose and time dependent antibacterial activity. Conclusion Rat Defb21, Defb24, Defb27, Defb30 and Defb36 are abundantly expressed in the male reproductive tract where they most likely protect against microbial invasion. They are developmentally regulated and androgen is required for full expression in the adult epididymis.

  3. Defensin expression in chronic pouchitis in patients with ulcerative colitis or familial adenomatous polyposis coli

    Institute of Scientific and Technical Information of China (English)

    Karlheinz Kiehne; Gabriele Brunke; Franziska Wegner; Tomas Banasiewicz; Ulrich R F(o)lsch; Karl-Heinz Herzig

    2006-01-01

    AIM:Pouchitis develops in ileoanal pouches in up to 50% of patients with ulcerative colitis during the first 10years after pouch surgery while being rare in patients after proctocolectomy for familial adenomatous polyposis coii (FAP) syndrome. Defensins are major components of the innate immune system and play a significant role in gastrointestinal microbial homeostasis. Pouch defensin and cytokine expression were correlated with states of pouch inflammation to study their role in pouchitis.METHODS:Patients with ulcerative colitis and FAP syndrome were stratified into groups with pouches after surgery, pouches without or with pouchitis. Biopsies from terminal ileum from a healthy intestine or from normal terminal ileum of patients with ulcerative colitis served as controls, mRNA from pouches and controls was analysed for defensin and cytokine expression.RESULTS: Expression of defensins was increased in all pouches immediately after surgery, compared to ileum of controls. Initially, pouches in ulcerative colitis revealed higher defensin expression than FAP pouches. Defensin expression declined in both patient groups and increased again slightly in pouchitis in patients with ulcerative colitis. FAP pouches without pouchitis had strong expression of β-defensin hBD-1, while all other defensins remained at low levels. Cytokine expression in ulcerative colitis pouches was high, while FAP pouches showed moderately elevated cytokines only after surgery.CONCLUSION: Development of pouchitis correlates with decreased defensin expression in ulcerative colitis in addition to high expression of cytokines. The low incidence of pouchitis in FAP pouches correlates with increased expression of hBD-1 β- defensin in association with low cytokine levels.

  4. Hidden Selection of Bacterial Resistance to Fluoroquinolones In Vivo: The Case of Legionella pneumophila and Humans

    Directory of Open Access Journals (Sweden)

    Lubana Shadoud

    2015-09-01

    Interpretation: In vivo selection of antibiotic resistances in L. pneumophila may be associated with treatment failures and poor prognosis. This hidden resistance must be carefully considered in the therapeutic management of legionellosis patients and in the control of the gradual loss of effectiveness of antibiotics.

  5. Dissemination of bacterial resistance to tetracycline antibiotics from animal husbandry to the soil.

    OpenAIRE

    HAVLÍČKOVÁ, Petra

    2011-01-01

    This bachaleor thesis is dedicated to occurence of tetracycline resistance genes in the soil environment influenced by wastes from a livestock productionanimal husbandry. In the experimental part, the transfer of tetracycline resistance genes from the excrements of a dairy cattle to the soils was studied.

  6. EDS1 mediates pathogen resistance and virulence function of a bacterial effector in soybean

    Science.gov (United States)

    Enhanced disease susceptibility 1 (EDS1) and phytoalexin deficient 4 (PAD4) are well known regulators of both basal and resistance (R) protein-mediated plant defense. We identified two EDS1- (GmEDS1a/b) and one PAD4-like (GmPAD4) protein that are required for resistance signaling in soybean. Consist...

  7. Impact of bacterial genetics on the transmission of isoniazid-resistant Mycobacterium tuberculosis.

    Directory of Open Access Journals (Sweden)

    Sebastian Gagneux

    2006-06-01

    Full Text Available Understanding the ecology of drug-resistant pathogens is essential for devising rational programs to preserve the effective lifespan of antimicrobial agents and to abrogate epidemics of drug-resistant organisms. Mathematical models predict that strain fitness is an important determinant of multidrug-resistant Mycobacterium tuberculosis transmission, but the effects of strain diversity have been largely overlooked. Here we compared the impact of resistance mutations on the transmission of isoniazid-resistant M. tuberculosis in San Francisco during a 9-y period. Strains with a KatG S315T or inhA promoter mutation were more likely to spread than strains with other mutations. The impact of these mutations on the transmission of isoniazid-resistant strains was comparable to the effect of other clinical determinants of transmission. Associations were apparent between specific drug resistance mutations and the main M. tuberculosis lineages. Our results show that in addition to host and environmental factors, strain genetic diversity can influence the transmission dynamics of drug-resistant bacteria.

  8. Bacterial urinary tract infection in renal transplant recipients and their antibiotic resistance pattern: A four-year study.

    Directory of Open Access Journals (Sweden)

    Azar Dokht Khosravi

    2014-04-01

    Full Text Available Urinary tract infections (UTIs are the most common infections in renal transplant recipients and are considered a potential cause of bacteremia, sepsis, and affects graft outcomes. The aim of the present study was to determine the incidence of UTI among renal transplant recipients and investigation of antimicrobial susceptibility pattern of causative agents.In total, 1165 patients from March 2009 to December 2012, in transplant center of Golestan Hospital, Ahvaz, Iran, were investigated. Qualitative urine cultures were performed for all cases, causative microorganisms were identified and colony count was performed according to the standard protocol. Antibiotic susceptibility testing was then performed to determine the susceptibility pattern of recovered bacteria from confirmed UTIs.UTI was diagnosed in 391 patients(33.56%. Gram-negative bacteria were the most prevalent isolated microorganisms with E. coli (43.53%, followed by Enterobacter spp. (35.37% as the major organisms. Among Gram positives, Coagulase-negative Staphylococci was isolated from 6.8% of cases. The rate of resistance to all tested antibiotics was highest in Enterobacter spp., however the most common resistance were seen against cefixime, cephalotin, and cotrimoxazole in all tested gram negatives.the rate of UTIs among renal transplant recipients was noticeable in this study with high antibiotic resistance. Multi-resistant bacterial infections are potentially life-threatening emerging problem in renal transplantation. Prophylactic measures must be applied to patients at greater risk.

  9. Increasing Ciprofloxacin Resistance Among Prevalent Urinary Tract Bacterial Isolates in Gaza Strip, Palestine

    Directory of Open Access Journals (Sweden)

    Zakaria El Astal

    2005-01-01

    Full Text Available This article presents the incidence of ciprofloxacin resistance among 480 clinical isolates obtained from patients with urinary tract infection (UTI during January to June 2004 in Gaza Strip, Palestine. The resistance rates observed were 15.0% to ciprofloxacin, 82.5% to amoxycillin, 64.4% to cotrimoxazole, 63.1% to doxycycline, 32.5% to cephalexin, 31.9% to nalidixic acid, and 10.0% to amikacin. High resistance to ciprofloxacin was detected among Acinetobacter haemolyticus (28.6%, Staphylococcus saprophyticus (25.0%,Pseudomonas aeruginosa (20.0%, Klebsiella pneumonia (17.6%, and Escherichia coli (12.0%. Minimal inhibitory concentration (MIC of ciprofloxacin evenly ranged from 4 to 32 μg/mL with a mean of 25.0 μg/mL. This study indicates emerging ciprofloxacin resistance among urinary tract infection isolates. Increasing resistance against ciprofloxacin demands coordinated monitoring of its activity and rational use of the antibiotics.

  10. Inhibition of cereal rust fungi by both class I and II defensins derived from the flowers of Nicotiana alata.

    Science.gov (United States)

    Dracatos, Peter M; van der Weerden, Nicole L; Carroll, Kate T; Johnson, Elizabeth D; Plummer, Kim M; Anderson, Marilyn A

    2014-01-01

    plants prior to the plants being inoculated with crown rust, they reduced the number of pustules per leaf area, as well as the amount of chlorosis induced by infection. Similar to observations in vitro, NaD1 was more effective as an antifungal control agent than NaD2. Further investigation revealed that both NaD1 and NaD2 permeabilized the plasma membranes of Puccinia spp. This study provides evidence that both secreted (NaD2) and nonsecreted (NaD1) defensins may be useful for broad-spectrum resistance to pathogens.

  11. Synergistic and additive effect of oregano essential oil and biological silver nanoparticles against multidrug-resistant bacterial strains

    Directory of Open Access Journals (Sweden)

    Sara eScandorieiro

    2016-05-01

    Full Text Available Bacterial resistance to conventional antibiotics has become a clinical and public health problem, making therapeutic decisions more challenging. Plant compounds and nanodrugs have been proposed as potential antimicrobial alternatives. Studies have shown that oregano (Origanum vulgare essential oil (OEO and silver nanoparticles have potent antibacterial activity, also against multidrug-resistant strains; however, the strong organoleptic characteristics of OEO and the development of resistance to these metal nanoparticles can limit their use. This study evaluated the antibacterial effect of a two-drug combination of biologically synthesized silver nanoparticles (bio-AgNP, produced by Fusarium oxysporum, and OEO against Gram-positive and Gram-negative bacteria, including multidrug-resistant strains. OEO and bio-AgNP showed bactericidal effects against all seventeen strains tested, with minimal inhibitory concentrations (MIC ranging from 0.298 to 1.193 mg/mL and 62.5 to 250 µM, respectively. Time-kill curves indicated that OEO acted rapidly (within 10 min, while the metallic nanoparticles took 4 h to kill Gram-negative bacteria and 24 h to kill Gram-positive bacteria. The combination of the two compounds resulted in a synergistic or additive effect, reducing their MIC values and reducing the time of action compared to bio-AgNP used alone, i.e., 20 min for Gram-negative bacteria and 7 h for Gram-positive bacteria. Scanning electron microscopy (SEM revealed similar morphological alterations in Staphylococcus aureus (non-methicillin-resistant S. aureus, non-MRSA cells exposed to three different treatments (OEO, bio-AgNP and combination of the two, which appeared cell surface blebbing. Individual and combined treatments showed reduction in cell density and decrease in exopolysaccharide matrix compared to untreated bacterial cells. It indicated that this composition have an antimicrobial activity against S. aureus by disrupting cells. Both compounds

  12. A rapid in situ procedure for determination of bacterial susceptibility or resistance to antibiotics that inhibit peptidoglycan biosynthesis

    Directory of Open Access Journals (Sweden)

    Bou Germán

    2011-08-01

    Full Text Available Abstract Background Antibiotics which inhibit bacterial peptidoglycan biosynthesis are the most widely used in current clinical practice. Nevertheless, resistant strains increase dramatically, with serious economic impact and effects on public health, and are responsible for thousands of deaths each year. Critical clinical situations should benefit from a rapid procedure to evaluate the sensitivity or resistance to antibiotics that act at the cell wall. We have adapted a kit for rapid determination of bacterial DNA fragmentation, to assess cell wall integrity. Results Cells incubated with the antibiotic were embedded in an agarose microgel on a slide, incubated in an adapted lysis buffer, stained with a DNA fluorochrome, SYBR Gold and observed under fluorescence microscopy. The lysis affects the cells differentially, depending on the integrity of the wall. If the bacterium is susceptible to the antibiotic, the weakened cell wall is affected by the lysing solution so the nucleoid of DNA contained inside the bacterium is released and spread. Alternatively, if the bacterium is resistant to the antibiotic, it is practically unaffected by the lysis solution and does not liberate the nucleoid, retaining its normal morphological appearance. In an initial approach, the procedure accurately discriminates susceptible, intermediate and resistant strains of Escherichia coli to amoxicillin/clavulanic acid. When the bacteria came from an exponentially growing liquid culture, the effect on the cell wall of the β-lactam was evident much earlier that when they came from an agar plate. A dose-response experiment with an E. coli strain susceptible to ampicillin demonstrated a weak effect before the MIC dose. The cell wall damage was not homogenous among the different cells, but the level of damage increased as dose increased with a predominant degree of effect for each dose. A microgranular-fibrilar extracellular background was evident in gram

  13. Synergistic and Additive Effect of Oregano Essential Oil and Biological Silver Nanoparticles against Multidrug-Resistant Bacterial Strains.

    Science.gov (United States)

    Scandorieiro, Sara; de Camargo, Larissa C; Lancheros, Cesar A C; Yamada-Ogatta, Sueli F; Nakamura, Celso V; de Oliveira, Admilton G; Andrade, Célia G T J; Duran, Nelson; Nakazato, Gerson; Kobayashi, Renata K T

    2016-01-01

    Bacterial resistance to conventional antibiotics has become a clinical and public health problem, making therapeutic decisions more challenging. Plant compounds and nanodrugs have been proposed as potential antimicrobial alternatives. Studies have shown that oregano (Origanum vulgare) essential oil (OEO) and silver nanoparticles have potent antibacterial activity, also against multidrug-resistant strains; however, the strong organoleptic characteristics of OEO and the development of resistance to these metal nanoparticles can limit their use. This study evaluated the antibacterial effect of a two-drug combination of biologically synthesized silver nanoparticles (bio-AgNP), produced by Fusarium oxysporum, and OEO against Gram-positive and Gram-negative bacteria, including multidrug-resistant strains. OEO and bio-AgNP showed bactericidal effects against all 17 strains tested, with minimal inhibitory concentrations (MIC) ranging from 0.298 to 1.193 mg/mL and 62.5 to 250 μM, respectively. Time-kill curves indicated that OEO acted rapidly (within 10 min), while the metallic nanoparticles took 4 h to kill Gram-negative bacteria and 24 h to kill Gram-positive bacteria. The combination of the two compounds resulted in a synergistic or additive effect, reducing their MIC values and reducing the time of action compared to bio-AgNP used alone, i.e., 20 min for Gram-negative bacteria and 7 h for Gram-positive bacteria. Scanning electron microscopy (SEM) revealed similar morphological alterations in Staphylococcus aureus (non-methicillin-resistant S. aureus, non-MRSA) cells exposed to three different treatments (OEO, bio-AgNP and combination of the two), which appeared cell surface blebbing. Individual and combined treatments showed reduction in cell density and decrease in exopolysaccharide matrix compared to untreated bacterial cells. It indicated that this composition have an antimicrobial activity against S. aureus by disrupting cells. Both compounds showed very low

  14. Synergistic and Additive Effect of Oregano Essential Oil and Biological Silver Nanoparticles against Multidrug-Resistant Bacterial Strains

    Science.gov (United States)

    Scandorieiro, Sara; de Camargo, Larissa C.; Lancheros, Cesar A. C.; Yamada-Ogatta, Sueli F.; Nakamura, Celso V.; de Oliveira, Admilton G.; Andrade, Célia G. T. J.; Duran, Nelson; Nakazato, Gerson; Kobayashi, Renata K. T.

    2016-01-01

    Bacterial resistance to conventional antibiotics has become a clinical and public health problem, making therapeutic decisions more challenging. Plant compounds and nanodrugs have been proposed as potential antimicrobial alternatives. Studies have shown that oregano (Origanum vulgare) essential oil (OEO) and silver nanoparticles have potent antibacterial activity, also against multidrug-resistant strains; however, the strong organoleptic characteristics of OEO and the development of resistance to these metal nanoparticles can limit their use. This study evaluated the antibacterial effect of a two-drug combination of biologically synthesized silver nanoparticles (bio-AgNP), produced by Fusarium oxysporum, and OEO against Gram-positive and Gram-negative bacteria, including multidrug-resistant strains. OEO and bio-AgNP showed bactericidal effects against all 17 strains tested, with minimal inhibitory concentrations (MIC) ranging from 0.298 to 1.193 mg/mL and 62.5 to 250 μM, respectively. Time-kill curves indicated that OEO acted rapidly (within 10 min), while the metallic nanoparticles took 4 h to kill Gram-negative bacteria and 24 h to kill Gram-positive bacteria. The combination of the two compounds resulted in a synergistic or additive effect, reducing their MIC values and reducing the time of action compared to bio-AgNP used alone, i.e., 20 min for Gram-negative bacteria and 7 h for Gram-positive bacteria. Scanning electron microscopy (SEM) revealed similar morphological alterations in Staphylococcus aureus (non-methicillin-resistant S. aureus, non-MRSA) cells exposed to three different treatments (OEO, bio-AgNP and combination of the two), which appeared cell surface blebbing. Individual and combined treatments showed reduction in cell density and decrease in exopolysaccharide matrix compared to untreated bacterial cells. It indicated that this composition have an antimicrobial activity against S. aureus by disrupting cells. Both compounds showed very low

  15. Rapid identification of bacterial resistance to Ciprofloxacin using surface-enhanced Raman spectroscopy

    Science.gov (United States)

    Kastanos, Evdokia; Hadjigeorgiou, Katerina; Pitris, Costas

    2014-02-01

    Due to its effectiveness and broad coverage, Ciprofloxacin is the fifth most prescribed antibiotic in the US. As current methods of infection diagnosis and antibiotic sensitivity testing (i.e. an antibiogram) are very time consuming, physicians prescribe ciprofloxacin before obtaining antibiogram results. In order to avoid increasing resistance to the antibiotic, a method was developed to provide both a rapid diagnosis and the sensitivity to the antibiotic. Using Surface Enhanced Raman Spectroscopy, an antibiogram was obtained after exposing the bacteria to Ciprofloxacin for just two hours. Spectral analysis revealed clear separation between sensitive and resistant bacteria and could also offer some inside into the mechanisms of resistance.

  16. Development of Gene-Pyramid Lines of the Elite Restorer Line, RPHR-1005 Possessing Durable Bacterial Blight and Blast Resistance.

    Science.gov (United States)

    Abhilash Kumar, V; Balachiranjeevi, C H; Bhaskar Naik, S; Rambabu, R; Rekha, G; Harika, G; Hajira, S K; Pranathi, K; Anila, M; Kousik, M; Vijay Kumar, S; Yugander, A; Aruna, J; Dilip Kumar, T; Vijaya Sudhakara Rao, K; Hari Prasad, A S; Madhav, M S; Laha, G S; Balachandran, S M; Prasad, M S; Viraktamath, B C; Ravindra Babu, V; Sundaram, R M

    2016-01-01

    RPHR-1005, the stable restorer line of the popular medium slender (MS) grain type rice hybrid, DRRH-3 was improved in this study for resistance against bacterial blight (BB) and blast diseases through marker-assisted backcross breeding (MABB). In this study, four major resistance genes (i.e., Xa21 and Xa33 for BB resistance and Pi2 and Pi54 for blast resistance) have been transferred to RPHR-1005 using RPBio Patho-1 (possessing Xa21 + Pi2), RPBio Patho-2 (possessing Xa21 + Pi54) and FBR1-15EM (possessing Xa33) as the donors. Foreground selection was carried out using PCR-based molecular markers specific for the target resistance genes and the major fertility restorer genes, Rf3 and Rf4, while background selection was carried out using a set of parental polymorphic rice SSR markers and backcrossing was continued uptoBC2 generation. At BC2F2, plants possessing the gene combination- Xa21 + Pi2, Xa21 + Pi54 and Xa33 in homozygous condition and with >92% recovery of the recurrent parent genome (RPG) were identified and intercrossed to combine all the four resistance genes. Twenty-two homozygous, pyramid lines of RPHR-1005 comprising of three single-gene containing lines, six 2-gene containing lines, eight 3-gene containing lines, and five 4-gene containing lines were identified among the double intercross lines at F3 generation (DICF3). They were then evaluated for their resistance against BB and blast, fertility restoration ability and for key agro-morphological traits. While single gene containing lines were resistant to either BB or blast, the 2-gene, 3-gene, and 4-gene pyramid lines showed good level of resistance against both and/or either of the two diseases. Most of the 2-gene, 3-gene, and 4-gene containing pyramid lines showed yield levels and other key agro-morphological and grain quality traits comparable to the original recurrent parent and showed complete fertility restoration ability, with a few showing higher yield as compared to RPHR-1005. Further, the

  17. Development of Gene-Pyramid Lines of the Elite Restorer Line, RPHR-1005 Possessing Durable Bacterial Blight and Blast Resistance.

    Science.gov (United States)

    Abhilash Kumar, V; Balachiranjeevi, C H; Bhaskar Naik, S; Rambabu, R; Rekha, G; Harika, G; Hajira, S K; Pranathi, K; Anila, M; Kousik, M; Vijay Kumar, S; Yugander, A; Aruna, J; Dilip Kumar, T; Vijaya Sudhakara Rao, K; Hari Prasad, A S; Madhav, M S; Laha, G S; Balachandran, S M; Prasad, M S; Viraktamath, B C; Ravindra Babu, V; Sundaram, R M

    2016-01-01

    RPHR-1005, the stable restorer line of the popular medium slender (MS) grain type rice hybrid, DRRH-3 was improved in this study for resistance against bacterial blight (BB) and blast diseases through marker-assisted backcross breeding (MABB). In this study, four major resistance genes (i.e., Xa21 and Xa33 for BB resistance and Pi2 and Pi54 for blast resistance) have been transferred to RPHR-1005 using RPBio Patho-1 (possessing Xa21 + Pi2), RPBio Patho-2 (possessing Xa21 + Pi54) and FBR1-15EM (possessing Xa33) as the donors. Foreground selection was carried out using PCR-based molecular markers specific for the target resistance genes and the major fertility restorer genes, Rf3 and Rf4, while background selection was carried out using a set of parental polymorphic rice SSR markers and backcrossing was continued uptoBC2 generation. At BC2F2, plants possessing the gene combination- Xa21 + Pi2, Xa21 + Pi54 and Xa33 in homozygous condition and with >92% recovery of the recurrent parent genome (RPG) were identified and intercrossed to combine all the four resistance genes. Twenty-two homozygous, pyramid lines of RPHR-1005 comprising of three single-gene containing lines, six 2-gene containing lines, eight 3-gene containing lines, and five 4-gene containing lines were identified among the double intercross lines at F3 generation (DICF3). They were then evaluated for their resistance against BB and blast, fertility restoration ability and for key agro-morphological traits. While single gene containing lines were resistant to either BB or blast, the 2-gene, 3-gene, and 4-gene pyramid lines showed good level of resistance against both and/or either of the two diseases. Most of the 2-gene, 3-gene, and 4-gene containing pyramid lines showed yield levels and other key agro-morphological and grain quality traits comparable to the original recurrent parent and showed complete fertility restoration ability, with a few showing higher yield as compared to RPHR-1005. Further, the

  18. Induction of bacterial blight resistance in elite Indian rice (Oryza sativa L.) cultivars using gamma irradiation and ethyl methane sulfonate

    International Nuclear Information System (INIS)

    Rice is one of the most important crops in the world, feeding more than 50% of the human population. During the last 30 years, mutation breeding has played a significant role in rice breeding programmes. Rice mutants with higher yield, greater tolerance to diseases and pests and other agronomic qualities have been released for commercial cultivation in many countries. By the year 1991, as many as 278 rice cultivars had been released world-wide out of which 24 were from India. Bacterial blight (BB) caused by Xanthomonas oryzae pv oryzae is the second most important disease in southeast Asia, causing an average of 21 kg/ha yield loss. In the Basmati field yield loss can reach up to 100%. Moreover, there is no resistant source of Basmati rice known for its quality and aroma. Induction of bacterial blight resistance in basmati rice will not only help in developing high yielding Basmati cultivars without compromising the quality but will also be a good source of resistance for other Basmati rice varieties. Therefore, seeds of two Indian rice varieties viz. PR106 and Pusa Basmati 1 were treated with EMS (0.25% and 0.5%) at pH 7.0 at 25 ± 1 deg C for 12 h and gamma rays (100 and 200 Gy). A 3500-curie 60Co gamma cell with a dose rate of 3200 radians per minute was used for gamma irradiation of the paddy seeds containing 13% moisture. After mutagenic treatment seeds were germinated along with corresponding controls in petri dishes lined with wet filter paper. The seeds from the M1 generation were grown in the plant-to- progeny method for the M2 generation at Kapurthala, Punjab Agricultural University. Each progeny had 22-25 plants. The plant-to-plant distance was 20 cm and row-to-row distance was 30 cm. For every 20 lines, one line of check (parent variety) was grown. Screening against BB was made in the M2 generation by inoculating the plants at maximum tillering stage, following Kauffman et al. (1973). Observations for disease severity were recorded after 14 days of

  19. Effect of Seed Treatment by Cold Plasma on the Resistance of Tomato to Ralstonia solanacearum (Bacterial Wilt)

    Science.gov (United States)

    Jiang, Jiafeng; Lu, Yufang; Li, Jiangang; Li, Ling; He, Xin; Shao, Hanliang; Dong, Yuanhua

    2014-01-01

    This study investigated the effect of cold plasma seed treatment on tomato bacterial wilt, caused by Ralstonia solanacearum (R. solanacearum), and the regulation of resistance mechanisms. The effect of cold plasma of 80W on seed germination, plant growth, nutrient uptake, disease severity, hydrogen peroxide (H2O2) concentration and activities of peroxidase (POD; EC 1.11.1.7), polyphenol oxidase (PPO; EC 1.10.3.2) and phenylalanine ammonia lyase (PAL; EC 4.3.1.5) were examined in tomato plants. Plasma treatment increased tomato resistance to R. solanacearum with an efficacy of 25.0%. Plasma treatment significantly increased both germination and plant growth in comparison with the control treatment, and plasma-treated plants absorbed more calcium and boron than the controls. In addition, H2O2 levels in treated plants rose faster and reached a higher peak, at 2.579 µM gFW−1, 140% greater than that of the control. Activities of POD (421.3 U gFW−1), PPO (508.8 U gFW−1) and PAL (707.3 U gFW−1) were also greater in the treated plants than in the controls (103.0 U gFW−1, 166.0 U gFW−1 and 309.4 U gFW−1, respectively). These results suggest that plasma treatment affects the regulation of plant growth, H2O2 concentration, and POD, PPO and PAL activity in tomato, resulting in an improved resistance to R. solanacearum. Consequently, cold plasma seed treatment has the potential to control tomato bacterial wilt caused by R. solanacearum. PMID:24840508

  20. Antibacterial activity of defensin PaDef from avocado fruit (Persea americana var. drymifolia) expressed in endothelial cells against Escherichia coli and Staphylococcus aureus.

    Science.gov (United States)

    Guzmán-Rodríguez, Jaquelina Julia; López-Gómez, Rodolfo; Suárez-Rodríguez, Luis M; Salgado-Garciglia, Rafael; Rodríguez-Zapata, Luis C; Ochoa-Zarzosa, Alejandra; López-Meza, Joel E

    2013-01-01

    Antimicrobial therapy is a useful tool to control infectious diseases in general and rising antibiotic resistant microorganisms in particular. Alternative strategies are desirable, and antimicrobial peptides (AMP) represent attractive control agents. Mexican avocado (Persea americana var. drymifolia) is used in traditional medicine; however, the AMP production has not been reported in this plant. We obtained a cDNA library from avocado fruit and clone PaDef was identified, which has a cDNA (249 bp) encoding a protein (78 aa) homologous with plant defensins (>80%). We expressed the defensin PaDef cDNA (pBME3) in the bovine endothelial cell line BVE-E6E7. Polyclonal and clonal populations were obtained and their activity was evaluated against Escherichia coli, Staphylococcus aureus, and Candida albicans. E. coli viability was inhibited with 100 μg/mL of total protein from clones (>55%). Also, S. aureus viability was inhibited from 50 μg/mL total protein (27-38%) but was more evident at 100 μg/mL (52-65%). This inhibition was higher than the effect showed by polyclonal population (~23%). Finally, we did not detect activity against C. albicans. These results are the first report that shows antimicrobial activity of a defensin produced by avocado and suggest that this AMP could be used in the control of pathogens.

  1. Antibacterial Activity of Defensin PaDef from Avocado Fruit (Persea americana var. drymifolia Expressed in Endothelial Cells against Escherichia coli and Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Jaquelina Julia Guzmán-Rodríguez

    2013-01-01

    Full Text Available Antimicrobial therapy is a useful tool to control infectious diseases in general and rising antibiotic resistant microorganisms in particular. Alternative strategies are desirable, and antimicrobial peptides (AMP represent attractive control agents. Mexican avocado (Persea americana var. drymifolia is used in traditional medicine; however, the AMP production has not been reported in this plant. We obtained a cDNA library from avocado fruit and clone PaDef was identified, which has a cDNA (249 bp encoding a protein (78 aa homologous with plant defensins (>80%. We expressed the defensin PaDef cDNA (pBME3 in the bovine endothelial cell line BVE-E6E7. Polyclonal and clonal populations were obtained and their activity was evaluated against Escherichia coli, Staphylococcus aureus, and Candida albicans. E. coli viability was inhibited with 100 μg/mL of total protein from clones (>55%. Also, S. aureus viability was inhibited from 50 μg/mL total protein (27–38% but was more evident at 100 μg/mL (52–65%. This inhibition was higher than the effect showed by polyclonal population (~23%. Finally, we did not detect activity against C. albicans. These results are the first report that shows antimicrobial activity of a defensin produced by avocado and suggest that this AMP could be used in the control of pathogens.

  2. Antibacterial activity of defensin PaDef from avocado fruit (Persea americana var. drymifolia) expressed in endothelial cells against Escherichia coli and Staphylococcus aureus.

    Science.gov (United States)

    Guzmán-Rodríguez, Jaquelina Julia; López-Gómez, Rodolfo; Suárez-Rodríguez, Luis M; Salgado-Garciglia, Rafael; Rodríguez-Zapata, Luis C; Ochoa-Zarzosa, Alejandra; López-Meza, Joel E

    2013-01-01

    Antimicrobial therapy is a useful tool to control infectious diseases in general and rising antibiotic resistant microorganisms in particular. Alternative strategies are desirable, and antimicrobial peptides (AMP) represent attractive control agents. Mexican avocado (Persea americana var. drymifolia) is used in traditional medicine; however, the AMP production has not been reported in this plant. We obtained a cDNA library from avocado fruit and clone PaDef was identified, which has a cDNA (249 bp) encoding a protein (78 aa) homologous with plant defensins (>80%). We expressed the defensin PaDef cDNA (pBME3) in the bovine endothelial cell line BVE-E6E7. Polyclonal and clonal populations were obtained and their activity was evaluated against Escherichia coli, Staphylococcus aureus, and Candida albicans. E. coli viability was inhibited with 100 μg/mL of total protein from clones (>55%). Also, S. aureus viability was inhibited from 50 μg/mL total protein (27-38%) but was more evident at 100 μg/mL (52-65%). This inhibition was higher than the effect showed by polyclonal population (~23%). Finally, we did not detect activity against C. albicans. These results are the first report that shows antimicrobial activity of a defensin produced by avocado and suggest that this AMP could be used in the control of pathogens. PMID:24319695

  3. Pre-adapting parasitic phages to a pathogen leads to increased pathogen clearance and lowered resistance evolution with Pseudomonas aeruginosa cystic fibrosis bacterial isolates.

    Science.gov (United States)

    Friman, V-P; Soanes-Brown, D; Sierocinski, P; Molin, S; Johansen, H K; Merabishvili, M; Pirnay, J-P; De Vos, D; Buckling, A

    2016-01-01

    Recent years have seen renewed interest in phage therapy--the use of viruses to specifically kill disease-causing bacteria--because of the alarming rise in antibiotic resistance. However, a major limitation of phage therapy is the ease at with bacteria can evolve resistance to phages. Here, we determined whether in vitro experimental coevolution can increase the efficiency of phage therapy by limiting the resistance evolution of intermittent and chronic cystic fibrosis Pseudomonas aeruginosa lung isolates to four different phages. We first pre-adapted all phage strains against all bacterial strains and then compared the efficacy of pre-adapted and nonadapted phages against ancestral bacterial strains. We found that evolved phages were more efficient in reducing bacterial densities than ancestral phages. This was primarily because only 50% of bacterial strains were able to evolve resistance to evolved phages, whereas all bacteria were able to evolve some level of resistance to ancestral phages. Although the rate of resistance evolution did not differ between intermittent and chronic isolates, it incurred a relatively higher growth cost for chronic isolates when measured in the absence of phages. This is likely to explain why evolved phages were more effective in reducing the densities of chronic isolates. Our data show that pathogen genotypes respond differently to phage pre-adaptation, and as a result, phage therapies might need to be individually adjusted for different patients. PMID:26476097

  4. Conjugative DNA transfer induces the bacterial SOS response and promotes antibiotic resistance development through integron activation.

    Directory of Open Access Journals (Sweden)

    Zeynep Baharoglu

    2010-10-01

    Full Text Available Conjugation is one mechanism for intra- and inter-species horizontal gene transfer among bacteria. Conjugative elements have been instrumental in many bacterial species to face the threat of antibiotics, by allowing them to evolve and adapt to these hostile conditions. Conjugative plasmids are transferred to plasmidless recipient cells as single-stranded DNA. We used lacZ and gfp fusions to address whether conjugation induces the SOS response and the integron integrase. The SOS response controls a series of genes responsible for DNA damage repair, which can lead to recombination and mutagenesis. In this manuscript, we show that conjugative transfer of ssDNA induces the bacterial SOS stress response, unless an anti-SOS factor is present to alleviate this response. We also show that integron integrases are up-regulated during this process, resulting in increased cassette rearrangements. Moreover, the data we obtained using broad and narrow host range plasmids strongly suggests that plasmid transfer, even abortive, can trigger chromosomal gene rearrangements and transcriptional switches in the recipient cell. Our results highlight the importance of environments concentrating disparate bacterial communities as reactors for extensive genetic adaptation of bacteria.

  5. Inheritance of rainbow trout Oncorhynchus mykiss spleen size and correlation with bacterial cold water disease resistance

    Science.gov (United States)

    Infectious disease causes substantial loss in aquaculture and selective breeding for increased innate resistance offers an attractive strategy for controlling disease. In 2005, the NCCCWA implemented a selective breeding program to increase rainbow trout survival following challenge with Flavobacte...

  6. Inhibition of Bacterial Multidrug Resistance by Celecoxib, a Cyclooxygenase-2 Inhibitor▿

    OpenAIRE

    Kalle, Arunasree M.; Rizvi, Arshad

    2010-01-01

    Multidrug resistance (MDR) is a major problem in the treatment of infectious diseases and cancer. Accumulating evidence suggests that the cyclooxygenase-2 (COX-2)-specific inhibitor celecoxib would not only inhibit COX-2 but also help in the reversal of drug resistance in cancers by inhibiting the MDR1 efflux pump. Here, we demonstrate that celecoxib increases the sensitivity of bacteria to the antibiotics ampicillin, kanamycin, chloramphenicol, and ciprofloxacin by accumulating the drugs ins...

  7. Response in soil of Cupriavidus necator and other copper-resistant bacterial predators of bacteria to addition of water, soluble nutrients, various bacterial species, or Bacillus thuringiensis spores and crystals

    Energy Technology Data Exchange (ETDEWEB)

    Casida, L.E. Jr. (Pennsylvania State Univ., University Park (USA))

    1988-09-01

    Soil was incubated with various species of bacteria, Bacillus subtilis, or Bacillus thuringiensis spores and crystals. These were added to serve as potential prey for indigenous, copper-resistant, nonobligate bacterial predators of bacteria in the soil. Alternatively, the soil was incubated with soluble nutrients or water only to cause potential indigenous prey cells to multiply so the predator cells would multiply. All of these incubation procedures caused excessive multiplication of some gram-negative bacteria in soil. Even greater multiplication, however, often occurred for certain copper-resistant bacterial predators of bacteria that made up a part of the gram-negative response. Incubation of the soil with copper per se did not give these responses. In most cases, the copper-resistant bacteria that responded were Cupriavidus necator, bacterial predator L-2, or previously unknown bacteria that resembled them. The results suggest that, under various conditions of soil incubation, gram-negative bacterial predators of bacteria multiply and that several copper-resistant types among them can be detected, counted, and isolated by plating dilutions of the soil onto media containing excess copper.

  8. Steering Evolution with Sequential Therapy to Prevent the Emergence of Bacterial Antibiotic Resistance.

    Directory of Open Access Journals (Sweden)

    Daniel Nichol

    2015-09-01

    Full Text Available The increasing rate of antibiotic resistance and slowing discovery of novel antibiotic treatments presents a growing threat to public health. Here, we consider a simple model of evolution in asexually reproducing populations which considers adaptation as a biased random walk on a fitness landscape. This model associates the global properties of the fitness landscape with the algebraic properties of a Markov chain transition matrix and allows us to derive general results on the non-commutativity and irreversibility of natural selection as well as antibiotic cycling strategies. Using this formalism, we analyze 15 empirical fitness landscapes of E. coli under selection by different β-lactam antibiotics and demonstrate that the emergence of resistance to a given antibiotic can be either hindered or promoted by different sequences of drug application. Specifically, we demonstrate that the majority, approximately 70%, of sequential drug treatments with 2-4 drugs promote resistance to the final antibiotic. Further, we derive optimal drug application sequences with which we can probabilistically 'steer' the population through genotype space to avoid the emergence of resistance. This suggests a new strategy in the war against antibiotic-resistant organisms: drug sequencing to shepherd evolution through genotype space to states from which resistance cannot emerge and by which to maximize the chance of successful therapy.

  9. [Biotypes and antibiotic resistance patterns of Gardnerella vaginalis strains isolated from healthy women and women with bacterial vaginosis].

    Science.gov (United States)

    Tosun, Ilknur; Alpay Karaoğlu, Sengül; Ciftçi, Hasan; Buruk, Celal Kurtuluş; Aydin, Faruk; Kiliç, Ali Osman; Ertürk, Murat

    2007-01-01

    As Gardnerella vaginalis is accepted as a member of normal vaginal flora, it is one of the dominant species which has been related to bacterial vaginosis (BV). The aim of this study was to determine the isolation rate, biotypes and antibiotic resistance patterns of G.vaginalis from the vaginal swab samples of 408 women who were admitted to the outpatient clinics of Family Planning Center. Hippurate hydrolysis, lipase and beta-galactosidase tests were performed for biotyping the isolates, and agar dilution (for metronidazole) and disk diffusion (for clindamycin) tests were used for the detection of antibiotic resistance patterns. As a result, by Nugent's BV scoring protocol, 122 (29.9%), 20 (29.4%), 137 (33.6%), and 18 (4.4%) of the women were diagnosed as BV, intermediate form, normal vaginal flora (NVF) and mycotic vaginosis, respectively. The overall isolation rate of G.vaginalis was found as 23% (94/408). Of them, 56.4% (53/94) and 8.5% (8/94) were isolated from samples of BV cases and subjects with NVF, respectively, and the difference was statistically significant (pbiotyping results showed that the most frequently detected types were biotype 1 (44%), 5 (20%) and 4 (18%). There was no statistically significant difference between the biotype distribution of BV patients and the subjects who have NVF (p=0.687). The results of antibiotic susceptibility tests indicated that 70% and 53% of the isolates were resistant to metronidazole and clindamycin, respectively. It was of interest that MIC values for metronidazole was > or =128 microg/ml in 57% of resistant strains. The data of this study has emphasized that the metronidazole resistance is very high in our population, and the large scale studies are needed to clarify the relationship between BV and G.vaginalis biotypes, which can be found in the normal vaginal flora.

  10. Improvement of Basmati rice varieties for resistance to blast and bacterial blight diseases using marker assisted backcross breeding.

    Science.gov (United States)

    Ellur, Ranjith K; Khanna, Apurva; Yadav, Ashutosh; Pathania, Sandeep; Rajashekara, H; Singh, Vikas K; Gopala Krishnan, S; Bhowmick, Prolay K; Nagarajan, M; Vinod, K K; Prakash, G; Mondal, Kalyan K; Singh, Nagendra K; Vinod Prabhu, K; Singh, Ashok K

    2016-01-01

    Marker assisted backcross breeding was employed to incorporate the blast resistance genes, Pi2 and Pi54 and bacterial blight (BB) resistance genes xa13 and Xa21 into the genetic background of Pusa Basmati 1121 (PB1121) and Pusa Basmati 6. Foreground selection for target gene(s) was followed by arduous phenotypic and background selection which fast-tracked the recovery of recurrent parent genome (RPG) to an extent of 95.8% in one of the near-isogenic lines (NILs) namely, Pusa 1728-23-33-31-56, which also showed high degree of resemblance to recurrent parent, PB6 in phenotype. The phenotypic selection prior to background selection provided an additional opportunity for identifying the novel recombinants viz., Pusa 1884-9-12-14 and Pusa 1884-3-9-175, superior to parental lines in terms of early maturity, higher yield and improved quality parameters. There was no significant difference between the RPG recovery estimated based on SSR or SNP markers, however, the panel of SNPs markers was considered as the better choice for background selection as it provided better genome coverage and included SNPs in the genic regions. Multi-location evaluation of NILs depicted their stable and high mean performance in comparison to the respective recurrent parents. The Pi2+Pi54 carrying NILs were effective in combating a pan-India panel of Magnaporthe oryzae isolates with high level of field resistance in northern, eastern and southern parts of India. Alongside, the PB1121-NILs and PB6-NILs carrying BB resistance genes xa13+Xa21 were resistant against Xanthomonas oryzae pv. oryzae races of north-western, southern and eastern parts of the country. Three of NILs developed in this study, have been promoted to final stage of testing during the ​Kharif 2015 in the Indian National Basmati Trial. PMID:26566849

  11. Combinative effects of a bacterial type-III effector and a biocontrol bacterium on rice growth and disease resistance

    Indian Academy of Sciences (India)

    Haiying Ren; Ganyu Gu; Juying Long; Qian Yin; Tingquan Wu; Tao Song; Shujian Zhang; Zhiyi Chen; Hansong Dong

    2006-12-01

    Expression of HpaGXoo, a bacterial type-III effector, in transgenic plants induces disease resistance. Resistance also can be elicited by biocontrol bacteria. In both cases, plant growth is often promoted. Here we address whether biocontrol bacteria and HpaGXoo can act together to provide better results in crop improvement. We studied effects of Pseudomonas cepacia on the rice variety R109 and the hpaGXoo-expressing rice line HER1. Compared to R109, HER1 showed increased growth, grain yield, and defense responses toward diseases and salinity stress. Colonization of roots by P. cepacia caused 20% and 13% increase, in contrast to controls, in root growth of R109 and HER1. Growth of leaves and stems also increased in R109 but that of HER1 was inhibited. When P. cepacia colonization was subsequent to plant inoculation with Rhizoctonia solani, a pathogen that causes sheath blight, the disease was less severe than controls in both R109 and HER1; HER1, nevertheless, was more resistant, suggesting that P. cepacia and HpaGXoo cooperate in inducing disease resistance. Several genes that critically regulate growth and defense behaved differentially in HER1 and R109 while responding to P. cepacia. In R109 leaves, the OsARF1 gene, which regulates plant growth, was expressed in consistence with growth promotion by P. cepacia. Inversely, OsARF1 expression was coincident with inhibition in growth of HER1 leaves. In both plants, the expression of OsEXP1, which encodes an expansin protein involved in plant growth, was concomitant with growth promotion in leaves instead of roots, in response to P. cepacia. We also studied OsMAPK, a gene that encodes a mitogen-activated protein kinase and controls defense responses toward salinity and infection by pathogens in rice. In response to P. cepacia, an early expression of OsMAPK was coincident with R109 resistance to the disease, while HER1 expressed the gene similarly whether P. cepacia was present or not. Evidently, P. cepacia and GXoo

  12. 越南对抗角斑病棉花品种的选育(英)%Screening of Promising Cotton Varieties for Bacterial Blight Resistance

    Institute of Scientific and Technical Information of China (English)

    Bui Thi Ngan

    2002-01-01

    @@ I Introduction Bacterial Blight (Xanthomonas malvacearum ,BB) was probably originated in India, although the disease was first reported in the USA by Atkinson (1891), who gave the names angular leaf spot, blackarm and bacterial boll rot to the various stages in the syndrome of the disease. The first programme to breed for cultivar resistance to the disease was initiated in Sudan by research officers with the Cotton Research Corporation. Methods adopted there were soon implemented in Uganda and most of the early resistant varieties grown in many African countries were derived from the Uganda programme.

  13. Towards a tolerance toolkit: Gene expression signatures enabling the emergence of resistant bacterial strains

    Science.gov (United States)

    Erickson, Keesha; Chatterjee, Anushree

    2014-03-01

    Microbial pathogens are able to rapidly acquire tolerance to chemical toxins. Developing next-generation antibiotics that impede the emergence of resistance will help avoid a world-wide health crisis. Conversely, the ability to induce rapid tolerance gains could lead to high-yielding strains for sustainable production of biofuels and commodity chemicals. Achieving these goals requires an understanding of the general mechanisms allowing microbes to become resistant to diverse toxins. We apply top-down and bottom-up methodologies to identify biological network changes leading to adaptation and tolerance. Using a top-down approach, we perform evolution experiments to isolate resistant strains, collect samples for transcriptomic and proteomic analysis, and use the omics data to inform mathematical gene regulatory models. Using a bottom-up approach, we build and test synthetic genetic devices that enable increased or decreased expression of selected genes. Unique patterns in gene expression are identified in cultures actively gaining resistance, especially in pathways known to be involved with stress response, efflux, and mutagenesis. Genes correlated with tolerance could potentially allow the design of resistance-free antibiotics or robust chemical production strains.

  14. Innate Defense against Influenza A Virus: Activity of Human Neutrophil Defensins and Interactions of Defensins with Surfactant Protein D

    DEFF Research Database (Denmark)

    Hartshorn, Kevan L.; White, Mitchell R.; Tecle, Tesfaldet;

    2006-01-01

    Surfactant protein D (SP-D) plays important roles in innate host defense against influenza A virus (IAV) infection, in part by modifying interactions with neutrophils. Human neutrophil defensins (HNPs) inhibit infectivity of enveloped viruses, including IAV. Our goal in this study...... was to characterize antiviral interactions between SP-D and HNPs. Recombinant and/or natural forms of SP-D and related collectins and HNPs were tested for antiviral activity against two different strains of IAV. HNPs 1 and 2 did not inhibit viral hemagglutination activity, but they interfered...

  15. The Role of Antimicrobial Peptides in Preventing Multidrug-Resistant Bacterial Infections and Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Kyung-Soo Hahm

    2011-09-01

    Full Text Available Over the last decade, decreasing effectiveness of conventional antimicrobial-drugs has caused serious problems due to the rapid emergence of multidrug-resistant pathogens. Furthermore, biofilms, which are microbial communities that cause serious chronic infections and dental plaque, form environments that enhance antimicrobial resistance. As a result, there is a continuous search to overcome or control such problems, which has resulted in antimicrobial peptides being considered as an alternative to conventional drugs. Antimicrobial peptides are ancient host defense effector molecules in living organisms. These peptides have been identified in diverse organisms and synthetically developed by using peptidomimic techniques. This review was conducted to demonstrate the mode of action by which antimicrobial peptides combat multidrug-resistant bacteria and prevent biofilm formation and to introduce clinical uses of these compounds for chronic disease, medical devices, and oral health. In addition, combinations of antimicrobial peptides and conventional drugs were considered due to their synergetic effects and low cost for therapeutic treatment.

  16. Antibiotic reduction campaigns do not necessarily decrease bacterial resistance: the example of methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Kardas-Sloma, Lidia; Boëlle, Pierre-Yves; Opatowski, Lulla; Guillemot, Didier; Temime, Laura

    2013-09-01

    Interventions designed to reduce antibiotic consumption are under way worldwide. While overall reductions are often achieved, their impact on the selection of antibiotic-resistant selection cannot be assessed accurately from currently available data. We developed a mathematical model of methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA) transmission inside and outside the hospital. A systematic simulation study was then conducted with two objectives: to assess the impact of antibiotic class-specific changes during an antibiotic reduction period and to investigate the interactions between antibiotic prescription changes in the hospital and the community. The model reproduced the overall reduction in MRSA frequency in French intensive-care units (ICUs) with antibiotic consumption in France from 2002 to 2003 as an input. However, the change in MRSA frequency depended on which antibiotic classes changed the most, with the same overall 10% reduction in antibiotic use over 1 year leading to anywhere between a 69% decrease and a 52% increase in MRSA frequency in ICUs and anywhere between a 37% decrease and a 46% increase in the community. Furthermore, some combinations of antibiotic prescription changes in the hospital and the community could act in a synergistic or antagonistic way with regard to overall MRSA selection. This study shows that class-specific changes in antibiotic use, rather than overall reductions, need to be considered in order to properly anticipate the impact of an antibiotic reduction campaign. It also highlights the fact that optimal gains will be obtained by coordinating interventions in hospitals and in the community, since the effect of an intervention in a given setting may be strongly affected by exogenous factors.

  17. Expression and functional characterization of the plant antimicrobial snakin-1 and defensin recombinant proteins.

    Science.gov (United States)

    Kovalskaya, Natalia; Hammond, Rosemarie W

    2009-01-01

    In this study, for the first time, functionally active, recombinant, cysteine-rich plant proteins snakin-1 (SN1) and defensin (PTH1) were expressed and purified using a prokaryotic expression system. The overall level of antimicrobial activities of SN1 and PTH1 produced in Escherichia coli was commensurate with that of the same proteins previously obtained from plant tissues. Both proteins exhibited strong antibacterial activity against the phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus (50% inhibitory concentration (IC(50)) 1.5-8 microM) and antifungal activity against the phytopathogenic fungi Colletotrichum coccoides and Botrytis cinerea (IC(50) 5-14 microM). Significantly weaker activity was observed against Pseudomonas syringae pv. syringae and Pseudomonas syringae pv. tabaci. A pronounced synergistic antimicrobial effect against P. syringae pv. syringae and an additive effect against P. syringae pv. tabaci occurred with a combination of SN1 and PTH1. Aggregation of C. michiganensis subsp. sepedonicus bacterial cells at all protein concentrations tested was observed with the combination of SN1 and PTH1 and with SN1 alone. Our results demonstrate the use of a cost effective prokaryotic expression system for generation and in vitro characterization of plant cysteine-rich proteins with potential antimicrobial activities against a wide range of phytopathogenic microorganisms in order to select the most effective agents for future in vivo studies. PMID:18824107

  18. Antimicrobial activity of human α-defensin 5 and its linear analogs: N-terminal fatty acylation results in enhanced antimicrobial activity of the linear analogs.

    Science.gov (United States)

    Mathew, Basil; Nagaraj, Ramakrishnan

    2015-09-01

    Human α-defensin 5 (HD5) exhibits broad spectrum antimicrobial activity and plays an important role in mucosal immunity of the small intestine. Although there have been several studies, the structural requirements for activity and mechanism of bacterial killing is yet to be established unequivocally. In this study, we have investigated the antimicrobial activity of HD5 and linear analogs. Cysteine deletions attenuated the antibacterial activity considerably. Candidacidal activity was affected to a lesser extent. Fatty acid conjugated linear analogs showed antimicrobial activity comparable activity to HD5. Effective surface charge neutralization of bacteria was observed for HD5 as compared to the non-fatty acylated linear analogs. Our results show that HD5 and non-fatty acylated linear analogs enter the bacterial cytoplasm without causing damage to the bacterial inner membrane. Although fatty acylated peptides exhibited antimicrobial activity comparable to HD5, their mechanism of action involved permeabilization of the Escherichia coli inner membrane. HD5 and analogs had the ability to bind plasmid DNA. HD5 had greater binding affinity to plasmid DNA as compared to the analogs. The three dimensional structure of HD5 favors greater interaction with the bacterial cell surface and also with DNA. Antibacterial activity of HD5 involves entry into bacterial cytoplasm and binding to DNA which would result in shut down of the bacterial metabolism leading to cell death. We show how a moderately active linear peptide derived from the α-defensin HD5 can be engineered to enhance antimicrobial activity almost comparable to the native peptide. PMID:26206286

  19. Antibiotic resistance pattern of bacterial isolates from skin and soft tissue infections

    Directory of Open Access Journals (Sweden)

    Debadutta Mishra

    2016-05-01

    Conclusions: Staphylococcus aureus exhibited high resistance to commonly prescribed antibiotics like beta-lactams, fluroquinolones and fusidic acid. Hence, it is recommended to base the treatment upon culture and sensitivity report. [Int J Res Med Sci 2016; 4(5.000: 1458-1462

  20. Reductions of bacterial antibiotic resistance through five biological treatment processes treated municipal wastewater.

    Science.gov (United States)

    Yuan, Qing-Bin; Guo, Mei-Ting; Wei, Wu-Ji; Yang, Jian

    2016-10-01

    Wastewater treatment plants are hot spots for antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). However, limited studies have been conducted to compare the reductions of ARB and ARGs by various biological treatment processes. The study explored the reductions of heterotrophic bacteria resistant to six groups of antibiotics (vancomycin, gentamicin, erythromycin, cephalexin, tetracycline, and sulfadiazine) and corresponding resistance genes (vanA, aacC1, ereA, ampC, tetA, and sulI) by five bench-scale biological reactors. Results demonstrated that membrane bioreactor (MBR) and sequencing batch reactor (SBR) significantly reduced ARB abundances in the ranges of 2.80∼3.54 log and 2.70∼3.13 log, respectively, followed by activated sludge (AS). Biological filter (BF) and anaerobic (upflow anaerobic sludge blanket, UASB) techniques led to relatively low reductions. In contrast, ARGs were not equally reduced as ARB. AS and SBR also showed significant potentials on ARGs reduction, whilst MBR and UASB could not reduce ARGs effectively. Redundancy analysis implied that the purification of wastewater quality parameters (COD, NH4 (+)-N, and turbidity) performed a positive correlation to ARB and ARGs reductions. PMID:27384166

  1. Bacterial antibiotic resistance levels in Danish farmland as a result of treatment with pig manure slurry

    DEFF Research Database (Denmark)

    Sengeløv, Gitte; Agersø, Yvonne; Halling-Sørensen, B.;

    2003-01-01

    Resistance to tetracycline, macrolides and streptomycin was measured for a period of 8 months in soil bacteria obtained from farmland treated with pig manure slurry. This was done by spread plating bacteria on selective media (Luria Bertani (LB) medium supplemented with antibiotics). To account...

  2. Changes of bacterial diversity and tetracycline resistance in sludge from AAO systems upon exposure to tetracycline pressure

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Manhong, E-mail: egghmh@163.com; Qi, Fangfang; Wang, Jue; Xu, Qi; Lin, Li

    2015-11-15

    Highlights: • High-throughput sequencing was used to compare sludge bacteria with and without TC. • Bacterial diversity increased with TC addition despite of various oxygen conditions. • Total TRGs proliferated with TC addition in three kinds of sludge. • The concentration of efflux pump genes was the highest in the three groups of TRGs. - Abstract: Two lab-scale anaerobic-anoxic-oxic (AAO) systems were used to investigate the changes in tetracycline (TC) resistance and bacterial diversity upon exposure to TC pressure. High-throughput sequencing was used to detect diversity changes in microorganisms at the level of class in sludge from different bioreactors with and without TC. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) was used to detect the abundances of eight tetracycline resistance genes (TRGs), tetA, tetB, tetC, tetE, tetM, tetO, tetS and tetX. The results showed that the diversities of the microbial communities of anoxic, anaerobic and aerobic sludge all increased with the addition of TC. TC substantially changed the structure of the microbial community regardless of oxygen conditions. Bacteroidetes and Proteobacteria were the dominant species in the three kinds of sludge and were substantially enriched with TC pressure. In sludge with TC added, almost all target TRGs proliferated more than those in sludge without TC except tetX, which decreased in anaerobic sludge with TC addition. The concentration of efflux pump genes, tet(A–C, E), was the highest among the three groups of TRGs in the different kinds of sludge.

  3. Changes of bacterial diversity and tetracycline resistance in sludge from AAO systems upon exposure to tetracycline pressure

    International Nuclear Information System (INIS)

    Highlights: • High-throughput sequencing was used to compare sludge bacteria with and without TC. • Bacterial diversity increased with TC addition despite of various oxygen conditions. • Total TRGs proliferated with TC addition in three kinds of sludge. • The concentration of efflux pump genes was the highest in the three groups of TRGs. - Abstract: Two lab-scale anaerobic-anoxic-oxic (AAO) systems were used to investigate the changes in tetracycline (TC) resistance and bacterial diversity upon exposure to TC pressure. High-throughput sequencing was used to detect diversity changes in microorganisms at the level of class in sludge from different bioreactors with and without TC. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) was used to detect the abundances of eight tetracycline resistance genes (TRGs), tetA, tetB, tetC, tetE, tetM, tetO, tetS and tetX. The results showed that the diversities of the microbial communities of anoxic, anaerobic and aerobic sludge all increased with the addition of TC. TC substantially changed the structure of the microbial community regardless of oxygen conditions. Bacteroidetes and Proteobacteria were the dominant species in the three kinds of sludge and were substantially enriched with TC pressure. In sludge with TC added, almost all target TRGs proliferated more than those in sludge without TC except tetX, which decreased in anaerobic sludge with TC addition. The concentration of efflux pump genes, tet(A–C, E), was the highest among the three groups of TRGs in the different kinds of sludge

  4. Selenium hyperaccumulators harbor a diverse endophytic bacterial community characterized by high selenium resistance and plant growth promoting properties

    Directory of Open Access Journals (Sweden)

    Martina eSura - de Jong

    2015-03-01

    Full Text Available Selenium (Se-rich plants may be used to provide dietary Se to humans and livestock, and also to clean up Se-polluted soils or waters. This study focused on endophytic bacteria of plants that hyperaccumulate selenium (Se to 0.5-1% of dry weight. Terminal restriction fragment length polymorphism (T-RFLP analysis was used to compare the diversity of endophytic bacteria of hyperaccumulators Stanleya pinnata (Brassicaceae and Astragalus bisulcatus (Fabaceae with those from related non-accumulators Physaria bellii (Brassicaceae and Medicago sativa (Fabaceae collected on the same, seleniferous site. Hyperaccumulators and non-accumulators showed equal T-RF diversity. Parsimony analysis showed that T-RFs from individuals of the same species were more similar to each other than to those from other species, regardless of plant Se content or spatial proximity. Cultivable endophytes from hyperaccumulators S. pinnata and A. bisulcatus were further identified and characterized. The 66 bacterial morphotypes were shown by MS MALDI-TOF Biotyper analysis and 16S rRNA gene sequencing to include strains of Bacillus, Pseudomonas, Pantoea, Staphylococcus, Paenibacillus, Advenella, Arthrobacter and Variovorax. Most isolates were highly resistant to selenate and selenite (up to 200 mM and all could reduce selenite to red elemental Se, reduce nitrite and produce siderophores. Seven isolates were selected for plant inoculation and found to have plant growth promoting properties, both in pure culture and when co-cultivated with crop species Brassica juncea (Brassicaceae or M. sativa. There were no effects on plant Se accumulation. We conclude that Se hyperaccumulators harbor an endophytic bacterial community in their natural seleniferous habitat that is equally diverse to that of comparable non-accumulators. The hyperaccumulator endophytes are characterized by high Se resistance, capacity to produce elemental Se and plant growth promoting properties.

  5. BACTERIAL PROFILE, ANTIBIOTIC SENSITIVITY AND RESISTANCE OF LOWER RESPIRATORY TRACT INFECTIONS IN UPPER EGYPT

    Directory of Open Access Journals (Sweden)

    Gamal Agmy

    2013-09-01

    Full Text Available BACKGROUND: Lower respiratory tract infections (LRTI account for a considerable proportion of morbidity and antibiotic use. We aimed to identify the causative bacteria, antibiotic sensitivity and resistance of hospitalized adult patients due to LRTI in Upper Egypt. METHODS: A multicentre prospective study was performed at 3 University Hospitals for 3 years. Samples included sputum or bronchoalveolar lavage (BAL for staining and culture, and serum for serology. Samples were cultured on 3 bacteriological media (Nutrient, Chocolate ,MacConkey's agars.Colonies were identified via MicroScan WalkAway-96. Pneumoslide IgM kit was used for detection of atypical pathogens via indirect immunofluorescent assay. RESULTS: The predominant isolates in 360 patients with CAP were S.pneumoniae (36%, C. pneumoniae (18%, and M. pneumoniae (12%. A higher sensitivity was recorded for moxifloxacin, levofloxacin, macrolides, and cefepime. A higher of resistance was recorded for doxycycline, cephalosporins, and β-lactam-β-lactamase inhibitors. The predominant isolates in 318 patients with HAP were, methicillin-resistant Staphylococcus aureus; MRSA (23%, K. pneumoniae (14%, and polymicrobial in 12%. A higher sensitivity was recorded for vancomycin, ciprofloxacin, and moxifloxacin. Very high resistance was recorded for β-lactam-β-lactamase inhibitors and cephalosporins. The predominant organisms in 376 patients with acute exacerbation of chronic obstructive pulmonary diseases (AECOPD were H. influnzae (30%, S. pneumoniae (25%, and M. catarrhalis(18%. A higher sensitivity was recorded for moxifloxacin, macrolides and cefepime. A higher rate of resistance was recorded for aminoglycosides and cephalosporins CONCLUSIONS: The most predominant bacteria for CAP in Upper Egypt are S. pneumoniae and atypical organisms, while that for HAP are MRSA and Gram negative bacteria. For acute exacerbation of COPD,H.influnzae was the commonest organism. Respiratory quinolones

  6. Overexpressing CYP71Z2 enhances resistance to bacterial blight by suppressing auxin biosynthesis in rice.

    Directory of Open Access Journals (Sweden)

    Wenqi Li

    Full Text Available The hormone auxin plays an important role not only in the growth and development of rice, but also in its defense responses. We've previously shown that the P450 gene CYP71Z2 enhances disease resistance to pathogens through regulation of phytoalexin biosynthesis in rice, though it remains unclear if auxin is involved in this process or not.The expression of CYP71Z2 was induced by Xanthomonas oryzae pv. oryzae (Xoo inoculation was analyzed by qRT-PCR, with GUS histochemical staining showing that CYP71Z2 expression was limited to roots, blades and nodes. Overexpression of CYP71Z2 in rice durably and stably increased resistance to Xoo, though no significant difference in disease resistance was detected between CYP71Z2-RNA interference (RNAi rice and wild-type. Moreover, IAA concentration was determined using the HPLC/electrospray ionization/tandem mass spectrometry system. The accumulation of IAA was significantly reduced in CYP71Z2-overexpressing rice regardless of whether plants were inoculated or not, whereas it was unaffected in CYP71Z2-RNAi rice. Furthermore, the expression of genes related to IAA, expansin and SA/JA signaling pathways was suppressed in CYP71Z2-overexpressing rice with or without inoculation.These results suggest that CYP71Z2-mediated resistance to Xoo may be via suppression of IAA signaling in rice. Our studies also provide comprehensive insight into molecular mechanism of resistance to Xoo mediated by IAA in rice. Moreover, an available approach for understanding the P450 gene functions in interaction between rice and pathogens has been provided.

  7. Bacterial isolate and antibacterial resistance pattern of ear infection among patients attending at Hawassa university referral Hospital, Hawassa, Ethiopia

    Directory of Open Access Journals (Sweden)

    Mesfin Worku

    2014-01-01

    Full Text Available Background: Ear infection is highly prevalent worldwide. In the older child, long-standing Chronic Supparative Ottitis Media can result in a severe conductive hearing loss with significant drawbacks in learning, communication, and social adjustment. It is associated with hearing impairment, death, and severe disability due to central nervous system involvement in developing countries. Objective: To determine the bacteriological profile and antibacterial resistance of ear infection from patients seen at Ear Nose and Throat clinic of Hawassa University Referral Hospital. Materials and Methods: A cross-sectional study was conducted at clinic of Hawassa University Referal Hospital. Result: A total 117 study subjects included in this study from June 2013 to October 2013. Among these, 57 (48.7% were male and 53 (45.3% were children. Bacteria identified from positive ear swabs were: Staphylococcus aureus 24 (20.5%, Pseudomonas aeroginosa 17 (14.5%, Klebsiella species 10 (8.5%, Proteus species 7 (6.0%, Entrobacter species 4 (3.4%, Escherchia coli 3 (2.6%, Citrobacter species 2 (1.7%, and Providentia species 2 (1.7%. The overall sensitivity and resistance profile of antibacterial agent, Amikacin (90.0% and Gentamycin (89.1 showed high level of antibacterial effect on all identified bacterial species. On other hand, all isolates were highly resistance to ampicilin (87.5%, oxacillin (84.0%, ceftriaxone (82.8%, cephalotin (81.4%, and penicillin G (73.8%. Conclusion: Most of the isolates were resistant to commonly prescribed drug in the area. However, Amikacin and Gentamycin were highly active against the isolated organism, whereas Ciprofloxacilin was moderately active. Therefore, culture and susceptibility test is vital for appropriate management of ear infection in study area.

  8. An evolutionary history of defensins: a role for copy number variation in maximizing host innate and adaptive immune responses.

    Directory of Open Access Journals (Sweden)

    Lee R Machado

    2015-03-01

    Full Text Available Defensins represent an evolutionary ancient family of antimicrobial peptides that play diverse roles in human health and disease. Defensins are cationic cysteine-containing multifunctional peptides predominantly expressed by epithelial cells or neutrophils. Defensins play a key role in host innate immune responses to infection and, in addition to their classically described role as antimicrobial peptides, have also been implicated in immune modulation, fertility, development and wound healing. Aberrant expression of defensins is important in a number of inflammatory diseases as well as modulating host immune responses to bacteria, unicellular pathogens and viruses. In parallel with their role in immunity, in other species, defensins have evolved alternative functions, including the control of coat color in dogs. Defensin genes reside in complex genomic regions that are prone to structural variations and some defensin family members exhibit copy number variation (CNV. Structural variations have mediated, and continue to influence, the diversification and expression of defensin family members. This review highlights the work currently being done to better understand the genomic architecture of the β-defensin locus. It evaluates current evidence linking defensin copy number variation to autoimmune disease (i.e. Crohn’s disease and psoriasis as well as the contribution CNV has in influencing immune responses to HIV infection.

  9. Mathematical modeling of bacterial kinetics to predict the impact of antibiotic colonic exposure and treatment duration on the amount of resistant enterobacteria excreted.

    OpenAIRE

    Thu Thuy Nguyen; Jeremie Guedj; Elisabeth Chachaty; Jean de Gunzburg; Antoine Andremont; France Mentré

    2014-01-01

    Fecal excretion of antibiotics and resistant bacteria in the environment are major public health threats associated with extensive farming and modern medical care. Innovative strategies that can reduce the intestinal antibiotic concentrations during treatments are in development. However, the effect of lower exposure on the amount of resistant enterobacteria excreted has not been quantified, making it difficult to anticipate the impact of these strategies. Here, we introduce a bacterial kinet...

  10. Mathematical Modeling of Bacterial Kinetics to Predict the Impact of Antibiotic Colonic Exposure and Treatment Duration on the Amount of Resistant Enterobacteria Excreted

    OpenAIRE

    Nguyen, Thu Thuy; Guedj, Jeremie; Chachaty, Elisabeth; de Gunzburg, Jean; Andremont, Antoine; Mentré, France

    2014-01-01

    Fecal excretion of antibiotics and resistant bacteria in the environment are major public health threats associated with extensive farming and modern medical care. Innovative strategies that can reduce the intestinal antibiotic concentrations during treatments are in development. However, the effect of lower exposure on the amount of resistant enterobacteria excreted has not been quantified, making it difficult to anticipate the impact of these strategies. Here, we introduce a bacterial kinet...

  11. Development of bacterial resistance to biocides and antimicrobial agents as a consequence of biocide usage

    DEFF Research Database (Denmark)

    Seier-Petersen, Maria Amalie

    Biocides are chemical compounds with antimicrobial properties and they are widely used for disinfection, antiseptic and preservation purposes. Biocides have been applied for centuries due to early empirical approaches, such as cleansing of wounds with wine, vinegar and honey and salting of fish...... determined (Manuscript III). The biocides comprised benzalkonium chloride (BC), hydrogen peroxide (HP), sodium hypochlorite (SH), formaldehyde (FH), and caustic soda (NaOH). S. aureus isolates did in general not show reduced susceptibility to the biocides tested. However, a quaternary ammonium compound (QAC...... be of potential risk for human health, since these disinfectants are widely used at hospitals and in the food industry. Mobile genetic elements such as conjugative transposons are important vectors in the dissemination of antibiotic resistance determinants. Tn916 including the tetracycline resistance gene tet...

  12. Country-to-country transfer of patients and the risk of multi-resistant bacterial infection.

    Science.gov (United States)

    Rogers, Benjamin A; Aminzadeh, Zohreh; Hayashi, Yoshiro; Paterson, David L

    2011-07-01

    Management of patients with a history of healthcare contact in multiple countries is now a reality for many clinicians. Leisure tourism, the burgeoning industry of medical tourism, military conflict, natural disasters, and changing patterns of human migration may all contribute to this emerging epidemiological trend. Such individuals may be both vectors and victims of healthcare-associated infection with multiresistant bacteria. Current literature describes intercountry transfer of multiresistant Acinetobacter spp and Klebsiella pneumoniae (including Klebsiella pneumoniae carbapenemase- and New Delhi metallo-β-lactamase-producing strains), methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and hypervirulent Clostridium difficile. Introduction of such organisms to new locations has led to their dissemination within hospitals. Healthcare institutions should have sound infection prevention strategies to mitigate the risk of dissemination of multiresistant organisms from patients who have been admitted to hospitals in other countries. Clinicians may also need to individualize empiric prescribing patterns to reflect the risk of multiresistant organisms in these patients. PMID:21653302

  13. Using wildlife activity and antibiotic resistance analysis to model bacterial water quality in coastal ponds

    OpenAIRE

    Pullaro, Thomas C.; Pan, Wei; Chiovarou, Erica D.; Daugomah, James W.; Shea, Norman R.; Siewicki, Thomas C.

    2009-01-01

    Models that help predict fecal coliform bacteria (FCB) levels in environmental waters can be important tools for resource managers. In this study, we used animal activity along with antibiotic resistance analysis (ARA), land cover, and other variables to build models that predict bacteria levels in coastal ponds that discharge into an estuary. Photographic wildlife monitoring was used to estimate terrestrial and aquatic wildlife activity prior to sampling. Increased duck activity was an impor...

  14. Analysis of Bacterial Drug Resistance%当前细菌抗药性探析

    Institute of Scientific and Technical Information of China (English)

    张建

    2014-01-01

    目的对当前细菌抗药性进行分析。方法对我院于2012年4月~2013年5月采集、分离1800株病原菌进行药物敏感性试验结果进行分析。结果在1800株病原菌中,革兰氏阴性菌1080株(60.00%),革兰氏阳性菌503株(27.94%),真菌217株(12.06%)。铜绿假单胞菌对各种常用抗生素均具有较强耐性,且三代与第四代头孢类抗生素病原菌抗药性不断增强。结论在抗生素临床应用中,应以病菌药敏试验结果为依据,选择病菌敏感性抗生素,才能提高治疗效果,降低致病菌抗药性。%Objective To analyze the drug resistance of bacteria. Methods In our hospital from 2012 April to 2013 May acquisition, isolated 1800 strains of pathogenic bacteria drug sensitivity test results. Results Among 1800 strains of pathogens, gram negative bacil i 1080 isolates (60%), gram positive bacil i 503 isolates (27.94%), 217 strains of fungi (12.06%). Pseudomonas aeruginosa has strong resistance to commonly used antibiotics, and the three and fourth generation cephalosporin antibiotic resistance of pathogens growing. Conclusion In the clinical application of antibiotics to bacteria, should be based on the drug sensitivity test, selection of antibiotic susceptibility of bacteria, can improve the treatment ef ect, reduce pathogenic bacteria resistance.

  15. Sterilization of hydrogen peroxide resistant bacterial spores with stabilized chlorine dioxide

    OpenAIRE

    Friedline, Anthony; Zachariah, Malcolm; Middaugh, Amy; Heiser, Matt; Khanna, Neeraj; Vaishampayan, Parag; Rice, Charles V.

    2015-01-01

    Bacillus pumilus SAFR-032 spores isolated from a clean room environment are known to exhibit enhanced resistance to peroxide, desiccation, UV radiation and chemical disinfection than other spore-forming bacteria. The survival of B. pumilus SAFR-032 spores to standard clean room sterilization practices requires development of more stringent disinfection agents. Here, we report the effects of a stabilized chlorine dioxide-based biocidal agent against spores of B. pumilus SAFR-032 and Bacillus s...

  16. [The role of antimicrobial stewardship programs in the control of bacterial resistance].

    Science.gov (United States)

    Pasquau, J; Sadyrbaeva, S; De Jesús, S E; Hidalgo-Tenorio, C

    2016-09-01

    In order to improve infection prognosis and reduce the existing microbial resistance problem (a challenge similar to that of climate change), a higher implication of the Administration, an increased level of social awareness and the development of specific corporate networks, including the pharmaceutical industry, is needed. However, we must first consolidate Antimicrobial Stewardship Programmes with experts who seek to improve antibiotic therapy effectivity in severe infections and to reduce global antibiotic exposure. PMID:27608314

  17. Development of a broad spectrum polymer-released antimicrobial coating for the prevention of resistant strain bacterial infections.

    Science.gov (United States)

    Sinclair, K D; Pham, T X; Farnsworth, R W; Williams, D L; Loc-Carrillo, C; Horne, L A; Ingebretsen, S H; Bloebaum, R D

    2012-10-01

    More than 400,000 primary hip and knee replacement surgeries are performed each year in the United States. From these procedures, approximately 0.5-3% will become infected and when considering revision surgeries, this rate has been found to increase significantly. Antibiotic-resistant bacterial infections are a growing problem in patient care. This in vitro research investigated the antimicrobial potential of the polymer released, broad spectrum, Cationic Steroidal Antimicrobial-13 (CSA-13) for challenges against 5 × 10(8) colony forming units (CFU) of methicillin-resistant Staphylococcus aureus (MRSA). It was hypothesized that a weight-to-weight (w/w) concentration of 18% CSA-13 in silicone would exhibit potent bactericidal potential when used as a controlled release device coating. When incorporated into a polymeric device coating, the 18% (w/w) broad-spectrum polymer released CSA-13 antimicrobial eliminated 5 × 10(8) CFU of MRSA within 8 h. In the future, these results will be utilized to develop a sheep model to assess CSA-13 for the prevention of perioperative device-related infections in vivo.

  18. Transgenic banana plants expressing Xanthomonas wilt resistance genes revealed a stable non-target bacterial colonization structure.

    Science.gov (United States)

    Nimusiima, Jean; Köberl, Martina; Tumuhairwe, John Baptist; Kubiriba, Jerome; Staver, Charles; Berg, Gabriele

    2015-12-10

    Africa is among the continents where the battle over genetically modified crops is currently being played out. The impact of GM in Africa could potentially be very positive. In Uganda, researchers have developed transgenic banana lines resistant to banana Xanthomonas wilt. The transgenic lines expressing hrap and pflp can provide a timely solution to the pandemic. However, the impact of the transgenes expression on non-target microorganisms has not yet been investigated. To study this effect, transgenic and control lines were grown under field conditions and their associated microbiome was investigated by 16S rRNA gene profiling combining amplicon sequencing and molecular fingerprinting. Three years after sucker planting, no statistically significant differences between transgenic lines and their non-modified predecessors were detected for their associated bacterial communities. The overall gammaproteobacterial rhizosphere microbiome was highly dominated by Xanthomonadales, while Pseudomonadales and Enterobacteriales were accumulated in the pseudostem. Shannon indices revealed much higher diversity in the rhizosphere than in the pseudostem endosphere. However, the expression of the transgenes did not result in changes in the diversity of Gammaproteobacteria, the closest relatives of the target pathogen. In this field experiment, the expression of the resistance genes appears to have no consequences for non-target rhizobacteria and endophytes.

  19. Antibacterial action of doped CoFe{sub 2}O{sub 4} nanocrystals on multidrug resistant bacterial strains

    Energy Technology Data Exchange (ETDEWEB)

    Velho-Pereira, S.; Noronha, A.; Mathias, A.; Zakane, R.; Naik, V.; Naik, P. [Department of Biotechnology, St. Xavier' s College, Goa (India); Salker, A.V. [Department of Chemistry, Goa University, Goa (India); Naik, S.R., E-mail: srnaik19@gmail.com [Department of Chemistry, St. Xavier' s College, Goa (India)

    2015-07-01

    The bactericidal effect of pristine and doped cobalt ferrite nanoparticles has been evaluated against multiple drug resistant clinical strains by assessing the number of colony-forming units (CFU). Monophasic polycrystalline ferrites have been prepared by the malate–glycolate sol–gel autocombustion method as confirmed by the X-ray diffraction study. Various changes occurring during the preparative stages have been demonstrated using TG–DTA analysis which is well complemented by the FTIR spectroscopy. The antibacterial studies carried out demonstrate a bactericidal effect of the nanoparticles wherein the number of CFU has been found to decrease with doping. Cellular distortions have been revealed through SEM. Variation in the number of CFU with dopant type has also been reported herein. - Graphical abstract: Antibacterial action of doped cobalt ferrites resulting in the lyses of multi-drug resistant bacterial strains. - Highlights: • The paper reports an antibacterial study of rare earth doped cobalt ferrite nanoparticles. • Monophasic compounds have been prepared by the sol–gel autocombustion method. • Bactericidal property has been evaluated based on the number of colony forming units. • Variation in bactericidal action with respect to the dopant type has been observed. • Cellular distortions resulting in cell lysis are confirmed from the SEM images.

  20. Fine mapping of the rice bacterial blight resistance gene Xa-4 and its co-segregation marker

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An F2 population developed from the Xa-4 near isogenic lines,IR24 and IRBB4,was used for fine mapping of the rice bacterial blight resistance gene,Xa-4.Some restriction fragment length polymorphism (RFLP) markers on the high-density map constructed by Harushima et al.and the amplified DNA fragments homologous to the conserved domains of plant disease resistance (R) genes were used to construct the genetic linkage map around the gene Xa-4 by scoring susceptible individuals in the population.Xa-4 was mapped between the RFLP marker G181 and the polymerase chain reaction (PCR) marker M55.The R gene homologous fragment marker RS13 was found co-segregating with Xa-4 by analyzing all the plants in the population.This result opened an approach to map-based cloning of this gene,and marker RS13 can be applied to molecular marker-assisted selection of Xa-4 in rice breeding programs.

  1. The Analysis Of Antibiotic Consumption And Bacterial Resistance As An Indicator Of Their Proper Use At The Urology Department In The Health Centre “Studenica” Kraljevo

    Directory of Open Access Journals (Sweden)

    Bukonjić Andriana

    2015-06-01

    Full Text Available The objective of the study was to analyze antibiotic consumption and determine bacterial resistance rates as an indicator of the rational utilization of this drug group at the urology department in the Health Centre “Studenica” Kraljevo.

  2. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    Management of bacterial infections is becoming increasingly difficult due to the emergence and increasing prevalence of bacterial pathogens that are resistant to available antibiotics. Conventional antibiotics generally kill bacteria by interfering with vital cellular functions, an approach that ...

  3. Chlor-alkali plant contamination of Aussa River sediments induced a large Hg-resistant bacterial community

    Science.gov (United States)

    Baldi, Franco; Marchetto, Davide; Gallo, Michele; Fani, Renato; Maida, Isabel; Covelli, Stefano; Fajon, Vesna; Zizek, Suzana; Hines, Mark; Horvat, Milena

    2012-11-01

    A closed chlor-alkali plant (CAP) discharged Hg for decades into the Aussa River, which flows into Marano Lagoon, resulting in the large-scale pollution of the lagoon. In order to get information on the role of bacteria as mercury detoxifying agents, analyses of anions in the superficial part (0-1 cm) of sediments were conducted at four stations in the Aussa River. In addition, measurements of biopolymeric carbon (BPC) as a sum of the carbon equivalent of proteins (PRT), lipids (LIP), and carbohydrates (CHO) were performed to correlate with bacterial biomass such as the number of aerobic heterotrophic cultivable bacteria and their percentage of Hg-resistant bacteria. All these parameters were used to assess the bioavailable Hg fraction in sediments and the potential detoxification activity of bacteria. In addition, fifteen isolates were characterized by a combination of molecular techniques, which permitted their assignment into six different genera. Four out of fifteen were Gram negative with two strains of Stenotrophomonas maltophilia, one Enterobacter sp., and one strain of Brevibacterium frigoritolerans. The remaining strains (11) were Gram positive belonging to the genera Bacillus and Staphylococcus. We found merA genes in only a few isolates. Mercury volatilization from added HgCl2 and the presence of plasmids with the merA gene were also used to confirm Hg reductase activity. We found the highest number of aerobic heterotrophic Hg-resistant bacteria (one order magnitude higher) and the highest number of Hg-resistant species (11 species out of 15) at the confluence of the River Aussa and Banduzzi's channel, which transport Hg from the CAP, suggesting that Hg is strongly detoxified [reduced to Hg(0)] at this location.

  4. The survey of bacterial etiology and their resistance to antibiotics of urinary tract infections in children of Birjand city

    Directory of Open Access Journals (Sweden)

    Azita Fesharakinia

    2012-08-01

    Full Text Available Background and Aim: Urinary tract infection is one of the most prevalent bacterial infections in childhood, which due to an inapproto determine the common bacteria and their antibiotic susceptibility in children with urinary tract infection.   Materials and Methods: This descriptive-analytical and prospective study was done in 2009-2010 on urine samples of all children under 13 years who had been referred to Emmam-Reza hospital laboratory in Birjand and had positive urine culture. Sex and age of children, the kind of isolated bacteria in urine culture, susceptibility and resistance of these bacteria to current antibiotics were studied.The obtained data was analyzed by means of SPSS using Fisher exact- test.   Results: 100 children (84 girls and 16 boys with positive urine culture were studied. The most common age of urinary tract infection was under two years. In all ages the rate of urinary tract infection in females was more than males. E.coli was the most common cause in both sexes. There was a significant relationship between kind of microorganism and age of infection. The most prevalent cause of urinary tract infection in all ages was E.coli (75% ,infection by Proteus was 11%, and other microorganism caused 14% of the cases. E.coli had the most susceptibility to ceftriaxone and ceftazidime and the most resistance to cephalexin and co-trimoxazol. Not taking the type of microorganism into consideration, the most sensitive antibiotics were ceftazidime, ceftriaxone, cefexim and nalidixic acid and the most resistance was against co-trimoxasol and cefalexin.   Conclusion: Regarding the results, it is recommended to use cefexime and nalidixic acid for outpatient treatment of urinary infection , and ceftazidime and ceftriaxon for inpatient treatment.Selecting of antibiotics for urinary infection therapy should be based on the local prevalence of pathogenic bacteria and antibiotic sensitivities rather than on a universal guideline.

  5. Antibacterial and antiviral roles of a fish β-defensin expressed both in pituitary and testis.

    Directory of Open Access Journals (Sweden)

    Jun-Yan Jin

    Full Text Available Defensins are a group of cationic peptides that exhibit broad-spectrum antimicrobial activity. In this study, we cloned and characterized a β-defensin from pituitary cDNA library of a protogynous hermaphroditic orange-spotted grouper (Epinephelus coioides. Interestingly, the β-defensin was shown to be dominantly expressed in pituitary and testis by RT-PCR and Western blot analysis, and its transcript level is significantly upregulated in reproduction organs from intersexual gonad to testis during the natural and artificial sex reversal. Promoter sequence and the responsible activity region analyses revealed the pituitary-specific POU1F1a transcription binding site and testis-specific SRY responsible site, and demonstrated that the pituitary-specific POU1F1a transcription binding site that locates between -180 and -208 bp is the major responsible region of grouper β-defensin promoter activity. Immunofluorescence localization observed its pituicyte expression in pituitary and spermatogonic cell expression in testis. Moreover, both in vitro antibacterial activity assay of the recombinant β-defensin and in vivo embryo microinjection of the β-defensin mRNA were shown to be effective in killing gram-negative bacteria. And, its antiviral role was also demonstrated in EPC cells transfected with the β-defensin construct. Additionally, the antibacterial activity was sensitive to concentrations of Na(+, K(+, Ca(2+ and Mg(2+. The above intriguing findings strongly suggest that the fish β-defensin might play significant roles in both innate immunity defense and reproduction endocrine regulation.

  6. Pyrosequencing the Bemisia tabaci transcriptome reveals a highly diverse bacterial community and a robust system for insecticide resistance.

    Directory of Open Access Journals (Sweden)

    Wen Xie

    Full Text Available BACKGROUND: Bemisia tabaci (Gennadius is a phloem-feeding insect poised to become one of the major insect pests in open field and greenhouse production systems throughout the world. The high level of resistance to insecticides is a main factor that hinders continued use of insecticides for suppression of B. tabaci. Despite its prevalence, little is known about B. tabaci at the genome level. To fill this gap, an invasive B. tabaci B biotype was subjected to pyrosequencing-based transcriptome analysis to identify genes and gene networks putatively involved in various physiological and toxicological processes. METHODOLOGY AND PRINCIPAL FINDINGS: Using Roche 454 pyrosequencing, 857,205 reads containing approximately 340 megabases were obtained from the B. tabaci transcriptome. De novo assembly generated 178,669 unigenes including 30,980 from insects, 17,881 from bacteria, and 129,808 from the nohit. A total of 50,835 (28.45% unigenes showed similarity to the non-redundant database in GenBank with a cut-off E-value of 10-5. Among them, 40,611 unigenes were assigned to one or more GO terms and 6,917 unigenes were assigned to 288 known pathways. De novo metatranscriptome analysis revealed highly diverse bacterial symbionts in B. tabaci, and demonstrated the host-symbiont cooperation in amino acid production. In-depth transcriptome analysis indentified putative molecular markers, and genes potentially involved in insecticide resistance and nutrient digestion. The utility of this transcriptome was validated by a thiamethoxam resistance study, in which annotated cytochrome P450 genes were significantly overexpressed in the resistant B. tabaci in comparison to its susceptible counterparts. CONCLUSIONS: This transcriptome/metatranscriptome analysis sheds light on the molecular understanding of symbiosis and insecticide resistance in an agriculturally important phloem-feeding insect pest, and lays the foundation for future functional genomics research of the

  7. Close linkage of a blast resistance gene, Pias(t), with a bacterial leaf blight resistance gene, Xa1-as(t), in a rice cultivar ‘Asominori’

    Science.gov (United States)

    Endo, Takashi; Yamaguchi, Masayuki; Kaji, Ryota; Nakagomi, Koji; Kataoka, Tomomori; Yokogami, Narifumi; Nakamura, Toshiki; Ishikawa, Goro; Yonemaru, Jun-ichi; Nishio, Takeshi

    2012-01-01

    It has long been known that a bacterial leaf blight-resistant line in rice obtained from a crossing using ‘Asominori’ as a resistant parent also has resistance to blast, but a blast resistance gene in ‘Asominori’ has not been investigated in detail. In the present study, a blast resistance gene in ‘Asominori’, tentatively named Pias(t), was revealed to be located within 162-kb region between DNA markers YX4-3 and NX4-1 on chromosome 4 and to be linked with an ‘Asominori’ allele of the bacterial leaf blight resistance gene Xa1, tentatively named Xa1-as(t). An ‘Asominori’ allele of Pias(t) was found to be dominant and difference of disease severity between lines having the ‘Asominori’ allele of Pias(t) and those without it was 1.2 in disease index from 0 to 10. Pias(t) was also closely linked with the Ph gene controlling phenol reaction, suggesting the possibility of successful selection of blast resistance using the phenol reaction. Since blast-resistant commercial cultivars have been developed using ‘Asominori’ as a parent, Pias(t) is considered to be a useful gene in rice breeding for blast resistance. PMID:23341747

  8. Ectopic Expression of Hrf1 Enhances Bacterial Resistance via Regulation of Diterpene Phytoalexins, Silicon and Reactive Oxygen Species Burst in Rice

    Science.gov (United States)

    Zhong, Weigong; Yang, Jie; Okada, Kazunori; Yamane, Hisakazu; Zhang, Lei; Wang, Guang; Wang, Dong; Xiao, Shanshan; Chang, Shanshan; Qian, Guoliang; Liu, Fengquan

    2012-01-01

    Harpin proteins as elicitor derived from plant gram negative bacteria such as Xanthomonas oryzae pv. oryzae (Xoo), Erwinia amylovora induce disease resistance in plants by activating multiple defense responses. However, it is unclear whether phytoalexin production and ROS burst are involved in the disease resistance conferred by the expression of the harpinXoo protein in rice. In this article, ectopic expression of hrf1 in rice enhanced resistance to bacterial blight. Accompanying with the activation of genes related to the phytoalexin biosynthesis pathway in hrf1-transformed rice, phytoalexins quickly and consistently accumulated concurrent with the limitation of bacterial growth rate. Moreover, the hrf1-transformed rice showed an increased ability for ROS scavenging and decreased hydrogen peroxide (H2O2) concentration. Furthermore, the localization and relative quantification of silicon deposition in rice leaves was detected by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometer (EDS). Finally, the transcript levels of defense response genes increased in transformed rice. These results show a correlation between Xoo resistance and phytoalexin production, H2O2, silicon deposition and defense gene expression in hrf1-transformed rice. These data are significant because they provide evidence for a better understanding the role of defense responses in the incompatible interaction between bacterial disease and hrf1-transformed plants. These data also supply an opportunity for generating nonspecific resistance to pathogens. PMID:22970151

  9. Ectopic expression of Hrf1 enhances bacterial resistance via regulation of diterpene phytoalexins, silicon and reactive oxygen species burst in rice.

    Directory of Open Access Journals (Sweden)

    Wenqi Li

    Full Text Available Harpin proteins as elicitor derived from plant gram negative bacteria such as Xanthomonas oryzae pv. oryzae (Xoo, Erwinia amylovora induce disease resistance in plants by activating multiple defense responses. However, it is unclear whether phytoalexin production and ROS burst are involved in the disease resistance conferred by the expression of the harpin(Xoo protein in rice. In this article, ectopic expression of hrf1 in rice enhanced resistance to bacterial blight. Accompanying with the activation of genes related to the phytoalexin biosynthesis pathway in hrf1-transformed rice, phytoalexins quickly and consistently accumulated concurrent with the limitation of bacterial growth rate. Moreover, the hrf1-transformed rice showed an increased ability for ROS scavenging and decreased hydrogen peroxide (H(2O(2 concentration. Furthermore, the localization and relative quantification of silicon deposition in rice leaves was detected by scanning electron microscopy (SEM and energy-dispersive X-ray spectrometer (EDS. Finally, the transcript levels of defense response genes increased in transformed rice. These results show a correlation between Xoo resistance and phytoalexin production, H(2O(2, silicon deposition and defense gene expression in hrf1-transformed rice. These data are significant because they provide evidence for a better understanding the role of defense responses in the incompatible interaction between bacterial disease and hrf1-transformed plants. These data also supply an opportunity for generating nonspecific resistance to pathogens.

  10. One-day workflow scheme for bacterial pathogen detection and antimicrobial resistance testing from blood cultures.

    Science.gov (United States)

    Hansen, Wendy L J; Beuving, Judith; Verbon, Annelies; Wolffs, Petra F G

    2012-07-09

    Bloodstream infections are associated with high mortality rates because of the probable manifestation of sepsis, severe sepsis and septic shock(1). Therefore, rapid administration of adequate antibiotic therapy is of foremost importance in the treatment of bloodstream infections. The critical element in this process is timing, heavily dependent on the results of bacterial identification and antibiotic susceptibility testing. Both of these parameters are routinely obtained by culture-based testing, which is time-consuming and takes on average 24-48 hours(2, 4). The aim of the study was to develop DNA-based assays for rapid identification of bloodstream infections, as well as rapid antimicrobial susceptibility testing. The first assay is a eubacterial 16S rDNA-based real-time PCR assay complemented with species- or genus-specific probes(5). Using these probes, Gram-negative bacteria including Pseudomonas spp., Pseudomonas aeruginosa and Escherichia coli as well as Gram-positive bacteria including Staphylococcus spp., Staphylococcus aureus, Enterococcus spp., Streptococcus spp., and Streptococcus pneumoniae could be distinguished. Using this multiprobe assay, a first identification of the causative micro-organism was given after 2 h. Secondly, we developed a semi-molecular assay for antibiotic susceptibility testing of S. aureus, Enterococcus spp. and (facultative) aerobe Gram-negative rods(6). This assay was based on a study in which PCR was used to measure the growth of bacteria(7). Bacteria harvested directly from blood cultures are incubated for 6 h with a selection of antibiotics, and following a Sybr Green-based real-time PCR assay determines inhibition of growth. The combination of these two methods could direct the choice of a suitable antibiotic therapy on the same day (Figure 1). In conclusion, molecular analysis of both identification and antibiotic susceptibility offers a faster alternative for pathogen detection and could improve the diagnosis of

  11. Correlation between plasma component levels of cultured fish and resistance to bacterial infection

    Science.gov (United States)

    Maita, M.; Satoh, K.-I.; Fukuda, Y.; Lee, H.-K.; Winton, J.R.; Okamoto, N.

    1998-01-01

    Mortalities of yellowtail Seriola quinqueradiata artificially infected with Lactococcus garvieae and of rainbow trout Oncorhynchus mykiss artificially infected with Vibrio anguillarum were compared with the levels of plasma components measured prior to challenge. The levels of plasma total cholesterol, free cholesterol and phospholipid of fish surviving infection were significantly higher in both yellowtail and rainbow trout than those of fish which died during the challenge test. Mortality of yellowtail with plasma total cholesterol levels lower than 250 mg/100 ml was significantly higher than that of fish which had cholesterol levels higher than 275 mg/100 ml (p < 0.05). Rainbow trout whose cholesterol was lower than 520 mg/100 ml suffered a significantly higher mortality due to vibriosis than fish having cholesterol levels higher than 560 mg/100 ml (p < 0.005). These results indicate that low levels of plasma lipid components may be an indicator of lowered disease resistance in cultured fish.

  12. Rat Cardiomyocytes Express a Classical Epithelial Beta-Defensin

    Directory of Open Access Journals (Sweden)

    Annika Linde

    2008-01-01

    Full Text Available Beta-defensins (BDs are classical epithelial antimicrobial peptides of immediate importance in innate host defense. Since recent studies have suggested that certain BDs are also expressed in non-traditional tissues, including whole heart homogenate and because effector molecules of innate immunity and inflammation can influence the development of certain cardiovascular disease processes, we hypothesized that BDs are produced by cardiomyocytes as a local measure of cardioprotection against danger signals. Here we report that at least one rat beta-defensin, rBD1, is expressed constitutively in cardiomyocytes specifically isolated using position-ablation-laser-microdissection (P.A.L.M. Microlaser Technologies. RT-PCR analysis showed expression of a single 318 bp transcript in adult rat heart (laser-excised cardiomyocytes and H9c2 cells (neonatal rat heart myoblasts. Moreover, the full length cDNA of rBD1 was established and translated into a putative peptide with 69 amino acid residues. The predicted amino acid sequence of the adult rat cardiac BD-1 peptide displayed 99% identity with the previously reported renal rBD1 and 88, 53, 53 and 50% identity with mouse, human, gorilla and rhesus monkey BD1 respectively. Furthermore, structural analysis of the cardiac rBD1 showed the classical six-cysteine conserved motif of the BD family with an alpha-helix and three beta-sheets. Additionally, rBD1 displayed a significantly greater number of amphoteric residues than any of the human analogs, indicating a strong pH functional dependence in the rat. We suggest that rBD1, which was initially believed to be a specific epithelium-derived peptide, may be also involved in local cardiac innate immune defense mechanisms.

  13. Study of β-defensin polymorphisms in Valle del Belice dairy sheep

    Directory of Open Access Journals (Sweden)

    Rosa Reina

    2010-01-01

    Full Text Available The aim of this work was to sequence the exons of β-defensin 1 and 2 genes (SBD1 and SBD2 in Valle del Belice dairy sheep in order to identify polymorphisms. The study was conducted on 60 samples from three flocks. Six SNPs were identified: two in SBD1 and four in SBD2. Both genes consist of two exons and one intron. In SBD1 gene, SNPs were found only in the exon 2, whereas in SBD2, SNPs were detected in both exons. In both genes, SNPs were located in the coding regions and in the 3'-UTR. The SNP in SBD2 located at position 1659 determined a change in the protein sequence. Further studies will be necessary to investigate if the amino acid change modifies the biological function of the protein and the association with SCC, in order to use this information in a breeding program for mastitis resistance in Valle del Belice sheep.

  14. Genetic transformation of Nannochloropsis oculata with a bacterial phleomycin resistance gene as dominant selective marker

    Science.gov (United States)

    Ma, Xiaolei; Pan, Kehou; Zhang, Lin; Zhu, Baohua; Yang, Guanpin; Zhang, Xiangyang

    2016-04-01

    The gene ble from Streptoalloteichus hindustanus is widely used as a selective antibiotic marker. It can control the phleomycin resistance, and significantly increase the tolerance of hosts to zeocin. The unicellular marine microalga Nannochloropsis oculata is extremely sensitive to zeocin. We selected ble as the selective marker for the genetic transformation of N. oculata. After the algal cells at a density of 2×107 cells mL-1 was digested with 4% hemicellulase and 2% driselase for 1 h, the protoplasts accounted for 90% of the total. The ble was placed at the downstream of promoter HSP70A-RUBS2 isolated from Chlamydomonas reinhardtii, yielding a recombinant expression construct pMS188. The construct was transferred into the protoplasts through electroporation (1 kV, 15 μS). The transformed protoplasts were cultured in fresh f/2 liquid medium, and selected on solid f/2 medium supplemented with 500 ng mL-1 zeocin. The PCR result proved that ble existed in the transformants. Three transformants had been cultured for at least 5 generations without losing ble. Southern blotting analysis showed that the ble has been integrated into the genome of N. oculata. The ble will serve as a new dominant selective marker in genetic engineering N. oculata.

  15. Bacterial biofilm shows persistent resistance to liquid wetting and gas penetration

    Energy Technology Data Exchange (ETDEWEB)

    Epstein, Alexander K.; Pokroy, Boaz; Seminara, Agnese; Aizenberg, Joanna (Harvard)

    2011-09-28

    Most of the world's bacteria exist in robust, sessile communities known as biofilms, ubiquitously adherent to environmental surfaces from ocean floors to human teeth and notoriously resistant to antimicrobial agents. We report the surprising observation that Bacillus subtilis biofilm colonies and pellicles are extremely nonwetting, greatly surpassing the repellency of Teflon toward water and lower surface tension liquids. The biofilm surface remains nonwetting against up to 80% ethanol as well as other organic solvents and commercial biocides across a large and clinically important concentration range. We show that this property limits the penetration of antimicrobial liquids into the biofilm, severely compromising their efficacy. To highlight the mechanisms of this phenomenon, we performed experiments with mutant biofilms lacking ECM components and with functionalized polymeric replicas of biofilm microstructure. We show that the nonwetting properties are a synergistic result of ECM composition, multiscale roughness, reentrant topography, and possibly yet other factors related to the dynamic nature of the biofilm surface. Finally, we report the impenetrability of the biofilm surface by gases, implying defense capability against vapor-phase antimicrobials as well. These remarkable properties of B. subtilis biofilm, which may have evolved as a protection mechanism against native environmental threats, provide a new direction in both antimicrobial research and bioinspired liquid-repellent surface paradigms.

  16. Antioxidant enzyme activity in bacterial resistance to nicotine toxicity by reactive oxygen species.

    Science.gov (United States)

    Shao, Tiejuan; Yuan, Haiping; Yan, Bo; Lü, Zhenmei; Min, Hang

    2009-10-01

    We analyzed superoxide dismutase (SOD), catalase (CAT), and ATPase activities in the highly nicotine-degrading strain Pseudomonas sp. HF-1 and two standard strains Escherichia coli and Bacillus subtilis in an attempt to understand antioxidant enzymes in bacteria are produced in response to nicotine, which increases the virulence of the bacteria. Nicotine had different effects on different antioxidant enzymes of different bacteria. SOD plays a more important role in resistance to nicotine stress in E. coli than it does in CAT. Multiple antioxidant enzymes are involved in combating oxidative stress caused by nicotine in Pseudomonas sp. HF-1. The contribution of a particular antioxidant enzyme for protection from nicotine stress varies with the growth phase involved. The inhibition of ATPase in Pseudomonas sp. HF-1 at the stationary phase was enhanced with increasing nicotine concentration, showing a striking dose-response relationship. Nicotine probably affected the metabolism of ATP to some extent. Furthermore, different bacteria possessed distinct SOD isoforms to cope with oxidative stress caused by nicotine. PMID:19294456

  17. Multidrug-resistant Escherichia coli soft tissue infection investigated with bacterial whole genome sequencing

    Science.gov (United States)

    Buchanan, Ruaridh; Stoesser, Nicole; Crook, Derrick; Bowler, Ian C J W

    2014-01-01

    A 45-year-old man with dilated cardiomyopathy presented with acute leg pain and erythema suggestive of necrotising fasciitis. Initial surgical exploration revealed no necrosis and treatment for a soft tissue infection was started. Blood and tissue cultures unexpectedly grew a Gram-negative bacillus, subsequently identified by an automated broth microdilution phenotyping system as an extended-spectrum β-lactamase producing Escherichia coli. The patient was treated with a 3-week course of antibiotics (ertapenem followed by ciprofloxacin) and debridement for small areas of necrosis, followed by skin grafting. The presence of E. coli triggered investigation of both host and pathogen. The patient was found to have previously undiagnosed liver disease, a risk factor for E. coli soft tissue infection. Whole genome sequencing of isolates from all specimens confirmed they were clonal, of sequence type ST131 and associated with a likely plasmid-associated AmpC (CMY-2), several other resistance genes and a number of virulence factors. PMID:25331151

  18. 2011年中国CHINET细菌耐药性监测%2011 CHINET surveillance of bacterial resistance in China

    Institute of Scientific and Technical Information of China (English)

    胡付品; 王传清; 王爱敏; 倪语星; 孙景勇; 俞云松; 林洁; 单斌; 杜艳; 徐元宏; 沈继录; 朱德妹; 张泓; 孔菁; 卓超; 苏丹虹; 张朝霞; 季萍; 胡云建; 艾效曼; 黄文祥; 贾蓓; 汪复; 魏莲花; 吴玲; 蒋晓飞; 杨青; 徐英春; 张小江; 孙自镛; 陈中举

    2012-01-01

    目的 了解国内主要地区临床分离菌对常用抗菌药的敏感性和耐药性.方法 国内主要地区15所教学医院(13所综合性医院、2所儿童医院)临床分离菌采用纸片扩散法或自动化仪器法按统一方案进行细菌药敏试验.按CLSI 2011年版判断结果.结果 2011年1 - 12月收集各医院临床分离菌共59 287株,其中革兰阳性菌16 872株,占28.5%,革兰阴性菌42 415株,占71.5%.金葡菌(SA)和凝固酶阴性葡萄球菌(CNS)中甲氧西林耐药株的检出率平均分别为50.6%和74.6%.甲氧西林耐药株对β内酰胺类抗生素和其他测试药的耐药率显著高于甲氧西林敏感株.MRSA中有73.3%的菌株对甲氧苄啶-磺胺甲(噁)唑敏感;MRCNS中有88.2%的菌株对利福平敏感.未发现万古霉素、替考拉宁和利奈唑胺耐药株.肠球菌属细菌中粪肠球菌对所测试的抗菌药(氯霉素除外)的耐药率均显著低于屎肠球菌,两者中均有少数万古霉素耐药株,根据表型推测多数为VanA型耐药.肺炎链球菌非脑膜炎株成人株和儿童株中PSSP所占比例较2010年均略有升高,PRSP的检出率均有所下降.大肠埃希菌、克雷伯菌属细菌(肺炎克雷伯菌和产酸克雷伯菌)和奇异变形杆菌中产ESBLs株分别平均为50.7%、38.5%和13.8%.肠杆菌科细菌中产ESBLs株对测试药物的耐药率均比非产ESBLs株高.肠杆菌科细菌对碳青霉烯类抗生素仍高度敏感,总耐药率4%~6%.不动杆菌属细菌(鲍曼不动杆菌占88.6%)对亚胺培南和美罗培南的耐药率分别为60.4%和61.4%.肺炎克雷伯菌、鲍曼不动杆菌和铜绿假单胞菌中仍有少数泛耐药株.结论 细菌耐药性仍呈增长趋势,多重耐药和泛耐药菌株在某些科室内的流行播敖对临床构成严重威胁,应进行流行病学调查并采取有效的控制措施.%Objective To investigate the susceptibility and resistance of clinical bacterial isolates from

  19. 由细菌耐药机制探讨临床抗生素的合理应用%Bacterial Resistance and Reasonable Application of the Antibiotics

    Institute of Scientific and Technical Information of China (English)

    陈世玲

    2013-01-01

    目的:通过对细菌耐药机制的分析,探讨临床上抗生素的合理使用,以应对细菌的耐药性.方法:结合已有文献报道和多年临床经验,分析细菌的耐药机制,探讨临床抗生素的合理应用原则和方法.结果:细菌的耐药机制分为遗传学机制和生化机制,其耐药性的产生与抗生素灭活酶的产生、膜通透性改变、新靶位的产生和改变等有关.结论:合理使用抗生素,防止其滥用,能有效较少细菌耐药性的产生.%Objective: By analyzing the mechanisms of bacterial resistance, to explore the rational clinical use of antibiotics. Method: According to the literatures reportsd and the clinical experiences, the mechanisms of bacterial resistance has been discussed. Result: The bacterial resistance mechanisms were divided into the genetic mechanisms and biochemical mechanisms. The produce of drug resistance was related to the produce of inactivation enzymes, the changes of the membrane permeability, the generation of new targets and so on. Conclusion: The rational use of antibiotics can effectively reduce the produce of bacterial drug resistance.

  20. Resistance and Inactivation Kinetics of Bacterial Strains Isolated from the Non-Chlorinated and Chlorinated Effluents of a WWTP

    Directory of Open Access Journals (Sweden)

    Claudia Coronel-Olivares

    2013-08-01

    Full Text Available The microbiological quality of water from a wastewater treatment plant that uses sodium hypochlorite as a disinfectant was assessed. Mesophilic aerobic bacteria were not removed efficiently. This fact allowed for the isolation of several bacterial strains from the effluents. Molecular identification indicated that the strains were related to Aeromonas hydrophila, Escherichia coli (three strains, Enterobacter cloacae, Kluyvera cryocrescens (three strains, Kluyvera intermedia, Citrobacter freundii (two strains, Bacillus sp. and Enterobacter sp. The first five strains, which were isolated from the non-chlorinated effluent, were used to test resistance to chlorine disinfection using three sets of variables: disinfectant concentration (8, 20 and 30 mg·L−1, contact time (0, 15 and 30 min and water temperature (20, 25 and 30 °C. The results demonstrated that the strains have independent responses to experimental conditions and that the most efficient treatment was an 8 mg·L−1 dose of disinfectant at a temperature of 20 °C for 30 min. The other eight strains, which were isolated from the chlorinated effluent, were used to analyze inactivation kinetics using the disinfectant at a dose of 15 mg·L−1 with various retention times (0, 10, 20, 30, 60 and 90 min. The results indicated that during the inactivation process, there was no relationship between removal percentage and retention time and that the strains have no common response to the treatments.

  1. Aloe vera extract functionalized zinc oxide nanoparticles as nanoantibiotics against multi-drug resistant clinical bacterial isolates.

    Science.gov (United States)

    Ali, Khursheed; Dwivedi, Sourabh; Azam, Ameer; Saquib, Quaiser; Al-Said, Mansour S; Alkhedhairy, Abdulaziz A; Musarrat, Javed

    2016-06-15

    ZnO nanoparticles (ZnONPs) were synthesised through a simple and efficient biogenic synthesis approach, exploiting the reducing and capping potential of Aloe barbadensis Miller (A. vera) leaf extract (ALE). ALE-capped ZnO nanoparticles (ALE-ZnONPs) were characterized using UV-Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) analyses. XRD analysis provided the average size of ZnONPs as 15 nm. FTIR spectral analysis suggested the role of phenolic compounds, terpenoids and proteins present in ALE, in nucleation and stability of ZnONPs. Flow cytometry and atomic absorption spectrophotometry (AAS) data analyses revealed the surface binding and internalization of ZnONPs in Gram +ve (Staphylococcus aureus) and Gram -ve (Escherichia coli) cells, respectively. Significant antibacterial activity of ALE-ZnONPs was observed against extended spectrum beta lactamases (ESBL) positive E. coli, Pseudomonas aeruginosa, and methicillin resistant S. aureus (MRSA) clinical isolates exhibiting the MIC and MBC values of 2200, 2400 μg/ml and 2300, 2700 μg/ml, respectively. Substantial inhibitory effects of ALE-ZnONPs on bacterial growth kinetics, exopolysaccharides and biofilm formation, unequivocally suggested the antibiotic and anti-biofilm potential. Overall, the results elucidated a rapid, environmentally benign, cost-effective, and convenient method for ALE-ZnONPs synthesis, for possible applications as nanoantibiotics or drug carriers. PMID:27031596

  2. Phylogenetic analysis of β-defensin-like genes of Bothrops, Crotalus and Lachesis snakes.

    Science.gov (United States)

    Correa, Poliana G; Oguiura, Nancy

    2013-07-01

    Defensins are components of the vertebrate innate immune system; they comprise a diverse group of small cationic antimicrobial peptides. Among them, β-defensins have a characteristic β-sheet-rich fold plus six conserved cysteines with particular spacing and intramolecular bonds. They have been fully studied in mammals, but there is little information about them in snakes. Using a PCR approach, we described 13 β-defensin-like sequences in Bothrops and Lachesis snakes. The genes are organized in three exons and two introns, with exception of B.atrox_defensinB_01 which has only two exons. They show high similarities in exon 1, intron 1 and intron 2, but exons 2 and 3 have undergone accelerated evolution. The theoretical translated sequences encode a pre-β-defensin-like molecule with a conserved signal peptide and a mature peptide. The signal peptides are leucine-rich and the mature β-defensin-like molecules have a size around 4.5 kDa, a net charge from +2 to +11, and the conserved cysteine motif. Phylogenetic analysis was done using maximum parsimony, maximum likelihood and Bayesian analyses, and all resulted in similar topologies with slight differences. The genus Bothrops displayed two separate lineages. The reconciliation of gene trees and species tree indicated eight to nine duplications and 23 to 29 extinctions depending on the gene tree used. Our results together with previously published data indicate that the ancestral β-defensin-like gene may have three exons in vertebrates and that their evolution occurred according to a birth-and-death model. PMID:23500066

  3. CHINET 2014 surveillance of bacterial resistance in China%2014年CHINET中国细菌耐药性监测

    Institute of Scientific and Technical Information of China (English)

    胡付品; 康梅; 王传清; 王爱敏; 徐元宏; 沈继录; 孙自镛; 陈中举; 倪语星; 孙景勇; 褚云卓; 朱德妹; 田素飞; 胡志东; 李金; 俞云松; 林洁; 单斌; 杜艳; 韩艳秋; 郭素芳; 魏莲花; 汪复; 吴玲; 张泓; 孔菁; 胡云建; 艾效曼; 卓超; 苏丹虹; 蒋晓飞; 徐英春; 张小江; 张朝霞; 季萍; 谢轶

    2015-01-01

    average . ESBLs‐producing Enterobacteriaceae strains were more resistant than non‐ESBLs‐producing strains in terms of antibiotic resistance rates . The strains of Enterobacteriaceae were still highly susceptible to carbapenems .Overall less than 10 % of these strains were resistant to carbapenems . About 62 .4% and 66 .7% of Acinetobacter spp .(A .baumannii accounts for 93 .0 % ) strains were resistant to imipenem and meropenem ,respectively . Compared with the data of year 2013 ,extensively‐drug resistant strains in K . pneumoniae and A .baumannii increased . Conclusions The antibiotic resistance of clinical bacterial isolates is growing .The disseminated multi‐drug or pan‐drug resistant strains in a special region poses a serious threat to clinical practice and implies the importance of strengthening infection control .%目的:了解国内主要地区临床分离菌对常用抗菌药物的敏感性和耐药性。方法国内主要地区17所教学医院(15所综合性医院、2所儿童医院)临床分离菌采用纸片扩散法或自动化仪器法按统一方案进行细菌药物敏感性试验。按美国临床和实验室标准化协会(CLSI)2014版标准判断结果。结果收集各医院2014年1—12月临床分离菌共78955株,其中革兰阳性菌21635株,占27.4%,革兰阴性菌57320株,占72.6%。金黄色葡萄球菌和凝固酶阴性葡萄球菌中甲氧西林耐药株的平均检出率分别为44.6%和83.0%。甲氧西林耐药株(MRSA和MRCNS)对β内酰胺类抗生素和其他测试药的耐药率均显著高于甲氧西林敏感株(MSSA和MSCNS)。MRSA中有92.0%菌株对甲氧苄啶‐磺胺甲口恶唑敏感;MRCNS中有85.6%的菌株对利福平敏感。未发现万古霉素、替考拉宁和利奈唑胺耐药株。肠球菌属中粪肠球菌对多数测试抗菌药物(氯霉素除外)的耐药率显著低于屎肠球菌,两者中均有少数万古霉素耐药株,表型或基因

  4. 2013年中国CHINET细菌耐药性监测%CHINET 2013 surveillance of bacterial resistance in China

    Institute of Scientific and Technical Information of China (English)

    胡付品; 康梅; 徐英春; 张小江; 张朝霞; 季萍; 王传清; 王爱敏; 倪语星; 孙景勇; 俞云松; 朱德妹; 林洁; 储云卓; 田素飞; 徐元宏; 沈继录; 单斌; 杜艳; 卓超; 苏丹虹; 张泓; 汪复; 孔菁; 魏莲花; 吴玲; 胡云建; 艾效曼; 蒋晓飞; 孙自镛; 陈中举; 胡志东; 李金; 谢轶

    2014-01-01

    -producing Enterobacteriaceae strains were more resistant than non-ESBLs-producing strains in terms of antibiotic resistance rates .The strains of Enterobacteriaceae were still highly susceptible to carbapenems .Overall less than 7 .0% of these strains were resistant to carbapenems .About 62 .8% and 59 .4% of Acinetobacter spp .(A .baumannii accounts for 89 .2% ) strains were resistant to imipenem and meropenem ,respectively .Compared with the data of year 2012 , extensively-drug resistant strains in K . pneumoniae and A . baumannii decreased .Conclusions The antibiotic resistance of clinical bacterial isolates is growing in 2013 .The disseminated multi-drug or pan-drug resistant strains in a special region poses a serious threat to clinical practice and implies the importance of strengthening infection control .%目的:了解国内主要地区临床分离菌对常用抗菌药物的敏感性和耐药性。方法国内主要地区16所教学医院(14所综合性医院、2所儿童医院)临床分离菌采用纸片扩散法或自动化仪器法按统一方案进行药物敏感性试验。按CLSI 2013年版标准判断结果。结果2013年1-12月收集各医院临床分离菌共84572株,其中革兰阳性菌22863株,占27.0%,革兰阴性菌61709株,占73.0%。金黄色葡萄球菌(金葡菌)和凝固酶阴性葡萄球菌(CNS )中甲氧西林耐药株的平均检出率分别为45.2%和73.5%。甲氧西林耐药株(MRSA和MRCNS)对β内酰胺类抗生素和其他测试药物的耐药率均显著高于甲氧西林敏感株(MSSA和MSCNS)。MRSA中有92.2%的菌株对甲氧苄啶-磺胺甲口恶唑敏感;MRCNS中有87.4%的菌株对利福平敏感。葡萄球菌属中均未发现对万古霉素、替考拉宁和利奈唑胺耐药株。肠球菌属中粪肠球菌对绝大多数所测试的抗菌药物(氯霉素除外)的耐药率均显著低于屎肠球菌,两者中均有少数万古霉素耐药株,根据表型推测多数为 v an

  5. Role of Toll-like receptor 4 and human defensin 5 in primary endocervical epithelial cells

    Institute of Scientific and Technical Information of China (English)

    MA Jing-mei; YANG Hui-xia

    2010-01-01

    Background Endocervical epithelial cells play early roles in the defense of upper female genital tract to pathogens. Toll-like receptors (TLRs) and human defensins (HD) have recently been identified as fundamental components of the innate immune responses to bacterial pathogens. We aimed to use in vitro model of human primary endocervical epithelial cells (HPECs) to investigate their roles in innate immune response of the endocervix.Methods TLR4 expression and distribution in HPECs and endocervix were investigated by immunofluorescence (IF). Cultured HPECs were divided into lipopolysaccharide (LPS) group which were treated by LPS for 0, 24 and 48 hours, and control group without treatment. At each time point, the levels of HD5, IL-6 and TNF-a in supernants were determined by ELISA. TLR4 and HD5 expressions of cells were detected by Western blotting simultaneously. HD5 expression pattern was also compared between the HeLa cell line and HPECs.Results Endocervix tissue surface and HPECs expressed TLR4. After incubated with LPS, HPECs expressed significantly higher levels of TLR4 than control group, especially after 24 hours (P <0.01), however decreased after 48 hours with a similar level of TLR4 expression compared with control group. LPS could upregulate the secretion of HD5, IL-6 and TNF-α in a time-dependent manner (24 hours: P <0.05; 48 hours: P <0.01, compared with control group). Intracellular HD5 expression levels decreased over time. HD5 expression patterns in HPECs were different from HeLa cell line.Conclusions To respond to LPS stimulation, HPECs may function in the mucosal immune defense through TLR4 activation and HD5 secretion. HPEC is considered a significant model for immunological study.

  6. Bacterial resistance to ciprofloxacin in Greece: results from the National Electronic Surveillance System. Greek Network for the Surveillance of Antimicrobial Resistance.

    OpenAIRE

    Vatopoulos, A. C.; Kalapothaki, V.; Legakis, N. J.

    1999-01-01

    According to 1997 susceptibility data from the National Electronic System for the Surveillance of Antimicrobial Resistance, Greece has high rates of ciprofloxacin resistance. For most species, the frequency of ciprofloxacin-resistant isolates (from highest to lowest, by patient setting) was as follows: intensive care unit > surgical > medical > outpatient. Most ciprofloxacin-resistant strains were multidrug resistant.

  7. A Family of CSαβ Defensins and Defensin-Like Peptides from the Migratory Locust, Locusta migratoria, and Their Expression Dynamics during Mycosis and Nosemosis

    Science.gov (United States)

    Zhang, Liwei; Zhang, Pengfei; Zhang, Long

    2016-01-01

    Insect defensins are effector components of the innate defense system. During infection, these peptides may play a role in the control of pathogens by providing protective antimicrobial barriers between epithelial cells and the hemocoel. The cDNAs encoding four defensins of the migratory locust, Locusta migratoria, designated LmDEF 1, 3–5, were identified for the first time by transcriptome-targeted analysis. Three of the members of this CSαβ defensin family, LmDEF 1, 3, and 5, were detected in locust tissues. The pro regions of their sequences have little-shared identities with other insect defensins, though the predicted mature peptides align well with other insect defensins. Phylogenetic analysis indicates a completely novel position of both LmDEF 1 and 3, compared to defensins from hymenopterans. The expression patterns of the genes encoding LmDEFs in the fat body and salivary glands were studied in response to immune-challenge by the microsporidian pathogen Nosema locustae and the fungus Metarhizium anisopliae after feeding or topical application, respectively. Focusing on Nosema-induced immunity, qRT-PCR was employed to quantify the transcript levels of LmDEFs. A higher transcript abundance of LmDEF5 was distributed more or less uniformly throughout the fat body along time. A very low baseline transcription of both LmDEFs 1 and 3 in naïve insects was indicated, and that transcription increases with time or is latent in the fat body or salivary glands of infected nymphs. In the salivary glands, expression of LmDEF3 was 20-40-times higher than in the fat body post-microbial infection. A very low expression of LmDEF3 could be detected in the fat body, but eventually increased with time up to a maximum at day 15. Delayed induction of transcription of these peptides in the fat body and salivary glands 5–15 days post-activation and the differential expression patterns suggest that the fat body/salivary glands of this species are active in the immune response

  8. Jasmonate induction of the monoterpene linalool confers resistance to rice bacterial blight and its biosynthesis is regulated by JAZ protein in rice.

    Science.gov (United States)

    Taniguchi, Shiduku; Hosokawa-Shinonaga, Yumi; Tamaoki, Daisuke; Yamada, Shoko; Akimitsu, Kazuya; Gomi, Kenji

    2014-02-01

    Jasmonic acid (JA) is involved in the regulation of host immunity in plants. Recently, we demonstrated that JA signalling has an important role in resistance to rice bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) in rice. Here, we report that many volatile compounds accumulate in response to exogenous application of JA, including the monoterpene linalool. Expression of linalool synthase was up-regulated by JA. Vapour treatment with linalool induced resistance to Xoo, and transgenic rice plants overexpressing linalool synthase were more resistance to Xoo, presumably due to the up-regulation of defence-related genes in the absence of any treatment. JA-induced accumulation of linalool was regulated by OsJAZ8, a rice jasmonate ZIM-domain protein involving the JA signalling pathway at the transcriptional level, suggesting that linalool plays an important role in JA-induced resistance to Xoo in rice.

  9. Identification of pathotypes of Xanthomonas axonopodis pv. manihotis in Africa and detection of quantitative trait loci and markers for resistance to bacterial blight of Cassava

    OpenAIRE

    Wydra, Kerstin; Zinsou, Valerien; Jorge, Véronique; Verdier, Valérie

    2004-01-01

    Cassava suffers from bacterial blight attack in all growing regions. Control by resistance is unstable due to high genotype–environment interactions. Identifying genes for resistance to African strains of Xanthomonas axonopodis pv. manihotis can support breeding efforts. Five F1 cassava genotypes deriving from the male parent ‘CM2177-2’ and the female parent ‘TMS30572’ were used to produce 111 individuals by backcrossing to the female parent. In all, 16 genotypes among the mapping population ...

  10. Are Bacterial Volatile Compounds Poisonous Odors to a Fungal Pathogen Botrytis cinerea, Alarm Signals to Arabidopsis Seedlings for Eliciting Induced Resistance, or Both?

    OpenAIRE

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    Biological control (biocontrol) agents act on plants via numerous mechanisms, and can be used to protect plants from pathogens. Biocontrol agents can act directly as pathogen antagonists or competitors or indirectly to promote plant induced systemic resistance (ISR). Whether a biocontrol agent acts directly or indirectly depends on the specific strain and the pathosystem type. We reported previously that bacterial volatile organic compounds (VOCs) are determinants for eliciting plant ISR. Eme...

  11. Increased Production of Lysozyme Associated with Bacterial Proliferation in Barrett's Esophagitis, Chronic Gastritis, Gluten-induced Atrophic Duodenitis (Celiac Disease), Lymphocytic Colitis, Collagenous Colitis, Ulcerative Colitis and Crohn's Colitis.

    Science.gov (United States)

    Rubio, Carlos A

    2015-12-01

    The mucosa of the esophagus, the stomach, the small intestine, the large intestine and rectum are unremittingly challenged by adverse micro-environmental factors, such as ingested pathogenic and non-pathogenic bacteria, and harsh secretions with digestive properties with disparate pH, as well as bacteria and secretions from upstream GI organs. Despite the apparently inauspicious mixture of secretions and bacteria, the normal GI mucosa retains a healthy state of cell renewal. To by-pass the tough microenvironment, the epithelia of the GI react by speeding-up cell exfoliation, by increasing peristalsis, eliminating bacteria through secretion of plasma cell-immunoglobulins and by increasing production of natural antibacterial enzymes (lysozyme) and host defense peptides (defensin-5). Lysozyme was recently found up-regulated in Barrett's esophagitis, in chronic gastritis, in gluten-induced atrophic duodenitis (celiac disease), in collagenous colitis, in lymphocytic colitis and in Crohn's colitis. This up-regulation is a response directed towards the special types of bacteria thriving in the microenvironment in each of the aforementioned clinical inflammatory maladies. The purpose of that up-regulation is to protect the mucosa affected by the ongoing chronic inflammation. Bacterial antibiotic resistance continues to exhaust our supply of effective antibiotics. The future challenge is how to solve the increasing menace of bacterial resistance to anti-bacterial drugs. Further research on natural anti-bacterial enzymes such as lysozyme, appears mandatory. PMID:26637845

  12. Resistência de bactérias ácido-láticas a bacteriófagos provenientes de unidades de processamento de queijo Coalho Phage resistance of acid lactic bacteria isolated from Coalho cheese industries

    Directory of Open Access Journals (Sweden)

    Cristiane Pereira de Lima

    2012-06-01

    Full Text Available Este trabalho teve como objetivos isolar bacteriófagos de amostras de leite, soro e queijo de Coalho e avaliar a resistência de cepas de Lactobacillus paracasei, pertencentes à Coleção de Micro-organismos de Interesse para a Agroindústria Tropical da Embrapa Agroindústria Tropical, aos fagos isolados. Posteriormente, a resistência destas cepas a fagos específicos para L. paracasei, da Coleção do Instituto de Lactología Industrial - INLAIN (Santa Fe, Argentina, também foi avaliada. As amostras para isolamento dos fagos foram obtidas em quatro unidades de processamento de queijo de Coalho, sendo duas artesanais e duas industriais, localizadas no Estado do Ceará. Para o isolamento dos bacteriófagos, foi empregado o teste de lise celular (spot, enquanto que a resistência das culturas aos fagos foi avaliada pelos testes de capacidade de produção de ácido e avaliação da turbidez. As cepas avaliadas foram resistentes aos bacteriófagos provenientes das unidades de processamento de queijo de Coalho e aos bacteriófagos da Coleção do INLAIN. Os resultados obtidos indicaram que as culturas láticas testadas, resistentes aos bacteriófagos, podem ser utilizadas na composição de fermento lático destinado à elaboração de queijo de Coalho, a partir de leite pasteurizado.The objectives of this research were to isolate bacteriophages from milk samples, whey and Coalho cheese and to evaluate the resistance of strains of Lactobacillus paracasei from the Collection of Microorganisms of Interest for the Tropical Agroindustry, belonging to Embrapa Tropical Agroindustry, to isolate phages. The strains resistance to specific L. paracasei phages from the collection of the Instituto de Lactología Industrial - INLAIN (Santa Fe, Argentina was also evaluated. Samples for phage isolation were from four Coalho cheese processing units, two artisanal and two industrial, localized in the state of Ceará. Spot test was employed for bacteriophages

  13. Recombinant expression and purification of the tomato defensin TPP3 and its preliminary X-ray crystallographic analysis

    OpenAIRE

    Lay, Fung T.; Veneer, Prem K.; Hulett, Mark D.; Kvansakul, Marc

    2012-01-01

    TPP3 is a class II plant defensin from tomato. Here, the expression, purification, crystallization and preliminary X-ray crystallographic analysis of recombinant TPP3 are reported in order to define its structure and function in relation to other class II plant defensins.

  14. Two novel non-cationic defensin-like antimicrobial peptides from haemolymph of the female tick, Amblyomma hebraeum.

    Science.gov (United States)

    Lai, Ren; Lomas, Lee O; Jonczy, Jan; Turner, Philip C; Rees, Huw H

    2004-01-01

    Two non-cationic defensin-like antimicrobial peptides, named Amblyomma defensin peptide 1 and Amblyomma defensin peptide 2, were identified from the hard tick, Amblyomma hebraeum, by a combination of suppression subtractive hybridization for differentially expressed genes and proteomics. cDNA clones encoding each of these two defensin-like antimicrobial peptides were isolated from the differentially expressed cDNA library of the tick synganglia (central nervous system). The preproproteins deduced from the cDNA sequences each have 92 amino acid residues. Amblyomma defensin peptide 2 was purified from the haemolymph of fed female ticks. The purified peptide displayed antibacterial activity against Gram-negative and Gram-positive bacteria. Amblyomma defensin peptide 1 was further identified by protein chip capture combined with SELDI-TOF (surface-enhanced laser desorption/ionization-time-of-flight) MS. By screening for differentially expressed proteins, it was found that the expression of Amblyomma defensin peptide 1 was upregulated during 4 days post-feeding. Our findings firstly provide two defensin-like antimicrobial peptides that are particularly novel in being anionic, together with corresponding cDNA sequences, in hard ticks, and prove that the combination of suppression subtractive hybridization and protein profiling is a powerful method to study differentially expressed proteins, especially for organisms without available genome sequence information. PMID:14705963

  15. Antimicrobial Human β-Defensins in the Colon and Their Role in Infectious and Non-Infectious Diseases

    Directory of Open Access Journals (Sweden)

    Eduardo R. Cobo

    2013-03-01

    Full Text Available β-defensins are small cationic antimicrobial peptides secreted by diverse cell types including colonic epithelial cells. Human β-defensins form an essential component of the intestinal lumen in innate immunity. The defensive mechanisms of β-defensins include binding to negatively charged microbial membranes that cause cell death and chemoattraction of immune cells. The antimicrobial activity of β-defensin is well reported in vitro against several enteric pathogens and in non-infectious processes such as inflammatory bowel diseases, which alters β-defensin production. However, the role of β-defensin in vivo in its interaction with other immune components in host defense against bacteria, viruses and parasites with more complex membranes is still not well known. This review focuses on the latest findings regarding the role of β-defensin in relevant human infectious and non-infectious diseases of the colonic mucosa. In addition, we summarize the most significant aspects of β-defensin and its antimicrobial role in a variety of disease processes.

  16. α-Defensins and outcome in patients with chronic heart failure

    DEFF Research Database (Denmark)

    Christensen, Heidi M; Frystyk, Jan; Faber, Jens;

    2012-01-01

    predictive ability of a-defensins, alone and combined with N-terminal pro brain natriuretic peptide (NT-proBNP), with respect to all-cause mortality. METHODS AND RESULTS: In a prospective observational study lasting 2.6 years we examined the prognostic value of plasma a-defensins with respect to mortality in...... 194 CHF patients, and compared plasma levels with those of 98 age-matched healthy controls. a-Defensin levels were twice as high among CHF patients in New York Heart Association (NYHA) functional class III-IV than in patients in NYHA class I-II and healthy controls (P = 0.001). The absolute increase.......65, 95% confidence interval 1.19-2.28, P = 0.002) per 1 standard deviation increment in Ln (natural logarithm)-transformed a-defensin values. The combination of high a-defensins and NT-proBNP levels provided incremental prognostic information independent of well-known prognostic biomarkers in heart...

  17. Functional characterization of two defensin isoforms of the hard tick Ixodes ricinus

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    Růžek Daniel

    2011-04-01

    Full Text Available Abstract Background The immune system of ticks is stimulated to produce many pharmacologically active molecules during feeding and especially during pathogen invasion. The family of cationic peptides - defensins - represents a specific group of antimicrobial compounds with six conserved cysteine residues in a molecule. Results Two isoforms of the defensin gene (def1 and def2 were identified in the European tick Ixodes ricinus. Expression of both genes was induced in different tick organs by a blood feeding or pathogen injection. We have tested the ability of synthetic peptides def1 and def2 to inhibit the growth or directly kill several pathogens. The antimicrobial activities (expressed as minimal inhibition concentration and minimal bactericidal concentration values against Gram positive bacteria were confirmed, while Gram negative bacteria, yeast, Tick Borne Encephalitis and West Nile Viruses were shown to be insensitive. In addition to antimicrobial activities, the hemolysis effect of def1 and def2 on human erythrocytes was also established. Conclusions Although there is nothing known about the realistic concentration of defensins in I. ricinus tick body, these results suggest that defensins play an important role in defence against different pathogens. Moreover this is a first report of a one amino acid substitution in a defensins molecule and its impact on antimicrobial activity.

  18. Polysaccharide-capped silver Nanoparticles inhibit biofilm formation and eliminate multi-drug-resistant bacteria by disrupting bacterial cytoskeleton with reduced cytotoxicity towards mammalian cells

    Science.gov (United States)

    Sanyasi, Sridhar; Majhi, Rakesh Kumar; Kumar, Satish; Mishra, Mitali; Ghosh, Arnab; Suar, Mrutyunjay; Satyam, Parlapalli Venkata; Mohapatra, Harapriya; Goswami, Chandan; Goswami, Luna

    2016-04-01

    Development of effective anti-microbial therapeutics has been hindered by the emergence of bacterial strains with multi-drug resistance and biofilm formation capabilities. In this article, we report an efficient green synthesis of silver nanoparticle (AgNP) by in situ reduction and capping with a semi-synthetic polysaccharide-based biopolymer (carboxymethyl tamarind polysaccharide). The CMT-capped AgNPs were characterized by UV, DLS, FE-SEM, EDX and HR-TEM. These AgNPs have average particle size of ~20–40 nm, and show long time stability, indicated by their unchanged SPR and Zeta-potential values. These AgNPs inhibit growth and biofilm formation of both Gram positive (B. subtilis) and Gram negative (E. coli and Salmonella typhimurium) bacterial strains even at concentrations much lower than the minimum inhibitory concentration (MIC) breakpoints of antibiotics, but show reduced or no cytotoxicity against mammalian cells. These AgNPs alter expression and positioning of bacterial cytoskeletal proteins FtsZ and FtsA. CMT-capped AgNPs can effectively block growth of several clinical isolates and MDR strains representing different genera and resistant towards multiple antibiotics belonging to different classes. We propose that the CMT-capped AgNPs can have potential bio-medical application against multi-drug-resistant microbes with minimal cytotoxicity towards mammalian cells.

  19. Stata统计软件在细菌耐药性实验中的应用%Application of Stata on the Experiment of Bacterial Resistance

    Institute of Scientific and Technical Information of China (English)

    张少俊; 莫传伟; 彭拓华; 钟世顺; 杨彤

    2012-01-01

    Objective This article introduce a new method to carry on the experiment of bacterial resistance design with the statistical software-stata. Methods Using the command group and the command replace achieve both equal and unequal probability allocations of the experiment of bacterial resistance. Using the swor command could ensure all samplings without repetitions. Results It's convenient to design the experiment of bacterial resistance with the help of Stata. Conclusion Compared with manual and excel allocations, Stata is a statistical software that is easy to learn, simple to operate and has high repeatability.%目的 应用Stata统计软件细菌耐药性辅助实验设计.方法 应用Stata统计软件中的group、replace对细菌耐药性实验进行等概率与不等概率的分组,应用swor命令实现无重复抽样.结果 Stata统计软件能够方便的辅助细菌耐药性实验设计.结论 对比手工分组与excel分组,Stata统计软件好学易用,操作简单,可重复性高.

  20. Are bacterial volatile compounds poisonous odors to a fungal pathogen Botrytis cinerea, alarm signals to Arabidopsis seedlings for eliciting induced resistance, or both?

    Directory of Open Access Journals (Sweden)

    Choong-Min eRyu

    2016-02-01

    Full Text Available Biological control (biocontrol agents act on plants via numerous mechanisms, and can be used to protect plants from pathogens. Biocontrol agents can act directly as pathogen antagonists or competitors or indirectly to promote plant induced systemic resistance (ISR. Whether a biocontrol agent acts directly or indirectly depends on the specific strain and the pathosystem type. We reported previously that bacterial volatile organic compounds (VOCs are determinants for eliciting plant ISR. Emerging data suggest that bacterial VOCs also can directly inhibit fungal and plant growth. The aim of the current study was to differentiate direct and indirect mechanisms of bacterial VOC effects against Botrytis cinerea infection of Arabidopsis. Volatile emissions from Bacillus subtilis GB03 successfully protected Arabidopsis seedlings against B. cinerea. First, we investigated the direct effects of bacterial VOCs on symptom development and different phenological stages of B. cinerea including spore germination, mycelial attachment to the leaf surface, mycelial growth, and sporulation in vitro and in planta. Volatile emissions inhibited hyphal growth in a dose-dependent manner in vitro, and interfered with fungal attachment on the hydrophobic leaf surface. Second, the optimized bacterial concentration that did not directly inhibit fungal growth successfully protected Arabidopsis from fungal infection, which indicates that bacterial VOC-elicited plant ISR has a more important role in biocontrol than direct inhibition of fungal growth on Arabidopsis. We performed qRT-PCR to investigate the priming of the defense-related genes PR1, PDF1.2, and ChiB at 0, 12, 24, and 36 hours post-infection and 14 days after the start of plant exposure to bacterial VOCs. The results indicate that bacterial VOCs potentiate expression of PR1 and PDF1.2 but not ChiB, which stimulates SA- and JA-dependent signaling pathways in plant ISR and protects plants against pathogen

  1. Are Bacterial Volatile Compounds Poisonous Odors to a Fungal Pathogen Botrytis cinerea, Alarm Signals to Arabidopsis Seedlings for Eliciting Induced Resistance, or Both?

    Science.gov (United States)

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    Biological control (biocontrol) agents act on plants via numerous mechanisms, and can be used to protect plants from pathogens. Biocontrol agents can act directly as pathogen antagonists or competitors or indirectly to promote plant induced systemic resistance (ISR). Whether a biocontrol agent acts directly or indirectly depends on the specific strain and the pathosystem type. We reported previously that bacterial volatile organic compounds (VOCs) are determinants for eliciting plant ISR. Emerging data suggest that bacterial VOCs also can directly inhibit fungal and plant growth. The aim of the current study was to differentiate direct and indirect mechanisms of bacterial VOC effects against Botrytis cinerea infection of Arabidopsis. Volatile emissions from Bacillus subtilis GB03 successfully protected Arabidopsis seedlings against B. cinerea. First, we investigated the direct effects of bacterial VOCs on symptom development and different phenological stages of B. cinerea including spore germination, mycelial attachment to the leaf surface, mycelial growth, and sporulation in vitro and in planta. Volatile emissions inhibited hyphal growth in a dose-dependent manner in vitro, and interfered with fungal attachment on the hydrophobic leaf surface. Second, the optimized bacterial concentration that did not directly inhibit fungal growth successfully protected Arabidopsis from fungal infection, which indicates that bacterial VOC-elicited plant ISR has a more important role in biocontrol than direct inhibition of fungal growth on Arabidopsis. We performed qRT-PCR to investigate the priming of the defense-related genes PR1, PDF1.2, and ChiB at 0, 12, 24, and 36 h post-infection and 14 days after the start of plant exposure to bacterial VOCs. The results indicate that bacterial VOCs potentiate expression of PR1 and PDF1.2 but not ChiB, which stimulates SA- and JA-dependent signaling pathways in plant ISR and protects plants against pathogen colonization. This study

  2. Identification of Pathotypes of Xanthomonas axonopodis pv. manihotis in Africa and Detection of Quantitative Trait Loci and Markers for Resistance to Bacterial Blight of Cassava.

    Science.gov (United States)

    Wydra, K; Zinsou, V; Jorge, V; Verdier, V

    2004-10-01

    ABSTRACT Cassava suffers from bacterial blight attack in all growing regions. Control by resistance is unstable due to high genotype-environment interactions. Identifying genes for resistance to African strains of Xanthomonas axonopodis pv. manihotis can support breeding efforts. Five F(1) cassava genotypes deriving from the male parent 'CM2177-2' and the female parent 'TMS30572' were used to produce 111 individuals by backcrossing to the female parent. In all, 16 genotypes among the mapping population were resistant to stem inoculation by four strains of X. axonopodis pv. manihotis from different locations in Africa, and 19 groups with differential reactions to the four strains were identified, suggesting that the strains represent different pathotypes. Four genotypes were resistant to leaf inoculation, and three were resistant to both stem and leaf inoculations. Genotypes with susceptible, moderately resistant, and resistant reactions after leaf and stem inoculation partly differed in their reactions on leaves and stems. Based on the genetic map of cassava, single-markeranalysis of disease severity after stem-puncture inoculation was performed. Eleven markers were identified, explaining between 16 and 33.3% of phenotypic variance of area under disease progress curve. Five markers on three and one linkage groups from the female- and male-derived framework of family CM8820, respectively, seem to be weakly associated with resistance to four strains of X. axonopodis pv. manihotis. Based on the segregation of alleles from the female of family CM8873, one marker was significantly associated with resistance to two X. axonopodis pv. manihotis strains, GSPB2506 and GSPB2511, whereas five markers were not linked to any linkage group. The quantitative trait loci (QTL) mapping results also suggest that the four African strains belong to four different pathotypes. The identified pathotypes should be useful for screening for resistance, and the QTL and markers will support

  3. Toward the positional cloning of qBlsr5a, a QTL underlying resistance to bacterial leaf streak, using overlapping sub-CSSLs in rice.

    Directory of Open Access Journals (Sweden)

    Xiaofang Xie

    Full Text Available Bacterial leaf steak (BLS is one of the most destructive diseases in rice. Studies have shown that BLS resistance in rice is quantitatively inherited, controlled by multiple quantitative trait loci (QTLs. A QTL with relatively large effect, qBlsr5a, was previously mapped in a region of ∼ 380 kb on chromosome 5. To fine map qBlsr5a further, a set of overlapping sub-chromosome segment substitution lines (sub-CSSLs were developed from a large secondary F2 population (containing more than 7000 plants, in which only the chromosomal region harboring qBlsr5a was segregated. By genotyping the sub-CSSLs with molecular markers covering the target region and phenotyping the sub-CSSLs with artificial inoculation, qBlsr5a was delimited to a 30.0-kb interval, in which only three genes were predicted. qRT-PCR analysis indicated that the three putative genes did not show significant response to the infection of BLS pathogen in both resistant and susceptible parental lines. However, two nucleotide substitutions were found in the coding sequence of gene LOC_Os05g01710, which encodes the gamma chain of transcription initiation factor IIA (TFIIAγ. The nucleotide substitutions resulted in a change of the 39th amino acid from valine (in the susceptible parent to glutamic acid (in the resistant parent. Interestingly, the resistant parent allele of LOC_Os05g01710 is identical to xa5, a major gene resistant to bacterial leaf blight (another bacterial disease of rice. These results suggest that LOC_Os05g01710 is very possibly the candidate gene of qBlsr5a.

  4. Legionella pneumophila induces human beta Defensin-3 in pulmonary cells

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    Hippenstiel Stefan

    2010-07-01

    Full Text Available Abstract Background Legionella pneumophila is an important causative agent of severe pneumonia in humans. Human alveolar epithelium and macrophages are effective barriers for inhaled microorganisms and actively participate in the initiation of innate host defense. The beta defensin-3 (hBD-3, an antimicrobial peptide is an important component of the innate immune response of the human lung. Therefore we hypothesize that hBD-3 might be important for immune defense towards L. pneumophila. Methods We investigated the effects of L. pneumophila and different TLR agonists on pulmonary cells in regard to hBD-3 expression by ELISA. Furthermore, siRNA-mediated inhibition of TLRs as well as chemical inhibition of potential downstream signaling molecules was used for functional analysis. Results L. pneumophila induced release of hBD-3 in pulmonary epithelium and alveolar macrophages. A similar response was observed when epithelial cells were treated with different TLR agonists. Inhibition of TLR2, TLR5, and TLR9 expression led to a decreased hBD-3 expression. Furthermore expression of hBD-3 was mediated through a JNK dependent activation of AP-1 (c-Jun but appeared to be independent of NF-κB. Additionally, we demonstrate that hBD-3 elicited a strong antimicrobial effect on L. pneumophila replication. Conclusions Taken together, human pulmonary cells produce hBD-3 upon L. pneumophila infection via a TLR-JNK-AP-1-dependent pathway which may contribute to an efficient innate immune defense.

  5. Influence of silver additions to type 316 stainless steels on bacterial inhibition, mechanical properties, and corrosion resistance

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Tseng, I-Sheng; Møller, Per;

    2010-01-01

    Bacterial contamination is a major concern in many areas. In this study, silver was added to type 316 stainless steels in order to obtain an expected bacteria inhibiting property to reduce the occurrence of bacterial contamination. Silver-bearing 316 stainless steels were prepared by vacuum melti...

  6. Identification and gene prediction of a 24 kb region containing xa5, a recessive bacterial blight resistance gene in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    ZHONG Yiming; JIANG Guanghuai; CHEN Xuewei; XIA Zhihui; LI Xiaobing; ZHU Lihuang; ZHAI Wenxue

    2003-01-01

    Rice xa5 gene provides recessive, race-specific resistance to bacterial blight disease caused by the pathogen Xanthomonas oryzae pv. oryzae and has great value for research and breeding. In an effort to clone xa5, an F2 population of 4892 individuals was developed from the xa5 near isogenic lines, IR24 and IRBB5. A fine mapping procedure was conducted and tightly linked RFLP markers were used to screen a BAC library of IRBB56, a resistant rice line containing the xa5 gene. A 213 kb contig covering the xa5 locus was constructed. According to the sequences from the International Rice Genome Sequening Project (IRGSP), the Chinese Superhybrid Rice Genome Project (SRGP) and some sub-clones of the contig, twelve SSLP and CAPS markers were developed for fine mapping. The xa5 gene was mapped to a 0.3 cM interval between markers K5 and T4, which spanned an interval of approximately 24 kb, co-segregating with marker T2. Sequence analysis of the 24 kb region revealed that an ABC transporter and a basal transcription factor (TFIIa) were potential candidates for the xa5 resistance gene product. The molecular mechanism by which the xa5 gene provides recessive, race-specific resistance to bacterial blight will be elucidated by the functional tests of the 24 kb DNA and the candidate genes.

  7. Altered cutaneous expression of beta-defensins in dogs with atopic dermatitis.

    Science.gov (United States)

    van Damme, Catharina M M; Willemse, Ton; van Dijk, Albert; Haagsman, Henk P; Veldhuizen, Edwin J A

    2009-08-01

    Canine atopic dermatitis (AD) is a chronic allergic skin disorder with an immunopathogenesis comparable to that in humans with AD. The high frequency of recurrent infections with Staphylococcus pseudo intermedius and Malassezia pachydermatis may indicate a defective innate immune response in the skin of atopic dogs. Production of beta-defensins constitutes an important role in skin defense but information on canine beta-defensin localization and regulation is scarce. We conducted a gene-expression study of 16 canine beta-defensins (cBDs) in 11 tissues of healthy dogs, which revealed a variable expression of cBDs in different organ systems of the dog. In skin, three beta-defensins, cBD1, cBD103 and cBD107, were extensively expressed, while inconsistent expression of five other beta-defensins was detected. Using immunohistochemistry abundant expression of cBD103 peptide was detected in the epidermis, hair follicles and sebaceous glands, comparable to hBD3 expression in human skin. To examine the gene-expression of beta-defensins in atopic dogs, full thickness skin biopsy specimens (non-lesional and lesional) of 10 atopic dogs and 7 healthy dogs were examined with real-time PCR. A significant 12-fold increased expression of cBD1 was detected in lesional atopic skin compared to healthy skin, while non-lesional skin showed a 5-fold increase. Contrary to cBD1, expression of cBD103 was slightly (2-fold) downregulated in skin of atopic dogs. Gene-expression levels of S100A8, a marker for atopic dermatitis, were also highly upregulated in skin of atopic dogs, confirming the diagnostics of the skin biopsies. Taken together these results provide new evidence for a possible defect in the innate immune response of dogs with atopic dermatitis, and indicate the potential of the dog as a model for human AD. PMID:19576634

  8. Robust and regulatory expression of defensin A gene driven by vitellogenin promoter in transgenic Anopheles stephensi

    Institute of Scientific and Technical Information of China (English)

    CHEN XiaoGuang; ZHANG YaJing; ZHENG XueLi; WANG ChunMei

    2007-01-01

    The use of genetically modified mosquitoes to reduce or replace field populations is a new strategy to control mosquito-borne diseases. The precondition of the implementation of this strategy is the ability to manipulate the genome of mosquitoes and to induce specific expression of the effector molecules driven by a suitable promoter. The objective of this study is to evaluate the expression of defensin A gene of Anopheles sinensis under the control of a vitellogenin promoter in transgenic Anopheles stephensi. The regulatory region of Anopheles gambiae vitellogenin was cloned and subcloned into transfer vector pSLFa consisting of an expression cassette with defensin A coding sequence. Then, the expression cassette was transferred into transformation vector pBac[3xP3-DsRedafm] using Asc I digestion. The recombinant plasmid DNA of pBac[3xP3DsRed-AgVgT2-DefA] and helper plasmid DNA of phsp-pBac were micro-injected into embryos of An. stephensi. The positive transgenic mosquitoes were screened by observing specific red fluorescence in the eyes of G1 larvae. Southern blot analysis showed that a single-copy transgene integrated into the genome of An. stephensi. RT-PCR analysis showed that the defensin A gene expressed specifically in fat bodies of female mosquitoes after a blood meal. Interestingly, the mRNA of defensin A is more stable compared with that of the endogenous vitellogenin gene. After multiple blood meals, the expression of defensin A appeared as a reducible and non-cycling type, a crucial feature for its anti-pathogen effect. From data above, we concluded that the regulatory function of the Vg promoter and the expression of defensin A gene were relatively conserved in different species of anopheles mosquitoes. These molecules could be used as candidates in the development of genetically modified mosquitoes.

  9. Human defensins 5 and 6 enhance HIV-1 infectivity through promoting HIV attachment

    Directory of Open Access Journals (Sweden)

    Lu Wuyuan

    2011-06-01

    Full Text Available Abstract Background Concurrent sexually transmitted infections (STIs increase the likelihood of HIV transmission. The levels of defensins are frequently elevated in genital fluids from individuals with STIs. We have previously shown that human defensins 5 and 6 (HD5 and HD6 promote HIV entry and contribute to Neisseria gonorrhoeae-mediated enhancement of HIV infectivity in vitro. In this study, we dissect the molecular mechanism of the HIV enhancing effect of defensins. Results HD5 and HD6 primarily acted on the virion to promote HIV infection. Both HD5 and HD6 antagonized the anti-HIV activities of inhibitors of HIV entry (TAK 779 and fusion (T-20 when the inhibitors were present only during viral attachment; however, when these inhibitors were added back during viral infection they overrode the HIV enhancing effect of defensins. HD5 and HD6 enhanced HIV infectivity by promoting HIV attachment to target cells. Studies using fluorescent HIV containing Vpr-GFP indicated that these defensins enhanced HIV attachment by concentrating virus particles on the target cells. HD5 and HD6 blocked anti-HIV activities of soluble glycosaminoglycans including heparin, chondroitin sulfate, and dextran sulfate. However, heparin, at a high concentration, diminished the HIV enhancing effect of HD5, but not HD6. Additionally, the degree of the HIV enhancing effect of HD5, but not HD6, was increased in heparinase-treated cells. These results suggest that HD5 and haparin/heparan sulfate compete for binding to HIV. Conclusions HD5 and HD6 increased HIV infectivity by concentrating virus on the target cells. These defensins may have a negative effect on the efficacy of microbicides, especially in the setting of STIs.

  10. Molecular cloning and characterization of three beta-defensins from canine testes.

    Science.gov (United States)

    Sang, Yongming; Ortega, M Teresa; Blecha, Frank; Prakash, Om; Melgarejo, Tonatiuh

    2005-05-01

    Mammalian beta-defensins are small cationic peptides possessing broad antimicrobial and physiological activities. Because dogs are particularly resilient to sexually transmitted diseases, it has been proposed that their antimicrobial peptide repertoire might provide insight into novel antimicrobial therapeutics and treatment regimens. To investigate this proposal, we cloned the full-length cDNA of three canine beta-defensin isoforms (cBD-1, -2, and -3) from canine testicular tissues. Their predicted peptides share identical N-terminal 65-amino-acid residues, including the beta-defensin consensus six-cysteine motif. The two longer isoforms, cBD-2 and -3, possess 4 and 34 additional amino acids, respectively, at the C terminus. To evaluate the antimicrobial activity of cBD, a 34-amino-acid peptide derived from the shared mature peptide region was synthesized. Canine beta-defensin displayed broad antimicrobial activity against gram-positive bacteria (Listeria monocytogenes and Staphylococcus aureus; MICs of 6 and 100 mug/ml, respectively), gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, and Neisseria gonorrhoeae; MICs of 20 to 50, 20, and 50 mug/ml, respectively), and yeast (Candida albicans; MIC of 5 to 50 mug/ml) and lower activity against Ureaplasma urealyticum and U. canigenitalium (MIC of 200 mug/ml). Antimicrobial potency was significantly reduced at salt concentrations higher than 140 mM. All three canine beta-defensins were highly expressed in testis. In situ hybridization indicated that cBD-1 was expressed primarily in Sertoli cells within the seminiferous tubules. In contrast, cBD-2 was located primarily within Leydig cells. The longest isoform, cBD-3, was detected in Sertoli cells and to a lesser extent in the interstitium. The tissue-specific expression and broad antimicrobial activity suggest that canine beta-defensins play an important role in host defense and other physiological functions of the male reproductive system. PMID:15845463

  11. A Comparison of the Molecular Organization of Genomic Regions Associated with Resistance to Common Bacterial Blight in Two Phaseolus vulgaris Genotypes

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    Gregory E. Perry

    2013-08-01

    Full Text Available Resistance to common bacterial blight, caused by Xanthomonas axonopodis pv. phaseoli, in Phaseolus vulgaris is conditioned by several loci on different chromosomes. Previous studies with OAC-Rex, a CBB-resistant, white bean variety of Mesoamerican origin, identified two resistance loci associated with the molecular markers Pv-CTT001 and SU91, on chromosome 4 and 8, respectively. Resistance to CBB is assumed to be derived from an interspecific cross with Phaseolus acutifolius in the pedigree of OAC-Rex. Our current whole genome sequencing effort with OAC-Rex provided the opportunity to compare its genome in the regions associated with CBB resistance with the v1.0 release of the P. vulgaris line G19833, which is a large seeded bean of Andean origin, and (assumed to be CBB susceptible.. In addition, the genomic regions containing SAP6, a marker associated with P. vulgaris-derived CBB-resistance on chromosome 10, were compared. These analyses indicated that gene content was highly conserved between G19833 and OAC-Rex across the regions examined (>80%. However, fifty-nine genes unique to OAC Rex were identified, with resistance gene homologues making up the largest category (10 genes identified. Two unique genes in OAC-Rex located within the SU91 resistance QTL have homology to P. acutifolius ESTs and may be potential sources of CBB resistance. As the genomic sequence assembly of OAC-Rex is completed, we expect that further comparisons between it and the G19833 genome will lead to a greater understanding of CBB resistance in bean.

  12. Acute bacterial meningitis caused by Streptococcus pneumoniae resistant to the antimicrobian agents and their serotypes Meningite bacteriana aguda por Streptococcus pneumoniae resistente aos antimicrobianos e seus sorotipos

    Directory of Open Access Journals (Sweden)

    Andrea Maciel de Oliveira Rossoni

    2008-09-01

    Full Text Available The main objectives of this study are to evaluate the resistance rates of Streptococcus pneumonia to penicillin G, ceftriaxone and vancomycin in patients with meningitis; to analyze possible risk factors to the antimicrobian resistance; to describe the serotypes detected and to suggest an initial empirical treatment for meningitis. The sensitiveness and serotypes of all isolated S. pneumoniae of patients with acute bacterial meningitis received by the Paraná State Central Laboratory from April 2001 to august 2002 have been evaluated. One hundred S. pneumoniae have been isolated, of which 15% were resistant to penicillin, 1% to cephalosporin and 0% to vancomycin. The serotypes most found were 14 (19%, 3 and 23F (10% each. When only the resistant serotypes were analyzed, the most prevalent was the 14 with 44%. The risk factors found in relation to the S. pneumoniae resistance were: age under one year old (p=0.01 and previous use of antibiotic (p=0.046. The resistance rates found, which were moderate to penicillin, low to cephalosporin and neutral to vancomycin, suggest the isolated use of a 3rd generation cephalosporin as an initial empirical therapy for the treatment of acute bacterial meningitis with a communitarian background.Este estudo teve como objetivo avaliar as taxas de resistência de Streptococcus pneumoniae, isolados de pacientes com meningite, à penicilina G, ceftriaxona e vancomicina; avaliar possíveis fatores de risco para resistência antimicrobiana; descrever os sorotipos encontrados e sugerir a terapêutica empírica inicial para meningite. Foram isoladas 100 amostras de S. pneumoniae, encontrando-se 15% de resistência à penicilina, 1% à cefalosporina e 0% à vancomicina. Os sorotipos mais encontrados foram 14 (19%, 3 e 23F (10% cada. Analisando-se os resistentes, o sorotipo 14 (44% também foi o mais freqüente. Os fatores de risco para resistência de S. pneumoniae encontrados foram: idade menor que um ano (p=0,01 e o uso

  13. Alpha-defensin DEFA1A3 gene copy number elevation in Danish Crohn's disease patients

    DEFF Research Database (Denmark)

    Jespersgaard, Cathrine; Fode, Peder; Dybdahl, Marianne;

    2011-01-01

    BACKGROUND AND PURPOSE OF STUDY: Extensive copy number variation is observed for the DEFA1A3 gene encoding alpha-defensins 1-3. The objective of this study was to determine the involvement of alpha-defensins in colonic tissue from Crohn's disease (CD) patients and the possible genetic association...... number of DEFA1A3 and individual alleles, DEFA1 and DEFA3, were compared with those for controls, by use of combined real-time quantitative PCR and pyrosequencing, and correlated with disease location. RESULTS: Inflammatory-dependent mRNA expression of DEFA1A3 (P

  14. Alpha-defensins 1-3 release by dendritic cells is reduced by estrogen

    Directory of Open Access Journals (Sweden)

    Sperling Rhoda

    2011-08-01

    Full Text Available Abstract Background During pregnancy the immune system of the mother must protect any activation that may negatively affect the fetus. Changes in susceptibility to infection as well as resolution of some autoimmune disorders represent empirical evidence for pregnancy related alterations in immunity. Sex hormones reach extremely high levels during pregnancy and have been shown to have direct effects on many immune functions including the antiviral response of dendritic cells. Among the immunologically active proteins secreted by monocyte derived DCs (MDDC are the alpha-defensins 1-3. This family of cationic antimicrobial peptides has a broad spectrum of microbicidal activity and has also been shown to link innate to adaptive immunity by attracting T cells and immature DCs, which are essential for initiating and polarizing the immune response. Methods We compare culture-generated monocyte derived DCs (MDDCs with directly isolated myeloid dendritic cells (mDCs and plasmacytoid dendritic cells (pDCs and measure their alpha-defensins 1-3 secretion by ELISA both, in basal situations and after hormone (E2 or PG treatments. Moreover, using a cohort of pregnant women we isolated mDCs from blood and also measure the levels of these anti-microbial peptides along pregnancy. Results We show that mDCs and pDCs constitutively produce alpha-defensins 1-3 and at much higher levels than MDDCs. Alpha-defensins 1-3 production from mDCs and MDDCs but not pDCs is inhibited by E2. PG does not affect alpha-defensins 1-3 in any of the populations. Moreover, alpha-defensins 1-3 production by mDCs was reduced in the later stages of pregnancy in 40% of the patients. Conclusions Here, we demonstrate that mDCs and pDCs secrete alpha-defensins 1-3 and present a novel effect of E2 on the secretion of alpha-defensins 1-3 by dendritic cells.

  15. 1,25-Dihydroxyvitamin-D3 Induces Avian β-Defensin Gene Expression in Chickens

    Science.gov (United States)

    Zhang, Guolong; Ouyang, Linghua; Robinson, Kelsy; Tang, Yanqiang; Zhu, Qing; Li, Diyan; Hu, Yaodong; Liu, Yiping

    2016-01-01

    Host defense peptides (HDPs) play a critical role in innate immunity. Specific modulation of endogenous HDP synthesis by dietary compounds has been regarded as a novel approach to boost immunity and disease resistance in animal production. 1,25-dihydroxy vitamin D3 (1,25D3) is well known as a powerful HDP inducer in humans, but limited information about the effect of 1,25D3 on HDPs in poultry is available. Here, we sought to examine whether 1,25D3 could stimulate avian β-defensin (AvBD) expression in chickens. We used chicken embryo intestinal epithelial cells (CEIEPCs) and peripheral blood mononuclear cells (PBMCs) to study the effect of 1,25D3 on the expression of AvBDs. We observed that 1,25D3 is able to up-regulate the expression of several AvBDs in CEIEPCs and PBMCs, whereas it increased the amounts of AvBD4 mRNA in CEIEPCs only in the presence of lipopolysaccharide (LPS). On the other hand, LPS treatment not only inhibited the expression of CYP24A1 but also altered the expression pattern of VDR in CEIEPCs. Furthermore, AvBDs were not directly regulated by 1,25D3, as cycloheximide completely blocked 1,25D3-induced expression of AvBDs. Our observations suggest that 1,25D3 is capable of inducing AvBD gene expression and is a potential antibiotic alternative through augmentation of host innate immunity as well as disease control in chickens. PMID:27135828

  16. 1,25-Dihydroxyvitamin-D3 Induces Avian β-Defensin Gene Expression in Chickens.

    Directory of Open Access Journals (Sweden)

    Long Zhang

    Full Text Available Host defense peptides (HDPs play a critical role in innate immunity. Specific modulation of endogenous HDP synthesis by dietary compounds has been regarded as a novel approach to boost immunity and disease resistance in animal production. 1,25-dihydroxy vitamin D3 (1,25D3 is well known as a powerful HDP inducer in humans, but limited information about the effect of 1,25D3 on HDPs in poultry is available. Here, we sought to examine whether 1,25D3 could stimulate avian β-defensin (AvBD expression in chickens. We used chicken embryo intestinal epithelial cells (CEIEPCs and peripheral blood mononuclear cells (PBMCs to study the effect of 1,25D3 on the expression of AvBDs. We observed that 1,25D3 is able to up-regulate the expression of several AvBDs in CEIEPCs and PBMCs, whereas it increased the amounts of AvBD4 mRNA in CEIEPCs only in the presence of lipopolysaccharide (LPS. On the other hand, LPS treatment not only inhibited the expression of CYP24A1 but also altered the expression pattern of VDR in CEIEPCs. Furthermore, AvBDs were not directly regulated by 1,25D3, as cycloheximide completely blocked 1,25D3-induced expression of AvBDs. Our observations suggest that 1,25D3 is capable of inducing AvBD gene expression and is a potential antibiotic alternative through augmentation of host innate immunity as well as disease control in chickens.

  17. Anti-hemolytic, hemagglutination inhibition and bacterial membrane disruptive properties of selected herbal extracts attenuate virulence of Carbapenem Resistant Escherichia coli.

    Science.gov (United States)

    Thakur, Pallavi; Chawla, Raman; Narula, Alka; Goel, Rajeev; Arora, Rajesh; Sharma, Rakesh Kumar

    2016-06-01

    Expression of a multitude of virulence factors by multi-drug resistant microbial strains, e.g., Carbapenem Resistant Escherichia coli (Family: Enterobacteriaceae; Class: Gammaproteobacteria), is responsible for resistance against beta-lactam antibiotics. Hemolysin production and induction of hemagglutination by bacterial surface receptors inflicts direct cytotoxicity by destroying host phagocytic and epithelial cells. We have previously reported that Berberis aristata, Camellia sinensis, Cyperus rotundus Holarrhena antidysenterica and Andrographis paniculata are promising herbal leads for targeting Carbapenem resistant Escherichia coli. These herbal leads were analyzed for their anti-hemolytic potential by employing spectrophotometric assay of hemoglobin liberation. Anti-hemagglutination potential of the extracts was assessed by employing qualitative assay of visible RBC aggregate formation. Camellia sinensis (PTRC-31911-A) exhibited anti-hemolytic potential of 73.97 ± 0.03%, followed by Holarrhena antidysenterica (PTRC-8111-A) i.e., 68.32 ± 0.05%, Berberis aristata (PTRC-2111-A) i.e., 60.26 ± 0.05% and Cyperus rotundus (PTRC-31811-A) i.e., 53.76 ± 0.03%. Comprehensive, visual analysis of hemagglutination inhibition revealed that only Berberis aristata (PTRC-2111-A) and Camellia sinensis (PTRC-31911-A) exhibited anti-hemagglutination activity. However, Andrographis paniculata (PTRC-11611-A) exhibited none of the inhibitory activities. Furthermore, the pair wise correlation analysis of the tested activities with quantitative phytochemical descriptors revealed that an increased content of alkaloid; flavonoids; polyphenols, and decreased content of saponins supported both the activities. Additionally, flow cytometry revealed that cell membrane structures of CRE were damaged by extracts of Berberis aristata (PTRC-2111-A) and Camellia sinensis (PTRC-31911-A) at their respective Minimum Inhibitory Concentrations, thereby confirming noteworthy antibacterial

  18. Analysis and characterization of cultivable heavy metal-resistant bacterial endophytes isolated from Cd-hyperaccumulator Solanum nigrum L. and their potential use for phytoremediation.

    Science.gov (United States)

    Luo, Sheng-lian; Chen, Liang; Chen, Jue-liang; Xiao, Xiao; Xu, Tao-ying; Wan, Yong; Rao, Chan; Liu, Cheng-bin; Liu, Yu-tang; Lai, Cui; Zeng, Guang-ming

    2011-11-01

    This study investigates the heavy metal-resistant bacterial endophytes of Cd-hyperaccumulator Solanum nigrum L. grown on a mine tailing by using cultivation-dependent technique. Thirty Cd-tolerant bacterial endophytes were isolated from roots, stems, and leaves of S. nigrum L. and classified by amplified ribosomal DNA-restriction analysis into 18 different types. Phylogenetic analysis based on 16S rDNA sequences showed that these isolates belonged to four groups: Actinobacteria (43%), Proteobacteria (23%), Bacteroidetes (27%) and Firmicutes (7%). All the isolates were then characterized for their plant growth promoting traits as well as their resistances to different heavy metals; and the actual plant growth promotion and colonization ability were also assessed. Four isolates were re-introduced into S. nigrum L. under Cd stress and resulted in Cd phytotoxicity decrease, as dry weights of roots increased from 55% to 143% and dry weights of above-ground from 64% to 100% compared to the uninoculated ones. The total Cd accumulation of inoculated plants increased from 66% to 135% (roots) and from 22% to 64% (above-ground) compared to the uninoculated ones. Our research suggests that bacterial endophytes are a most promising resource and may be the excellent candidates of bio-inoculants for enhancing the phytoremediation efficiency. PMID:21868057

  19. In vitro antibacterial activity of venom protein isolated from sea snake Enhydrina schistosa against drug-resistant human pathogenic bacterial strains

    Institute of Scientific and Technical Information of China (English)

    Palani Damotharan; Anguchamy Veeruraj; Muthuvel Arumugam; Thangavel Balasubramanian

    2015-01-01

    Objective:To evaluate the antibacterial activity of sea snake (Enhydrina schistosa) venom protein against drug-resistant human pathogenic bacterial strains. Methods:The venom was collected by milking process from the live specimens of sea snake are using capillary tubes or glass plates. Venom was purified by ion exchange chromatography and it was tested for in-vitro antibacterial activity against 10 drug-resistant human pathogenic bacterial strains using the standard disc diffusion method. Results:The notable antibacterial activity was observed at 150 µg/mL concentration of purified venom and gave its minimum inhibitory concentrations values exhibited between 200-100 µg/mL against all the tested bacterial strains. The maximum zone of inhibition was observed at 16.4 mm against Salmonella boydii and the minimum activity was observed at 7.5 mm against Pseudomonas aeruginosa. After the sodium-dodecyl-sulfate-polyacrylamide gel electrophoresis there were a clear single band was detected in the gel that corresponding to purified venom protein molecular weight of 44 kDa. Conclusions:These results suggested that the sea snake venom might be a feasible source for searching potential antibiotics agents against human pathogenic diseases.

  20. In vitro antibacterial activity of methanol and water extracts of adiantum capillus veneris and tagetes patula against multidrug resistant bacterial strains

    International Nuclear Information System (INIS)

    The aim of present study was to screen the antimicrobial activities of extracts of leaves and stems of Adiantum capillus veneris and Tagetes patula against multidrug-resistant (MDR) bacterial strains. Extracts from the leaves and stems of these plants were extracted with methanol and water and tested for their antibacterial activity by disc diffusion method against ten MDR bacterial strains i.e., Citrobacter freundii, Escherichia coli, Providencia, Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, Proteus vulgaris, Salmonella typhi, Shigella and Vibrio cholerae. Leaves methanol extract (LME) of Adiantum showed maximum Zone of Inhibition (ZI) against Providencia, Klebsiella pneumoniae, Shigella, Vibrio cholerae, Staphylococcus aureus, Proteus vulgaris and Salmonella typhi, whereas its stem methanol extract (SME) was very active against Escherichia coli, Klebsiella pneumoniae and Salmonella typhi. Similarly LME of Tagetes showed highest ZI against Escherichia coli and Vibrio cholerae while SME showed highest ZI to Escherichia coli, Vibrio cholerae, Providencia, Shigella and Klebsiella pneumoniae. Leaves water extract (LWE) of Adiantum was very active against all ten bacterial strains while its stem water extract (SWE) showed maximum ZI against Escherichia coli, Klebsiella pneumoniae and Salmonella typhi, Shigella, Proteus vulgaris and Providencia. LWE of Tagetes was only active against Vibrio cholerae whereas SWE was very active against Salmonella typhi and active against P. vulgaris, Citrobacter freundii and Vibrio cholerae. It was concluded from this study that extracts of both Adiantum and Tagetes have prominent activities against most of the MDR bacterial strains and needs further studies for utmost benefits. (author)

  1. Mathematical modeling of bacterial kinetics to predict the impact of antibiotic colonic exposure and treatment duration on the amount of resistant enterobacteria excreted.

    Directory of Open Access Journals (Sweden)

    Thu Thuy Nguyen

    2014-09-01

    Full Text Available Fecal excretion of antibiotics and resistant bacteria in the environment are major public health threats associated with extensive farming and modern medical care. Innovative strategies that can reduce the intestinal antibiotic concentrations during treatments are in development. However, the effect of lower exposure on the amount of resistant enterobacteria excreted has not been quantified, making it difficult to anticipate the impact of these strategies. Here, we introduce a bacterial kinetic model to capture the complex relationships between drug exposure, loss of susceptible enterobacteria and growth of resistant strains in the feces of piglets receiving placebo, 1.5 or 15 mg/kg/day ciprofloxacin, a fluoroquinolone, for 5 days. The model could well describe the kinetics of drug susceptible and resistant enterobacteria observed during treatment, and up to 22 days after treatment cessation. Next, the model was used to predict the expected amount of resistant enterobacteria excreted over an average piglet's lifetime (150 days when varying drug exposure and treatment duration. For the clinically relevant dose of 15 mg/kg/day for 5 days, the total amount of resistant enterobacteria excreted was predicted to be reduced by 75% and 98% when reducing treatment duration to 3 and 1 day treatment, respectively. Alternatively, for a fixed 5-days treatment, the level of resistance excreted could be reduced by 18%, 33%, 57.5% and 97% if 3, 5, 10 and 30 times lower levels of colonic drug concentrations were achieved, respectively. This characterization on in vivo data of the dynamics of resistance to antibiotics in the colonic flora could provide new insights into the mechanism of dissemination of resistance and can be used to design strategies aiming to reduce it.

  2. Antibiotic resistance of bacterial isolates from aquatic animals and its prevention and control%水产动物源细菌耐药性与预防控制

    Institute of Scientific and Technical Information of China (English)

    李国烈; 李林桂; 房文红

    2012-01-01

    Bacterial resistance is the ability of a disease-causing bacterium to resist being killed by antibiotics. The formation of bacterial resistance is the result of the development of bacterial evolution and the manifest of bacterial adaptability; however, it threatens the development of aquaculture and human health. Firstly, this paper summarized the research progress on the bacterial resistance in aquatic animals in recent years, including plasmid-mediated resistance of bacteria, resistance gene of bacterial isolates from aquatic animals, and the genetic mechanism of antibiotic resistance and so on. Secondly, the paper analyzed the harm of bacterial resistance, which included the pathogen of bacterial resistance that caused epidemics and the antibiotic resistance of bacterial isolates from aquatic animals that threatened public health. Finally, from rational and standardized use of drugs, speeding up the development and application of aquatic vaccines and new antimicrobial drugs alternatives, strengthening of the surveillance about pathogen isolates from aquatic animals and so on, the paper provided some valuable methods and strategies on the prevention and control for bacterial resistance in aquatic animals.%细菌耐药性是指细菌对于抗菌药物作用的耐受性。细菌耐药性的形成,是细菌进化发展的结果,是细菌适应性的表现,但它却给养殖业的发展和人类的健康带来威胁。本文首先综述了水产动物源细菌耐药性研究现状,主要包括质粒介导的水产动物源细菌耐药性、细菌耐药基因、细菌耐药性遗传学机制等;其次,从病原菌耐药性会导致水产疾病流行爆发和水产细菌耐药性对人类公共卫生安全的影响两方面,分析了水产动物源细菌耐药性的危害;最后,从合理、规范用药,加快水产疫苗和新型抗菌药物替代品的研制与应用,加强水产动物致病菌耐药性监测等方面,提出了预防和控制

  3. Epidemiology of plasmid-mediated quinolone resistance determinants in bacterial isolates from animals and foods with co-resistance to several antibiotics

    OpenAIRE

    Ferreira, Eugénia; Francisco, Ana Patrícia; Jones-Dias, Daniela; Manageiro, Vera; Caniça, Manuela

    2011-01-01

    Background: The use of (fluoro)quinolones both in humans and animals has contributed to the selection of resistant bacteria, limiting the agents available for treatment. This study aims to search for plasmid-mediated quinolone resistance (PMQR) determinants to give information about these expanding resistance mechanisms, their capacity of dissemination among different bacteria by mobile elements, and the role that they play in facilitating co-resistance to several antimicrobials. Methods: ...

  4. Prevalence of antimicrobial resistance among bacterial pathogens isolated from cattle in different European countries: 2002–2004

    DEFF Research Database (Denmark)

    Hendriksen, Rene S.; Mevius, Dik J; Schroeter, Andreas;

    2008-01-01

    from 13 European countries. For Staphylococcus aureus from bovine mastitis major differences were apparent in the occurrence of resistance between countries and between the different antimicrobial agents tested. The highest frequency of resistance was observed for penicillin. For Mannheimia haemolytica...

  5. Prevalência de resistência bacteriana nas infecções de ferida operatória em cirurgia arterial periférica Prevalence of bacterial resistance in surgical wound infections in peripheral arterial surgery

    Directory of Open Access Journals (Sweden)

    Eduardo Lichtenfels

    2008-09-01

    Full Text Available CONTEXTO: A infecção de sítio cirúrgico é uma complicação grave da cirurgia vascular periférica. O recente aparecimento de microorganismos resistentes e agressivos gera uma nova preocupação com relação ao manejo dessas infecções. OBJETIVO: Verificar a prevalência de resistência bacteriana, a epidemiologia, os possíveis fatores associados e o padrão de resistência nas infecções de ferida operatória das cirurgias arteriais periféricas. MÉTODOS: Estudo de prevalência, envolvendo 40 pacientes portadores de infecção da ferida operatória e submetidos à cirurgia de revascularização arterial periférica no período de janeiro de 2007 a maio de 2008. RESULTADOS: Participaram do estudo pacientes com média de idade de 64,2 anos, predominantemente do sexo masculino (70%. A prevalência geral de resistência bacteriana foi 72,5%, e de multirresistência, 60%. O microorganismo mais freqüentemente isolado foi o Staphylococcus aureus (40%, sendo 11 das 16 culturas (68,7% resistentes à oxacilina. As taxas de resistência aos principais antimicrobianos testados foram: ampicilina, 85,7%; cefalosporina, 76,9%; oxacilina, 65%; e ciprofloxacina, 62,5%. Não foi identificada resistência à vancomicina e ao imipenem. CONCLUSÕES: Os achados deste estudo sugerem que a resistência bacteriana é um problema atual e muito prevalente nas cirurgias arteriais periféricas. O Staphylococcus aureus segue sendo o principal patógeno envolvido, demonstrando altas taxas de resistência. A vancomicina e o imipenem seguem sendo as principais opções terapêuticas para esse tipo de infecção.BACKGROUND: Surgical wound infection is a severe complication of peripheral vascular surgery. The recent appearance of resistant and aggressive pathogens brings new concerns related to the management of these infections. OBJECTIVE: To verify the prevalence of bacterial resistance, epidemiology, possibly associated factors and resistance patterns in wound

  6. 新生儿细菌性结膜炎的细菌分布及耐药情况分析%Analysis of bacterial distribution and drug resistance of bacterial conjunc-tivitis in newborn

    Institute of Scientific and Technical Information of China (English)

    张萌; 王媛; 邬丽霞; 谢镜花

    2015-01-01

    目的:探讨新生儿细菌性结膜炎的细菌分布及耐药情况,为新生儿细菌性结膜炎的临床治疗和相关研究提供参考依据。方法选取2009年7月~2013年7月门诊就诊的150例新生儿细菌性结膜炎患儿作为研究对象,对患儿的眼分泌物病原学和药敏试验结果进行统计分析。结果共检出革兰氏阳性致病菌115株(83.33%),革兰氏阴性致病菌23株(16.67%)。对革兰氏阳性菌耐药的前5种抗菌药物为红霉素、妥布霉素、庆大霉素、新霉素、氯霉素,耐药率分别为89.57%、63.48%、41.74%、32.17%、9.57%。对革兰氏阴性菌耐药的前5种抗菌药物为红霉素、青霉素、新霉素、妥布霉素、氨苄西林,耐药率分别为95.65%、65.22%、65.22%、65.22%、60.87%。结论临床上导致新生儿细菌性结膜炎主要以革兰氏阳性致病菌为主,应根据药敏试验结果选择耐药率水平低的抗菌药物进行治疗。%Objective To explore the bacterial distribution and drug resistance of bacterial conjunctivitis in newborn,so as to provide reference for the clinical treatment and research in newborn with infections of the eye. Methods 150 cas-es of bacterial conjunctivitis in newborn from July 2009 to July 2013 in the clinic hospital were selected as the re-search object.The results of etiology and drug susceptibility test for the bacterium retrospectively was statistically ana-lyzed. Results 115 strains of gram positive pathogens were detected,the proportion of 83.33%.23 strains of gram nega-tive pathogenic bacteria were identified,the proportion of 16.67%.To be ranked in the top 5 of antimicrobial resistant gram positive pathogens were erythromycin,neomycin,gentamicin,tobramycin,chloramphenicol,drug resistance rate was 89.57%,63.48%,41.74%,32.17%,9.57%reapectively.To be ranked in the top 5 on antimicrobial resistance of gram neg-ative pathogenic bacteria were erythromycin

  7. Antibiotic resistance pattern of bacterial isolates from cases of urinary tract infections among hospitalized and out-patients at a tertiary health facility in South Western Nigeria

    Directory of Open Access Journals (Sweden)

    Oyekale Oluwalana Timothy

    2014-01-01

    Full Text Available Aim: Urinary tract infections (UTIs are among the most common human infections with distribution of causative agents and their susceptibility pattern to antibiotics varying from region to region. This study aimed at determining the bacterial uropathogens and their antibiotic resistance profile among patients in a Nigerian tertiary health care facility. Materials and Methods: Appropriate urine specimens (midstream/catheter specimen urine of all suspected cases of UTI by clinicians were processed in the medical microbiology laboratory for detection of significant bacteriuria. Bacteria uropathogens isolated were identified by standard biochemical tests and antibiotic susceptibility test to eight antibiotics was carried out on them using Kirby-Bauer disc diffusion technique. Methicillin-resistant Staphylococcus aureus (MRSA was identified by cefoxitin disc diffusion technique and extended-spectrum beta-lactamase (ESBL producing enterobacteria were detected using double-disc synergy test. Results: Of the total 157 males and 189 females investigated, 35.7% and 66.1% respectively had significant bacteriuria. Escherichia coli was the most commonly isolated bacterial pathogen both among in- and out-patients (52.6% vs. 65.5%. Other isolated organisms were S. aureus (13.4% vs. 19.0%, Pseudomonas aeruginosa (10.3% vs. 2.4%, Klebsiella pneumoniae (7.2% vs. 7.1% and K. aerogenes (7.2% vs. 1.2%. Resistance rate of uropathogens to antibiotics was higher among in-patients. Resistance rate to ofloxacin, ceftazidime and ceftriaxone was generally very low compared to other tested antibiotics. Multiple resistant bacteria: MRSA and ESBL-producing enterobacteria were detected among both in-and out-patient with no significant difference in isolation rate. Conclusion: There is a need for continuous monitoring of uropathogens and their antibiotic sensitivity profile for evidence-based empirical treatment of UTI. There is an urgent need for the establishment of antibiotic

  8. Comparative transcriptome proifling of two maize near-isogenic lines differing in the allelic state for bacterial brown spot disease resistance

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-jun; Xu Li; ZHAO Pan-feng; LI Na; WU Lei; HE Yan; WANG Shou-cai

    2015-01-01

    The bacterial brown spot disease (BBS), caused primarily by Pseudomonas syringae pv. syringae van Hal (Pss), reduces plant vigor, yield and quality in maize. To reveal the nature of the defense mechanisms and identify genes involved in the effective host resistance, the dynamic changes of defense transcriptome triggered by the infection of Pss were investigated and compared between two maize near-isogenic lines (NILs). We found that Pss infection resulted in a sophisticated tran-scriptional reprogramming of several biological processes and the resistant NIL employed much faster defense responses than the susceptible NIL. Numerous genes encoding essential components of plant basal resistance would be able to be activated in the susceptible NIL, such as PEN1, PEN2, PEN3, and EDR1, however, in a basic manner, such resistance might not be sufifcient for suppressing Pss pathogenesis. In addition, the expressions of a large number of PTI-, ETI-, PR-, and WRKY-related genes were pronouncedly activated in the resistant NIL, suggesting that maize employ a multitude of defense pathways to defend Pss infection. Six R-gene homologs were identiifed to have signiifcantly higher expression levels in the resistant NIL at early time point, indicating that a robust surveil ance system (gene-to-gene model) might operate in maize during Pss attacks, and these homolog genes are likely to be potential candidate resistance genes involved in BBS disease resistance. Furthermore, a holistic group of novel pathogen-responsive genes were deifned, providing the repertoire of candidate genes for further functional characterization and identiifcation of their regulation patterns during pathogen infection.

  9. Generation of transgenic cattle expressing human β-defensin 3 as an approach to reducing susceptibility to Mycobacterium bovis infection.

    Science.gov (United States)

    Su, Feng; Wang, Yongsheng; Liu, Guanghui; Ru, Kun; Liu, Xin; Yu, Yuan; Liu, Jun; Wu, Yongyan; Quan, Fusheng; Guo, Zekun; Zhang, Yong

    2016-03-01

    Bovine tuberculosis results from infection with Mycobacterium bovis, a member of the Mycobacterium tuberculosis family. Worldwide, M. bovis infections result in economic losses in the livestock industry; cattle production is especially hard-hit by this disease. Generating M. bovis-resistant cattle may potentially mitigate the impact of this disease by reducing M. bovis infections. In this study, we used transgenic somatic cell nuclear transfer to generate cattle expressing the gene encoding human β-defensin 3 (HBD3), which confers resistance to mycobacteria in vitro. We first generated alveolar epithelial cells expressing HBD3 under the control of the bovine MUC1 promoter, and confirmed that these cells secreted HBD3 and possessed anti-mycobacterial capacity. We then generated and identified transgenic cattle by somatic cell nuclear transfer. The cleavage and blastocyst formation rates of genetically modified embryos provided evidence that monoclonal transgenic bovine fetal fibroblast cells have an integral reprogramming ability that is similar to that of normal cells. Five genetically modified cows were generated, and their anti-mycobacterial capacities were evaluated. Alveolar epithelial cells and macrophages from these cattle expressed higher levels of HBD3 protein compared with non-transgenic cells and possessed effective anti-mycobacterial capacity. These results suggest that the overall risk of M. bovis infection in transgenic cattle is efficiently reduced, and support the development of genetically modified animals as an effective tool to reduce M. bovis infection.

  10. Proteinase 3 carries small unusual carbohydrates and associates with αlpha-defensins

    DEFF Research Database (Denmark)

    Zoega, Morten; Ravnsborg, Tina; Højrup, Peter;

    2012-01-01

    with carbohydrates at Asn 102 and 147 carrying unusual small moieties indicating heavy processing. Mass spectrometric analysis and immuno blotting revealed strong association of highly purified PR3 with α-defensins and oligomers hereof. Irreversible inhibition of PR3 by α1-antitrypsin did not affect its association...

  11. Psoriasis is associated with increased beta-defensin genomic copy number.

    NARCIS (Netherlands)

    Hollox, E.J.; Huffmeier, U.; Zeeuwen, P.L.J.M.; Palla, R.; Lascorz, J.; Rodijk-Olthuis, D.; Kerkhof, P.C.M. van de; Traupe, H.; Jongh, G. de; Heijer, M. den; Reis, A.; Armour, J.A.; Schalkwijk, J.

    2008-01-01

    Psoriasis is a common inflammatory skin disease with a strong genetic component. We analyzed the genomic copy number polymorphism of the beta-defensin region on human chromosome 8 in 179 Dutch individuals with psoriasis and 272 controls and in 319 German individuals with psoriasis and 305 controls.

  12. Expression and purification of recombinant human alpha-defensins in Escherichia coli.

    Science.gov (United States)

    Pazgier, Marzena; Lubkowski, Jacek

    2006-09-01

    Different strategies have been developed to produce small antimicrobial peptides (AMPs) using recombinant techniques. Up to now, all efforts to obtain larger quantities of active recombinant human alpha-defensins have been only moderately successful. Here we report an effective method of biosynthesis of human alpha-defensins (hNP-1 to hNP-3 and hD-5 and hD-6) in the Escherichia coli. All the peptides, expressed as insoluble fusions with the peptide encoded by a portion of E. coli tryptophan operon (trp DeltaLE 1413 polypeptide), were isolated from the inclusion bodies by immobilized metal affinity chromatography (IMAC) and separated from the fusion leader by chemical cleavage. Fully reduced peptides that were purified according to a straightforward protocol were subsequently folded, oxidized, and subjected to functional and structural analyses. With the exception of hD-6, all recombinant alpha-defensins exhibit expected anti-E. coli activity, as measured by the colony counting method. The method described in this report is a low-cost, efficient way of generating alpha-defensins in quantities ranging from milligrams to grams. PMID:16839776

  13. [Empirical therapeutic approach to infection by resistant gram positive (acute bacterial skin and skin structure infections and health care pneumonia). Value of risk factors].

    Science.gov (United States)

    González-DelCastillo, J; Núñez-Orantos, M J; Candel, F J; Martín-Sánchez, F J

    2016-09-01

    Antibiotic treatment inadequacy is common in these sites of infection and may have implications for the patient's prognosis. In acute bacterial skin and skin structure infections, the document states that for the establishment of an adequate treatment it must be assessed the severity, the patient comorbidity and the risk factors for multidrug-resistant microorganism. The concept of health care-associated pneumonia is discussed and leads to errors in the etiologic diagnosis and therefore in the selection of antibiotic treatment. This paper discusses how to perform this approach to the possible etiology to guide empirical treatment. PMID:27608306

  14. Elevated Plasma α-Defensins (HNP1-3) Levels Correlated with IgA1 Glycosylation and Susceptibility to IgA Nephropathy.

    Science.gov (United States)

    Qi, Yuan-Yuan; Zhou, Xu-Jie; Cheng, Fa-Juan; Zhang, Hong

    2016-01-01

    Aim. IgA nephropathy (IgAN) is the most common form of glomerulonephritis. Recent genome-wide association study (GWAS) suggested that DEFA locus (which encodes α-defensins) may play a key role in IgAN. Methods. The levels of α-defensins in 169 IgAN patients and 83 healthy controls were tested by ELISA. Results. We observed that α-defensins human neutrophil peptides 1-3 (HNP1-3) in IgAN patients were elevated compared with healthy controls. The mean levels of α-defensins of 83 healthy controls and 169 IgAN patients were 50 ng/mL and 78.42 ng/mL. When the results were adjusted to the mean levels of α-defensins of IgAN patients, the percentage of individuals with high levels of α-defensins increased in IgAN patients (22.5%) compared to healthy controls (9.6%) (p = 0.013). The elevation of α-defensins in IgAN patients was independent of renal function or neutrophil count, which were major sources of α-defensins in circulation. More importantly, negative correlation was observed between galactose-deficient IgA1and α-defensins. Conclusion. As α-defensin is a lectin-like peptide, we speculated that it might be involved in IgA galactose deficiency. The data implied that patients with IgAN had higher plasma α-defensins levels and high α-defensins correlated with IgA galactose deficiency, further suggesting a pathogenic role of α-defensins in IgAN. PMID:27563166

  15. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    that imposes selection pressure for resistant bacteria. New approaches are urgently needed. Targeting bacterial virulence functions directly is an attractive alternative. An obvious target is bacterial adhesion. Bacterial adhesion to surfaces is the first step in colonization, invasion, and biofilm formation....... As such, adhesion represents the Achilles heel of crucial pathogenic functions. It follows that interference with adhesion can reduce bacterial virulence. Here, we illustrate this important topic with examples of techniques being developed that can inhibit bacterial adhesion. Some of these will become...

  16. Antifungal Pisum sativum defensin 1 interacts with Neurospora crassa cyclin F related to the cell cycle.

    Science.gov (United States)

    Lobo, Denise S; Pereira, Iuri B; Fragel-Madeira, Lucianne; Medeiros, Luciano N; Cabral, Luiz M; Faria, Jane; Bellio, Maria; Campos, Reinaldo C; Linden, Rafael; Kurtenbach, Eleonora

    2007-01-30

    Plant defensins, components of the plant innate immune system, are cationic cysteine-rich antifungal peptides. Evidence from the literature [Thevissen, K., et al. (2003) Peptides 24, 1705-1712] has demonstrated that patches of fungi membrane containing mannosyldiinositolphosphorylceramide and glucosylceramides are selective binding sites for the plant defensins isolated from Dahlia merckii and Raphanus sativus, respectively. Whether plant defensins interact directly or indirectly with fungus intracellular targets is unknown. To identify physical protein-protein interactions, a GAL4-based yeast two-hybrid system was performed using the antifungal plant peptide Pisum sativum defensin 1 (Psd1) as the bait. Target proteins were screened within a Neurospora crassa cDNA library. Nine out of 11 two-hybrid candidates were nuclear proteins. One clone, detected with high frequency per screening, presented sequence similarity to a cyclin-like protein, with F-box and WD-repeat domains, related to the cell cycle control. GST pull-down assay corroborated in vitro this two-hybrid interaction. Fluorescence microscopy analysis of FITC-conjugated Psd1 and DAPI-stained fungal nuclei showed in vivo the colocalization of the plant peptide Psd1 and the nucleus. Analysis of the DNA content of N. crassa conidia using flow cytometry suggested that Psd1 directed cell cycle impairment and caused conidia to undergo endoreduplication. The developing retina of neonatal rats was used as a model to observe the interkinetic nuclear migration during proliferation of an organized tissue from the S toward the M phase of the cell cycle in the presence of Psd1. The results demonstrated that the plant defensin Psd1 regulates interkinetic nuclear migration in retinal neuroblasts. PMID:17240982

  17. The complexity of selection at the major primate β-defensin locus

    Directory of Open Access Journals (Sweden)

    Eastwood Hayden

    2005-05-01

    Full Text Available Abstract Background We have examined the evolution of the genes at the major human β-defensin locus and the orthologous loci in a range of other primates and mouse. For the first time these data allow us to examine selective episodes in the more recent evolutionary history of this locus as well as the ancient past. We have used a combination of maximum likelihood based tests and a maximum parsimony based sliding window approach to give a detailed view of the varying modes of selection operating at this locus. Results We provide evidence for strong positive selection soon after the duplication of these genes within an ancestral mammalian genome. Consequently variable selective pressures have acted on β-defensin genes in different evolutionary lineages, with episodes both of negative, and more rarely positive selection, during the divergence of primates. Positive selection appears to have been more common in the rodent lineage, accompanying the birth of novel, rodent-specific β-defensin genes. These observations allow a fuller understanding of the evolution of mammalian innate immunity. In both the rodent and primate lineages, sites in the second exon have been subject to positive selection and by implication are important in functional diversity. A small number of sites in the mature human peptides were found to have undergone repeated episodes of selection in different primate lineages. Particular sites were consistently implicated by multiple methods at positions throughout the mature peptides. These sites are clustered at positions predicted to be important for the specificity of the antimicrobial or chemoattractant properties of β-defensins. Surprisingly, sites within the prepropeptide region were also implicated as being subject to significant positive selection, suggesting previously unappreciated functional significance for this region. Conclusions Identification of these putatively functional sites has important implications for our

  18. Development of bacterial spot on near-isogenic lines of bell pepper carrying gene pyramids composed of defeated major resistance genes.

    Science.gov (United States)

    Kousik, C S; Ritchie, D F

    1999-11-01

    ABSTRACT Disease severity caused by races 1 through 6 of Xanthomonas campestris pv. vesicatoria on eight near-isogenic lines (isolines) of Early Calwonder (ECW) with three major resistance genes (Bs1, Bs2, and Bs3) in different combinations was evaluated in the greenhouse and field. Strains representing races 1, 3, 4, and 6 caused similar high levels of disease severity, followed by races 2 and 5 on susceptible ECW. Race 3 caused severe disease on all isolines lacking resistance gene Bs2. Race 4, which defeats Bs1 and Bs2, caused less disease on isoline ECW-12R (carries Bs1 + Bs2), than on isolines ECW, ECW-10R (carries Bs1), and ECW-20R (carries Bs2). Similar results were obtained with race 4 strains in field studies conducted during 1997 and 1998. In greenhouse studies, race 6, which defeats all three major genes, caused less disease on isoline ECW-13R (carries Bs1 + Bs3) and ECW-123R (carries Bs1 + Bs2 + Bs3) than on isolines ECW, ECW-10R, ECW-20R, and ECW-30R (carries Bs3), but not on ECW-23R (carries Bs2 + Bs3). In greenhouse studies with commercial hybrids, strains of races 4 and 6 caused less disease on Boynton Bell (carries Bs1 + Bs2) than on Camelot (carries no known resistance genes), King Arthur (carries Bs1), and X3R Camelot (carries Bs2). Race 6 caused less disease on hybrid R6015 (carries Bs1 + Bs2 + Bs3) and Sentinel (carries Bs1 + Bs3) than on Camelot. Residual effects were not as evident in field studies with race 6 strains. Defeated major resistance genes deployed in specific gene combinations (i.e., gene pyramids) were associated with less area under the disease progress curve than when genes were deployed individually in isolines of ECW or commercial hybrids. Successful management of bacterial spot of pepper is achieved incrementally by integrating multiple tactics. Although there is evidence of residual effects from defeated genes, these effects alone likely will not provide acceptable bacterial spot control in commercial production fields

  19. The Causes, Mechanism and Preventive Measures of Bacterial Resistance%细菌耐药性产生的原因、机制及防治措施

    Institute of Scientific and Technical Information of China (English)

    赵明秋; 沈海燕; 潘文; 王佳莹; 李银光; 常艳

    2011-01-01

    20世纪40年代青霉素的问世将人类带入了抗生素时代,抗感染治疗由此进入了新纪元,感染性疾病的病死率大大降低.半个世纪以来,人类一直把抗菌药物作为抗感染治疗最有力的武器.然而随着抗菌药物的广泛应用,感染性疾病的治疗又遇到了新的挑战--细菌对抗生素产生了耐药性,而此种耐药性表现为抗菌药物使用得越多耐药性亦变得越严重.目前已发现某些细菌对现有的几乎全部抗菌药物产生耐药,超级细菌的出现使人类有可能再次回到面临感染而无药可医的困境,控制细菌耐药性的增长已成为医学界乃至全人类的当务之急.正在逐渐建立自己的细菌耐药监测网络,监测细菌耐药的流行状况和规律,研究细菌产生耐药性的机制.%With the advent of penicillin in the 1940s an era of antibiotics was started, anti-infection treatment thus entered a new era, the mortality rate of infectious diseases decreased dramatically.For a half century, humans have always considered antibacterial drugs as the most powerful weapon of anti-infection treatment.However, with the wide application of antimicrobial agents, the treatment of infectious diseases also meet the new challenges-bacterial resistance to antibiotics, which become more serious as the usage of antimicrobial is increased.Currently some bacteria have been found susceptible to almost all the antimicrobial agents, the appearance of super bacteria may bring humans back to the dilemma of no medicine for infectious diseases, so the control of the increase of bacterial resistance has become urgent for medicine and humankind.Our country is gradually building our own monitoring network of bacterial resistance, monitoring of the current epidemic status and trends of bacteria resistant, studying on the mechanism of bacteria resistant.

  20. Bacteriophage Resistance Mechanisms in the Fish Pathogen Flavobacterium psychrophilum: Linking Genomic Mutations to Changes in Bacterial Virulence Factors

    DEFF Research Database (Denmark)

    Castillo, Daniel; Christiansen, Rói Hammershaimb; Dalsgaard, Inger;

    2015-01-01

    Flavobacterium psychrophilum is an important fish pathogen in salmonid aquaculture worldwide. Due to increased antibiotic resistance, pathogen control using bacteriophages has been explored as a possible alternative treatment. However, the effective use of bacteriophages in pathogen control...... resistance and the genetic modifications were supported by direct measurements of bacteriophage adsorption rates, biofilm formation, and secretion of extracellular enzymes, which were all impaired in the resistant strains, probably due to superficial structural changes. The clustered regularly interspaced...

  1. Integration of selective breeding and vaccination to improve disease resistance in aquaculture: Application to control bacterial cold water disease

    Science.gov (United States)

    Bacterial cold water disease (BCWD) is a frequent cause of elevated mortality in rainbow trout and the development of effective control strategies is a priority within the U.S. A goal of the NCCCWA breeding program is to produce germplasm with superior growth and survival following exposure to infe...

  2. Cloning of Human α-defensin-1 (HNP-1) Gene and Construction of Its Eukaryotic Expression Vector

    Institute of Scientific and Technical Information of China (English)

    Hua-Hua CHEN; Jing-Ping Ou YANG; Bao-Hua WANG; Yue Yang; Han-Qiao ZHENG

    2005-01-01

    @@ 1 Introduction Defensins are small cationic antimicrobial peptides that function in the host's innate immune system. The human defensin family includes three small peptides from the azurophil granules of polymorphonuclear cells named human neutrophil peptide (HNP)-1, HNP-2, HNP-3,which consist 5%-7% of the protein of human neutrophil. HNP-4 is approximately one hundred times less abundant. They demonstrate antibacterial, antifungal and antiviral properties in vitro. HNPs are important component of nonoxidative mechanism in macrophages, and can direct inactivate the enveloped viruses. Because only special cells express defensins. And it is hard to extract them naturally and the production is few. So researcher expect to obtain defensins highly through heterogenous expression by gene engineering technology. In order to express HNP-1, we cloned the cDNA of HNP-1 from human polymorphonuclear cells in peripheral blood, and constructed its eukaryotic expression vector, which provided a base for the further study on its mechanism of antimicrobial effect.

  3. Selective breeding improves rainbow trout resistance against bacterial cold water disease with little evidence for change in tolerance

    Science.gov (United States)

    Animals exhibit two broadly-defined defense strategies upon pathogen exposure: resistance and tolerance. Resistance is a measure of the host's capacity to limit pathogen number, while tolerance is defined as the host's ability to limit the negative health impact of a defined pathogen load. Most an...

  4. Influence of First-Line Antibiotics on the Antibacterial Activities of Acetone Stem Bark Extract of Acacia mearnsii De Wild. against Drug-Resistant Bacterial Isolates

    Directory of Open Access Journals (Sweden)

    Olufunmiso O. Olajuyigbe

    2014-01-01

    Full Text Available Background. This study was aimed at evaluating the antibacterial activity of the acetone extract of A. mearnsii and its interactions with antibiotics against some resistant bacterial strains. Methods. The antibacterial susceptibility testing was determined by agar diffusion and macrobroth dilution methods while the checkerboard method was used for the determination of synergy between the antibiotics and the extract. Results. The results showed that the susceptibility of the different bacterial isolates was concentration dependent for the extract and the different antibiotics. With the exception of S. marcescens, the inhibition zones of the extract produced by 20 mg/mL ranged between 18 and 32 mm. While metronidazole did not inhibit any of the bacterial isolates, all the antibiotics and their combinations, except for ciprofloxacin and its combination, did not inhibit Enterococcus faecalis. The antibacterial combinations were more of being antagonistic than of being synergistic in the agar diffusion assay. From the macrobroth dilution, the extract and the antibiotics exerted a varied degree of inhibitory effect on the test organisms. The MIC values of the acetone extract which are in mg/mL are lower than those of the different antibiotics which are in μg/mL. From the checkerboard assay, the antibacterial combinations showed varied degrees of interactions including synergism, additive, indifference, and antagonism interactions. While antagonistic and additive interactions were 14.44%, indifference interaction was 22.22% and synergistic interaction was 37.78% of the antibacterial combinations against the test isolates. While the additivity/indifference interactions indicated no interactions, the antagonistic interaction may be considered as a negative interaction that could result in toxicity and suboptimal bioactivity. Conclusion. The synergistic effects of the herbal-drug combinations may be harnessed for the discovery and development of more

  5. Hospital Effluents Are One of Several Sources of Metal, Antibiotic Resistance Genes, and Bacterial Markers Disseminated in Sub-Saharan Urban Rivers

    Science.gov (United States)

    Laffite, Amandine; Kilunga, Pitchouna I.; Kayembe, John M.; Devarajan, Naresh; Mulaji, Crispin K.; Giuliani, Gregory; Slaveykova, Vera I.; Poté, John

    2016-01-01

    Data concerning the occurrence of emerging biological contaminants such as antibiotic resistance genes (ARGs) and fecal indicator bacteria (FIB) in aquatic environments in Sub-Saharan African countries is limited. On the other hand, antibiotic resistance remains a worldwide problem which may pose serious potential risks to human and animal health. Consequently, there is a growing number of reports concerning the prevalence and dissemination of these contaminants into various environmental compartments. Sediments provide the opportunity to reconstruct the pollution history and evaluate impacts so this study investigates the abundance and distribution of toxic metals, FIB, and ARGs released from hospital effluent wastewaters and their presence in river sediments receiving systems. ARGs (blaTEM, blaCTX-M, blaSHV, and aadA), total bacterial load, and selected bacterial species FIB [Escherichia coli, Enterococcus (ENT)] and species (Psd) were quantified by targeting species specific genes using quantitative PCR (qPCR) in total DNA extracted from the sediments recovered from 4 hospital outlet pipes (HOP) and their river receiving systems in the City of Kinshasa in the Democratic Republic of the Congo. The results highlight the great concentration of toxic metals in HOP, reaching the values (in mg kg−1) of 47.9 (Cr), 213.6 (Cu), 1434.4 (Zn), 2.6 (Cd), 281.5 (Pb), and 13.6 (Hg). The results also highlight the highest (P effluent water is not an exclusive source of the biological contaminants entering the urban rivers. Significant correlation were observed between (i) all analyzed ARGs and total bacterial load (16S rRNA) 0.51 to 0.72 (p toxic metals (Cd, Cr, Cu, and Zn) 0.44 to 0.72, (p toxic metals and biological emerging contaminants in aquatic ecosystems. PMID:27499749

  6. Surveillance of bacterial resistance in Streptococcus pneumoniae%肺炎链球菌的耐药性监测

    Institute of Scientific and Technical Informati