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Sample records for bacterial pathogen vibrio

  1. Selective Media for In Vitro Activity Evaluation of Bacterial Biocontrol Against Pathogenic Vibrio

    OpenAIRE

    ALIM ISNANSETYO; MUHTADI; INDAH ISTIQOMAH; KAMISO HANDOYO NITIMULYO; TRIYANTO

    2011-01-01

    In vitro activity test is a critical evaluation to screen the potential biocontrol agent. We developed a selective medium for quantitative in vitro activity evaluation of bacterial biocontrol agents against pathogenic Vibrio in aquaculture. Sensitivity test of bacterial biocontrol and Vibrio spp. to nine antibiotics showed that oxytetracycline inhibited the growth of Vibrio spp., but did not inhibit the growth of the bacterial biocontrol. This selective inhibition activity of oxytetracycline ...

  2. Zoosporic plant pathogens produce bacterial autoinducer-2 that affects Vibrio harveyi quorum sensing

    Science.gov (United States)

    Kong, Ping; Lee, Bobby W.K.; Zhou, Zhaohui Sunny; Hong, Chuanxue

    2009-01-01

    The frequent co-isolation of bacteria with Phytophthora and Pythium species suggests possible interspecies communication. Zoospore free fluids (ZFF) from bacteria-free and nutrient-depleted zoospore suspensions were examined to investigate production of autoinducer-2 (AI-2), a bacterial interspecies signal molecule, by zoosporic oomycetes. ZFF from P. nicotianae, P. sojae and Py. aphanidermatum triggered luminescence of Vibrio harveyi AI-2 reporter, indicating the presence of AI-2 in zoospore extracellular products and the potential of cross-kingdom communication between oomycetes and bacteria. Production of AI-2 by zoospores was confirmed by chemical assays. These results provide new insight into the physiology and ecology of oomycetes. PMID:20002192

  3. Multidrug Efflux Pumps from Enterobacteriaceae, Vibrio cholerae and Staphylococcus aureus Bacterial Food Pathogens

    Directory of Open Access Journals (Sweden)

    Jody L. Andersen

    2015-01-01

    Full Text Available Foodborne illnesses caused by bacterial microorganisms are common worldwide and constitute a serious public health concern. In particular, microorganisms belonging to the Enterobacteriaceae and Vibrionaceae families of Gram-negative bacteria, and to the Staphylococcus genus of Gram-positive bacteria are important causative agents of food poisoning and infection in the gastrointestinal tract of humans. Recently, variants of these bacteria have developed resistance to medically important chemotherapeutic agents. Multidrug resistant Escherichia coli, Salmonella enterica, Vibrio cholerae, Enterobacter spp., and Staphylococcus aureus are becoming increasingly recalcitrant to clinical treatment in human patients. Of the various bacterial resistance mechanisms against antimicrobial agents, multidrug efflux pumps comprise a major cause of multiple drug resistance. These multidrug efflux pump systems reside in the biological membrane of the bacteria and actively extrude antimicrobial agents from bacterial cells. This review article summarizes the evolution of these bacterial drug efflux pump systems from a molecular biological standpoint and provides a framework for future work aimed at reducing the conditions that foster dissemination of these multidrug resistant causative agents through human populations.

  4. Development of a polymerase chain reaction (PCR assay targeted to the dnaJ gene of Vibrio harveyi, a bacterial pathogen in Asian seabass, Lates calcarifer

    Directory of Open Access Journals (Sweden)

    Norwell B. Bautista

    2011-10-01

    Full Text Available Partial sequence of the dnaJ gene of Vibrio harveyi, which was isolated from diseased juvenileAsian seabass, Lates calcarifer was identified. The partial sequence of dnaJ gene of V. harveyi was 447 bp and shared at least 77% identity at the nucleotide level with the dnaJ gene of other Vibrios. It was distinct from the dnaJ gene of other Vibrios but was closely related with the dnaJ gene of V. rotiferianus and V. campbellii having at least 90% nucleotide identity. PCR primers targeting this gene were designed to detect the pathogen in Asian seabass. The assay was specific to V. harveyi and the limit of detection was 100 pg of genomic DNA ml-1 or 100 fg of bacterial genomic DNA in a PCR reaction. Thiscorresponded to a sensitivity of approximately 20 genome equivalents (GE of V. harveyi. These resultsindicate that the dnaJ gene is a good candidate to develop primers for the PCR assay in detecting V.harveyi in fish.

  5. Evolution of tolerance to PCBs and susceptibility to a bacterial pathogen (Vibrio harveyi) in Atlantic killifish (Fundulus heteroclitus) from New Bedford (MA, USA) harbor

    Science.gov (United States)

    Nacci, Diane; Huber, Marina; Champlin, Denise; Jayaraman, Saro; Cohen, Sarah; Gauger, Eric; Fong, Allison; Gomez-Chiarri, Marta

    2009-01-01

    A population of the non-migratory estuarine fish Fundulus heteroclitus (Atlantic killifish) resident to New Bedford (NB), Massachusetts, USA, an urban harbor highly contaminated with polychlorinated biphenyls (PCBs), demonstrates recently evolved tolerance to some aspects of PCB toxicity. PCB toxicology, ecological theory, and some precedence supported expectations of increased susceptibility to pathogens in NB killifish. However, laboratory bacterial challenges of the marine pathogen Vibrio harveyi to wild fish throughout the reproductive season and to their mature laboratory-raised progeny demonstrated comparable survival by NB and reference killifish, and improved survival by NB males. These results are inconsistent with hypothesized tradeoffs of adaptation, and suggest that evolved tolerance in NB killifish may include mechanisms that minimize the immunosuppressive effects of PCBs. Compensatory strategies of populations persisting in highly contaminated environments provide a unique perspective for understanding the long-term ecological effects of toxic chemicals. PMID:19110353

  6. Extracellular proteolytic enzymes produced by human pathogenic vibrio species

    OpenAIRE

    Miyoshi, Shin-Ichi

    2013-01-01

    Bacteria in the genus Vibrio produce extracellular proteolytic enzymes to obtain nutrients via digestion of various protein substrates. However, the enzymes secreted by human pathogenic species have been documented to modulate the bacterial virulence. Several species including Vibrio cholerae and V. vulnificus are known to produce thermolysin-like metalloproteases termed vibriolysin. The vibriolysin from V. vulnificus, a causative agent of serious systemic infection, is a major toxic factor e...

  7. Evolution of tolerance to PCBs and susceptibility to a bacterial pathogen (Vibrio harveyi) in Atlantic killifish (Fundulus heteroclitus) from New Bedford (MA, USA) harbor

    International Nuclear Information System (INIS)

    A population of the non-migratory estuarine fish Fundulus heteroclitus (Atlantic killifish) resident to New Bedford (NB), Massachusetts, USA, an urban harbor highly contaminated with polychlorinated biphenyls (PCBs), demonstrates recently evolved tolerance to some aspects of PCB toxicity. PCB toxicology, ecological theory, and some precedence supported expectations of increased susceptibility to pathogens in NB killifish. However, laboratory bacterial challenges of the marine pathogen Vibrio harveyi to wild fish throughout the reproductive season and to their mature laboratory-raised progeny demonstrated comparable survival by NB and reference killifish, and improved survival by NB males. These results are inconsistent with hypothesized trade-offs of adaptation, and suggest that evolved tolerance in NB killifish may include mechanisms that minimize the immunosuppressive effects of PCBs. Compensatory strategies of populations persisting in highly contaminated environments provide a unique perspective for understanding the long-term ecological effects of toxic chemicals. - Killifish resident to a highly PCB-contaminated estuary survive pathogenic bacterial challenges well, suggesting their tolerance to PCB immunosuppression

  8. Evolution of tolerance to PCBs and susceptibility to a bacterial pathogen (Vibrio harveyi) in Atlantic killifish (Fundulus heteroclitus) from New Bedford (MA, USA) harbor

    Energy Technology Data Exchange (ETDEWEB)

    Nacci, Diane [US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, Narragansett, RI (United States)], E-mail: nacci.diane@epa.gov; Huber, Marina [US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, Narragansett, RI (United States)], E-mail: akualtzin@yahoo.com; Champlin, Denise [US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, Narragansett, RI (United States)], E-mail: champlin.denise@epa.gov; Jayaraman, Saro [US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, Narragansett, RI (United States)], E-mail: jayaraman.saro@epa.gov; Cohen, Sarah [San Francisco State University, Department of Biology, Romberg Tiburon Center, San Francisco, CA (United States)], E-mail: sarahcoh@sfsu.edu; Gauger, Eric [University of Rhode Island, Department of Fisheries, Aquaculture, and Veterinary Sciences, Kingston, RI (United States)], E-mail: ejgauger@yahoo.com; Fong, Allison [University of Rhode Island, Department of Fisheries, Aquaculture, and Veterinary Sciences, Kingston, RI (United States)], E-mail: fonga@hawaii.edu; Gomez-Chiarri, Marta [University of Rhode Island, Department of Fisheries, Aquaculture, and Veterinary Sciences, Kingston, RI (United States)], E-mail: gomezchi@uri.edu

    2009-03-15

    A population of the non-migratory estuarine fish Fundulus heteroclitus (Atlantic killifish) resident to New Bedford (NB), Massachusetts, USA, an urban harbor highly contaminated with polychlorinated biphenyls (PCBs), demonstrates recently evolved tolerance to some aspects of PCB toxicity. PCB toxicology, ecological theory, and some precedence supported expectations of increased susceptibility to pathogens in NB killifish. However, laboratory bacterial challenges of the marine pathogen Vibrio harveyi to wild fish throughout the reproductive season and to their mature laboratory-raised progeny demonstrated comparable survival by NB and reference killifish, and improved survival by NB males. These results are inconsistent with hypothesized trade-offs of adaptation, and suggest that evolved tolerance in NB killifish may include mechanisms that minimize the immunosuppressive effects of PCBs. Compensatory strategies of populations persisting in highly contaminated environments provide a unique perspective for understanding the long-term ecological effects of toxic chemicals. - Killifish resident to a highly PCB-contaminated estuary survive pathogenic bacterial challenges well, suggesting their tolerance to PCB immunosuppression.

  9. Response of Pathogenic Vibrio Species to High Hydrostatic Pressure

    OpenAIRE

    Berlin, Daniel L.; Herson, Diane S.; Hicks, Doris T.; Hoover, Dallas G.

    1999-01-01

    Vibrio parahaemolyticus ATCC 17802, Vibrio vulnificus ATCC 27562, Vibrio cholerae O:1 ATCC 14035, Vibrio cholerae non-O:1 ATCC 14547, Vibrio hollisae ATCC 33564, and Vibrio mimicus ATCC 33653 were treated with 200 to 300 MPa for 5 to 15 min at 25°C. High hydrostatic pressure inactivated all strains of pathogenic Vibrio without triggering a viable but nonculturable (VBNC) state; however, cells already existing in a VBNC state appeared to possess greater pressure resistance.

  10. Pathogenicity of Vibrios in Fish: an Overview

    Institute of Scientific and Technical Information of China (English)

    LI Jun; Norman Y.S. Woo

    2003-01-01

    Bacteria of the genus Vibrio are ubiquitously distributed in the marine environment. Due to the rapid expansion of intensive mariculture and the consequent deterioration of culture conditions, more and more Vibrio spp. have been recognized as pathogenic agents in outbreaks of vibriosis, a serious epizootic disease affecting most wild and farmed fish species worldwide, which has become the most important limiting factor for the development of intensive mariculture industry. Attempts have been made to understand the pathogenicity of vibrios in host fish with the ultimate aim of elucidating the best means for disease control. After an extensive literature survey of the recent advances in the field of fish vibriosis, the pathological changes, virulence factors and associated potential pathogenic mechanisms, transmission routes and related environmental factors involved in outbreak of vibriosis, as well as the controlling strategies are reviewed in the present paper.

  11. Extracellular proteolytic enzymes produced by human pathogenic Vibrio species

    Directory of Open Access Journals (Sweden)

    Shin-IchiMiyoshi

    2013-11-01

    Full Text Available Bacteria in the genus Vibrio produce extracellular proteolytic enzymes to obtain nutrients via digestion of various protein substrates. However, the enzymes secreted by human pathogenic species have been documented to modulate the bacterial virulence. Several species including Vibrio cholerae and V. vulnificus are known to produce thermolysin-like metalloproteases termed vibriolysin. The vibriolysin from V. vulnificus, a causative agent of serious systemic infection, is a major toxic factor eliciting the secondary skin damage characterized by formation of the hemorrhagic brae. The vibriolysin from intestinal pathogens may play indirect roles in pathogenicity because it can activate protein toxins and hemagglutinin by the limited proteolysis and can affect the bacterial attachment to or detachment from the intestinal surface by degradation of the mucus layer. Two species causing wound infections, V. alginolyticus and V. parahaemolyticus, produce another metalloproteases so-called collagenases. Although the detailed pathological roles have not been studied, the collagenase is potent to accelerate the bacterial dissemination through digestion of the protein components of the extracellular matrix. Some species produce cymotrypsin-like serine proteases, which may also affect the bacterial virulence potential. The intestinal pathogens produce sufficient amounts of the metalloprotease at the small intestinal temperature; however, the metalloprotease production by extra-intestinal pathogens is much higher around the body surface temperature. On the other hand, the serine protease is expressed only in the absence of the metalloprotease.

  12. Pathogenicity comparison of high and low virulent strains of Vibrio scophthalmi in olive flounder (Paralichthys olivaceus)

    Science.gov (United States)

    Vibrio scophthalmi is a bacterial pathogen of olive flounder (Paralichthys olivaceus) and virulence is different from various strains. There is not information available on pathogenicity to olive flounder caused by different strains of V. scophthalmi. In this study, the high and low virulent strains...

  13. Temperature-dependent inhibition of opportunistic Vibrio pathogens by native coral commensal bacteria.

    Science.gov (United States)

    Frydenborg, Beck R; Krediet, Cory J; Teplitski, Max; Ritchie, Kim B

    2014-02-01

    Bacteria living within the surface mucus layer of corals compete for nutrients and space. A number of stresses affect the outcome of this competition. The interactions between native microorganisms and opportunistic pathogens largely determine the coral holobiont's overall health and fitness. In this study, we tested the hypothesis that commensal bacteria isolated from the mucus layer of a healthy elkhorn coral, Acropora palmata, are capable of inhibition of opportunistic pathogens, Vibrio shiloi AK1 and Vibrio coralliilyticus. These vibrios are known to cause disease in corals and their virulence is temperature dependent. Elevated temperature (30 °C) increased the cell numbers of one commensal and both Vibrio pathogens in monocultures. We further tested the hypothesis that elevated temperature favors pathogenic organisms by simultaneously increasing the fitness of vibrios and decreasing the fitness of commensals by measuring growth of each species within a co-culture over the course of 1 week. In competition experiments between vibrios and commensals, the proportion of Vibrio spp. increased significantly under elevated temperature. We finished by investigating several temperature-dependent mechanisms that could influence co-culture differences via changes in competitive fitness. The ability of Vibrio spp. to utilize glycoproteins found in A. palmata mucus increased or remained stable when exposed to elevated temperature, while commensals' tended to decrease utilization. In both vibrios and commensals, protease activity increased at 30 °C, while chiA expression increased under elevated temperatures for Vibrio spp. These results provide insight into potential mechanisms through which elevated temperature may select for pathogenic bacterial dominance and lead to disease or a decrease in coral fitness. PMID:24370863

  14. Diversity and pathogenic potential of vibrios isolated from Abrolhos Bank corals.

    Science.gov (United States)

    Alves, Nelson; Neto, Oswaldo S Maia; Silva, Bruno S O; De Moura, Rodrigo L; Francini-Filho, Ronaldo B; Barreira E Castro, Clovis; Paranhos, Rodolfo; Bitner-Mathé, Blanche C; Kruger, Ricardo H; Vicente, Ana Carolina P; Thompson, Cristiane C; Thompson, Fabiano L

    2010-02-01

    We performed the first taxonomic characterization of vibrios and other culturable microbiota from apparently healthy and diseased Brazilian-endemic corals at the Abrolhos reef bank. The diseases affecting corals were tissue necrosis in Phyllogorgia dillatata, white plague and bleaching in Mussismilia braziliensis and bleaching in Mussismilia hispida. Bacterial isolates were obtained from mucus of 22 coral specimens originated from the Abrolhos Bank (i.e. Itacolomis reef, Recife de Fora reef and Santa Barbara Island) in 2007. Vibrios counts in the water and coral mucus were approximately 104 cfu ml(-1) and 106 cfu ml(-1) respectively. One hundred and thirty-one representative vibrio isolates were identified. Most vibrio isolates (n = 79) fell into the core group using the pyrH identification marker. According to our analysis, diseased corals did not possess a unique vibrio microbiota. Vibrio species encompassed strains originated from both apparently healthy and diseased corals. The pathogenic potential of representative vibrio isolates (V. alginolyticus 40B, V. harveyi-like 1DA3 and V. coralliilyticus 2DA3) were evaluated in a standardized bioassay using the animal model Drosophila melanogaster and caused 25-88% mortality. This is the first taxonomic characterization of the culturable microbiota from the Brazilian-endemic corals. Endemic Brazilian corals are a reservoir of the vibrio core group. Vibrio alginolyticus, V. harveyi and V. coralliilyticus are dominant in the mucus of these corals and may be a normal component of the holobiont. PMID:23766002

  15. Virulence of an emerging pathogenic lineage of Vibrio nigripulchritudo is dependent on two plasmids

    OpenAIRE

    Le Roux, Frédérique; Labreuche, Yannick; Davis, Brigid M.; Iqbal, Naeem; Mangenot, Sophie; Goarant, Cyrille; Mazel, Didier; Waldor, Matthew K.

    2011-01-01

    Summary Vibrioses are the predominant bacterial infections in marine shrimp farms. Vibrio nigripulchritudo is an emerging pathogen of the cultured shrimp Litopenaeus stylirostris in New Caledonia and other regions in the Indo-Pacific. The molecular determinants of V. nigripulchritudo pathogenicity are unknown; however, molecular epidemiological studies have revealed that recent pathogenic V. nigripulchritudo isolates from New Caledonia all cluster into a monophyletic clade and contain a small...

  16. Overexpression, Purification, Characterization, and Pathogenicity of Vibrio harveyi Hemolysin VHH

    Science.gov (United States)

    Zhong, Yingbin; Zhang, Xiao-Hua; Chen, Jixiang; Chi, Zhenghao; Sun, Boguang; Li, Yun; Austin, Brian

    2006-01-01

    Vibrio harveyi VHH hemolysin is a putative pathogenicity factor in fish. In this study, the hemolysin gene vhhA was overexpressed in Escherichia coli, and the purified VHH was characterized with regard to pH and temperature profiles, phospholipase activity, cytotoxicity, pathogenicity to flounder, and the signal peptide. PMID:16988279

  17. Unique and conserved genome regions in Vibrio harveyi and related species in comparison with the shrimp pathogen Vibrio harveyi CAIM 1792

    DEFF Research Database (Denmark)

    Valles, Iliana Espinoza; Vora, Gary J; Lin, Baochuan;

    2015-01-01

    Vibrio harveyi CAIM 1792 is a marine bacterial strain that causes mortality in farmed shrimp in north-west Mexico, and the identification of virulence genes in this strain is important for understanding its pathogenicity. The aim of this work was to compare the V. harveyi CAIM 1792 genome...

  18. Genome sequence of the human pathogen Vibrio cholerae Amazonia.

    NARCIS (Netherlands)

    Thompson, C.C.; Marin, M.A.; Dias, G.M.; Dutilh, B.E.; Edwards, R.A.; Iida, T.; Thompson, F.L.; Vicente, A.C.

    2011-01-01

    Vibrio cholerae O1 Amazonia is a pathogen that was isolated from cholera-like diarrhea cases in at least two countries, Brazil and Ghana. Based on multilocus sequence analysis, this lineage belongs to a distinct profile compared to strains from El Tor and classical biotypes. The genomic analysis rev

  19. Quorum Sensing-Disrupting Brominated Furanones Protect the Gnotobiotic Brine Shrimp Artemia franciscana from Pathogenic Vibrio harveyi, Vibrio campbellii, and Vibrio parahaemolyticus Isolates†

    OpenAIRE

    Defoirdt, Tom; Crab, Roselien; Wood, Thomas K.; Sorgeloos, Patrick; Verstraete, Willy; Bossier, Peter

    2006-01-01

    Autoinducer 2 (AI-2) quorum sensing was shown before to regulate the virulence of Vibrio harveyi towards the brine shrimp Artemia franciscana. In this study, several different pathogenic V. harveyi, Vibrio campbellii, and Vibrio parahaemolyticus isolates were shown to produce AI-2. Furthermore, disruption of AI-2 quorum sensing by a natural and a synthetic brominated furanone protected gnotobiotic Artemia from the pathogenic isolates in in vivo challenge tests.

  20. Quorum Sensing-Disrupting Brominated Furanones Protect the Gnotobiotic Brine Shrimp Artemia franciscana from Pathogenic Vibrio harveyi, Vibrio campbellii, and Vibrio parahaemolyticus Isolates†

    Science.gov (United States)

    Defoirdt, Tom; Crab, Roselien; Wood, Thomas K.; Sorgeloos, Patrick; Verstraete, Willy; Bossier, Peter

    2006-01-01

    Autoinducer 2 (AI-2) quorum sensing was shown before to regulate the virulence of Vibrio harveyi towards the brine shrimp Artemia franciscana. In this study, several different pathogenic V. harveyi, Vibrio campbellii, and Vibrio parahaemolyticus isolates were shown to produce AI-2. Furthermore, disruption of AI-2 quorum sensing by a natural and a synthetic brominated furanone protected gnotobiotic Artemia from the pathogenic isolates in in vivo challenge tests. PMID:16957276

  1. Heme uptake in bacterial pathogens

    OpenAIRE

    Contreras, Heidi; Chim, Nicholas; Credali, Alfredo; Goulding, Celia W.

    2014-01-01

    Iron is an essential nutrient for the survival of organisms. Bacterial pathogens possess specialized pathways to acquire heme from their human hosts. In this review, we present recent structural and biochemical data that provide mechanistic insights into several bacterial heme uptake pathways, encompassing the sequestration of heme from human hemoproteins to secreted or membrane-associated bacterial proteins, the transport of heme across bacterial membranes, and the degradation of heme within...

  2. Bacteriophages for detection of bacterial pathogens

    International Nuclear Information System (INIS)

    The G. Eliava Institute of Bacteriophages, Microbiology and Virology (Tbilisi, Georgia) is one of the most famous institutions focused on bacteriophage research for the elaboration of appropriate phage methodologies for human and animal protection. The main direction of the institute is the study and production of bacteriophages against intestinal disorders (dysentery, typhoid, intesti) and purulent-septic infections (staphylococcus, streptococcus, pyophage, etc.). These preparations were successfully introduced during the Soviet era, and for decades were used throughout the former Soviet Union and in other Socialist countries for the treatment, prophylaxis, and diagnosis of various infectious diseases, including those caused by antibiotic-resistant bacterial strains. Bacteriophages were widely used for identifying and detecting infections caused by the most dangerous pathogens and causative agents of epidemiological outbreaks. The specific topic of this presentation is the phage typing of bacterial species, which can be an important method for epidemiological diagnostics. Together with different genetic methodologies - such as PCR-based methods, PFGE, plasmid fingerprinting, and ribosomal typing - phage typing is one method for identifying bacterial pathogens. The method has a high percentage of determination of phage types, high specificity of reaction, and is easy for interpretation and use by health workers. Phage typing was applied for inter-species differentiation of different species of Salmonella, S. typhi, Brucella spp, Staphylococcus aureus, E. col,i Clostridium deficile, Vibrio cholerae, Yersinia pestis, Yersinia enterocolitica, Lysteria monocytogenes, Clostridium perfringens, Clostridium tetani, plant pathogens, and other bacterial pathogens. In addition to addressing the utility and efficacy of phage typing, the paper will discuss the isolation and selection of diagnostic typing phages for interspecies differentiation of pathogens that is necessary

  3. Vibriophages and Their Interactions with the Fish Pathogen Vibrio anguillarum

    DEFF Research Database (Denmark)

    Tan, Demeng; Gram, Lone; Middelboe, Mathias

    2014-01-01

    Vibrio anguillarum is an important pathogen in aquaculture, responsible for the disease vibriosis in many fish and invertebrate species. Disease control by antibiotics is a concern due to potential development and spread of antibiotic resistance. The use of bacteriophages to control the pathogen...... may offer a non-antibiotic-based approach to reduce vibriosis. A detailed understanding of the phage-host interaction is needed to evaluate the potential of phages to control the pathogen. In this study, we examined the diversity and interactions of 11 vibriophages, 24 V. anguillarum strains, and 13...

  4. Occurrence, Diversity, and Pathogenicity of Halophilic Vibrio spp. and Non-O1 Vibrio cholerae from Estuarine Waters along the Italian Adriatic Coast

    OpenAIRE

    Barbieri, Elena; Falzano, Loredana; Fiorentini, Carla; Pianetti, Anna; Baffone, Wally; Fabbri, Alessia; Matarrese, Paola; Casiere, Annarita; Katouli, Mohammad; Kühn, Inger; Möllby, Roland; Bruscolini, Francesca; Donelli, Gianfranco

    1999-01-01

    The occurrence, diversity, and pathogenicity of Vibrio spp. were investigated in two estuaries along the Italian Adriatic coast. Vibrio alginolyticus was the predominant species, followed by Vibrio parahaemolyticus, non-O1 Vibrio cholerae, and Vibrio vulnificus. By using a biochemical fingerprinting method, all isolates were grouped into nine phenotypes with similarity levels of 75 to 97.5%. The production of toxins capable of causing cytoskeleton-dependent changes was detected in a large num...

  5. Proteomics of foodborne bacterial pathogens

    Science.gov (United States)

    This chapter focuses on recent research on foodborne bacterial pathogens that use mass spectrometry-based proteomic techniques as well as protein microarrays. Mass spectrometry ionization techniques (e.g. electrospray ionization and matrix-assisted laser desorption/ionization), analyzers (e.g. ion ...

  6. Species Richness and Spatial Distribution of Pathogenic Vibrio (Bacteria, Vibrionaceae in Tropical Surface Waters: Yaoundé Metropolis Case (Cameroon, Central Africa

    Directory of Open Access Journals (Sweden)

    Tamatcho Kweyang Blandine Pulchérie

    2012-09-01

    Full Text Available In the present study, six species of Vibrio that are potential human pathogens have been isolated from surface water resources in an urban environment and have been identified. The variation of some physico-chemical factors known to have significant effects on bacterial growth and spread are also considered. The latter include: electrical conductivity, pH, total suspended solids, temperature, dissolved oxygen and carbon dioxide, and rate of water flow. All investigations were conducted according to standard methods. Application of classical bacteriological techniques led to the identification of six species of the genus. Vibrio cholera, Vibrio fluvialis, Vibrio mimicus, Vibrio alginolyticus, Vibrio parahaemolyticus and Vibrio vulnificus. Vibrio cholerae was isolated in all water sampling points, with the highest frequency 79% upstream the Mfoundi River at Etoa-Meki. Rates of isolation of Vibrio mimicus increased with increased O2 (p<0.05. Identification of these potential pathogens is a serious public health hazard highlighting the needs for resource management.

  7. Temporal and Spatial Distribution Patterns of Potentially Pathogenic Vibrio spp. at Recreational Beaches of the German North Sea

    OpenAIRE

    Böer, S.; Heinemeyer, E.A.; Luden, K.; Erler, Rene; Gerdts, Gunnar; Janssen, Frank; Brennholt, Nicole

    2013-01-01

    The number of reported Vibrio-related wound infections associated with recreational bathing in Northern Europe has increased within the last decades. In order to study the health risk from potentially pathogenic Vibrio spp. in the central Wadden Sea, the seasonal and spatial distribution of Vibrio vulnificus, Vibrio parahaemolyticus, Vibrio alginolyticus and Vibrio cholerae were investigated at ten recreational beaches in this area over a 2-year period. V. alginolyticus and V. parahaemolyt...

  8. Toxic factors of Vibrio strains pathogenic to shrimp.

    Science.gov (United States)

    Goarant, C; Herlin, J; Brizard, R; Marteau, A L; Martin, C; Martin, B

    2000-03-14

    Vibriosis is a major disease problem in shrimp aquaculture. 'Syndrome 93' is a seasonal juvenile vibriosis caused by Vibrio penaeicida which affects Litopenaeus stylirostris in grow-out ponds in New Caledonia. This study assessed the toxic activities of extracellular products (ECPs) from V. penaeicida, V. alginolyticus and V. nigripulchritudo using in vivo injections in healthy juvenile L. stylirostris (= Penaeus stylirostris) and in vitro assays on shrimp primary cell cultures and the fish cell line epithelioma papulosum cyprini (EPC). Toxic effects of ECPs were demonstrated for all pathogenic Vibrio strains tested both in vivo and in vitro, but for shrimp only; no effect was observed on the fish cell line. ECP toxicity for New Caledonian V. penaeicida was found only after cultivation at low temperature (20 degrees C) and not at higher temperature (30 degrees C). This points to the fact that 'Syndrome 93' episodes are triggered by temperature drops. The assays used here demonstrate the usefulness of primary shrimp cell cultures to study virulence mechanisms of shrimp pathogenic bacteria. PMID:10782343

  9. Bacterial dynamics in intestines of the black tiger shrimp and the Pacific white shrimp during Vibrio harveyi exposure.

    Science.gov (United States)

    Rungrassamee, Wanilada; Klanchui, Amornpan; Maibunkaew, Sawarot; Karoonuthaisiri, Nitsara

    2016-01-01

    The intestinal microbiota play important roles in health of their host, contributing to maintaining the balance and resilience against pathogen. To investigate effects of pathogen to intestinal microbiota, the bacterial dynamics upon a shrimp pathogen, Vibrio harveyi, exposures were determined in two economically important shrimp species; the black tiger shrimp (BT) and the Pacific white shrimp (PW). Both shrimp species were reared under the same diet and environmental conditions. Shrimp survival rates after the V. harveyi exposure revealed that the PW shrimp had a higher resistance to the pathogen than the BT shrimp. The intestinal bacterial profiles were determined by denaturing gradient gel electrophoresis (DGGE) and barcoded pyrosequencing of the 16S rRNA sequences under no pathogen challenge control and under pathogenic V. harveyi challenge. The DGGE profiles showed that the presence of V. harveyi altered the intestinal bacterial patterns in comparison to the control in BT and PW intestines. This implies that bacterial balance in shrimp intestines was disrupted in the presence of V. harveyi. The barcoded pyrosequencing analysis showed the similar bacterial community structures in intestines of BT and PW shrimp under a normal condition. However, during the time course exposure to V. harveyi, the relative abundance of bacteria belong to Vibrio genus was higher in the BT intestines at 12h after the exposure, whereas relative abundance of vibrios was more stable in PW intestines. The principle coordinates analysis based on weighted-UniFrac analysis showed that intestinal bacterial population in the BT shrimp lost their ability to restore their bacterial balance during the 72-h period of exposure to the pathogen, while the PW shrimp were able to reestablish their bacterial population to resemble those seen in the unexposed control group. This observation of bacterial disruption might correlate to different mortality rates observed between the two shrimp species

  10. Unique and conserved genome regions in Vibrio harveyi and related species in comparison with the shrimp pathogen Vibrio harveyi CAIM 1792.

    Science.gov (United States)

    Espinoza-Valles, Iliana; Vora, Gary J; Lin, Baochuan; Leekitcharoenphon, Pimlapas; González-Castillo, Adrián; Ussery, Dave; Høj, Lone; Gomez-Gil, Bruno

    2015-09-01

    Vibrio harveyi CAIM 1792 is a marine bacterial strain that causes mortality in farmed shrimp in north-west Mexico, and the identification of virulence genes in this strain is important for understanding its pathogenicity. The aim of this work was to compare the V. harveyi CAIM 1792 genome with related genome sequences to determine their phylogenic relationship and explore unique regions in silico that differentiate this strain from other V. harveyi strains. Twenty-one newly sequenced genomes were compared in silico against the CAIM 1792 genome at nucleotidic and predicted proteome levels. The proteome of CAIM 1792 had higher similarity to those of other V. harveyi strains (78%) than to those of the other closely related species Vibrio owensii (67%), Vibrio rotiferianus (63%) and Vibrio campbellii (59%). Pan-genome ORFans trees showed the best fit with the accepted phylogeny based on DNA-DNA hybridization and multi-locus sequence analysis of 11 concatenated housekeeping genes. SNP analysis clustered 34/38 genomes within their accepted species. The pangenomic and SNP trees showed that V. harveyi is the most conserved of the four species studied and V. campbellii may be divided into at least three subspecies, supported by intergenomic distance analysis. blastp atlases were created to identify unique regions among the genomes most related to V. harveyi CAIM 1792; these regions included genes encoding glycosyltransferases, specific type restriction modification systems and a transcriptional regulator, LysR, reported to be involved in virulence, metabolism, quorum sensing and motility. PMID:26198743

  11. Quantitative Microbial Risk Assessment of Pathogenic Vibrios in Marine Recreational Waters of Southern California

    OpenAIRE

    Dickinson, Gregory; Lim, Keah-ying; Jiang, Sunny C.

    2013-01-01

    This study investigated the occurrence of three types of vibrios in Southern California recreational beach waters during the peak marine bathing season in 2007. Over 160 water samples were concentrated and enriched for the detection of vibrios. Four sets of PCR primers, specific for Vibrio cholerae, V. parahaemolyticus, and V. vulnificus species and the V. parahaemolyticus toxin gene, respectively, were used for the amplification of bacterial genomic DNA. Of 66 samples from Doheny State Beach...

  12. Universal primer PCR with DGGE for rapid detection of bacterial pathogens.

    Science.gov (United States)

    Ji, Niannian; Peng, Bo; Wang, Guizhong; Wang, Sanying; Peng, Xuanxian

    2004-06-01

    A universal primer PCR (UPPCR) combined with denaturing gradient gel electrophoresis (DGGE) was evaluated as a method permitting the rapid detection of pathogens. The results show that this method is efficient at amplifying the conserved regions of bacterial 16S rRNA genes with universal primers and can detect causative bacterial pathogens rapidly. Six species of bacteria from fisheries (Pseudomonas fluorescens, Vibrio anguillarum, Aeromonas hydrophila, Vibrio fluvialis, Providencia rettgeri and Aeromonas sobria) were examined. Our results indicate that the approach we undertook can be adopted not only for axenic bacterial populations but also for mixed communities as well. Furthermore, we were able to achieve the rapid detection of multiple bacteria a single in sample. In addition, UPPCR-DGGE was shown to be better than previously reported UPPCR-single-stranded conformation polymorphism (SSCP)-based methods for the rapid detection of bacterial pathogens. PMID:15134888

  13. Detection of major diarrheagenic bacterial pathogens by multiplex PCR panels.

    Science.gov (United States)

    Sjöling, Åsa; Sadeghipoorjahromi, Leila; Novak, Daniel; Tobias, Joshua

    2015-03-01

    Diarrheal diseases remain a major threat to the youngest population in low- and middle-income countries. The main bacterial pathogens causing diarrhea are diarrheagenic Escherichia coli (DEC) that consists of enteroaggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enterohemorrhagic EHEC and enteroinvasive E. coli (EIEC), Salmonella, Shigella spp. (S. dysenteria, S. sonnei, S. flexneri) Campylobacter (C. coli, C. jejuni), Vibrio (V. vulnificus, V. parahaemolyticusm, V. cholerae), Yersinia enterocolitica and Aeromonas hydrophila. The aim of this study was to set up rapid multiplex PCR (mPCR) panels to identify these diarrheagenic pathogens based on their specific virulence genes. Primers against specific target genes were combined into three mPCR panels: one for diarrheal E. coli, one for pathogens causing mainly bloody diarrhea, and the third for the remaining pathogens. The panels were tested against a set of stool samples from Swedish children with diarrhea and controls and the analysis identified bacterial pathogens in 14/54 (26%) of the samples. These results show that our three developed mPCR panels can detect main bacterial diarrheagenic pathogens in clinical samples. PMID:25542594

  14. Onderzoek pathogene vibrio soorten in Nederlandse mosselen en oesters in augustus en september 2003

    NARCIS (Netherlands)

    Aalberts, C.H.J.

    2003-01-01

    Naar aanleiding van de hoge weerstemperatuur in augustus 2003 zijn in de kweek- en verwatergebieden van mosselen en oesters in Nederland enkele monsters onderzocht op de aanwezigheid van voor de mens pathogene vibrio soorten. In geen van de 18 monsters is Vibrio parahaemolyticus, vulnificus of chole

  15. From cholera to corals: Viruses as drivers of virulence in a major coral bacterial pathogen

    KAUST Repository

    Weynberg, Karen D.

    2015-12-08

    Disease is an increasing threat to reef-building corals. One of the few identified pathogens of coral disease is the bacterium Vibrio coralliilyticus. In Vibrio cholerae, infection by a bacterial virus (bacteriophage) results in the conversion of non-pathogenic strains to pathogenic strains and this can lead to cholera pandemics. Pathogenicity islands encoded in the V. cholerae genome play an important role in pathogenesis. Here we analyse five whole genome sequences of V. coralliilyticus to examine whether virulence is similarly driven by horizontally acquired elements. We demonstrate that bacteriophage genomes encoding toxin genes with homology to those found in pathogenic V. cholerae are integrated in V. coralliilyticus genomes. Virulence factors located on chromosomal pathogenicity islands also exist in some strains of V. coralliilyticus. The presence of these genetic signatures indicates virulence in V. coralliilyticus is driven by prophages and other horizontally acquired elements. Screening for pathogens of coral disease should target conserved regions in these elements.

  16. Virulence of an emerging pathogenic lineage of Vibrio nigripulchritudo is dependent on two plasmids.

    Science.gov (United States)

    Le Roux, Frédérique; Labreuche, Yannick; Davis, Brigid M; Iqbal, Naeem; Mangenot, Sophie; Goarant, Cyrille; Mazel, Didier; Waldor, Matthew K

    2011-02-01

    Vibrioses are the predominant bacterial infections in marine shrimp farms. Vibrio nigripulchritudo is an emerging pathogen of the cultured shrimp Litopenaeus stylirostris in New Caledonia and other regions in the Indo-Pacific. The molecular determinants of V. nigripulchritudo pathogenicity are unknown; however, molecular epidemiological studies have revealed that recent pathogenic V. nigripulchritudo isolates from New Caledonia all cluster into a monophyletic clade and contain a small plasmid, pB1067. Here, we report that a large plasmid, pA1066 (247 kb), can also serve as a marker for virulent V. nigripulchritudo, and that an ancestral version of this plasmid was likely acquired prior to other virulence-linked markers. Additionally, we demonstrate that pA1066 is critical for the full virulence of V. nigripulchritudo in several newly developed experimental models of infection. Plasmid pB1067 also contributes to virulence; only strains containing both plasmids induced the highest level of shrimp mortality. Thus, it appears that these plasmids, which are absent from non-pathogenic isolates, may be driving forces, as well as markers, for the emergence of a pathogenic lineage of V. nigripulchritudo. PMID:20825454

  17. Experimental Reservoirs of Human Pathogens: The Vibrio Cholerae Paradigm (7th Annual SFAF Meeting, 2012)

    Energy Technology Data Exchange (ETDEWEB)

    Colwell, Rita [University of Maryland

    2012-06-01

    Rita Colwell on "Experimental Reservoirs of Human Pathogens: The Vibrio cholerae paradigm" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  18. Starvation effects on pathogenic Vibrio alginolyticus in natural seawater

    Institute of Scientific and Technical Information of China (English)

    YI Jiabo; CHEN Qiang; ZOU Wenzheng; YAN Qingpi; ZHUANG Zhixia; WANG Xiaoru

    2008-01-01

    To get a better understanding of the starvation survival strategy of pathogenic Vibrio alginolyticus,log-phase cells were inoculated into sterile natural seawater for starvation studies.The results showed that all of total bacteria number,viable bacteria number and CFU number of V. alginolyticus increased remarkably at the initial starvation stage;after reaching their peaks at 5 d,both total bacteria number and viable bacteria number of V. alginolyricus fell slowly,while the CFU number fell more quickly after reaching its peak at 10 d;V.alginolyticus elongated their cells at the porphase of starvation,and then shrunk their volume and turned their shapes into ovals from rods at the anaphase of starvation;starved cells showed more sensitivity to heating and UV;starved cells showed n0 significant difference from unstarved ones at the lowest detection limit determined by indirect enzyme-linked immu-nosorbent assay(ELISA);starred cells'ability to adhere to the skin mucus of large yellow croaker(Pseudosciaena crocea)shorwed a sharp decline as the starvation time increases;the cellular protein of V.alginotyticus increased remarkably at the ana-phase of starvation.The results indicated that pathogenic V. alginolyticus could survive in starvation for relatively long periods of time(≥2 months)in 28℃ natural seawater due to the morphological and physiological changes;however,starved V. alginolytic-us cells showed Iess virulence and higher sensitivity under environmental stresses.

  19. Insights from Genomics into Bacterial Pathogen Populations

    OpenAIRE

    Wilson, DJ

    2012-01-01

    Bacterial pathogens impose a heavy burden of disease on human populations worldwide. The gravest threats are posed by highly virulent respiratory pathogens, enteric pathogens, and HIV-associated infections. Tuberculosis alone is responsible for the deaths of 1.5 million people annually. Treatment options for bacterial pathogens are being steadily eroded by the evolution and spread of drug resistance. However, population-level whole genome sequencing offers new hope in the fight against pathog...

  20. Proteinaceous exotoxins of shrimp-pathogenic isolates of Vibrio penaeicida and Vibrio nigripulchritudo

    OpenAIRE

    Aguirre-Guzman, Gabriel; Labreuche, Yannick; Ansquer, Dominique; Espiau, Benoit; Levy, Peva; Ascencio, Felipe; Saulnier, Denis

    2003-01-01

    The pathogenicity of two V. penaeicida strains, AM101 and KH-1, with different geographic origin, and V. nigripulchritudo strain AM102, were investigated in juvenile blue shrimp species Litopenaeus stylirostris. Alive bacteria and protein fractions (PFs) obtained from cell-free supernatants (CFS) were used in experimental challenges. Strains AM102, AM101, and KH-1 produced respectively 60, 54 and 12% mortality at 96h after infection using 104 cfu mL-1 of bacterial suspension. Exocellular toxi...

  1. Detection of Pathogenic Vibrio spp. in Shellfish by Using Multiplex PCR and DNA Microarrays

    OpenAIRE

    Panicker, Gitika; Call, Douglas R.; Krug, Melissa J.; Bej, Asim K.

    2004-01-01

    This study describes the development of a gene-specific DNA microarray coupled with multiplex PCR for the comprehensive detection of pathogenic vibrios that are natural inhabitants of warm coastal waters and shellfish. Multiplex PCR with vvh and viuB for Vibrio vulnificus, with ompU, toxR, tcpI, and hlyA for V. cholerae, and with tlh, tdh, trh, and open reading frame 8 for V. parahaemolyticus helped to ensure that total and pathogenic strains, including subtypes of the three Vibrio spp., coul...

  2. Visualization of coral host-pathogen interactions using a stable GFP-labeled Vibrio coralliilyticus strain

    Science.gov (United States)

    Pollock, F. Joseph; Krediet, Cory J.; Garren, Melissa; Stocker, Roman; Winn, Karina; Wilson, Bryan; Huete-Stauffer, Carla; Willis, Bette L.; Bourne, David G.

    2015-06-01

    The bacterium Vibrio coralliilyticus has been implicated as the causative agent of coral tissue loss diseases (collectively known as white syndromes) at sites across the Indo-Pacific and represents an emerging model pathogen for understanding the mechanisms linking bacterial infection and coral disease. In this study, we used a mini-Tn7 transposon delivery system to chromosomally label a strain of V. coralliilyticus isolated from a white syndrome disease lesion with a green fluorescent protein gene (GFP). We then tested the utility of this modified strain as a research tool for studies of coral host-pathogen interactions. A suite of biochemical assays and experimental infection trials in a range of model organisms confirmed that insertion of the GFP gene did not interfere with the labeled strain's virulence. Using epifluorescence video microscopy, the GFP-labeled strain could be reliably distinguished from non-labeled bacteria present in the coral holobiont, and the pathogen's interactions with the coral host could be visualized in real time. This study demonstrates that chromosomal GFP labeling is a useful technique for visualization and tracking of coral pathogens and provides a novel tool to investigate the role of V. coralliilyticus in coral disease pathogenesis.

  3. Sodium Ion Cycle in Bacterial Pathogens: Evidence from Cross-Genome Comparisons

    OpenAIRE

    Häse, Claudia C.; Fedorova, Natalie D.; Galperin, Michael Y.; Dibrov, Pavel A.

    2001-01-01

    Analysis of the bacterial genome sequences shows that many human and animal pathogens encode primary membrane Na+ pumps, Na+-transporting dicarboxylate decarboxylases or Na+-translocating NADH:ubiquinone oxidoreductase, and a number of Na+-dependent permeases. This indicates that these bacteria can utilize Na+ as a coupling ion instead of or in addition to the H+ cycle. This capability to use a Na+ cycle might be an important virulence factor for such pathogens as Vibrio cholerae, Neisseria m...

  4. Xylella Genomics and Bacterial Pathogenicity to Plants

    OpenAIRE

    Dow, J. M.; Daniels, M. J.

    2000-01-01

    Xylella fastidiosa, a pathogen of citrus, is the first plant pathogenic bacterium for which the complete genome sequence has been published. Inspection of the sequence reveals high relatedness to many genes of other pathogens, notably Xanthomonas campestris. Based on this, we suggest that Xylella possesses certain easily testable properties that contribute to pathogenicity. We also present some general considerations for deriving information on pathogenicity from bacterial genomics.

  5. 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...

  6. Quorum sensing positively regulates flagellar motility in pathogenic Vibrio harveyi.

    Science.gov (United States)

    Yang, Qian; Defoirdt, Tom

    2015-04-01

    Vibrios belonging to the Harveyi clade are among the major pathogens of aquatic organisms. Quorum sensing (QS) is essential for virulence of V. harveyi towards different hosts. However, most virulence factors reported to be controlled by QS to date are negatively regulated by QS, therefore suggesting that their impact on virulence is limited. In this study, we report that QS positively regulates flagellar motility. We found that autoinducer synthase mutants showed significantly lower swimming motility than the wild type, and the swimming motility could be restored by adding synthetic signal molecules. Further, motility of a luxO mutant with inactive QS (LuxO D47E) was significantly lower than that of the wild type and of a luxO mutant with constitutively maximal QS activity (LuxO D47A). Furthermore, we found that the expression of flagellar genes (both early, middle and late genes) was significantly lower in the luxO mutant with inactive QS when compared with wild type and the luxO mutant with maximal QS activity. Motility assays and gene expression also revealed the involvement of the quorum-sensing master regulator LuxR in the QS regulation of motility. Finally, the motility inhibitor phenamil significantly decreased the virulence of V. harveyi towards gnotobiotic brine shrimp larvae. PMID:24528485

  7. 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.

  8. Quorum sensing-disrupting brominated furanones protect the gnotobiotic brine shrimp Artemia franciscana from pathogenic Vibrio harveyi, Vibrio campbellii, and Vibrio parahaemolyticus isolates

    OpenAIRE

    Defoirdt, T; Crab, R.; Wood, T. K.; Sorgeloos, P.; Verstraete, W; P. Bossier

    2006-01-01

    Autoinducer 2 (AI-2) quorum sensing was shown before to regulate the virulence of Vibrio harveyi towards the brine shrimp Artemia franciscana. In this study, several different pathogenic V. harveyi, Vibrio campbellii, and Vibrio parahaemolyticus isolates were shown to produce AI-2. Furthermore, disruption of AI-2 quorum sensing by a natural and a synthetic brominated furanone protected gnotobiotic Artemia from the pathogenic isolates in in vivo challenge tests.

  9. Vibrio ecology - Identifying Environmental Determinants Favorable for the Presence and Transmission of Pathogenic Vibrios

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In a tri-coastal collaborative study, the population densities of vibrios are being determined in the Mississippi Sound, Puget Sound, Chesapeake Bay, and Timbalier...

  10. First evidence for a Vibrio strain pathogenic to Mytilus edulis altering hemocyte immune capacities.

    Science.gov (United States)

    Ben Cheikh, Yosra; Travers, Marie-Agnès; Morga, Benjamin; Godfrin, Yoann; Rioult, Damien; Le Foll, Frank

    2016-04-01

    Bacterial isolates were obtained from mortality events affecting Mytilus edulis and reported by professionals in 2010-2013 or from mussel microflora. Experimental infections allowed the selection of two isolates affiliated to Vibrio splendidus/Vibrio hemicentroti type strains: a virulent 10/068 1T1 (76.6% and 90% mortalities in 24 h and 96 h) and an innocuous 12/056 M24T1 (0% and 23.3% in 24 h and 96 h). These two strains were GFP-tagged and validated for their growth characteristics and virulence as genuine models for exposure. Then, host cellular immune responses to the microbial invaders were assessed. In the presence of the virulent strain, hemocyte motility was instantaneously enhanced but markedly slowed down after 2 h exposure. By contrast, hemocyte velocity increased in the presence of the innocuous 12/056 M24T1. At the same time interval, 10/068 1T1 invaded hemocytes and was more rapidly internalized than the innocuous strain. Extracellular products (ECPs) prepared from 10/068 1T1 cultures significantly inhibited phagocytic activity while 12/056 M24T1 ECPs had no effect. Furthermore, the pathogenic strain and its ECPs inhibited oxidative burst unlike 12/056 M24T1 strain/ECPs which enhanced ROS production. Taken together, our results suggest that the mussel pathogen 10/068 1T1 may escape immune response by altering hemocytes functions. PMID:26719026

  11. Temperature-induced behavioral switches in a bacterial coral pathogen.

    Science.gov (United States)

    Garren, Melissa; Son, Kwangmin; Tout, Jessica; Seymour, Justin R; Stocker, Roman

    2016-06-01

    Evidence to date indicates that elevated seawater temperatures increase the occurrence of coral disease, which is frequently microbial in origin. Microbial behaviors such as motility and chemotaxis are often implicated in coral colonization and infection, yet little is known about the effect of warming temperatures on these behaviors. Here we present data demonstrating that increasing water temperatures induce two behavioral switches in the coral pathogen Vibrio coralliilyticus that considerably augment the bacterium's performance in tracking the chemical signals of its coral host, Pocillopora damicornis. Coupling field-based heat-stress manipulations with laboratory-based observations in microfluidic devices, we recorded the swimming behavior of thousands of individual pathogen cells at different temperatures, associated with current and future climate scenarios. When temperature reached ⩾23 °C, we found that the pathogen's chemotactic ability toward coral mucus increased by >60%, denoting an enhanced capability to track host-derived chemical cues. Raising the temperature further, to 30 °C, increased the pathogen's chemokinetic ability by >57%, denoting an enhanced capability of cells to accelerate in favorable, mucus-rich chemical conditions. This work demonstrates that increasing temperature can have strong, multifarious effects that enhance the motile behaviors and host-seeking efficiency of a marine bacterial pathogen. PMID:26636553

  12. Bats and bacterial pathogens: a review.

    Science.gov (United States)

    Mühldorfer, K

    2013-02-01

    The occurrence of emerging infectious diseases and their relevance to human health has increased the interest in bats as potential reservoir hosts and vectors of zoonotic pathogens. But while previous and ongoing research activities predominantly focused on viral agents, the prevalence of pathogenic bacteria in bats and their impact on bat mortality have largely neglected. Enteric pathogens found in bats are often considered to originate from the bats' diet and foraging habitats, despite the fact that little is known about the actual ecological context or even transmission cycles involving bats, humans and other animals like pets and livestock. For some bacterial pathogens common in human and animal diseases (e.g. Pasteurella, Salmonella, Escherichia and Yersinia spp.), the pathogenic potential has been confirmed for bats. Other bacterial pathogens (e.g. Bartonella, Borrelia and Leptospira spp.) provide evidence for novel species that seem to be specific for bat hosts but might also be of disease importance in humans and other animals. The purpose of this review is to summarize the current knowledge of bacterial pathogens identified in bats and to consider factors that might influence the exposure and susceptibility of bats to bacterial infection but could also affect bacterial transmission rates between bats, humans and other animals. PMID:22862791

  13. Role of Flagella in Virulence of the Coral Pathogen Vibrio coralliilyticus▿ †

    OpenAIRE

    Meron, Dalit; Efrony, Rotem; Johnson, Wesley R; Schaefer, Amy L.; Morris, Pamela J.; Rosenberg, Eugene; Greenberg, E. Peter; Banin, Ehud

    2009-01-01

    A recently available transposition system was utilized to isolate a nonmotile mutant of the coral-bleaching pathogen Vibrio coralliilyticus. The mutation was localized to the fhlA gene, and the mutant lacked flagella. The flhA mutant was unable to exhibit chemotaxis toward coral mucus or to adhere to corals and subsequently cause infection.

  14. Draft Genome Sequences of the Fish Pathogen Vibrio harveyi Strains VH2 and VH5.

    Science.gov (United States)

    Castillo, Daniel; D'Alvise, Paul; Middelboe, Mathias; Gram, Lone; Liu, Siyang; Kalatzis, Panos G; Kokkari, Constantina; Katharios, Pantelis

    2015-01-01

    Vibrio harveyi is an important marine pathogen that is responsible for vibriosis outbreaks in cultured fish and invertebrates worldwide. Here, we announce the draft genome sequences of V. harveyi strains VH2 and VH5, isolated from farmed juvenile Seriola dumerili during outbreaks of vibriosis in Crete, Greece. PMID:26383670

  15. Draft Genome Sequence of the Opportunistic Marine Pathogen Vibrio harveyi Strain E385.

    Science.gov (United States)

    Yu, Mingjia; Ren, Chunhua; Qiu, Jinrong; Luo, Peng; Zhu, Ruyi; Zhao, Zhe; Hu, Chaoqun

    2013-01-01

    Vibrio harveyi strain E385 was isolated from a diseased cage-cultured grouper in Daya Bay, China. Phylogenetic analysis based on the 16S rRNA gene sequence showed similarity with V. harveyi strain BAA-1116. We sequenced the pathogenic strain V. harveyi E385 and compared the genome with that of the nonpathogenic strain V. harveyi BAA-1116. PMID:24336361

  16. Draft genome sequence of the fish pathogen Vibrio harveyi strain ZJ0603.

    Science.gov (United States)

    Huang, Yucong; Jian, Jichang; Lu, Yishan; Cai, Shuanghu; Wang, Bei; Tang, Jufen; Pang, Huanying; Ding, Yu; Wu, Zaohe

    2012-12-01

    Vibrio harveyi is an important pathogen that causes vibriosis in various aquatic organisms. Here, we announce the draft genome sequence of V. harveyi strain ZJ0603, which was isolated from diseased Orange-spotted grouper (Epinephelus coioides) in Guangdong, China. PMID:23144396

  17. Toxic factors of Vibrio strains pathogenic to shrimp

    OpenAIRE

    Goarant, Cyrille; Herlin, Jose; Brizard, Raphael; Marteau, Anne-laure; Martin, C.; Martin, B.(CERN, Geneva, Switzerland)

    2000-01-01

    Vibriosis is a major disease problem in shrimp aquaculture. 'Syndrome 93' is a seasonal juvenile vibriosis caused by Vibrio penaeicida which affects Litopenaeus stylirostris in grow-out ponds in New Caledonia. This study assessed the toxic activities of extracellular products (ECPs) from V: penaeicida, V. alginolyticus and V, nigripulchritudo using in vivo injections in healthy juvenile L. stylirostris (= Penaeus stylirostris) and in vitro assays on shrimp primary cell cultures and the fish c...

  18. Within-host evolution of bacterial pathogens.

    OpenAIRE

    Didelot, X.; Walker, AS; Peto, TE; Crook, DW; Wilson, DJ

    2016-01-01

    Whole-genome sequencing has opened the way for investigating the dynamics and genomic evolution of bacterial pathogens during the colonization and infection of humans. The application of this technology to the longitudinal study of adaptation in an infected host - in particular, the evolution of drug resistance and host adaptation in patients who are chronically infected with opportunistic pathogens - has revealed remarkable patterns of convergent evolution, suggestive of an inherent repeatab...

  19. Microbial minimalism: genome reduction in bacterial pathogens.

    Science.gov (United States)

    Moran, Nancy A

    2002-03-01

    When bacterial lineages make the transition from free-living or facultatively parasitic life cycles to permanent associations with hosts, they undergo a major loss of genes and DNA. Complete genome sequences are providing an understanding of how extreme genome reduction affects evolutionary directions and metabolic capabilities of obligate pathogens and symbionts. PMID:11893328

  20. Temporal and spatial distribution patterns of potentially pathogenic Vibrio spp. at recreational beaches of the German north sea.

    Science.gov (United States)

    Böer, Simone I; Heinemeyer, Ernst-August; Luden, Katrin; Erler, René; Gerdts, Gunnar; Janssen, Frank; Brennholt, Nicole

    2013-05-01

    The number of reported Vibrio-related wound infections associated with recreational bathing in Northern Europe has increased within the last decades. In order to study the health risk from potentially pathogenic Vibrio spp. in the central Wadden Sea, the seasonal and spatial distribution of Vibrio vulnificus, Vibrio parahaemolyticus, Vibrio alginolyticus and Vibrio cholerae were investigated at ten recreational beaches in this area over a 2-year period. V. alginolyticus and V. parahaemolyticus were found to be omnipresent all year round in the study area, while V. vulnificus occurrence was restricted to summer months in the estuaries of the rivers Ems and Weser. Multiple linear regression models revealed that water temperature is the most important determinant of Vibrio spp. occurrence in the area. Differentiated regression models showed a species-specific response to water temperature and revealed a particularly strong effect of even minor temperature increases on the probability of detecting V. vulnificus in summer. In sediments, Vibrio spp. concentrations were up to three orders of magnitude higher than in water. Also, V. alginolyticus and V. parahaemolyticus were found to be less susceptible towards winter temperatures in the benthic environment than in the water, indicating an important role of sediments for Vibrio ecology. While only a very small percentage of tested V. parahaemolyticus proved to be potentially pathogenic, the presence of V. vulnificus during the summer months should be regarded with care. PMID:23563708

  1. Iron and virulence in the zoonotic pathogen Vibrio vulnificus

    OpenAIRE

    Pajuelo Gámez, David

    2014-01-01

    Vibrio vulnificus es un patógeno humano emergente que es autóctono de ecosistemas acuáticos salobres de climas templados, tropicales y subtropicales. La especie se subdivide en 3 biotipos (Bt), de los cuales el Bt2 contiene un grupo de cepas que, además de poder infectar al hombre, pueden causar infecciones en peces. Este grupo es un complejo clonal serológicamente homogéneo que denominamos serovar E o serovar zoonótica (VvBt2SerE). Como patógeno humano, VvBt2SerE causa casos esporádicos de i...

  2. Detection of pathogenic Vibrio parahaemolyticus in Butrinti Lagoon shellfish

    Directory of Open Access Journals (Sweden)

    FATMIRA SHEHU

    2014-06-01

    Full Text Available Given the considerable public health implications, monitoring of V. parahaemolyticus in shellfish is crucial. The 50 shellfish samples from Butrinti Lagoon showed bacteriological parameters, Salmonella and E. coli, according to Commission Regulation EC No. 2073/2005 on microbiological criteria for foodstuffs. In particular, Salmonella was absent in 25 g and E. coli less 230/100 g of flesh and intra-valvular liquid. The PCRs performed on enrichment broth from each sample gave positive results for V. parahaemolyticus in 45/50 shellfish samples. The TDH virulence factor was detected in 15/45 samples only, whereas TRH factor was not highlighted at all. The results confirmed the need for a specific shellfish inspection plan to detect the presence of Vibrio species and viruses in order to eliminate public health risks associated with shellfish consumption

  3. Emerging bacterial pathogens: the past and beyond.

    Science.gov (United States)

    Vouga, M; Greub, G

    2016-01-01

    Since the 1950s, medical communities have been facing with emerging and reemerging infectious diseases, and emerging pathogens are now considered to be a major microbiologic public health threat. In this review, we focus on bacterial emerging diseases and explore factors involved in their emergence as well as future challenges. We identified 26 major emerging and reemerging infectious diseases of bacterial origin; most of them originated either from an animal and are considered to be zoonoses or from water sources. Major contributing factors in the emergence of these bacterial infections are: (1) development of new diagnostic tools, such as improvements in culture methods, development of molecular techniques and implementation of mass spectrometry in microbiology; (2) increase in human exposure to bacterial pathogens as a result of sociodemographic and environmental changes; and (3) emergence of more virulent bacterial strains and opportunistic infections, especially affecting immunocompromised populations. A precise definition of their implications in human disease is challenging and requires the comprehensive integration of microbiological, clinical and epidemiologic aspects as well as the use of experimental models. It is now urgent to allocate financial resources to gather international data to provide a better understanding of the clinical relevance of these waterborne and zoonotic emerging diseases. PMID:26493844

  4. Emerging food pathogens and bacterial toxins.

    Science.gov (United States)

    Bielecki, Jacek

    2003-01-01

    Many different foodborne diseases have been described. For example, Shigella bacteria, hepatitis A virus and Norwalk virus were shown as a unwashed hands microorganisms, but pathogen Campylobacter and Escherichia coli were named as raw and undercooked meat and poultry or raw milk and untreated water born bacteria. However, two of them: Listeria monocytogenes and Yersinia enterocolitica are known as growing at refrigerator temperatures. Essential virulence determinants of Listeria monocytogenes pathogenicity are well known as a bacterial toxins. Basic molecular mechanisms of pathogenicity depending from these toxins were presented. It was shown that other bacterial toxins may act as very danger food poisoning substances. This is why elimination of pathogenic microorganisms from foods is an obvious solution in some food processes, however this approach is not practical or even desirable in many processes. Thus, risk assessment and microbial monitoring will continue to play important roles in ensuring food safety. Some technological advances have the capability of delivering detection systems that can not only monitor pathogenic microorganisms, but also entire microbial populations in the food matrix. PMID:15058810

  5. Host-pathogen interactions in bacterial meningitis.

    Science.gov (United States)

    Doran, Kelly S; Fulde, Marcus; Gratz, Nina; Kim, Brandon J; Nau, Roland; Prasadarao, Nemani; Schubert-Unkmeir, Alexandra; Tuomanen, Elaine I; Valentin-Weigand, Peter

    2016-02-01

    Bacterial meningitis is a devastating disease occurring worldwide with up to half of the survivors left with permanent neurological sequelae. Due to intrinsic properties of the meningeal pathogens and the host responses they induce, infection can cause relatively specific lesions and clinical syndromes that result from interference with the function of the affected nervous system tissue. Pathogenesis is based on complex host-pathogen interactions, some of which are specific for certain bacteria, whereas others are shared among different pathogens. In this review, we summarize the recent progress made in understanding the molecular and cellular events involved in these interactions. We focus on selected major pathogens, Streptococcus pneumonia, S. agalactiae (Group B Streptococcus), Neisseria meningitidis, and Escherichia coli K1, and also include a neglected zoonotic pathogen, Streptococcus suis. These neuroinvasive pathogens represent common themes of host-pathogen interactions, such as colonization and invasion of mucosal barriers, survival in the blood stream, entry into the central nervous system by translocation of the blood-brain and blood-cerebrospinal fluid barrier, and induction of meningeal inflammation, affecting pia mater, the arachnoid and subarachnoid spaces. PMID:26744349

  6. In vitro and in vivo bactericidal activity of Vitex negundo leaf extract against diverse multidrug resistant enteric bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Muhammad Kamruzzaman; S.M. Nayeemul Bari; Shah M. Faruque

    2013-01-01

    Objective: To investigate in vitro and in vivo antibacterial potentials of Vitex negundo (V. negundo) leaf extracts against diverse enteric pathogens. Methods: Water and methanol extracts of V. negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion, viable bacterial cell count methods, determination of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC). Results: Methanol extract of V. negundo leaves showed potent antibacterial activity (inhibition zone: 9.9-22.6 mm, MIC:200-3 200 μg/mL, MBC: 200-6 400 μg/mL) against all the pathogenic enteric bacteria (Vibriocholerae , Vibrio parahaemolyticus, Vibrio mimicus, Echerichia coli, Shigella spps., and Aeromonas spps) tested. Methanol extract of V. negundo leaves showed potent bactericidal activity both in vitro laboratory conditions (MBC, 200-400 μg/mL) and in the intestinal environment (Dose, 1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae, the major causative agent of cholera. Furthermore, assays using the mice cholera model showed that V. negundo methanol extract can protect mice from Vibrio cholerae infection and significantly decrease the mortality rate (P<0.0001). Conclusions: For the first time we showed that methanol extract of V. negundo leaves exhibited strong vibriocidal activity both in vitro and in vivo conditions. Therefore, it will be useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.

  7. Vaccines for viral and bacterial pathogens causing acute gastroenteritis: Part II: Vaccines for Shigella, Salmonella, enterotoxigenic E. coli (ETEC) enterohemorragic E. coli (EHEC) and Campylobacter jejuni.

    Science.gov (United States)

    O'Ryan, Miguel; Vidal, Roberto; del Canto, Felipe; Carlos Salazar, Juan; Montero, David

    2015-01-01

    In Part II we discuss the following bacterial pathogens: Shigella, Salmonella (non-typhoidal), diarrheogenic E. coli (enterotoxigenic and enterohemorragic) and Campylobacter jejuni. In contrast to the enteric viruses and Vibrio cholerae discussed in Part I of this series, for the bacterial pathogens described here there is only one licensed vaccine, developed primarily for Vibrio cholerae and which provides moderate protection against enterotoxigenic E. coli (ETEC) (Dukoral(®)), as well as a few additional candidates in advanced stages of development for ETEC and one candidate for Shigella spp. Numerous vaccine candidates in earlier stages of development are discussed. PMID:25715096

  8. Application of bacterial lipopolysaccharide to improve survival of the black tiger shrimp after Vibrio harveyi exposure.

    Science.gov (United States)

    Rungrassamee, Wanilada; Maibunkaew, Sawarot; Karoonuthaisiri, Nitsara; Jiravanichpaisal, Pikul

    2013-10-01

    This study investigates an effect of bacterial lipopolysaccharide (LPS) as feed supplement to improve immunity of the black tiger shrimp (Penaeus monodon). LPS was coated to commercial feed pellets and given to the shrimp once or twice a day for 10 days before an exposure with shrimp pathogenic bacterium Vibrio harveyi. The growth rates, percent weight gains, total hemocyte and granulocyte counts and survival rates of shrimp between the LPS-coated pellet fed groups and a control group where shrimp fed with commercial feed pellets were compared. After 10 days of the feeding trials, growth rates were not significantly different in all groups, suggesting no toxicity from LPS supplement. To determine beneficial effect of LPS diets, each group was subsequently exposed to V. harveyi by immersion method and the survival rates were recorded for seven days after the immersion. Regardless of the dosages of LPS, the shrimp groups fed with LPS-coated pellets showed higher survival rates than the control group. There was no significant difference in survival rates between the two LPS dosages groups. In addition to survival under pathogen challenge, we also determine effect of LPS on immune-related genes after 10-day feeding trial. Gene expression analysis in the P. monodon intestines revealed that antilipopolysaccharide factor isoform 3 (ALF3), C-type lectin, and mucine-like peritrophin (mucin-like PM) were expressed significantly higher in a group fed with LPS supplemental diet once or twice a day than in a control group. The transcript levels of C-type lectin and mucin-like PM had increased significantly when LPS was given once a day, while significant induction of ALF3 transcripts was observed when shrimp were fed with LPS twice a day. The up-regulation of the immune gene levels in intestines and higher resistance to V. harveyi of the shrimp fed with LPS provide the evidence for potential application of LPS as an immunostimulant in P. monodon farming. PMID:23751331

  9. Antagonistic effect of Pseudomonas aeruginosa isolates from various ecological niches on Vibrio species pathogenic to crustaceans

    Institute of Scientific and Technical Information of China (English)

    Prabhakaran Priyaja; Puthumana Jayesh; Neil Scolastin Correya; Balachandran Sreelakshmi; Naduthalmuriparambil S Sudheer; Rosamma Philip; Isaac Sarogeni Bright Singh

    2014-01-01

    Objective: To abrogate pathogenic vibrios in aquaculture by testing the potential of Pseudomonas isolates from fresh water, brackish and marine environments as probiotics.Methods:Antagonistic activity of the compound against 7 Vibrio spp. was performed. Influence of salinity on the production of pyocyanin and the toxicity was done through the compound using brine shrimp lethality assay. Molecular characterization was performed to confirm that the isolates werePseudomonas aeruginosa. Results: Salinity was found to regulate the levels of pyocyanin production, with 5-10 g/L as the optimum. All Pseudomonas isolates grew at salinities ranging from 5 to 70 g/L. Isolates of marine origin produced detectable levels of pyocyanin up to 45 g/L salinity. Brackish and freshwater isolates ceased to produce pyocyanin at salinities above 30 g/L and 20 g/L, respectively. Culture supernatants of all 5 Pseudomonas isolates possessed the ability to restrict the growth of Vibrio spp. and maximum antagonistic effect on Vibrio harveyi was obtained when they were grown at salinities of 5 to 10 g/L. The marine isolate MCCB117, even when grown at a salinity of 45 g/L possessed the ability to inhibit Vibrio spp.Conclusions:Purification and structural elucidation of antagonistic compound were carried out. ideal for application in freshwater, MCCB102 and MCCB103 in brackish water and MCCB117 and The present investigation showed that Pseudomonas aeruginosa MCCB119 would be MCCB118 in marine aquaculture systems as putative probiotics in the management of vibrios.

  10. Searching for genetic markers of virulence in Vibrio nigripulchritudo, a Litopenaeus stylirostris shrimp pathogen

    OpenAIRE

    Reynaud, Yann

    2007-01-01

    Since 1997, a new pathology seasonally occurs in new caledonian shrimp farms during the warm season. Diseased Litopenaeus stylirostris shrimp suffer from a systemic vibriosis which was attributed to highly pathogenic Vibrio nigripulchritudo. At the present time, only two farms among 17 are affected by the so called "summer syndrome". In such a context it appears urgent to develop reliable diagnostic tools to detect V. nigripulchritudo strains and to differentiate highly virulent strains from ...

  11. Molecular epidemiology of Vibrio nigripulchritudo, a pathogen of cultured penaeid shrimp (Litopenaeus stylirostris) in New Caledonia

    OpenAIRE

    Goarant, Cyrille; Reynaud, Yann; Ansquer, Dominique; De Decker, Sophie; Saulnier, Denis; Leroux, Frederique

    2006-01-01

    A collection of 57 isolates of Vibrio nigripulchritudo from either diseased or healthy shrimp and from shrimp farms environment was studied in order to gain a better understanding of the epidemiology of this pathogen, notably isolated from two distinct shrimp disease complexes. Molecular typing using two different techniques, arbitrarily primed PCR (AP-PCR) and multi-locus sequence typing (MLST), studied together with experimental pathology data allowed a relevant epidemiological insight into...

  12. Formaldehyde stress responses in bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Nathan Houqian Chen

    2016-03-01

    Full Text Available Formaldehyde is the simplest of all aldehydes and is highly cytotoxic. Its use and associated dangers from environmental exposure have been well documented. Detoxification systems for formaldehyde are found throughout the biological world and they are especially important in methylotrophic bacteria, which generate this compound as part of their metabolism of methanol. Formaldehyde metabolizing systems can be divided into those dependent upon pterin cofactors, sugar phosphates and those dependent upon glutathione. The more prevalent thiol-dependent formaldehyde detoxification system is found in many bacterial pathogens, almost all of which do not metabolize methane or methanol. This review describes the endogenous and exogenous sources of formaldehyde, its toxic effects and mechanisms of detoxification. The methods of formaldehyde sensing are also described with a focus on the formaldehyde responsive transcription factors HxlR, FrmR and NmlR. Finally, the physiological relevance of detoxification systems for formaldehyde in bacterial pathogens is discussed.

  13. Formaldehyde Stress Responses in Bacterial Pathogens.

    Science.gov (United States)

    Chen, Nathan H; Djoko, Karrera Y; Veyrier, Frédéric J; McEwan, Alastair G

    2016-01-01

    Formaldehyde is the simplest of all aldehydes and is highly cytotoxic. Its use and associated dangers from environmental exposure have been well documented. Detoxification systems for formaldehyde are found throughout the biological world and they are especially important in methylotrophic bacteria, which generate this compound as part of their metabolism of methanol. Formaldehyde metabolizing systems can be divided into those dependent upon pterin cofactors, sugar phosphates and those dependent upon glutathione. The more prevalent thiol-dependent formaldehyde detoxification system is found in many bacterial pathogens, almost all of which do not metabolize methane or methanol. This review describes the endogenous and exogenous sources of formaldehyde, its toxic effects and mechanisms of detoxification. The methods of formaldehyde sensing are also described with a focus on the formaldehyde responsive transcription factors HxlR, FrmR, and NmlR. Finally, the physiological relevance of detoxification systems for formaldehyde in bacterial pathogens is discussed. PMID:26973631

  14. Bacterial food-borne pathogens in Indian food

    International Nuclear Information System (INIS)

    Food technology and food processing techniques have made tremendous advances in preservation of food and ensuring safety of food by killing food-borne pathogens. In addition to old techniques such as pasteurization, canning, dehydration, fermentation and salting, a number of new techniques such as radiation processing, high pressure technology and pulsed electric field technology are being applied for preservation of food and to ensure food safety. Total Quality Management (TQM) concepts have been developed to take care of food safety from farm to table. Hazard Analysis at Critical Control Points (HACCP) is being applied for mass scale production of food to make food free from pathogens. Despite these advances, food-borne diseases have become one of the most widespread public health problems in the world. About two thirds of all the outbreaks are traced to microbial contaminated food. According to World Health Organization (WHO) estimates, food-borne and waterborne diarrhoeal diseases kill an estimated 2 million people annually, including many children. Food safety is a major concern not only for developing countries but also for the developed countries. A number of factors such as emergence of new food-borne pathogens, development of drug resistance in pathogens, changing life style, globalization of the food supply etc. are responsible for the continuous persistence of food-borne diseases. The food-borne disease outbreaks due to E. coli O157:H7, Listeria monocytogenes, Salmonella and Campylobacter, are responsible for recall of many foods resulting in heavy losses to food industry. Due to consumer demand, a number of Ready-To-Eat (RTE) minimally processed foods are increasingly marketed; however, there is increased risk of foodborne diseases with these products. Food Technology Division of Bhabha Atomic Research Centre, Mumbai, has been working on food-borne bacterial pathogens particularly Salmonella, Campylobacter, Listeria monocytogenes, Vibrio and Aeromonasf

  15. Genome characterization of a novel vibriophage VpKK5 (Siphoviridae) specific to fish pathogenic strain of Vibrio parahaemolyticus.

    Science.gov (United States)

    Lal, Tamrin M; Sano, Motohiko; Ransangan, Julian

    2016-08-01

    Vibrio parahaemolyticus has long been known pathogenic to shrimp but only recently it is also reported pathogenic to tropical cultured marine finfish. Traditionally, bacterial diseases in aquaculture are often treated using synthetic antibiotics but concern due to side effects of these chemicals is elevating hence, new control strategies which are both environmental and consumer friendly, are urgently needed. One promising control strategy is the bacteriophage therapy. In this study, we report the isolation and characterization of a novel vibriophage (VpKK5), belonging to the family Siphoviridae that was specific and capable of complete lysing the fish pathogenic strain of V. parahaemolyticus. The VpKK5 exhibited short eclipse and latent periods of 24 and 36 min, respectively, but with a large burst size of 180 pfu/cell. The genome analysis revealed that the VpKK5 is a novel bacteriophage with the estimated genome size of 56,637 bp and has 53.1% G + C content. The vibriophage has about 80 predicted open reading frames consisted of 37 complete coding sequences which did not match to any protein databases. The analysis also found no lysogeny and virulence genes in the genome of VpKK5. With such genome features, we suspected the vibriophage is novel and could be explored for phage therapy against fish pathogenic strains of V. parahaemolyticus in the near future. PMID:26960780

  16. Isolation of TDA-producing Phaeobacter strains from sea bass larval rearing units and their probiotic effect against pathogenic Vibrio spp. in Artemia cultures.

    Science.gov (United States)

    Grotkjær, Torben; Bentzon-Tilia, Mikkel; D'Alvise, Paul; Dourala, Nancy; Nielsen, Kristian Fog; Gram, Lone

    2016-05-01

    Fish-pathogenic Vibrio can cause large-scale crashes in marine larval rearing units and, since the use of antibiotics can result in bacterial antibiotic resistance, new strategies for disease prevention are needed. Roseobacter-clade bacteria from turbot larval rearing facilities can antagonize Vibrio anguillarum and reduce mortality in V. anguillarum-infected cod and turbot larvae. In this study, it was demonstrated that antagonistic Roseobacter-clade bacteria could be isolated from sea bass larval rearing units. In addition, it was shown that they not only antagonized V. anguillarum but also V. harveyi, which is the major bacterial pathogen in crustaceans and Mediterranean sea bass larvae cultures. Concomitantly, they significantly improved survival of V. harveyi-infected brine shrimp. 16S rRNA gene sequence homology identified the antagonists as Phaeobacter sp., and in silico DNA-DNA hybridization indicated that they could belong to a new species. The genomes contained genes involved in synthesis of the antibacterial compound tropodithietic acid (TDA), and its production was confirmed by UHPLC-TOFMS. The new Phaeobacter colonized live feed (Artemia) cultures and reduced Vibrio counts significantly, since they reached only 10(4)CFUmL(-1), as opposed to 10(8)CFUmL(-1) in non-Phaeobacter treated controls. Survival of V. anguillarum-challenged Artemia nauplii was enhanced by the presence of wild type Phaeobacter compared to challenged control cultures (89±1.0% vs 8±3.2%). In conclusion, TDA-producing Phaeobacter isolated from Mediterranean marine larviculture are promising probiotic bacteria against pathogenic Vibrio in crustacean live-feed cultures for marine fish larvae. PMID:26922490

  17. Evaluation of PCR Based Assays for the Improvement of Proportion Estimation of Bacterial and Viral Pathogens in Diarrheal Surveillance.

    Science.gov (United States)

    Guan, Hongxia; Zhang, Jingyun; Xiao, Yong; Sha, Dan; Ling, Xia; Kan, Biao

    2016-01-01

    Diarrhea can be caused by a variety of bacterial, viral and parasitic organisms. Laboratory diagnosis is essential in the pathogen-specific burden assessment. In the pathogen spectrum monitoring in the diarrheal surveillance, culture methods are commonly used for the bacterial pathogens' detection whereas nucleic acid based amplification, the non-cultural methods are used for the viral pathogens. Different methodology may cause the inaccurate pathogen spectrum for the bacterial pathogens because of their different culture abilities with the different media, and for the comparison of bacterial vs. viral pathogens. The application of nucleic acid-based methods in the detection of viral and bacterial pathogens will likely increase the number of confirmed positive diagnoses, and will be comparable since all pathogens will be detected based on the same nucleic acid extracts from the same sample. In this study, bacterial pathogens, including diarrheagenic Escherichia coli (DEC), Salmonella spp., Shigella spp., Vibrio parahaemolyticus and V. cholerae, were detected in 334 diarrheal samples by PCR-based methods using nucleic acid extracted from stool samples and associated enrichment cultures. A protocol was established to facilitate the consistent identification of bacterial pathogens in diarrheal patients. Five common enteric viruses were also detected by RT-PCR, including rotavirus, sapovirus, norovirus (I and II), human astrovirus, and enteric adenovirus. Higher positive rates were found for the bacterial pathogens, showing the lower proportion estimation if only using culture methods. This application will improve the quality of bacterial diarrheagenic pathogen survey, providing more accurate information pertaining to the pathogen spectrum associated with finding of food safety problems and disease burden evaluation. PMID:27065958

  18. The intrinsic resistome of bacterial pathogens

    Directory of Open Access Journals (Sweden)

    JoseLMartinez

    2013-04-01

    Full Text Available Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally a low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that the characteristic phenotype of susceptibility to antibiotics of a given bacterial species depends on the concerted activity of several elements, what has been named as intrinsic resistome. These determinants comprise not just classical resistance genes. Other elements, several of them involved in basic bacterial metabolic processes, are of relevance for the intrinsic resistance of bacterial pathogens. In the present review we analyse recent publications on the intrinsic resistomes of Escherichia coli and Pseudomonas aeruginosa. We present as well information on the role that global regulators of bacterial metabolism, as Crc from P. aeruginosa, may have on modulating bacterial susceptibility to antibiotics. Finally, we discuss the possibility of searching inhibitors of the intrinsic resistome in the aim of improving the activity of drugs currently in use for clinical practice.

  19. Effect of low temperature on starvation-survival of the eel pathogen Vibrio vulnificus biotype 2.

    OpenAIRE

    Biosca, E G; Amaro, C; Marco-Noales, E; Oliver, J D

    1996-01-01

    At present, no reports exist on the isolation of the eel pathogen Vibrio vulnificus biotype 2 from water samples. Nevertheless, it has recently been demonstrated that this biotype can use water as a route of infection. In the present study, the survival of this pathogen in artificial seawater (ASW) microcosms at different temperatures (25 and 5 degrees C) was investigated during a 50-day period, with biotype 1 as a control, V. vulnificus biotype 2 was able to survive in the culturable state i...

  20. Immunological study of the outer membrane proteins of Vibrio harveyi: insights that link immunoprotectivity to interference with bacterial infection.

    Science.gov (United States)

    Yu, Lan-ping; Hu, Yong-hua; Sun, Bo-guang; Sun, Li

    2013-10-01

    Vibrio harveyi is a bacterial pathogen that affects marine vertebrates and invertebrates. In this study, we identified 13 outer membrane proteins (OMPs) from a pathogenic V. harveyi strain and analyzed their immunological properties. In vivo immunogenicity analysis showed that antibodies specific to recombinant proteins of the 13 OMPs were detected in the antiserum of V. harveyi-infected rat. When used as subunit vaccines to immunize Japanese flounder (Paralichthys olivaceus), all OMPs were able to elicit specific serum antibody production in the vaccinated fish; however, only two OMPs (OMP173 and OMP214) induced high levels (>70%) of relative percent survival. Pre-incubation of V. harveyi with the antisera of protective OMPs significantly impaired bacterial infectivity against peripheral blood leukocytes (PBL), whereas the antisera of non-protective OMPs had no apparent effect on infection. OMP173 antibodies could bind whole V. harveyi cells and exhibit bactericidal effect in a complement-dependent manner. Passive immunization showed that fish received OMP173 antiserum before being infected with V. harveyi exhibited significantly reduced mortality rate and lower bacterial loads in liver, spleen, and kidney. Finally, treatment of FG cells with OMP173 prior to V. harveyi infection protected the cells from bacterial invasion to a significant extent. Take together, these results indicate that two of the examined OMPs induce protective immunity through production of specific antibodies that block bacterial invasion, and that one OMP is likely to be involved in host cell interaction during the infection process. Thus, the immunoprotectivity of the OMPs is probably associated with functional participations of the OMPs in bacterial infection. PMID:23932987

  1. Evaluation of PCR based assays for the improvement of proportion estimation of bacterial and viral pathogens in diarrheal surveillance

    Directory of Open Access Journals (Sweden)

    Hongxia eGuan

    2016-03-01

    Full Text Available AbstractDiarrhea can be caused by a variety of bacterial, viral and parasitic organisms. Laboratory diagnosis is essential in the pathogen-specific burden assessment. In the pathogen spectrum monitoring in the diarrheal surveillance, culture methods are commonly used for the bacterial pathogens’ detection whereas nucleic acid based amplification, the non-cultural methods are used for the viral pathogens. Different methodology may cause the inaccurate pathogen spectrum for the bacterial pathogens because of their different culture abilities with the different media, and for the comparison of bacterial vs. viral pathogens. The application of nucleic acid-based methods in the detection of viral and bacterial pathogens will likely increase the number of confirmed positive diagnoses, and will be comparable since all pathogens will be detected based on the same nucleic acid extracts from the same sample. In this study, bacterial pathogens, including diarrheagenic Escherichia coli (DEC, Salmonella spp., Shigella spp., Vibrio parahaemolyticus and V. cholerae, were detected in 334 diarrheal samples by PCR-based methods using nucleic acid extracted from stool samples and associated enrichment cultures. A protocol was established to facilitate the consistent identification of bacterial pathogens in diarrheal patients. Five common enteric viruses were also detected by RT-PCR, including rotavirus, sapovirus, norovirus (I and II, human astrovirus, and enteric adenovirus. Higher positive rates were found for the bacterial pathogens, showing the lower proportion estimation if only using culture methods. This application will improve the quality of bacterial diarrheagenic pathogen survey, providing more accurate information pertaining to the pathogen spectrum associated with finding of food safety problems and disease burden evaluation.

  2. Clostridium difficile is an autotrophic bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    Michael Köpke

    Full Text Available During the last decade, Clostridium difficile infection showed a dramatic increase in incidence and virulence in the Northern hemisphere. This incessantly challenging disease is the leading cause of antibiotic-associated and nosocomial infectious diarrhea and became life-threatening especially among elderly people. It is generally assumed that all human bacterial pathogens are heterotrophic organisms, being either saccharolytic or proteolytic. So far, this has not been questioned as colonization of the human gut gives access to an environment, rich in organic nutrients. Here, we present data that C. difficile (both clinical and rumen isolates is also able to grow on CO2+H2 as sole carbon and energy source, thus representing the first identified autotrophic bacterial pathogen. Comparison of several different strains revealed high conservation of genes for autotrophic growth and showed that the ability to use gas mixtures for growth decreases or is lost upon prolonged culturing under heterotrophic conditions. The metabolic flexibility of C. difficile (heterotrophic growth on various substrates as well as autotrophy could allow the organism in the gut to avoid competition by niche differentiation and contribute to its survival when stressed or in unfavorable conditions that cause death to other bacteria. This may be an important trait for the pathogenicity of C. difficile.

  3. Involvement of penaeidins in defense reactions of the shrimp Litopenaeus stylirostris to a pathogenic vibrio.

    Science.gov (United States)

    Munoz, M; Vandenbulcke, F; Garnier, J; Gueguen, Y; Bulet, P; Saulnier, D; Bachère, E

    2004-04-01

    The present study reports for the first time the involvement of an antimicrobial peptide in the defense reactions of a shrimp infected by a pathogenic Vibrio, Vibrio penaeicida. New members of the penaeidin family were characterized in the shrimp Litopenaeus stylirostris by RT-PCR and RACE-PCR from hemocyte total RNAs, and by mass spectrometry detection and immunolocalization of mature peptides in shrimp hemocytes. In infected shrimps, bacteria and penaeidin distribution colocalized in the gills and the lymphoid organ that represented the main infected sites. Moreover, the shrimp immune response to infection involved massive hemocyte recruitment to infection sites where released penaeidin may participate in the isolation and elimination of the bacteria, We show that the ability of the shrimps to circumvent shrimp infections is closely related to a recovery phase based on the hematopoietic process. PMID:15095016

  4. Occurrence of potentially pathogenic Vibrio species in raw, processed, and ready-to-eat seafood and seafood products

    Directory of Open Access Journals (Sweden)

    Thararat Chitov

    2009-02-01

    Full Text Available This study investigated the occurrence (by means of the presence-absence test and level (by means of a plate count technique of selected potentially pathogenic Vibrio species in processed and ready-to-eat seafood, and some raw seafood normally used as raw materials or ingredients in these products, that were commercially available in Chiang Mai, Thailand. The level of Vibrio in raw seafood was found to range from 50 to 104 cfu/g. V. alginolyticus was the most frequently found species, followed by V. parahaemolyticus, V. cholerae, V. mimicus, and V. vulnificus, in that order. Processed and ready-to-eat products were contaminated with at least one of the potentially pathogenic vibrios at significant frequencies (25 and 17.5 % of samples, respectively, with the level as high as 103 to 104 per gram in some samples. Incidences of vibrios revealed by the presence-absence test were significantly higher than those revealed by the plate count assay. These data point to the hazard potential relating to Vibrio in processed and ready-to-eat seafood and the need to strictly apply preventive measures against Vibrio gastroenteritis through consumption of these food products. They also suggest that analytical methods used in food safety evaluation in relation to potentially hazardous Vibrio species should be carefully considered.

  5. Sigma E Regulators Control Hemolytic Activity and Virulence in a Shrimp Pathogenic Vibrio harveyi

    Science.gov (United States)

    Rattanama, Pimonsri; Thompson, Janelle R.; Kongkerd, Natthawan; Srinitiwarawong, Kanchana; Vuddhakul, Varaporn; Mekalanos, John J.

    2012-01-01

    Members of the genus Vibrio are important marine and aquaculture pathogens. Hemolytic activity has been identified as a virulence factor in many pathogenic vibrios including V. cholerae, V. parahaemolyticus, V. alginolyticus, V. harveyi and V. vulnificus. We have used transposon mutagenesis to identify genes involved in the hemolytic activity of shrimp-pathogenic V. harveyi strain PSU3316. Out of 1,764 mutants screened, five mutants showed reduced hemolytic activity on sheep blood agar and exhibited virulence attenuation in shrimp (Litopenaeus vannamei). Mutants were identified by comparing transposon junction sequences to a draft of assembly of the PSU3316 genome. Surprisingly none of the disrupted open reading frames or gene neighborhoods contained genes annotated as hemolysins. The gene encoding RseB, a negative regulator of the sigma factor (σE), was interrupted in 2 out of 5 transposon mutants, in addition, the transcription factor CytR, a threonine synthetase, and an efflux-associated cytoplasmic protein were also identified. Knockout mutations introduced into the rpoE operon at the rseB gene exhibited low hemolytic activity in sheep blood agar, and were 3-to 7-fold attenuated for colonization in shrimp. Comparison of whole cell extracted proteins in the rseB mutant (PSU4030) to the wild-type by 2-D gel electrophoresis revealed 6 differentially expressed proteins, including two down-regulated porins (OmpC-like and OmpN) and an upregulated protease (DegQ) which have been associated with σE in other organisms. Our study is the first report linking hemolytic activity to the σE regulators in pathogenic Vibrio species and suggests expression of this virulence-linked phenotype is governed by multiple regulatory pathways within the V. harveyi. PMID:22384269

  6. Mlp24 (McpX) of Vibrio cholerae Implicated in Pathogenicity Functions as a Chemoreceptor for Multiple Amino Acids

    OpenAIRE

    Nishiyama, So-ichiro; Suzuki, Daisuke; Itoh, Yasuaki; Suzuki, Kazuho; Tajima, Hirotaka; Hyakutake, Akihiro; Homma, Michio; Butler-Wu, Susan M.; Camilli, Andrew; Kawagishi, Ikuro

    2012-01-01

    The chemotaxis of Vibrio cholerae, the causative agent of cholera, has been implicated in pathogenicity. The bacterium has more than 40 genes for methyl-accepting chemotaxis protein (MCP)-like proteins (MLPs). In this study, we found that glycine and at least 18 l-amino acids, including serine, arginine, asparagine, and proline, serve as attractants to the classical biotype strain O395N1. Based on the sequence comparison with Vibrio parahaemolyticus, we speculated that at least 17 MLPs of V. ...

  7. Comparison of Plasmid Deoxyribonucleic Acid Contents, Culture Characteristics, and Indices of Pathogenicity Among Selected Strains of Vibrio parahaemolyticus

    OpenAIRE

    Twedt, R M; Brown, D F; Zink, D L

    1981-01-01

    Thirty-one Kanagawa-positive and -negative Vibrio parahaemolyticus isolates from patient stools and seafood were examined for plasmid deoxyribonucleic acid content, culture characteristics, and indices of pathogenicity. No significant correlation was found between plasmid deoxyribonucleic acid contents and indices of pathogenicity for the strains tested.

  8. Molecular epidemiology of Vibrio nigripulchritudo, a pathogen of cultured penaeid shrimp (Litopenaeus stylirostris) in New Caledonia.

    Science.gov (United States)

    Goarant, Cyrille; Reynaud, Yann; Ansquer, Dominique; de Decker, Sophie; Saulnier, Denis; le Roux, Frédérique

    2006-11-01

    A collection of 57 isolates of Vibrio nigripulchritudo from either diseased or healthy shrimp and from shrimp farms environment was studied in order to gain a better understanding of the epidemiology of this pathogen, notably isolated from two distinct shrimp disease complexes. Molecular typing using two different techniques, arbitrarily primed PCR (AP-PCR) and multi-locus sequence typing (MLST), studied together with experimental pathology data allowed a relevant epidemiological insight into this possibly emerging pathogen. Additionally, results obtained with the two molecular typing techniques were congruent and allowed discriminating the strains associated with the "Summer Syndrome" from strains isolated from other contexts, especially the other shrimp vibriosis "Syndrome 93". These results highlight that the "Summer Syndrome" is most probably caused by an emergent clonal pathogen that therefore deserves surveillance and that AP-PCR can satisfactorily be used for that purpose. PMID:16413158

  9. Population of Vibrio Parahaemolyticus (Pathogen and Bacillus (Beneficial Bacteria in Penaeus Monodon (Fabricus, 1798 Culture

    Directory of Open Access Journals (Sweden)

    V. Pattukumar

    2010-01-01

    Full Text Available Problem statement: The present work was attempted to evaluate the probiotic activity of Bacillus spp. in shrimp health management. Approach: Penaeid culture ecosystem as a confined environment with huge inputs always encourages the proliferation of pathogenic bacteria like Vibrios. Results: From the present study and earlier reports it is understood that these pathogens alone or combine with virus especially White Spot Syndrome Virus (WSSV lead to sudden disease outbreaks and mortality. However the unwarranted and unwanted usage of antibiotics causes negative impacts rather than controlling diseases. Conclusion: Based on this, it is concluded that application of suitable and effective probiotics (Bacillus will certainly reduce population of pathogens and provide a congenial pond environment for shrimp culture. However, this could be achieved by the effective usage of commercially available probiotics for maintaining good pond environment.

  10. An improved detection and quantification method for the coral pathogen Vibrio coralliilyticus.

    Directory of Open Access Journals (Sweden)

    Bryan Wilson

    Full Text Available DNA- and RNA-based PCR and reverse-transcription real-time PCR assays were developed for diagnostic detection of the vcpA zinc-metalloprotease implicated in the virulence of the coral pathogen Vibrio coralliilyticus. Both PCR methods were highly specific for V. coralliilyticus and failed to amplify strains of closely-related Vibrio species. The assays correctly detected all globally occurring V. coralliilyticus isolates including a newly-described isolate [TAV24] infecting gorgonians in the Mediterranean Sea and highlighted those isolates that had been potentially misidentified, in particular V. tubiashii strains ATCC 19105 and RE22, historically described as important oyster pathogens. The real-time assay is sensitive, detecting 10 gene copies and the relationships between gene copy number and cycle threshold (C T were highly linear (R(2≥ 99.7. The real-time assay was also not affected by interference from non-target DNA. These assays are useful for rapid detection of V. coralliilyticus and monitoring of virulence levels in environmental samples, allowing for implementation of timely management steps to limit and possibly prevent losses due to V. coralliilyticus infection, as well as furthering investigations of factors affecting pathogenesis of this important marine pathogen.

  11. A simple and rapid immunochromatographic test strip for detection of pathogenic isolates of Vibrio harveyi.

    Science.gov (United States)

    Sithigorngul, Paisarn; Rukpratanporn, Sombat; Pecharaburanin, Nilawan; Suksawat, Pornthip; Longyant, Siwaporn; Chaivisuthangkura, Parin; Sithigorngul, Weerawan

    2007-12-01

    Mouse monoclonal antibodies (MAbs) and rabbit polyclonal antibody (PAb) against Vibrio harveyi were generated from immunization of mice and rabbits with highly virulent isolate of V. harveyi. Two MAbs specific to virulent isolates of V. harveyi were obtained and one of them (VH4) was selected to conjugate with colloidal gold as the detector antibody was laid on a sample pad. Rabbit polyclonal antibody was used as the capture antibody at the test line (T) and goat anti-mouse IgG antibody (GAM) was used as the capture antibody at the control line (C) of nitrocellulose strip. The ready-to-use strip was held in a plastic case and then stored in a desiccated plastic bag. A sample volume of 100 microl of bacterial suspension from various sources mixed with application buffer was applied to the sample chamber at one end of the strip and allowed to flow by chromatography through the nitrocellulose membrane to the other end. In test samples containing virulent isolates of V. harveyi, the bacteria would bind to the monoclonal antibody conjugated with colloidal gold and the resulting complex would be captured by the antibodies at the test line to give a reddish-purple band. Any unbound monoclonal antibody conjugated with colloidal gold moved across the test line would be captured by the GAM and form a band at the control line (C). In sample without V. harveyi or with V. harveyi below the limit (<10(6) CFU/ml) of detection for the kit, only the control line band was observed. If the test sample was pre-enriched in tryptic soy broth (TSB) for 6 h before application to the strip, the sensitivity would increase to 1-10 CFU/ml which is comparable to that of PCR. This method could be used to detect pathogenic isolates of V. harveyi in pond water or infected shrimp in order to monitor and to reduce the risk of V. harveyi outbreak in the shrimp culture. The beneficial features of this kit are that simple, convenient and quick results (within 15 min) can be obtained without the

  12. Finding immune gene expression differences induced by marine bacterial pathogens in the Deep-sea hydrothermal vent mussel Bathymodiolus azoricus

    Science.gov (United States)

    Martins, E.; Queiroz, A.; Serrão Santos, R.; Bettencourt, R.

    2013-11-01

    The deep-sea hydrothermal vent mussel Bathymodiolus azoricus lives in a natural environment characterised by extreme conditions of hydrostatic pressure, temperature, pH, high concentrations of heavy metals, methane and hydrogen sulphide. The deep-sea vent biological systems represent thus the opportunity to study and provide new insights into the basic physiological principles that govern the defense mechanisms in vent animals and to understand how they cope with microbial infections. Hence, the importance of understanding this animal's innate defense mechanisms, by examining its differential immune gene expressions toward different pathogenic agents. In the present study, B. azoricus mussels were infected with single suspensions of marine bacterial pathogens, consisting of Vibrio splendidus, Vibrio alginolyticus, or Vibrio anguillarum, and a pool of these Vibrio bacteria. Flavobacterium suspensions were also used as a non-pathogenic bacterium. Gene expression analyses were carried out using gill samples from infected animals by means of quantitative-Polymerase Chain Reaction aimed at targeting several immune genes. We also performed SDS-PAGE protein analyses from the same gill tissues. We concluded that there are different levels of immune gene expression between the 12 h to 24 h exposure times to various bacterial suspensions. Our results from qPCR demonstrated a general pattern of gene expression, decreasing from 12 h over 24 h post-infection. Among the bacteria tested, Flavobacterium is the bacterium inducing the highest gene expression level in 12 h post-infections animals. The 24 h infected animals revealed, however, greater gene expression levels, using V. splendidus as the infectious agent. The SDS-PAGE analysis also pointed at protein profile differences between 12 h and 24 h, particularly evident for proteins of 18-20 KDa molecular mass, where most dissimilarity was found. Multivariate analyses demonstrated that immune genes, as well as experimental

  13. The neglected intrinsic resistome of bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Alicia Fajardo

    Full Text Available Bacteria with intrinsic resistance to antibiotics are a worrisome health problem. It is widely believed that intrinsic antibiotic resistance of bacterial pathogens is mainly the consequence of cellular impermeability and activity of efflux pumps. However, the analysis of transposon-tagged Pseudomonas aeruginosa mutants presented in this article shows that this phenotype emerges from the action of numerous proteins from all functional categories. Mutations in some genes make P. aeruginosa more susceptible to antibiotics and thereby represent new targets. Mutations in other genes make P. aeruginosa more resistant and therefore define novel mechanisms for mutation-driven acquisition of antibiotic resistance, opening a new research field based in the prediction of resistance before it emerges in clinical environments. Antibiotics are not just weapons against bacterial competitors, but also natural signalling molecules. Our results demonstrate that antibiotic resistance genes are not merely protective shields and offer a more comprehensive view of the role of antibiotic resistance genes in the clinic and in nature.

  14. Prevalences of pathogenic and nonpathogenic Vibrio parahaemolyticus in mollusks from the Spanish Mediterranean Coast

    Directory of Open Access Journals (Sweden)

    Carmen eLopez-Joven

    2015-07-01

    Full Text Available Vibrio parahaemolyticus is a well-recognized pathogen of humans. To better understand the ecology of the human-pathogenic variants of this bacterium in the environment, a study on the prevalence in bivalves of pathogenic variants (tlh + and tdh+ and/or trh+ versus a nonpathogenic one (only tlh+ as species marker for V. parahaemolyticus, was performed in two bays in Catalonia, Spain. Environmental factors that might affect dynamics of both variants of V. parahaemolyticus were taken into account. The results showed that the global prevalence of total V. parahaemolyticus found in both bays was 14.2% (207/1459. It was, however, significantly dependent on sampling point, campaign (year and bivalve species. Pathogenic variants of V. parahaemolyticus (tdh+ and/or trh+ were detected in 3.8% of the samples (56/1459, meaning that the proportion of bivalves who contained tlh gene were contaminated by pathogenic V. parahaemolyticus strains is 27.1% (56/207. Moreover, the presence of pathogenic V. parahaemolyticus (trh+ was significantly correlated with water salinity, thus the probability of finding pathogenic V. parahaemolyticus decreased 1.45 times with every salinity unit (ppt increased. Additionally, data showed that V. parahaemolyticus could establish close associations with Ruditapes spp. (P-value < 0.001, which could enhance the transmission of illness to human by pathogenic variants, when clams were eaten raw or slightly cooked.This study provides information on the abundance, ecology and characteristics of total and human-pathogenic V. parahaemolyticus variants associated with bivalves cultured in the Spanish Mediterranean Coast.

  15. Efficacy of zinc as an antibacterial agent against enteric bacterial pathogens

    International Nuclear Information System (INIS)

    Background: Diarrhoea is a serious threat all over the world with great economic implications especially evident in the developing world. This study was aimed at determining in vitro efficacy of Zinc (Zn) against common enteric bacterial pathogens. Method: A total of 100 bacterial enteric pathogens: Salmonellae (n=16), enteropathogenic Escherichia coli (EPEC) (n=26), Shigellae (n=28) and Vibrio cholerae (n=30) were isolated from diarrhoeal stool specimens at Department of Microbiology, Armed Forces Institute of Pathology Rawalpindi during April 2009 to Jan 2010. These isolates were tested against various concentrations of Zn supplemented in Mueller Hinton (MH) agar using a multipoint inoculator. A minimum inhibitory concentration of active Zn in ZnSO/sub 4/.7H/sub 2/O ranging from 0.03 mg/ml to 1 mg/ml was used. Results: Zn completely inhibited the growth of all the tested pathogens and most of them were inhibited at a concentration of 0.06 mg/ml to 0.5 mg/ml of Zn. Conclusions: Zinc has an excellent antibacterial activity against enteric bacterial pathogens common in our setup which may provide basis for treatment of diarrhoea. Clinical study based on these findings is recommended. (author)

  16. Draft Genome Sequences of the Fish Pathogen Vibrio harveyi Strains VH2 and VH5

    DEFF Research Database (Denmark)

    Castillo, Daniel; D'Alvise, Paul; Middelboe, Mathias; Gram, Lone; Liu, Siyang; Kalatzis, Panos G.; Kokkari, Constantina; Katharios, Pantelis

    2015-01-01

    Vibrio harveyi is an important marine pathogen that is responsible for vibriosis outbreaks in cultured fish and invertebrates worldwide. Here, we announce the draft genome sequences of V. harveyi strains VH2 and VH5, isolated from farmed juvenile Seriola dumerili during outbreaks of vibriosis in...

  17. Bacterial pathogens modulate an apoptosis differentiation program in human neutrophils

    OpenAIRE

    Kobayashi, Scott D.; Braughton, Kevin R.; Whitney, Adeline R.; Voyich, Jovanka M.; Schwan, Tom G.; Musser, James M.; DeLeo, Frank R.

    2003-01-01

    Human polymorphonuclear leukocytes (PMNs or neutrophils) are essential to the innate immune response against bacterial pathogens. Recent evidence suggests that PMN apoptosis facilitates resolution of inflammation during bacterial infection. Although progress has been made toward understanding apoptosis in neutrophils, very little is known about transcriptional regulation of this process during bacterial infection. To gain insight into the molecular processes that facilitate resolution of infe...

  18. Incidence of enteric bacterial pathogens in water found at the bottom of commercial freezers in calabar, southeastern Nigeria.

    Science.gov (United States)

    Eja, Matthew Egbobor; Etok, Comfort A; Asikong, Bassey E; Mboto, Clement I; Arikpo, Giddings E

    2006-03-01

    Bacteriological analysis of water that accumulates at the bottom of freezers in restaurants when the power was cut in Calabar, southeastern Nigeria, was carried out using standard procedures. Mean heterotrophic bacterial counts and Escherichia coli counts ranged from 3.1 +/- 0.02 to 7.1 +/- 0.30 x 10(4) cfu/ml and 0.2 +/- 0.10 to 0.6 +/- 0.50 x 10(4) cfu/ml, respectively, indicating heavy bacterial contamination whose source was mostly fecal. There was no significant difference (p > 0.05, 0.01) in bacterial counts between freezers. Some biochemically identified enteric bacterial pathogens were Salmonella typhi, Shigella sp, enteropathogenic E. coli, Yersinia sp, Klebsiella pneumoniae, Vibrio cholerae O1 and Vibrio parahaemolyticus. This reveals that the hygienic quality of the food items stored in the freezers and the hygienic status of the restaurants are in doubt. Infection could be going on unnoticed and thus endemicity maintained in the area. The pathogens showed alarming antibiotic resistance. The water in the freezers was a "soup" in which different species of the enteric pathogens were close to each other and could transfer drug resistance among themselves. Public health education of restaurant operators in southeastern Nigeria is recommended. PMID:17125005

  19. Cellphones A Modern Stayhouse For Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Usha Arora

    2009-07-01

    Full Text Available Cellphones are increasingly used by health care personnels for communication. These can harbour variouspotential pathogens and become an exogenous source of nosocomial infections. A total of 160 cellphonesbelonging to doctors and paramedical staff working in various departments at govt. medical college andhospital, Amritsar were screened for bacterial isolates. Sterile swabs moistened with nutrient broth wereused to swab the front, back and the sides of the cellphones and were subjected to culture and sensitivity.The same procedure was repeated after decontamination with 70% iso propyl alcohol.Out of total 160cellphones growth was obtained in 65(40.62% cellphones. 31(19.37% from clinical workers and34(21.25% from non clinical workers. Coagulase negative staphylococcus was the most commonly isolatedorganism.The efficacy of decontamination with 70% isopropyl alcohol was found to be 98% as only 5cellphones showed growth after decontamination.It was found that around 40% of the cellphones ofhealth care workers were contaminated and thus acted as a potential source of nosocomial infections.Simple measures like decontamination with 70% isopropyl alcohol was found to be 98% effective.

  20. Occurrence of potentially pathogenic Vibrio species in raw, processed, and ready-to-eat seafood and seafood products

    OpenAIRE

    Thararat Chitov

    2009-01-01

    This study investigated the occurrence (by means of the presence-absence test) and level (by means of a plate count technique) of selected potentially pathogenic Vibrio species in processed and ready-to-eat seafood, and some raw seafood normally used as raw materials or ingredients in these products, that were commercially available in Chiang Mai, Thailand. The level of Vibrio in raw seafood was found to range from 50 to 104 cfu/g. V. alginolyticus was the most frequently found species, follo...

  1. Poly-beta-hydroxybutyrate-accumulating bacteria protect gnotobiotic Artemia franciscana from pathogenic Vibrio campbellii.

    Science.gov (United States)

    Halet, Dirk; Defoirdt, Tom; Van Damme, Petra; Vervaeren, Han; Forrez, Ilse; Van de Wiele, Tom; Boon, Nico; Sorgeloos, Patrick; Bossier, Peter; Verstraete, Willy

    2007-06-01

    A poly-beta-hydroxybutyrate (PHB)-accumulating enrichment culture was obtained using activated sludge from a polyphosphate-accumulating reactor as inoculum. PHB accumulated by the enrichment culture significantly enhanced the survival of Artemia nauplii, infected with the virulent pathogen Vibrio campbellii LMG 21363. A strain was isolated from the enrichment culture, based on its ability to accumulate PHB, and 16S rRNA gene sequencing of the isolate revealed 99% sequence similarity to Brachymonas denitrificans AS-P1. The isolate, named PHB2, showed good PHB-accumulating activity (up to 32% of the cell dry weight). PHB accumulated by isolate PHB2 was able to protect Artemia completely from the V. campbellii strain. Our data indicate that PHB-accumulating bacteria, such as B. denitrificans PHB2, could be used as an an effective and economically interesting alternative strategy to control infections in aquaculture. PMID:17391334

  2. The influence of the accessory genome on bacterial pathogen evolution

    OpenAIRE

    Jackson, Robert W.; Vinatzer, Boris; Arnold, Dawn L.; Dorus, Steve; Murillo, Jesus

    2011-01-01

    Bacterial pathogens exhibit significant variation in their genomic content of virulence factors. This reflects the abundance of strategies pathogens evolved to infect host organisms by suppressing host immunity. Molecular arms-races have been a strong driving force for the evolution of pathogenicity, with pathogens often encoding overlapping or redundant functions, such as type III protein secretion effectors and hosts encoding ever more sophisticated immune systems. The pathogens’ frequent e...

  3. Genome anatomy of the gastrointestinal pathogen, Vibrio parahaemolyticus of crustacean origin.

    Science.gov (United States)

    Tiruvayipati, Suma; Bhassu, Subha; Kumar, Narender; Baddam, Ramani; Shaik, Sabiha; Gurindapalli, Anil Kumar; Thong, Kwai Lin; Ahmed, Niyaz

    2013-01-01

    Vibrio parahaemolyticus, an important human pathogen, is associated with gastroenteritis and transmitted through partially cooked seafood. It has become a major concern in the production and trade of marine food products. The prevalence of potentially virulent and pathogenic V. parahaemolyticus in raw seafood is of public health significance. Here we describe the genome sequence of a V. parahaemolyticus isolate of crustacean origin which was cultured from prawns in 2008 in Selangor, Malaysia (isolate PCV08-7). The next generation sequencing and analysis revealed that the genome of isolate PCV08-7 has closest similarity to that of V. parahaemolyticus RIMD2210633. However, there are certain unique features of the PCV08-7 genome such as the absence of TDH-related hemolysin (TRH), and the presence of HU-alpha insertion. The genome of isolate PCV08-7 encodes a thermostable direct hemolysin (TDH), an important virulence factor that classifies PCV08-7 isolate to be a serovariant of O3:K6 strain. Apart from these, we observed that there is certain pattern of genetic rearrangements that makes V. parahaemolyticus PCV08-7 a non-pandemic clone. We present detailed genome statistics and important genetic features of this bacterium and discuss how its survival, adaptation and virulence in marine and terrestrial hosts can be understood through the genomic blueprint and that the availability of genome sequence entailing this important Malaysian isolate would likely enhance our understanding of the epidemiology, evolution and transmission of foodborne Vibrios in Malaysia and elsewhere. PMID:24330647

  4. Adhesion of pathogenic Vibrio alginolyticus to the gill mucus of Pseudosciaena crocea

    Institute of Scientific and Technical Information of China (English)

    CHEN Qiang; YAN Qingpi; MA Shen; ZHUANG Zhixia; WANG Xiaoru

    2007-01-01

    Adhesion of Vibrio alginolyticus to the gill mucus of Pseudosciaena crocea has been investigated using [methyl-3H]thymidine as isotope tracer. The results showed that: the adhesive quantity of V. alginolyticus increased with bacterial concentrations and reached equilibrium after incubated for 180 min; the higher adhesive quantity was obtained at 15~30 ℃ and sourish conditions; adhesion of V. alginolyticus could not achieved without Na+, and Ca2+ played an auxiliary role in the bacterial adhesion; adhesion of V. alginolyticus was inhibited remarkably by starvation, heat treatment and periodic acid treatment; all of the eight kinds of carbohydrates investigated enhanced the adhesion of V. alginolyticus to the gill mucus of P. crocea, among them, glucose, mannose, fructose and maltose showed the specially enhanced adhesion. The results indicated that V. alginolyticus could adhere to the gill mucus of P. crocea facilely in seawater, and this bacterial adhesion was influenced by environmental factors and closely related to superficial carbohydrate structures and some heat-sensitive structures.

  5. Antibiotic Susceptibility and Immunomodulatory Potential of Chosen Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    M. Sujatha

    2010-01-01

    Full Text Available Problem statement: Antibiotic susceptibility is still the best way for bacterial pathogen escape mechanism against immunity. Approach: In the present investigation, bacterial pathogens like Staphylococcus aureus, Escherichia coli, Aeromonas hydrophila, Klebsiella and Pseudomonas aeruginosa were used to screen antibiotic susceptibility and immunomodulatory potential. Results: All the test pathogens were sensitive to all the test antibiotics 11±2 mm except penicillin. The conditions for the preparation of antigens of intact natural composition and conformation from pathogens (whole cell and heat killed, were determined using Swiss albino mice (Balb/C as experimental species. Immunomodulatory potential of test pathogens were screened using animal model. Test pathogen decreases the body weight comparing that of normal mice, some notable changes were also noted in activity, growth, water consumption, feed consumption. Antibody titre level in animal serum decreased upto 50% in whole cell pathogen and heat killed pathogen treated animals. Conclusion: The five pathogens administered animals, decrement in B-lymphocyte was much pronounced in Pseudomonas aeruginosa followed by Escherichia coli, Staphylococcus aureus, Klebsiella sp., Aeromonas hydrophila in the 5 week. Pathogen treated mice showed an IgG suppressive effect. It is found to be suppressive to T cell production, so induction in cell mediated immunity has confirmed pathogenic potential of test pathogens. All these test pathogenic strains were remarkably suppressing immune system of pathogen exposed animals.

  6. Molecular Epidemiology and Genetic Variation of Pathogenic Vibrio parahaemolyticus in Peru

    Science.gov (United States)

    Gavilan, Ronnie G.; Zamudio, Maria L.; Martinez-Urtaza, Jaime

    2013-01-01

    Vibrio parahaemolyticus is a foodborne pathogen that has become a public health concern at the global scale. The epidemiological significance of V. parahaemolyticus infections in Latin America received little attention until the winter of 1997 when cases related to the pandemic clone were detected in the region, changing the epidemic dynamics of this pathogen in Peru. With the aim to assess the impact of the arrival of the pandemic clone on local populations of pathogenic V. parahaemolyticus in Peru, we investigated the population genetics and genomic variation in a complete collection of non-pandemic strains recovered from clinical sources in Peru during the pre- and post-emergence periods of the pandemic clone. A total of 56 clinical strains isolated in Peru during the period 1994 to 2007, 13 strains from Chile and 20 strains from Asia were characterized by Multilocus Sequence Typing (MLST) and checked for the presence of Variable Genomic Regions (VGRs). The emergence of O3:K6 cases in Peru implied a drastic disruption of the seasonal dynamics of infections and a shift in the serotype dominance of pathogenic V. parahaemolyticus. After the arrival of the pandemic clone, a great diversity of serovars not previously reported was detected in the country, which supports the introduction of additional populations cohabitating with the pandemic group. Moreover, the presence of genomic regions characteristic of the pandemic clone in other non-pandemic strains may represent early evidence of genetic transfer from the introduced population to the local communities. Finally, the results of this study stress the importance of population admixture, horizontal genetic transfer and homologous recombination as major events shaping the structure and diversity of pathogenic V. parahaemolyticus. PMID:23696906

  7. Anion inhibition profiles of α-, β- and γ-carbonic anhydrases from the pathogenic bacterium Vibrio cholerae.

    Science.gov (United States)

    Del Prete, Sonia; Vullo, Daniela; De Luca, Viviana; Carginale, Vincenzo; di Fonzo, Pietro; Osman, Sameh M; AlOthman, Zeid; Supuran, Claudiu T; Capasso, Clemente

    2016-08-15

    Among the numerous metalloenzymes known to date, carbonic anhydrase (CA, EC 4.2.1.1) was the first zinc containing one, being discovered decades ago. CA is a hydro-lyase, which catalyzes the following hydration-dehydration reaction: CO2+H2O⇋HCO3(-)+H(+). Several CA classes are presently known, including the α-, β-, γ-, δ-, ζ- and η-CAs. In prokaryotes, the existence of genes encoding CAs from at least three classes (α-, β- and γ-class) suggests that these enzymes play a key role in the physiology of these organisms. In many bacteria CAs are essential for the life cycle of microbes and their inhibition leads to growth impairment or growth defects of the pathogen. CAs thus started to be investigated in detail in bacteria, fungi and protozoa with the aim to identify antiinfectives with a novel mechanism of action. Here, we investigated the catalytic activity, biochemical properties and anion inhibition profiles of the three CAs from the bacterial pathogen Vibrio cholera, VchCA, VchCAβ and VchCAγ. The three enzymes are efficient catalysts for CO2 hydration, with kcat values ranging between (3.4-8.23)×10(5)s(-1) and kcat/KM of (4.1-7.0)×10(7)M(-1)s(-1). A set of inorganic anions and small molecules was investigated for inhibition of these enzymes. The most potent VchCAγ inhibitors were N,N-diethyldithiocarbamate, sulfamate, sulfamide, phenylboronic acid and phenylarsonic acid, with KI values ranging between 44 and 91μM. PMID:27283786

  8. Identifying Pathogenicity Islands in Bacterial Pathogenomics Using Computational Approaches

    Directory of Open Access Journals (Sweden)

    Dongsheng Che

    2014-01-01

    Full Text Available High-throughput sequencing technologies have made it possible to study bacteria through analyzing their genome sequences. For instance, comparative genome sequence analyses can reveal the phenomenon such as gene loss, gene gain, or gene exchange in a genome. By analyzing pathogenic bacterial genomes, we can discover that pathogenic genomic regions in many pathogenic bacteria are horizontally transferred from other bacteria, and these regions are also known as pathogenicity islands (PAIs. PAIs have some detectable properties, such as having different genomic signatures than the rest of the host genomes, and containing mobility genes so that they can be integrated into the host genome. In this review, we will discuss various pathogenicity island-associated features and current computational approaches for the identification of PAIs. Existing pathogenicity island databases and related computational resources will also be discussed, so that researchers may find it to be useful for the studies of bacterial evolution and pathogenicity mechanisms.

  9. The Emergence of Vibrio pathogens in Europe: Ecology, Evolution and Pathogenesis (Paris, 11-12 March 2015

    Directory of Open Access Journals (Sweden)

    Frederique eLe Roux

    2015-08-01

    Full Text Available Global change has caused a worldwide increase in reports of Vibrio-associated diseases with ecosystem-wide impacts on humans and marine animals. In Europe, higher prevalence of human infections followed regional climatic trends with outbreaks occurring during episodes of unusually warm weather. Similar patterns were also observed in Vibrio-associated diseases affecting marine organisms such as fish, bivalves and corals. Basic knowledge is still lacking on the ecology and evolutionary biology of these bacteria as well as on their virulence mechanisms. Current limitations in experimental systems to study infection and the lack of diagnostic tools still prevent a better understanding of Vibrio emergence. A major challenge is to foster cooperation between fundamental and applied research in order to investigate the consequences of pathogen emergence in natural Vibrio populations and answer federative questions that meet societal needs. Here we report the proceedings of the first European workshop dedicated to these specific goals of the Vibrio research community by connecting current knowledge to societal issues related to ocean health and food security.

  10. The emergence of Vibrio pathogens in Europe: ecology, evolution, and pathogenesis (Paris, 11–12th March 2015)

    Science.gov (United States)

    Roux, Frédérique Le; Wegner, K. Mathias; Baker-Austin, Craig; Vezzulli, Luigi; Osorio, Carlos R.; Amaro, Carmen; Ritchie, Jennifer M.; Defoirdt, Tom; Destoumieux-Garzón, Delphine; Blokesch, Melanie; Mazel, Didier; Jacq, Annick; Cava, Felipe; Gram, Lone; Wendling, Carolin C.; Strauch, Eckhard; Kirschner, Alexander; Huehn, Stephan

    2015-01-01

    Global change has caused a worldwide increase in reports of Vibrio-associated diseases with ecosystem-wide impacts on humans and marine animals. In Europe, higher prevalence of human infections followed regional climatic trends with outbreaks occurring during episodes of unusually warm weather. Similar patterns were also observed in Vibrio-associated diseases affecting marine organisms such as fish, bivalves and corals. Basic knowledge is still lacking on the ecology and evolutionary biology of these bacteria as well as on their virulence mechanisms. Current limitations in experimental systems to study infection and the lack of diagnostic tools still prevent a better understanding of Vibrio emergence. A major challenge is to foster cooperation between fundamental and applied research in order to investigate the consequences of pathogen emergence in natural Vibrio populations and answer federative questions that meet societal needs. Here we report the proceedings of the first European workshop dedicated to these specific goals of the Vibrio research community by connecting current knowledge to societal issues related to ocean health and food security. PMID:26322036

  11. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff.

    Science.gov (United States)

    Miller, Melissa A; Byrne, Barbara A; Jang, Spencer S; Dodd, Erin M; Dorfmeier, Elene; Harris, Michael D; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A; Miller, Woutrina A

    2010-01-01

    Although protected for nearly a century, California's sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health. PMID:19720009

  12. Parallel bacterial evolution within multiple patients identifies candidate pathogenicity genes

    OpenAIRE

    Lieberman, Tami D; Michel, Jean-Baptiste; Aingaran, Mythili; Potter-Bynoe, Gail; Roux, Damien; Davis, Michael R.; Skurnik, David; Leiby, Nicholas; LiPuma, John J.; Goldberg, Joanna B.; McAdam, Alexander J.; Priebe, Gregory P.; Kishony, Roy

    2011-01-01

    Bacterial pathogens evolve during the infection of their human hosts 1-8 , but separating adaptive and neutral mutations remains challenging 9-11 . Here, we identify bacterial genes under adaptive evolution by tracking recurrent patterns of mutations in the same pathogenic strain during the infection of multiple patients. We conducted a retrospective study of a Burkholderia dolosa outbreak among people with cystic fibrosis, sequencing the genomes of 112 isolates collected from 14 individuals ...

  13. Hijacking of eukaryotic functions by intracellular bacterial pathogens

    OpenAIRE

    Alonso, Ana; García del Portillo, Francisco

    2004-01-01

    Intracellular bacterial pathogens have evolved as a group of microorganisms endowed with weapons to hijack many biological processes of eukaryotic cells. This review discusses how these pathogens perturb diverse host cell functions, such as cytoskeleton dynamics and organelle vesicular trafficking. Alteration of the cytoskeleton is discussed in the context of the bacterial entry process (invasion), which occurs either by activation of membrane-located host receptors ("zipper" mechani...

  14. Biological control of kiwifruit and tomato bacterial pathogens

    OpenAIRE

    Balestra, Dr Giorgio M.; Rossetti, Dr Antonio; Quattrucci, Dr Alessio

    2008-01-01

    Biocontrol of bacterial pathogens is effected by using cupric salts associate to appropriate agronomical practices such as seed certification, irrigation and fertilization. In in vitro and in in vivo tests, aqueous extracts from Allium sativum and Ficus carica fruits reduce the survival and the damages (disease incidence and disease severity) caused by bacterial pathogens of kiwifruit (Pseudomonas syringae pv. syringae, Pseudomonas viridiflava) and of tomato (Pseudomonas syringae pv. tomat...

  15. The bacterial microbiome of Dermacentor andersoni ticks influences pathogen susceptibility.

    Science.gov (United States)

    Gall, Cory A; Reif, Kathryn E; Scoles, Glen A; Mason, Kathleen L; Mousel, Michelle; Noh, Susan M; Brayton, Kelly A

    2016-08-01

    Ticks are of medical importance owing to their ability to transmit pathogens to humans and animals. The Rocky Mountain wood tick, Dermacentor andersoni, is a vector of a number of pathogens, including Anaplasma marginale, which is the most widespread tick-borne pathogen of livestock. Although ticks host pathogenic bacteria, they also harbor bacterial endosymbionts that have a role in tick physiology, survival, as well as pathogen acquisition and transmission. The goal of this study was to characterize the bacterial microbiome and examine the impact of microbiome disruption on pathogen susceptibility. The bacterial microbiome of two populations of D. andersoni with historically different susceptibilities to A. marginale was characterized. In this study, the microbiome was disrupted and then ticks were exposed to A. marginale or Francisella novicida to determine whether the microbiome correlated with pathogen susceptibility. Our study showed that an increase in proportion and quantity of Rickettsia bellii in the microbiome was negatively correlated to A. marginale levels in ticks. Furthermore, a decrease in Francisella endosymbionts was associated with lower F. novicida infection levels, demonstrating a positive pathogen-endosymbiont relationship. We demonstrate that endosymbionts and pathogens have varying interactions, and suggest that microbiome manipulation may provide a possible method for biocontrol by decreasing pathogen susceptibility of ticks. PMID:26882265

  16. Vibrio cholerae hemagglutinin(HA)/protease: An extracellular metalloprotease with multiple pathogenic activities.

    Science.gov (United States)

    Benitez, Jorge A; Silva, Anisia J

    2016-06-01

    Vibrio cholerae of serogroup O1 and O139, the etiological agent of the diarrheal disease cholera, expresses the extracellular Zn-dependent metalloprotease hemagglutinin (HA)/protease also reported as vibriolysin. This enzyme is also produced by non-O1/O139 (non-cholera) strains that cause mild, sporadic illness (i.e. gastroenteritis, wound or ear infections). Orthologs of HA/protease are present in other members of the Vibrionaceae family pathogenic to humans and fish. HA/protease belongs to the M4 neutral peptidase family and displays significant amino acid sequence homology to Pseudomonas aeruginosa elastase (LasB) and Bacillus thermoproteolyticus thermolysin. It exhibits a broad range of potentially pathogenic activities in cell culture and animal models. These activities range from the covalent modification of other toxins, the degradation of the protective mucus barrier and disruption of intestinal tight junctions. Here we review (i) the structure and regulation of HA/protease expression, (ii) its interaction with other toxins and the intestinal mucosa and (iii) discuss the possible role(s) of HA/protease in the pathogenesis of cholera. PMID:26952544

  17. Looking in ticks for human bacterial pathogens

    OpenAIRE

    Mediannikov, Oleg; Fenollar, F.

    2014-01-01

    Ticks are considered to be second worldwide to mosquitoes as vectors of human diseases and the most important vectors of disease-causing pathogens in domestic- and wild animals. A number of emerging tick-borne pathogens are already discovered; however, the proportion of undiagnosed infectious diseases, especially in tropical regions, may suggest that there are still more pathogens associated with ticks. Moreover, the identification of bacteria associated with ticks may provide new tool for th...

  18. Methods to classify bacterial pathogens in cystic fibrosis

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Nielsen, Xiaohui Chen; Johansen, Ulla;

    2011-01-01

    Many bacteria can be detected in CF sputum, pathogenic and commensal. Modified Koch's criteria for identification of established and emerging CF pathogens are therefore described. Methods are described to isolate bacteria and to detect bacterial biofilms in sputum or lung tissue from CF patients ...

  19. ANTIMICROBIAL ACTIVITY OF SOME MEDICINAL HERBAL EXTRACTS ON CLINICALLY IMPORTANT BACTERIAL PATHOGENS

    Directory of Open Access Journals (Sweden)

    J. Suriya et al.

    2012-01-01

    Full Text Available The antibacterial activity of methanol extract of Abutilon indicum, Hygrophila spinosa and Mimosa pudica were studied by agar well diffusion method in vitro. The effect of antibacterial potential was examined against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Proteus vulgaris, Enterococcus faecalis, Klebsiella pneumoniae, Vibrio cholerae, Salmonella typhi and Salmonella paratyphi. The methanol extract of these medicinal plants have showed consistently significant inhibitory activity on different bacterial pathogens tested. Furthermore, the Minimum Inhibitory Concentration (MIC studies carried out by broth dilution assay and found the MIC ranged between 0.2 to 0.9mg/ml. Overall the methanol extracts was found to be more effective. The results of the extracts were compared with the standard antibiotics Kanamycin.

  20. Marine Lactobacillus pentosus H16 protects Artemia franciscana from Vibrio alginolyticus pathogenic effects.

    Science.gov (United States)

    Garcés, M E; Sequeiros, C; Olivera, N L

    2015-02-10

    Vibrio alginolyticus is an opportunistic pathogen which may affect different aquatic organisms. The aim of this study was to assess the probiotic properties and the protective mode of action of Lactobacillus pentosus H16 against V. alginolyticus 03/8525, through in vitro and in vivo studies using Artemia franciscana (hereafter Artemia). This strain showed antimicrobial activity against V. alginolyticus 03/8525 and Aeromonas salmonicida subsp. salmonicida ATCC33658 possibly related to lactobacilli organic acid production. It was able to survive at high rainbow trout bile concentrations and showed high selective adhesion to rainbow trout mucus (1.2×10(5)±8.0×10(3) cells cm(-2)). H16 outcompeted V. alginolyticus 03/8525 and A. salmonicida subsp. salmonicida ATCC33658, greatly reducing their adherence to rainbow trout mucus (64.8 and 74.1%, respectively). Moreover, H16 produced a cell-bound biosurfactant which caused an important decrease in the surface tension. H16 also protected Artemia nauplii against mortality when it was administered previous to V. alginolyticus 03/8525 inoculation. Furthermore, H16 bioencapsulated in Artemia, suggesting that it is possible to use live carriers in its administration. We conclude that the ability of L. pentosus H16 to selectively adhere to mucosal surfaces and produce cell-bound biosurfactants, displacing pathogenic strains, in addition to its antimicrobial activity, confer H16 competitive advantages against pathogens as demonstrated in in vivo challenge experiments. Thus, L. pentosus H16, a marine bacterium from the intestinal tract of hake, is an interesting probiotic for Artemia culture and also has the potential to prevent vibriosis in other aquaculture activities such as larvae culture and fish farming. PMID:25667335

  1. FIRST ISOLATION OF VIBRIO PROBIOTICUS FROM THE GUT OF PORTUNUS PELAGICUS (LINNAEUS, 1758 AND ITS PROBIOTIC COMPETENCY AGAINST SHELLFISH PATHOGENS

    Directory of Open Access Journals (Sweden)

    Mhd Ikhwanuddin

    2012-09-01

    Full Text Available In this study, the Vibrio probioticus was isolated from the gut of female Portunus pleagicus, identified through 16S rDNA gene sequencing, and was evaluated for its probiotic features. The probiont was tested in co-culture assay at various concentrations against three target shellfish pathogens including V. harveyi, V. parahaemolyticus and Pseudoalteromonas piscicida. In a co-culture assay it was apparent that the V. probioticus had shown to outcompete the growth of tested pathogenic bacteria due to its antibacteriocin properties. Different ratios produced different effect on tested pathogens, however, the highest ratio (pathogen:probiont was more effective in suppressing the pathogen. A maximum inhibition growth was recorded for V. harveyi and P. piscicida. The probionts could further be tested in vivo culture environment to understand the effectiveness in microbial control of P. pelagicus larviculture and other aquaculture species.

  2. Hemolysin, Protease, and EPS Producing Pathogenic Aeromonas hydrophila Strain An4 Shows Antibacterial Activity against Marine Bacterial Fish Pathogens

    Directory of Open Access Journals (Sweden)

    Anju Pandey

    2010-01-01

    Full Text Available A pathogenic Aeromonas hydrophila strain An4 was isolated from marine catfish and characterized with reference to its proteolytic and hemolytic activity along with SDS-PAGE profile (sodium dodecyl sulphate-Polyacrylamide gel electrophoresis of ECPs (extracellular proteins showing hemolysin (approximately 50 kDa. Agar well diffusion assay using crude cell extract of the bacterial isolate clearly demonstrated antibacterial activity against indicator pathogenic bacteria, Staphylococcus arlettae strain An1, Acinetobacter sp. strain An2, Vibrio parahaemolyticus strain An3, and Alteromonas aurentia SE3 showing inhibitory zone >10 mm well comparable to common antibiotics. Further GC-MS analysis of crude cell extract revealed several metabolites, namely, phenolics, pyrrolo-pyrazines, pyrrolo-pyridine, and butylated hydroxytoluene (well-known antimicrobials. Characterization of EPS using FTIR indicated presence of several protein-related amine and amide groups along with peaks corresponding to carboxylic and phenyl rings which may be attributed to its virulent and antibacterial properties, respectively. Besides hemolysin, EPS, and protease, Aeromonas hydrophila strain An4 also produced several antibacterial metabolites.

  3. Sulfonamide inhibition studies of the β-carbonic anhydrase from the pathogenic bacterium Vibrio cholerae.

    Science.gov (United States)

    Del Prete, Sonia; Vullo, Daniela; De Luca, Viviana; Carginale, Vincenzo; Ferraroni, Marta; Osman, Sameh M; AlOthman, Zeid; Supuran, Claudiu T; Capasso, Clemente

    2016-03-01

    The genome of the pathogenic bacterium Vibrio cholerae encodes for three carbonic anhydrases (CAs, EC 4.2.1.1) belonging to the α-, β- and γ-classes. VchCA, the α-CA from this species was investigated earlier, whereas the β-class enzyme, VchCAβ was recently cloned, characterized kinetically and its X-ray crystal structure reported by this group. Here we report an inhibition study with sulfonamides and one sulfamate of this enzyme. The best VchCAβ inhibitors were deacetylated acetazolamide and methazolamide and hydrochlorothiazide, which showed inhibition constants of 68.2-87.0nM. Other compounds, with medium potency against VchCAβ, (KIs in the range of 275-463nM), were sulfanilamide, metanilamide, sulthiame and saccharin whereas the clinically used agents such as acetazolamide, methazolamide, ethoxzolamide, dorzolamide, zonisamide and celecoxib were micromolar inhibitors (KIs in the range of 4.51-8.57μM). Identification of potent and possibly selective inhibitors of VchCA and VchCAβ over the human CA isoforms, may lead to pharmacological tools useful for understanding the physiological role(s) of this under-investigated enzymes. PMID:26850377

  4. Anion inhibition studies of the β-carbonic anhydrase from the pathogenic bacterium Vibrio cholerae.

    Science.gov (United States)

    Vullo, Daniela; Del Prete, Sonia; De Luca, Viviana; Carginale, Vincenzo; Ferraroni, Marta; Dedeoglu, Nurcan; Osman, Sameh M; AlOthman, Zeid; Capasso, Clemente; Supuran, Claudiu T

    2016-03-01

    The genome of the pathogenic bacterium Vibrio cholerae encodes for three carbonic anhydrases (CAs, EC 4.2.1.1) belonging to the α-, β- and γ-classes. Here we report and anion inhibition study of the β-CA, VchCAβ with anions and other small molecules which inhibit metalloenzymes. The best VchCAβ anion inhibitors were sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid, which showed KIs in the range of 54-86μM. Diethyldithiocarbonate was also an effective VchCAβ inhibitor, with an inhibition constant of 0.73mM. The halides, cyanate, thiocyanate, cyanide, bicarbonate, carbonate, nitrate, nitrite, stannate, selenate, tellurate, divanadate, tetraborate, perrhenate, perruthenate, peroxydisulfate, selenocyanide, trithiocarbonate, and fluorosulfonate showed affinity in the low millimolar range, with KIs of 2.3-9.5mM. Identification of selective inhibitors of VchCAβ (over the human CA isoforms) may lead to pharmacological tools useful for understanding the physiological role(s) of this under-investigated enzyme. PMID:26853167

  5. A potent fish pathogenic bacterial killer Streptomyces sp. isolated from the soils of east coast region, South India

    Institute of Scientific and Technical Information of China (English)

    Durairaj Thirumurugan; Ramasamy Vijayakumar

    2013-01-01

    Objective: To investigate the potentiality of the marine actinobacteria isolated from marine soil against fish pathogenic bacteria.Methods:east coast region (ECR) of Tamilnadu, South India. Then they were used for the isolation of actinobacteria by using conventional serial dilution technique on starch casein agar medium. The antibacterial activities of the actinobacteria were screened primarily by using cross streak plate method against fish pathogenic bacteria namely Vibrio alginolyticus, Vibrio parahaemolyticus,Vibrio cholera, Aeromonas sp. and Pseudomonas sp. The antimicrobial efficacy of the selected isolates was carried out with various organic solvents, and finally the active compound was subjected to chromatographic techniques including TLC and GC-MS.Results:In the present study, a total of 33 soil samples were collected from the Bay of Bengal, against fish pathogenic bacteria. Out of 21 antibacterial isolates, the isolate ECR77 was selected for further study based on its potential activity against fish pathogenic bacteria. Of the various solvents tested, the ethyl acetate extract had good antibacterial activity against the tested bacterial pathogens. The isolate ECR77 grew well on oat meal agar medium with 2% salt level at 35 °C. GC-MS study found that the presence of bioactive compounds namely tetradecanoic acid,n-hexadecanoic acid and octadecanoic acid. The morphological, physiological, biochemical and cultural characteristics of the potential isolate were supported the identity up to generic level asStreptomyces sp. ECR77. Conclusions: The results obtained from this study concludes that the ECR soils of South India is a hot spot of novel bioactive compound producing marine actinobacteria with great pharmaceutical values. Of the 82 actinobacteria isolated, 21 (26%) isolates were possessed antibacterial activity.

  6. Shotgun proteomics of bacterial pathogens: advances, challenges and clinical implications.

    Science.gov (United States)

    Semanjski, Maja; Macek, Boris

    2016-02-01

    Mass spectrometry-based proteomics is increasingly used in analysis of bacterial pathogens. Simple experimental set-ups based on high accuracy mass spectrometry and powerful biochemical and bioinformatics tools are capable of reliably quantifying levels of several thousand bacterial proteins in a single experiment, reaching the analytical capacity to completely map whole proteomes. Here the authors present the state-of-the-art in bacterial pathogen proteomics and discuss challenges that the field is facing, especially in analysis of low abundant, modified proteins from organisms that are difficult to culture. Constant improvements in speed and sensitivity of mass spectrometers, as well as in bioinformatic and biochemical workflows will soon allow for comprehensive analysis of regulatory mechanisms of pathogenicity and enable routine application of proteomics in the clinical setting. PMID:26653908

  7. The intrinsic resistome of bacterial pathogens

    OpenAIRE

    Olivares, Jorge; Bernardini, Alejandra; Garcia-Leon, Guillermo; Corona, Fernando; B. Sanchez, Maria; Martinez, Jose L.

    2013-01-01

    Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that...

  8. Bacterial interactions in pathogenic subgingival plaque.

    Science.gov (United States)

    Ng, Hong Min; Kin, Lin Xin; Dashper, Stuart G; Slakeski, Nada; Butler, Catherine A; Reynolds, Eric C

    2016-05-01

    Chronic periodontitis has a polymicrobial biofilm aetiology. Polymicrobial biofilms are complex, dynamic microbial communities formed by two or more bacterial species that are important for the persistence and proliferation of participating microbes in the environment. Interspecies adherence, which often involves bacterial surface-associated molecules, and communications are essential in the spatial and temporal development of a polymicrobial biofilm, which in turn is necessary for the overall fitness of a well-organized multispecies biofilm community. In the oral cavity, interactions between key oral bacterial species, including Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia, are essential for the progression of chronic periodontitis. In vivo, P. gingivalis and T. denticola are frequently found to co-exist in deep periodontal pockets and have been co-localized to the superficial layers of subgingival plaque as microcolony blooms adjacent to the pocket epithelium, suggesting possible interbacterial interactions that contribute towards disease. The motility and chemotactic ability of T. denticola, although not considered as classic virulence factors, are likely to be important in the synergistic biofilm formation with P. gingivalis. In vitro, P. gingivalis and T. denticola display a symbiotic relationship in nutrient utilization and growth promotion. Together these data suggest there is an intimate relationship between these two species that has evolved to enhance their survival and virulence. PMID:26541672

  9. Ethanolamine utilization in Vibrio alginolyticus

    Directory of Open Access Journals (Sweden)

    Khatri Neelam

    2012-12-01

    Full Text Available Abstract Ethanolamine is used as an energy source by phylogenetically diverse bacteria including pathogens, by the concerted action of proteins from the eut-operon. Previous studies have revealed the presence of eutBC genes encoding ethanolamine-ammonia lyase, a key enzyme that breaks ethanolamine into acetaldehyde and ammonia, in about 100 bacterial genomes including members of gamma-proteobacteria. However, ethanolamine utilization has not been reported for any member of the Vibrio genus. Our comparative genomics study reveals the presence of genes that are involved in ethanolamine utilization in several Vibrio species. Using Vibrio alginolyticus as a model system we demonstrate that ethanolamine is better utilized as a nitrogen source than as a carbon source. Reviewers This article was reviewed by Dr. Lakshminarayan Iyer and Dr. Vivek Anantharaman (nominated by Dr. L Aravind.

  10. Conformation of protein secreted across bacterial outer membranes: a study of enterotoxin translocation from Vibrio cholerae

    International Nuclear Information System (INIS)

    The secretion of enterotoxin by Vibrio cholerae is punctuated by the transient entry of the toxin subunits into the periplasm. In this paper, the authors show that the subunits oligomerize into an assembled holotoxin within the periplasm prior to their secretion across the outer membrane. The rate of toxin assembly was studied by pulse-labeling cells with [35S]-methionine and then monitoring the turnover of radiolabeled subunits as they assembled within the periplasm. The subunits entered the periplasm as monomers and assembled into oligomers with a half-time of ≅ 1 min. Since assembly was a rapid event compared to the rate of toxin efflux from the periplasm, which had a half-time of ≅ 13 min, they conclude that all of the subunits that pass through the periplasm assemble before they traverse the outer membrane. The average concentration of subunit monomers and assembled holotoxin within the periplasm was calculated to be ≅ 20 and ≅ 260 μg/ml, respectively. This indicates that the periplasm is a suitably concentrated milieu where spontaneous toxin assembly can occur. These findings suggest that protein movement across bacterial outer membranes, in apparent contrast to export across other biological membranes, involves translocation of polypeptides that have already folded into tertiary and even quaternary conformations

  11. Bacterial pathogens in a reactor cooling reservoir

    International Nuclear Information System (INIS)

    The results of the sampling in both Par Pond and Clark Hill Reservoir are given. The frequency of isolation is a qualitative parameter which indicates how often the specified bacterium was isolated from each habitat. Initial scoping experiments demonstrated that a wider variety of pathogenic bacteria occur in Par Pond than in Clark Hill Reservoir. Such findings are interesting because Par Pond does not receive any human wastes directly, yet bacteria generally associated with human wastes are more frequently isolated from Par Pond. Previous studies have demonstrated that certain non-spore-forming enteric bacteria do not survive the intense heat associated with the cooling water when the reactor is operating. However, even when the reactor is not operating, cooling water, consisting of 10% makeup water from Savannah River, continues to flow into Par Pond. This flow provides a source of bacteria which inoculate Par Pond. Once the reactor is again operating, these same bacteria appear to be able to survive and grow within the Par Pond system. Thus, Par Pond and the associated lakes and canals of the Par Pond system provide a pool of pathogens that normally would not survive in natural waters

  12. Finding immune gene expression differences induced by marine bacterial pathogens in the deep-sea hydrothermal vent mussel Bathymodiolus azoricus

    Directory of Open Access Journals (Sweden)

    R. Bettencourt

    2013-02-01

    Full Text Available The deep-sea hydrothermal vent mussel Bathymodiolus azoricus lives in a natural environment characterized by extreme conditions of hydrostatic pressure, temperature, pH, high concentrations of heavy metals, methane and hydrogen sulphide. The deep-sea vent biological systems represent thus the opportunity to study and provide new insights into the basic physiological principles that govern the defense mechanisms in vent animals and to understand how they cope with microbial infections. Hence, the importance of understanding this animal's innate defense mechanisms, by examining its differential immune gene expressions toward different pathogenic agents. In the present study, B. azoricus mussels were infected with single suspensions of marine bacterial pathogens, consisting of Vibrio splendidus, Vibrio alginolyticus, or Vibrio anguillarum, and a pool of these Vibrio strains. Flavobacterium suspensions were also used as an irrelevant bacterium. Gene expression analyses were carried out using gill samples from animals dissected at 12 h and 24 h post-infection times by means of quantitative-Polymerase Chain Reaction aimed at targeting several immune genes. We also performed SDS-PAGE protein analyses from the same gill tissues. We concluded that there are different levels of immune gene expression between the 12 h and 24 h exposure times to various bacterial suspensions. Our results from qPCR demonstrated a general pattern of gene expression, decreasing from 12 h over 24 h post-infection. Among the bacteria tested, Flavobacterium is the microorganism species inducing the highest gene expression level in 12 h post-infections animals. The 24 h infected animals revealed, however, greater gene expression levels, using V. splendidus as the infectious agent. The SDS-PAGE analysis also pointed at protein profile differences between 12 h and 24 h, particularly around a protein area, of 18 KDa molecular mass, where most dissimilarities were found. Multivariate

  13. Diversity of Clinical and Environmental Isolates of Vibrio cholerae in Natural Transformation and Contact-Dependent Bacterial Killing Indicative of Type VI Secretion System Activity.

    Science.gov (United States)

    Bernardy, Eryn E; Turnsek, Maryann A; Wilson, Sarah K; Tarr, Cheryl L; Hammer, Brian K

    2016-05-01

    The bacterial pathogenVibrio choleraecan occupy both the human gut and aquatic reservoirs, where it may colonize chitinous surfaces that induce the expression of factors for three phenotypes: chitin utilization, DNA uptake by natural transformation, and contact-dependent bacterial killing via a type VI secretion system (T6SS). In this study, we surveyed a diverse set of 53 isolates from different geographic locales collected over the past century from human clinical and environmental specimens for each phenotype outlined above. The set included pandemic isolates of serogroup O1, as well as several serogroup O139 and non-O1/non-O139 strains. We found that while chitin utilization was common, only 22.6% of the isolates tested were proficient at chitin-induced natural transformation, suggesting that transformation is expendable. Constitutive contact-dependent killing ofEscherichia coliprey, which is indicative of a functional T6SS, was rare among clinical isolates (only 4 of 29) but common among environmental isolates (22 of 24). These results bolster the pathoadaptive model in which tight regulation of T6SS-mediated bacterial killing is beneficial in a human host, whereas constitutive killing by environmental isolates may give a competitive advantage in natural settings. Future sequence analysis of this set of diverse isolates may identify previously unknown regulators and structural components for both natural transformation and T6SS. PMID:26944842

  14. Unraveling plant responses to bacterial pathogens through proteomics

    KAUST Repository

    Zimaro, Tamara

    2011-11-03

    Plant pathogenic bacteria cause diseases in important crops and seriously and negatively impact agricultural production. Therefore, an understanding of the mechanisms by which plants resist bacterial infection at the stage of the basal immune response or mount a successful specific R-dependent defense response is crucial since a better understanding of the biochemical and cellular mechanisms underlying these interactions will enable molecular and transgenic approaches to crops with increased biotic resistance. In recent years, proteomics has been used to gain in-depth understanding of many aspects of the host defense against pathogens and has allowed monitoring differences in abundance of proteins as well as posttranscriptional and posttranslational processes, protein activation/inactivation, and turnover. Proteomics also offers a window to study protein trafficking and routes of communication between organelles. Here, we summarize and discuss current progress in proteomics of the basal and specific host defense responses elicited by bacterial pathogens. Copyright 2011 Tamara Zimaro et al.

  15. A Nonluminescent and Highly Virulent Vibrio harveyi Strain Is Associated with “Bacterial White Tail Disease” of Litopenaeus vannamei Shrimp

    Science.gov (United States)

    Zhou, Junfang; Fang, Wenhong; Yang, Xianle; Zhou, Shuai; Hu, Linlin; Li, Xincang; Qi, Xinyong; Su, Hang; Xie, Layue

    2012-01-01

    Recurrent outbreaks of a disease in pond-cultured juvenile and subadult Litopenaeus vannamei shrimp in several districts in China remain an important problem in recent years. The disease was characterized by “white tail” and generally accompanied by mass mortalities. Based on data from the microscopical analyses, PCR detection and 16S rRNA sequencing, a new Vibrio harveyi strain (designated as strain HLB0905) was identified as the etiologic pathogen. The bacterial isolation and challenge tests demonstrated that the HLB0905 strain was nonluminescent but highly virulent. It could cause mass mortality in affected shrimp during a short time period with a low dose of infection. Meanwhile, the histopathological and electron microscopical analysis both showed that the HLB0905 strain could cause severe fiber cell damages and striated muscle necrosis by accumulating in the tail muscle of L. vannamei shrimp, which led the affected shrimp to exhibit white or opaque lesions in the tail. The typical sign was closely similar to that caused by infectious myonecrosis (IMN), white tail disease (WTD) or penaeid white tail disease (PWTD). To differentiate from such diseases as with a sign of “white tail” but of non-bacterial origin, the present disease was named as “bacterial white tail disease (BWTD)”. Present study revealed that, just like IMN and WTD, BWTD could also cause mass mortalities in pond-cultured shrimp. These results suggested that some bacterial strains are changing themselves from secondary to primary pathogens by enhancing their virulence in current shrimp aquaculture system. PMID:22383954

  16. Isolation of bioactive compound from marine seaweeds against fish pathogenic bacteria Vibrio alginolyticus (VA09) and characterisation by FTIR

    Institute of Scientific and Technical Information of China (English)

    Rajasekar Thirunavukkarasu; Priyadharshini Pandiyan; Deivasigamani Balaraman; Kumaran Subaramaniyan; George Edward Gnana Jothi; Sakthivel Manikkam; Balamurugan Sadaiyappan

    2013-01-01

    Objective: Fresh marine seaweeds Gracilaria edulis, Gracillaria verrcosa, Acanthospora spicifera,Ulva facita, Ulva lacta (U. lacta), Kappaphycus spicifera, Sargassum ilicifolium, Sargassum wightii (S. wightii), Padina tetramatica and Padina gymonospora were collected from Mandapam (Rameshwaram, Tamil Nadu) of South East coast of India and were screened for antibacterial activity.Methods:All the collected seaweeds were extracted by using five different solvent (methanol, isopropanol, acetone, chloroform, diethyl ether) to study their extracts against fish pathogenic bacteria V. alginolyticus (VA09) purchased from MTCC. And minimum inhibition carried out by using Resazurin micro-titre assay. Crude extract of S. wightii analysied by FTIR.Results:The methanolic extract of S. wightii produced a maximum zone of inhibition (1.95±0.11) cm, isopropanol extract maximum inhibition was produced by S. wightii (1.93±0.78) cm, Acetone extract of Gracilaria verrcosa showed maximum zone of inhibition (1.36±0.05) cm, chloroform extract of S. wightii produced a maximum zone (1.56±0.25) cm and diethyl ether extract of S.wightii produced maximum zone of inhibition(1.86±0.11) cm. Based on the antibacterial activity S. wightii, U. lacta and Padina tetramatica showed best antibacterial activity against Vibrio harveyi. In this three seaweeds were taken for MIC study. The S. wightii methanolic extract, U. lacta diethyl ether extract and Padina tetramatica methanolic extract showed a higher MIC values, and despectively were 25 mg/mL, 50 mg/mL and 50 mg/mL. FTIR result showed that mostly phenolic compounds were present in the S. wightii.Conclusions:Based on the FTIR result S. wightii have high amount of phenolic compound. Phenolic compound have the good antimicrobial activity. The results clearly show that seaweedS. wightii is an interesting source for biologically active compounds that may be applied for prophylaxis and therapy of bacterial fish diseases and it should be used for

  17. Essential oils of Nigella sativa protects Artemia from the pathogenic effect of Vibrio parahaemolyticus Dahv2.

    Science.gov (United States)

    Manju, Sivalingam; Malaikozhundan, Balasubramanian; Withyachumnarnkul, Boonsirm; Vaseeharan, Baskaralingam

    2016-05-01

    The anti-Vibrio activity of essential oils (EOs) of nine medicinal plants was tested against 28 Vibrio spp. isolated from diseased Fenneropenaeus indicus. EO of Nigella sativa exhibited anti-Vibrio activity against all Vibrio spp. and greater inhibition was noted for the isolate V2 which was identified as Vibrio parahaemolyticus Dahv2. Further, EO of N. sativa effectively inhibited V. parahaemolyticus Dahv2 with an inhibition zone of 23.9mm at 101.2μgml(-1). Moreover, EO of N. sativa revealed anti-biofilm activity at 101.2μgml(-1) against V. parahaemolyticus Dahv2 and inhibited the growth of V. parahaemolyticus Dahv2 at 100μgml(-1).In vivo experimental infection studies showed that the survival of Artemia spp. infected with V. parahaemolyticus Dahv2 at 1×10(3)cfuml(-1) was only 40%. However, the survival of Artemia spp. was significantly increased after challenge with 100μgml(-1) of EO of N. sativa. EO of N. sativa showed higher anti-oxidant potential and total phenol content than other EOs tested. The anti-oxidant activity of EO of N. sativa was highly correlated to their total phenolic contents (r=0.836, P<0.05). This observation suggests that EO of N. sativa protected the Artemia spp. after experimental infection of V. parahaemolyticus Dahv2. PMID:26945773

  18. Estimating Bacterial Pathogen Levels in New Zealand Bulk Tank Milk.

    Science.gov (United States)

    Marshall, J C; Soboleva, T K; Jamieson, P; French, N P

    2016-05-01

    Zoonotic bacteria such as Campylobacter, Listeria, and Shiga toxin-producing Escherichia coli have been found in bulk tank milk in many countries, and the consumption of raw milk has been implicated in outbreaks of disease in New Zealand. Fecal contamination at milking is probably the most common source of pathogenic bacteria in bulk tank milk. Raw milk was collected from 80 New Zealand dairy farms during 2011 and 2012 and tested periodically for Campylobacter, E. coli O157, Listeria monocytogenes, and Salmonella. Milk quality data such as coliform counts, total bacterial counts, and somatic cell counts also were collected. By treating the total bacterial count as a proxy for fecal contamination of milk and utilizing farm and animal level prevalence and shedding rates of each pathogen, a predictive model for the level of pathogenic bacteria in bulk tank raw milk was developed. The model utilizes a mixture distribution to combine the low level of contamination inherent in the milking process with isolated contamination events associated with significantly higher pathogen levels. By simulating the sampling and testing process, the predictive model was validated against the observed prevalence of each pathogen in the survey. The predicted prevalence was similar to the observed prevalence for E. coli O157 and Salmonella, although the predicted prevalence was higher than that observed in samples tested for Campylobacter. PMID:27296424

  19. Acetone Formation in the Vibrio Family: a New Pathway for Bacterial Leucine Catabolism

    OpenAIRE

    Nemecek-Marshall, Michele; Wojciechowski, Cheryl; William P. Wagner; Fall, Ray

    1999-01-01

    There is current interest in biological sources of acetone, a volatile organic compound that impacts atmospheric chemistry. Here, we determined that leucine-dependent acetone formation is widespread in the Vibrionaceae. Sixteen Vibrio isolates, two Listonella species, and two Photobacterium angustum isolates produced acetone in the presence of l-leucine. Shewanella isolates produced much less acetone. Growth of Vibrio splendidus and P. angustum in a fermentor with controlled aeration revealed...

  20. Exposure to the Paralytic Shellfish Toxin Producer Alexandrium catenella Increases the Susceptibility of the Oyster Crassostrea gigas to Pathogenic Vibrios.

    Science.gov (United States)

    Abi-Khalil, Celina; Lopez-Joven, Carmen; Abadie, Eric; Savar, Veronique; Amzil, Zouher; Laabir, Mohamed; Rolland, Jean-Luc

    2016-01-01

    The multifactorial etiology of massive Crassostrea gigas summer mortalities results from complex interactions between oysters, opportunistic pathogens and environmental factors. In a field survey conducted in 2014 in the Mediterranean Thau Lagoon (France), we evidenced that the development of the toxic dinoflagellate Alexandrium catenella, which produces paralytic shellfish toxins (PSTs), was concomitant with the accumulation of PSTs in oyster flesh and the occurrence of C. gigas mortalities. In order to investigate the possible role of toxic algae in this complex disease, we experimentally infected C. gigas oyster juveniles with Vibrio tasmaniensis strain LGP32, a strain associated with oyster summer mortalities, after oysters were exposed to Alexandrium catenella. Exposure of oysters to A. catenella significantly increased the susceptibility of oysters to V. tasmaniensis LGP32. On the contrary, exposure to the non-toxic dinoflagellate Alexandrium tamarense or to the haptophyte Tisochrysis lutea used as a foraging alga did not increase susceptibility to V. tasmaniensis LGP32. This study shows for the first time that A. catenella increases the susceptibility of Crassostrea gigas to pathogenic vibrios. Therefore, in addition to complex environmental factors explaining the mass mortalities of bivalve mollusks, feeding on neurotoxic dinoflagellates should now be considered as an environmental factor that potentially increases the severity of oyster mortality events. PMID:26784228

  1. Exposure to the Paralytic Shellfish Toxin Producer Alexandrium catenella Increases the Susceptibility of the Oyster Crassostrea gigas to Pathogenic Vibrios

    Directory of Open Access Journals (Sweden)

    Celina Abi-Khalil

    2016-01-01

    Full Text Available The multifactorial etiology of massive Crassostrea gigas summer mortalities results from complex interactions between oysters, opportunistic pathogens and environmental factors. In a field survey conducted in 2014 in the Mediterranean Thau Lagoon (France, we evidenced that the development of the toxic dinoflagellate Alexandrium catenella, which produces paralytic shellfish toxins (PSTs, was concomitant with the accumulation of PSTs in oyster flesh and the occurrence of C. gigas mortalities. In order to investigate the possible role of toxic algae in this complex disease, we experimentally infected C. gigas oyster juveniles with Vibrio tasmaniensis strain LGP32, a strain associated with oyster summer mortalities, after oysters were exposed to Alexandrium catenella. Exposure of oysters to A. catenella significantly increased the susceptibility of oysters to V. tasmaniensis LGP32. On the contrary, exposure to the non-toxic dinoflagellate Alexandrium tamarense or to the haptophyte Tisochrysis lutea used as a foraging alga did not increase susceptibility to V. tasmaniensis LGP32. This study shows for the first time that A. catenella increases the susceptibility of Crassostrea gigas to pathogenic vibrios. Therefore, in addition to complex environmental factors explaining the mass mortalities of bivalve mollusks, feeding on neurotoxic dinoflagellates should now be considered as an environmental factor that potentially increases the severity of oyster mortality events.

  2. Importance of prophages to evolution and virulence of bacterial pathogens.

    Science.gov (United States)

    Fortier, Louis-Charles; Sekulovic, Ognjen

    2013-07-01

    Bacteriophages, or simply phages, are viruses infecting bacteria. With an estimated 10 ( 31) particles in the biosphere, phages outnumber bacteria by a factor of at least 10 and not surprisingly, they influence the evolution of most bacterial species, sometimes in unexpected ways. "Temperate" phages have the ability to integrate into the chromosome of their host upon infection, where they can reside as "quiescent" prophages until conditions favor their reactivation. Lysogenic conversion resulting from the integration of prophages encoding powerful toxins is probably the most determinant contribution of prophages to the evolution of pathogenic bacteria. We currently grasp only a small fraction of the total phage diversity. Phage biologists keep unraveling novel mechanisms developed by phages to parasitize their host. The purpose of this review is to give an overview of some of the various ways by which prophages change the lifestyle and boost virulence of some of the most dangerous bacterial pathogens. PMID:23611873

  3. Defining pathogenic bacterial species in the genomic era

    OpenAIRE

    DidierRaoult

    2011-01-01

    Actual definitions of bacterial species are limited due to the current criteria of definition and the use of restrictive genetic tools. The 16S rRNA sequence, for example, has been widely used as a marker for phylogenetic analyses; however, its use often leads to misleading species definitions. According to the first genetic studies, removing a certain number of genes from pathogenic bacteria removes their capacity to infect hosts. However, more recent studies have demonstrated that the speci...

  4. Autophagic clearance of bacterial pathogens: molecular recognition of intracellular microorganisms

    OpenAIRE

    Mansilla Pareja, Maria Eugenia; Colombo, Maria I

    2013-01-01

    Autophagy is involved in several physiological and pathological processes. One of the key roles of the autophagic pathway is to participate in the first line of defense against the invasion of pathogens, as part of the innate immune response. Targeting of intracellular bacteria by the autophagic machinery, either in the cytoplasm or within vacuolar compartments, helps to control bacterial proliferation in the host cell, controlling also the spreading of the infection. In this review we will d...

  5. A Two-Tube Multiplex Reverse Transcription PCR Assay for Simultaneous Detection of Viral and Bacterial Pathogens of Infectious Diarrhea

    Directory of Open Access Journals (Sweden)

    Ji Wang

    2014-01-01

    Full Text Available Diarrhea caused by viral and bacterial infections is a major health problem in developing countries. The purpose of this study is to develop a two-tube multiplex PCR assay using automatic electrophoresis for simultaneous detection of 13 diarrhea-causative viruses or bacteria, with an intended application in provincial Centers for Diseases Control and Prevention, China. The assay was designed to detect rotavirus A, norovirus genogroups GI and GII, human astrovirus, enteric adenoviruses, and human bocavirus (tube 1, and Salmonella, Vibrio parahaemolyticus, diarrheagenic Escherichia coli, Campylobacter jejuni, Shigella, Yersinia, and Vibrio cholera (tube 2. The analytical specificity was examined with positive controls for each pathogen. The analytical sensitivity was evaluated by performing the assay on serial tenfold dilutions of in vitro transcribed RNA, recombinant plasmids, or bacterial culture. A total of 122 stool samples were tested by this two-tube assay and the results were compared with those obtained from reference methods. The two-tube assay achieved a sensitivity of 20–200 copies for a single virus and 102-103 CFU/mL for bacteria. The clinical performance demonstrated that the two-tube assay had comparable sensitivity and specificity to those of reference methods. In conclusion, the two-tube assay is a rapid, cost-effective, sensitive, specific, and high throughput method for the simultaneous detection of enteric bacteria and virus.

  6. Probiotic modulation of the gut bacterial community of juvenile Litopenaeus vannamei challenged with Vibrio parahaemolyticus CAIM 170

    Directory of Open Access Journals (Sweden)

    Irasema E Luis-Villaseñor

    2015-09-01

    Full Text Available The protective effects of two probiotic mixtures was studied using the fingerprints of the bacterial community of Litopenaeus vannamei juveniles exposed to probiotics and challenged with Vibrio parahaemolyticus CAIM 170. Fingerprints were constructed using 16S rRNA gene and the PCR-SSCP (Single strand conformation polymorphism technique, and the probiotics used were an experimental Bacillus mixture (Bacillus tequilensis YC5-2 + B. endophyticus C2-2 and YC3-B and the commercial probiotic Alibio. The DNA for PCR-SSCP analyses was extracted directly from the guts of shrimps treated for 20 days with the probiotics and injected with 2.5*10(5 CFU g-1 of V. parahaemolyticus one week after suspension of the probiotic treatment. Untreated shrimps served as positive (injected with V. parahaemolyticus and negative (not injected controls Analysis of the bacterial community carried out after inoculation and 12 and 48 h later confirmed that V. parahaemolyticus was present in shrimps of the positive control , but not in the negative control or treated with the probiotic mixtures. A significant difference in the diversity of the bacterial community was observed between times after infection. The band patterns in 0-12 h were clustered into a different group from that determined after 48 h, and suggested that during bacterial infection the guts of whiteleg shrimp were dominated by gamma proteobacteria represented by Vibrio sp. and Photobacterium sp. Our results indicate that the experimental and the commercial mixtures are suitable to modulate the bacterial community of L. vannamei and could be used as a probiotic to control vibriosis in juvenile shrimp.

  7. Cutaneous bacterial species from Lithobates catesbeianus can inhibit pathogenic dermatophytes.

    Science.gov (United States)

    Lauer, Antje; Hernandez, Trang

    2015-04-01

    Antibiotics are being successfully used to fight many infectious diseases caused by pathogenic microorganisms. However, new infectious diseases are continuously being identified, and some known pathogens are becoming resistant against known antibiotics. Furthermore, many antifungals are causing serious side effects in long-term treatments of patients, and many skin infections caused by dermatophytes are difficult to cure. The beneficial roles of resident cutaneous microbiota to inhibit pathogenic microorganisms have been shown for many vertebrate species. Microbial symbionts on the amphibian skin for example can be a source of powerful antimicrobial metabolites that can protect amphibians against diseases, such as chytridiomycosis, caused by a fungal pathogen. In this research, we investigated whether cutaneous bacterial species isolated from Lithobates catesbeianus (North American bullfrog), an invasive amphibian species that is resistant to chytridiomycosis, produce secondary metabolites that can be used to inhibit the growth of three species of dermatophytes (Microsporum gypseum, Epidermophyton floccosum, and Trichophyton mentagrophytes) which are known to cause topical or subdermal skin infections in humans. Strongly anti-dermatophyte bacterial species that belonged to the Bacillaceae, Streptomycetaceae, Pseudomonadaceae, Xanthomonadaceae, Aeromonadaceae, and Enterobacteriaceae were identified. This research has provided evidence of the presence of cutaneous anti-dermatophyte bacteria from L. catesbeianus which might provide a basis for health care providers to experiment with new antifungals in the future. PMID:25431089

  8. Determination of Contamination Profiles of Human Bacterial Pathogens in Shrimp Obtained from Java, Indonesia

    International Nuclear Information System (INIS)

    Shrimp continues to be an important export commodity for Indonesia and contributed significantly to the country’s revenue. However, shrimp exports have been frequently rejected by importing countries due to filth, Salmonella and insanitary conditions. This study was conducted to evaluate the profiles of bacterial contamination of ocean and aquaculture shrimp obtained from the area of West, Central and East Java; frozen shrimp and shrimp during industry production of frozen shrimp. The study indicated that both ocean and aquaculture shrimp obtained from the study area were heavily contaminated. On the average, shrimp obtained from West Java were more contaminated than those obtained from East and Central Java. The total bacterial counts were generally higher in ocean shrimp than those of aquaculture ones. Salmonella was present in two of 32 samples of ocean shrimp and in four of 32 samples of aquaculture shrimp obtained from the study area. Vibrio cholerae was not detected in shrimp from West Java, but was found in three out of 16 samples obtained from East and Central Java. V. parahaemolyticus was frequently identified in aquaculture shrimp but absent in fresh ocean shrimp. Studies on shrimp collected from six sampling points during frozen shrimp production revealed that processing will reduce the number of total bacterial, E. coli, and Staphylococal counts. However, the processing did not effectively reduce the incidence of Salmonella or V. parahaemolyticus when the raw material has been contaminated with the pathogens. Sizing and grading as well as arrangement of shrimp before freezing were considered as the critical points where bacteria should be controlled to inhibit growth and cross contamination with bacteria such as Listeria. Implementation of Good Agricultural Practices in production of raw shrimp as well as Hazard Analysis Critical Control Point at the line processing are expected to improve the quality of fresh and frozen shrimp. (author)

  9. Identification of a bacterial pathogen associated with Porites white patch syndrome in the Western Indian Ocean.

    Science.gov (United States)

    Séré, Mathieu G; Tortosa, Pablo; Chabanet, Pascale; Quod, Jean-Pascal; Sweet, Michael J; Schleyer, Michael H

    2015-09-01

    Porites white patch syndrome (PWPS) is a coral disease recently described in the Western Indian Ocean. This study aimed to isolate and identify potential pathogens associated with PWPS utilizing both culture and nonculture screening techniques and inoculation trials. A total of 14 bacterial strains (those dominant in disease lesions, absent or rare in healthy tissues and considered potential pathogens in a previous study) were cultured and used to experimentally inoculate otherwise healthy individuals in an attempt to fulfil Henle-Koch's postulates. However, only one (P180R), identified as closely related (99-100% sequence identity based on 1.4 kb 16S RNA sequence) to Vibrio tubiashii, elicited signs of disease in tank experiments. Following experimental infection (which resulted in a 90% infection rate), the pathogen was also successfully re-isolated from the diseased tissues and re-inoculated in healthy corals colonies, therefore fulfilling the final stages of Henle-Koch's postulates. Finally, we report that PWPS appears to be a temperature-dependent disease, with significantly higher tissue loss (anova: d.f. = 2, F = 39.77, P < 0.01) occurring at 30 °C [1.45 ± 0.85 cm(2) per day (mean ± SE)] compared to ambient temperatures of 28 and 26 °C (0.73 ± 0.80 cm(2) per day (mean ± SE) and 0.51 ± 0.50 cm(2) per day (mean ± SE), respectively). PMID:26193772

  10. Detection of bacterial pathogens in environmental samples using DNA microarrays.

    Science.gov (United States)

    Call, Douglas R; Borucki, Monica K; Loge, Frank J

    2003-05-01

    Polymerase chain reaction (PCR) is an important tool for pathogen detection, but historically, it has not been possible to accurately identify PCR products without sequencing, Southern blots, or dot-blots. Microarrays can be coupled with PCR where they serve as a set of parallel dot-blots to enhance product detection and identification. Microarrays are composed of many discretely located probes on a solid substrate such as glass. Each probe is composed of a sequence that is complimentary to a pathogen-specific gene sequence. PCR is used to amplify one or more genes and the products are then hybridized to the array to identify species-specific polymorphism within one or more genes. We illustrate this type of array using 16S rDNA probes suitable for distinguishing between several salmonid pathogens. We also describe the use of microarrays for direct detection of either RNA or DNA without the aid of PCR, although the sensitivity of these systems currently limits their application for pathogen detection. Finally, microarrays can also be used to "fingerprint" bacterial isolates and they can be used to identify diagnostic markers suitable for developing new PCR-based detection assays. We illustrate this type of array for subtyping an important food-borne pathogen, Listeria monocytogenes. PMID:12654494

  11. Molecular Detection of Common Bacterial Pathogens Causing Meningitis

    Directory of Open Access Journals (Sweden)

    H Sadighian

    2009-03-01

    Full Text Available "nBackground: The clinical diagnosis of meningitis is crucial, particularly in children. The early diagnosis and empiric an­tibi­otic treatments have led to a reduction in morbidity and mortality rates. PCR and the enzymatic digestion of 16SrDNA frag­ment which is produced by universal primers led up fast and sensitive determination. The purpose of this study was to investi­gate a rapid method for detection of common bacterial pathogens causing meningitis."nMethods: According to the gene encoding 16SrDNA found in all bacteria, a pair of primers was designed. Then the univer­sal PCR was performed for bacterial agents of meningitis (Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influ­enzae, etc. by employing broad- range DNA extraction method. The ob­tained uni­versal PCR products were digested with restriction enzymes (HaeIII, AluI and MnlI to identify bacterial species. "nResults: By the enzymatic digestion of the universal products of each standard strain of the above bacteria, specific patterns were achieved. These specific patterns may be used for comparison in CSF examination. The analytical sensitivity of the as­say was approximately 1.5´102 CFU/ml of CSF even in samples with high amount of proteins. Conclusion: The universal PCR coupled with enzymatic digestion can be used to detect and identify bacterial pathogens in clini­cal specimens rapidly and accurately. Molecular diagnostic of bacterial meningitis, though expensive and labor-inten­sive, but is valuable and critical in patient management.

  12. Genome Assembly and Computational Analysis Pipelines for Bacterial Pathogens

    KAUST Repository

    Rangkuti, Farania Gama Ardhina

    2011-06-01

    Pathogens lie behind the deadliest pandemics in history. To date, AIDS pandemic has resulted in more than 25 million fatal cases, while tuberculosis and malaria annually claim more than 2 million lives. Comparative genomic analyses are needed to gain insights into the molecular mechanisms of pathogens, but the abundance of biological data dictates that such studies cannot be performed without the assistance of computational approaches. This explains the significant need for computational pipelines for genome assembly and analyses. The aim of this research is to develop such pipelines. This work utilizes various bioinformatics approaches to analyze the high-­throughput genomic sequence data that has been obtained from several strains of bacterial pathogens. A pipeline has been compiled for quality control for sequencing and assembly, and several protocols have been developed to detect contaminations. Visualization has been generated of genomic data in various formats, in addition to alignment, homology detection and sequence variant detection. We have also implemented a metaheuristic algorithm that significantly improves bacterial genome assemblies compared to other known methods. Experiments on Mycobacterium tuberculosis H37Rv data showed that our method resulted in improvement of N50 value of up to 9697% while consistently maintaining high accuracy, covering around 98% of the published reference genome. Other improvement efforts were also implemented, consisting of iterative local assemblies and iterative correction of contiguated bases. Our result expedites the genomic analysis of virulent genes up to single base pair resolution. It is also applicable to virtually every pathogenic microorganism, propelling further research in the control of and protection from pathogen-­associated diseases.

  13. Simultaneous detection of six diarrhea-causing bacterial pathogens with an in-house PCR-luminex assay.

    Science.gov (United States)

    Liu, Jie; Gratz, Jean; Maro, Athanasia; Kumburu, Happy; Kibiki, Gibson; Taniuchi, Mami; Howlader, Arif Mahmud; Sobuz, Shihab U; Haque, Rashidul; Talukder, Kaisar A; Qureshi, Shahida; Zaidi, Anita; Haverstick, Doris M; Houpt, Eric R

    2012-01-01

    Diarrhea can be caused by a range of pathogens, including several bacteria. Conventional diagnostic methods, such as culture, biochemical tests, and enzyme-linked immunosorbent assay (ELISA), are laborious. We developed a 7-plex PCR-Luminex assay to simultaneously screen for several of the major diarrhea-causing bacteria directly in fecal specimens, including pathogenic Aeromonas, Campylobacter jejuni, Campylobacter coli, Salmonella, Shigella, enteroinvasive Escherichia coli (EIEC), Vibrio, and Yersinia. We included an extrinsic control to verify extraction and amplification. The assay was first validated with reference strains or isolates and exhibited a limit of detection of 10(3) to 10(5) CFU/g of stool for each pathogen as well as quantitative detection up to 10(9) CFU/g. A total of 205 clinical fecal specimens from individuals with diarrhea, previously cultured for enteric pathogens and tested for Campylobacter by ELISA, were evaluated. Using these predicate methods as standards, sensitivities and specificities of the PCR-Luminex assay were 89% and 94% for Aeromonas, 89% and 93% for Campylobacter, 96% and 95% for Salmonella, 94% and 94% for Shigella, 92% and 97% for Vibrio, and 100% and 100% for Yersinia, respectively. All discrepant results were further examined by singleplex real-time PCR assays targeting different gene regions, which revealed 89% (55/62 results) concordance with the PCR-Luminex assay. The fluorescent signals obtained with this approach exhibited a statistically significant correlation with the cycle threshold (C(T)) values from the cognate real-time PCR assays (P PCR-Luminex assay enables sensitive, specific, and quantitative detection of the major bacterial causes of gastroenteritis. PMID:22075596

  14. Highly Potent, Chemically Stable Quorum Sensing Agonists for Vibrio Cholerae

    OpenAIRE

    Perez, Lark J; Karagounis, Theodora K.; Hurley, Amanda; Bassler, Bonnie L.; Semmelhack, Martin F.

    2013-01-01

    In the Vibrio cholerae pathogen, initiation of bacterial quorum sensing pathways serves to suppress virulence. We describe herein a potent and chemically stable small molecule agonist of V. cholerae quorum sensing, which was identified through rational drug design based on the native quorum sensing signal. This novel agonist may serve as a useful lead compound for the control of virulence in V. cholerae.

  15. Antibacterial Property of a Coral-Associated Bacterium Pseudoalteromonas luteoviolacea Against Shrimp Pathogenic Vibrio harveyi (In Vitro Study

    Directory of Open Access Journals (Sweden)

    OCKY KARNA RADJASA

    2005-06-01

    Full Text Available A coral-associated bacterium was successfully screened for secondary metabolites production based on PCR amplification of the nonribosomal peptide synthetase gene and was identified as closely related to Pseudoalteromonas luteoviolacea based on its 16S rDNA.The bacterium was found to inhibit the growth of shrimp pathogenic bacterium tested, Vibrio harveyi. To characterize the inhibiting metabolite, a 279 bp long DNA fragment was obtained and the deduced amino acid sequence showed conserved signature regions for peptide synthetases and revealed a high similarity to NosD (40% identity, a multifunctional peptide synthetase from Nostoc sp. GSV224, and NdaB (44% identity, a peptide synthetase module of Nodularia spumigena.

  16. DNA cloning, characterization, and inhibition studies of an α-carbonic anhydrase from the pathogenic bacterium Vibrio cholerae.

    Science.gov (United States)

    Del Prete, Sonia; Isik, Semra; Vullo, Daniela; De Luca, Viviana; Carginale, Vincenzo; Scozzafava, Andrea; Supuran, Claudiu T; Capasso, Clemente

    2012-12-13

    We have cloned, purified, and characterized an α-carbonic anhydrase (CA, EC 4.2.1.1) from the human pathogenic bacterium Vibrio cholerae, VchCA. The new enzyme has significant catalytic activity, and an inhibition study with sulfonamides and sulfamates led to the detection of a large number of low nanomolar inhibitors, among which are methazolamide, acetazolamide, ethoxzolamide, dorzolamide, brinzolamide, benzolamide, and indisulam (KI values in the range 0.69-8.1 nM). As bicarbonate is a virulence factor of this bacterium and since ethoxzolamide was shown to inhibit the in vivo virulence, we propose that VchCA may be a target for antibiotic development, exploiting a mechanism of action rarely considered until now. PMID:23181552

  17. Ceftaroline activity tested against contemporary Latin American bacterial pathogens (2011

    Directory of Open Access Journals (Sweden)

    Robert K. Flamm

    2014-04-01

    Full Text Available A total of 2484 target bacterial pathogens were collected (one per patient episode from patients in 16 Latin American medical centers located in seven nations during 2011. Isolate identity was confirmed at a coordinating laboratory and susceptibility testing was performed for ceftaroline and comparator agents according to reference broth microdilution methods. A total of 30.0% of isolates were from respiratory tract, 29.4% from skin and skin structure, 21.4% from blood stream, 7.9% from urinary tract and 11.3% from other sites. Ceftaroline was active againstStaphylococcus aureus (42.8% MRSA with 83.6% of the isolates at 90.0% of the non-ESBL-phenotype. The spectrum of activity of ceftaroline against pathogens from Latin America indicates that it merits further study for its potential use in the Latin American region.

  18. Pathotypes of Bacterial Spot Pathogen Infecting Capsicum Peppers in Korea

    OpenAIRE

    Wai, Khin Pa Pa; Siddique, Muhammad Irfan; Mo, Hwang-Sung; Yoo, Hee Ju; Byeon, Si-Eun; Jegal, Yoonhyuk; Mekuriaw, Alebel A.; Kim, Byung-Soo

    2015-01-01

    Sixty-seven isolates of bacterial spot pathogen (Xanthomonas spp.) collected from six provinces of Korea were tested for the identification of their pathotypes and determination of their distribution throughout Korea in an effort to genetically manage the disease. Near isogenic lines of Early Calwonder (Capsicum annuum) pepper plants carrying Bs1 , Bs2 and Bs3 , and PI235047 (C. pubescens) were used as differential hosts. Race P1 was found to be predominant, followed by race P7, and races P3 ...

  19. A bacterial pathogen infecting gametophytes of Saccharina japonica (Laminariales, Phaeophyceae)

    Institute of Scientific and Technical Information of China (English)

    PENG Yanting; LI Wei

    2013-01-01

    A newly identified bacterial disease of kelp (Saccharinajaponica) gametophytes was found in clone cultures.It is characterized by swollen gametophyte cells in the early period of infection followed by filamentous fading.An alginolytic marine bacterium referred to as A-1 was isolated from the diseased gametophytes.On the basis of 16S rDNA sequencing and morphological,physiological and biochemical characteristics,the bacterium was identified as a strain of the genus Alteromonas.By testing Koch's postulates,Alteromonas sp.A-1 was further confirmed as the pathogen.The infection process was also investigated using both scanning electron and light microscopy.

  20. Microbiological food safety issues in Brazil: bacterial pathogens.

    Science.gov (United States)

    Gomes, Bruna Carrer; Franco, Bernadette Dora Gombossy de Melo; De Martinis, Elaine Cristina Pereira

    2013-03-01

    The globalization of food supply impacts patterns of foodborne disease outbreaks worldwide, and consumers are having increased concern about microbiological food safety. In this sense, the assessment of epidemiological data of foodborne diseases in different countries has not only local impact, but it can also be of general interest, especially in the case of major global producers and exporters of several agricultural food products, such as Brazil. In this review, the most common agents of foodborne illnesses registered in Brazil will be presented, compiled mainly from official databases made available to the public. In addition, some representative examples of studies on foodborne bacterial pathogens commonly found in Brazilian foods are provided. PMID:23489044

  1. Characterization of DegQVh, a Serine Protease and a Protective Immunogen from a Pathogenic Vibrio harveyi Strain▿ †

    Science.gov (United States)

    Zhang, Wei-wei; Sun, Kun; Cheng, Shuang; Sun, Li

    2008-01-01

    Vibrio harveyi is an important marine pathogen that can infect a number of aquaculture species. V. harveyi degQ (degQVh), the gene encoding a DegQ homologue, was cloned from T4, a pathogenic V. harveyi strain isolated from diseased fish. DegQVh was closely related to the HtrA family members identified in other Vibrio species and could complement the temperature-sensitive phenotype of an Escherichia coli strain defective in degP. Expression of degQVh in T4 was modulated by temperature, possibly through the σE-like factor. Enzymatic analyses demonstrated that the recombinant DegQVh protein expressed in and purified from E. coli was an active serine protease whose activity required the integrity of the catalytic site and the PDZ domains. The optimal temperature and pH of the recombinant DegQVh protein were 50°C and pH 8.0. A vaccination study indicated that the purified recombinant DegQVh was a protective immunogen that could confer protection upon fish against infection by V. harveyi. In order to improve the efficiency of DegQVh as a vaccine, a genetic construct in the form of the plasmid pAQ1 was built, in which the DNA encoding the processed DegQVh protein was fused with the DNA encoding the secretion region of AgaV, an extracellular β-agarase. The E. coli strain harboring pAQ1 could express and secrete the chimeric DegQVh protein into the culture supernatant. Vaccination of fish with viable E. coli expressing chimeric degQVh significantly (P < 0.001) enhanced the survival of fish against V. harveyi challenge, which was possibly due to the relatively prolonged exposure of the immune system to the recombinant antigen produced constitutively, albeit at a gradually decreasing level, by the carrier strain. PMID:18723647

  2. Resistance to Antimicrobial Peptides in Vibrios

    Directory of Open Access Journals (Sweden)

    Delphine Destoumieux-Garzón

    2014-10-01

    Full Text Available Vibrios are associated with a broad diversity of hosts that produce antimicrobial peptides (AMPs as part of their defense against microbial infections. In particular, vibrios colonize epithelia, which function as protective barriers and express AMPs as a first line of chemical defense against pathogens. Recent studies have shown they can also colonize phagocytes, key components of the animal immune system. Phagocytes infiltrate infected tissues and use AMPs to kill the phagocytosed microorganisms intracellularly, or deliver their antimicrobial content extracellularly to circumvent tissue infection. We review here the mechanisms by which vibrios have evolved the capacity to evade or resist the potent antimicrobial defenses of the immune cells or tissues they colonize. Among their strategies to resist killing by AMPs, primarily vibrios use membrane remodeling mechanisms. In particular, some highly resistant strains substitute hexaacylated Lipid A with a diglycine residue to reduce their negative surface charge, thereby lowering their electrostatic interactions with cationic AMPs. As a response to envelope stress, which can be induced by membrane-active agents including AMPs, vibrios also release outer membrane vesicles to create a protective membranous shield that traps extracellular AMPs and prevents interaction of the peptides with their own membranes. Finally, once AMPs have breached the bacterial membrane barriers, vibrios use RND efflux pumps, similar to those of other species, to transport AMPs out of their cytoplasmic space.

  3. Design of Vibrio 16S rRNA Gene Specific Primers and Their Application in the Analysis of Seawater Vibrio Community

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; YANG Guanpin; WANG Hualei; CHEN Jixiang; SHI Xianming; ZOU Guiwei; WEI Qiwei; SUN Xiuqin

    2006-01-01

    The pathogenic species of genus Vibrio cause vibriosis, one of the most prevalent diseases of maricultured animals and seafood consumers. Monitoring their kinetics in the chain of seafood production, processing and consumption is of great importance for food and mariculture safety. In order to enrich Vibrio-representing 16S ribosomal RNA gene (rDNA) fragments and identify these bacteria further real-timely and synchronously among bacterial flora in the chain, a pair of primers that selectively amplify Vibrio 16S rDNA fragments were designed with their specificities and coverage testified in the analysis of seawater Vibrio community. The specificities and coverage of two primers, VF169 and VR744, were determined theoretically among bacterial 16S rDNAs available in GenBank by using BLAST program and practically by amplifying Vibrio 16S rDNA fragments from seawater DNA. More than 88.3% of sequences in GenBank, which showed identical matches with VR744, belong to Vibrio genus. A total of 33 clones were randomly selected and sequenced. All of the sequences showed their highest similarities to and clustered around those of diverse known Vibrio species. The primers designed are capable of retrieving a wide range of Vibrio 16S rDNA fragments specifically among bacterial flora in seawater, the most important natural environment of seafood cultivation.

  4. Antibacterial effect of Costus spiralis leaves extract on pathogenic strains of Vibrio cholerae

    Directory of Open Access Journals (Sweden)

    Celso Pérez

    2008-01-01

    pueden ser extraídos y purificados a partir de plantas para el desarrollo de nuevos medicamentos. Entre las diversas enfermedades que históricamente han afectado al hombre, el cólera ha sido potencialmente epidémico y una de las más sobresalientes. La bacteria Vibrio cholerae, el agente causal, puede ser eliminado mediante antibióticos, de modo que además del tratamiento tradicional de la enfermedad de rehidratación vía oral o intravenosa, comúnmente son aplicados antibióticos tales como la tetraciclina, ciprofloxacina, norfloxacina o azitromicina. El efecto antimicrobiano in vitro de extractos de hojas de Costus spiralis (Roscoe sobre varias cepas patógenas de Vibrio cholerae fue ensayado mediante la técnica de difusión en placas de agar. Hojas verdes de la plantas fueron colectadas, secadas en horno a 50 ºC durante 48 h, molidas y finalmente, sometidas a extracción con etanol. Luego de secado, el material residual fue resuspendido en agua destilada a 100 mg/mL (p/v y realizados los ensayos de actividad antimicrobiana. Aparentemente, las cepas patógenas que representan las pandemias del siglo xx: C7258 (O1, El Tor, Ogawa, C6706 (O1, El Tor, Inaba, O395 (O1, Clásica, Ogawa, CRC266 (O139 y 569B (O1, Clásica, Inaba fueron matadas, a juzgar por la presencia de halos de inhibición de crecimiento en los ensayos. Adicionalmente, se eterminaron las concentraciones mínimas inhibitorias de los extractos para las diferentes cepas. Los resultados anteriores fueron similares a los de la Ampicillina, lo que sugiere que Costus spiralis pude utilizarse como fuente de principios activos contra Vibrio cholerae.

  5. Application of photostable quantum dots for indirect immunofluorescent detection of specific bacterial serotypes on small marine animals

    Energy Technology Data Exchange (ETDEWEB)

    Decho, Alan W; Beckman, Erin M; Chandler, G Thomas; Kawaguchi, Tomohiro [Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208 (United States)

    2008-06-11

    An indirect immunofluorescence approach was developed using semiconductor quantum dot nanocrystals to label and detect a specific bacterial serotype of the bacterial human pathogen Vibrio parahaemolyticus, attached to small marine animals (i.e. benthic harpacticoid copepods), which are suspected pathogen carriers. This photostable labeling method using nanotechnology will potentially allow specific serotypes of other bacterial pathogens to be detected with high sensitivity in a range of systems, and can be easily applied for sensitive detection to other Vibrio species such as Vibrio cholerae.

  6. Application of photostable quantum dots for indirect immunofluorescent detection of specific bacterial serotypes on small marine animals

    Science.gov (United States)

    Decho, Alan W.; Beckman, Erin M.; Chandler, G. Thomas; Kawaguchi, Tomohiro

    2008-06-01

    An indirect immunofluorescence approach was developed using semiconductor quantum dot nanocrystals to label and detect a specific bacterial serotype of the bacterial human pathogen Vibrio parahaemolyticus, attached to small marine animals (i.e. benthic harpacticoid copepods), which are suspected pathogen carriers. This photostable labeling method using nanotechnology will potentially allow specific serotypes of other bacterial pathogens to be detected with high sensitivity in a range of systems, and can be easily applied for sensitive detection to other Vibrio species such as Vibrio cholerae.

  7. Application of photostable quantum dots for indirect immunofluorescent detection of specific bacterial serotypes on small marine animals

    International Nuclear Information System (INIS)

    An indirect immunofluorescence approach was developed using semiconductor quantum dot nanocrystals to label and detect a specific bacterial serotype of the bacterial human pathogen Vibrio parahaemolyticus, attached to small marine animals (i.e. benthic harpacticoid copepods), which are suspected pathogen carriers. This photostable labeling method using nanotechnology will potentially allow specific serotypes of other bacterial pathogens to be detected with high sensitivity in a range of systems, and can be easily applied for sensitive detection to other Vibrio species such as Vibrio cholerae

  8. Engineered bacterial communication prevents Vibrio cholerae virulence in an infant mouse model

    OpenAIRE

    Duan, Faping; March, John C.

    2010-01-01

    To investigate the possibility of using commensal bacteria as signal mediators for inhibiting the disease cholera, we stably transformed Escherichia coli Nissle 1917 (Nissle) to express the autoinducer molecule cholera autoinducer 1 (CAI-1) (shown previously to prevent virulence when present with another signaling molecule, autoinducer 2, at high concentrations) and determined the effect on Vibrio cholerae virulence gene expression and colonization in an infant mouse model. We found that pret...

  9. Acetone formation in the Vibrio family: a new pathway for bacterial leucine catabolism.

    Science.gov (United States)

    Nemecek-Marshall, M; Wojciechowski, C; Wagner, W P; Fall, R

    1999-12-01

    There is current interest in biological sources of acetone, a volatile organic compound that impacts atmospheric chemistry. Here, we determined that leucine-dependent acetone formation is widespread in the Vibrionaceae. Sixteen Vibrio isolates, two Listonella species, and two Photobacterium angustum isolates produced acetone in the presence of L-leucine. Shewanella isolates produced much less acetone. Growth of Vibrio splendidus and P. angustum in a fermentor with controlled aeration revealed that acetone was produced after a lag in late logarithmic or stationary phase of growth, depending on the medium, and was not derived from acetoacetate by nonenzymatic decarboxylation in the medium. L-Leucine, but not D-leucine, was converted to acetone with a stoichiometry of approximately 0.61 mol of acetone per mol of L-leucine. Testing various potential leucine catabolites as precursors of acetone showed that only alpha-ketoisocaproate was efficiently converted by whole cells to acetone. Acetone production was blocked by a nitrogen atmosphere but not by electron transport inhibitors, suggesting that an oxygen-dependent reaction is required for leucine catabolism. Metabolic labeling with deuterated (isopropyl-d(7))-L-leucine revealed that the isopropyl carbons give rise to acetone with full retention of deuterium in each methyl group. These results suggest the operation of a new catabolic pathway for leucine in vibrios that is distinct from the 3-hydroxy-3-methylglutaryl-coenzyme A pathway seen in pseudomonads. PMID:10601206

  10. Meeting report: Adaptation and communication of bacterial pathogens.

    Science.gov (United States)

    Aussel, Laurent; Beuzón, Carmen R; Cascales, Eric

    2016-05-18

    Bacteria usually live in complex environments, sharing niche and resources with other bacterial species, unicellular eukaryotic cells or complex organisms. Thus, they have evolved mechanisms to communicate, to compete and to adapt to changing environment as diverse as human tissues, animals or plants. Understanding the molecular mechanisms underlying these adaptation processes is therefore of primary importance for epidemiology and human health protection, and was the focus of a Current Trends in Biomedicine workshop organized by the International University of Andalucia in late October 2015 in Baeza (Spain). The topic was covered by complementary sessions: (i) interbacterial communication and competition that enable a better access to nutrients or a more efficient colonization of the ecological niche, (ii) adaptation of intracellular pathogens to their host, focusing on metabolic pathways, adaptive mechanisms and populational heterogeneity, and (iii) adaptation of animal and plant pathogens as well as plant-associated bacteria to a plant niche. This workshop emphasized the broad repertoire of mechanisms and factors bacteria have evolved to become efficient pathogens. PMID:26890494

  11. Quorum sensing and bacterial pathogenicity: From molecules to disease

    Directory of Open Access Journals (Sweden)

    Antariksh Deep

    2011-01-01

    Full Text Available Quorum sensing in prokaryotic biology refers to the ability of a bacterium to sense information from other cells in the population when they reach a critical concentration (i.e. a Quorum and communicate with them. The "language" used for this intercellular communication is based on small, self-generated signal molecules called as autoinducers. Quorum sensing is thought to afford pathogenic bacteria a mechanism to minimize host immune responses by delaying the production of tissue-damaging virulence factors until sufficient bacteria have amassed and are prepared to overwhelm host defense mechanisms and establish infection. Quorum sensing systems are studied in a large number of gram-negative bacterial species belonging to α, β, and γ subclasses of proteobacteria. Among the pathogenic bacteria, Pseudomonas aeruginosa is perhaps the best understood in terms of the virulence factors regulated and the role the Quorum sensing plays in pathogenicity. Presently, Quorum sensing is considered as a potential novel target for antimicrobial therapy to control multi/all drug-resistant infections. This paper reviews Quorum sensing in gram positive and gram negative bacteria and its role in biofilm formation.

  12. Bacterial Pathogens of Ventilator Associated Pneumonia in a Tertiary Referral Hospital

    OpenAIRE

    Chi, Su Young; Kim, Tae Ok; Park, Chan Woo; Yu, Jin Yeong; Lee, Boram; Lee, Ho Sung; Kim, Yu Il; Lim, Sung Chul; Kwon, Yong Soo

    2012-01-01

    Background This study evaluates the bacterial pathogens of Ventilator-associated pneumonia (VAP) in a tertiary referral hospital. Methods A total of 109 bacterial pathogens from 91 adult patients with VAP, who were admitted to the medical intensive care unit from January 2008 to December 2009, were examined. Clinical characteristics, bacterial pathogens, and resistance profiles were analyzed. Results Staphylococcus aureus (44%) was the most frequently isolated. Acinetobacter baumanii (30%), P...

  13. Enterobacteria and Vibrio from Macrobrachium amazonicum prawn farming in Fortaleza, Ceará, Brazil

    Institute of Scientific and Technical Information of China (English)

    Manoel de Arajo Neto Paiva; Rossana de Aguiar Cordeiro; Andr Jalles Monteiro; Jos Jlio Costa Sidrim; Marcos Fbio Gadelha Rocha; Jamille Alencar Sales; Glaucia Morgana de Melo Guedes; Yago Brito de Ponte; Clia Maria de Souza Sampaio; Jos Luciano Bezerra Moreira; Lucas Pereira de Alencar

    2016-01-01

    Objective: To investigate the isolation of enterobacteria associated with Macrobrachium amazonicum (M. amazonicum) farming and evaluate the in vitro antimicrobial susceptibility of Vibrio strains. Methods: Strains were isolated from female M. amazonicum prawns and environmental and hatchery water. Biochemical assays were used to identify bacterial genera and those belonging to the genus Vibrio were submitted to further analyses for species identification, through Vitek 2 automated system and serotyping. Susceptibility test was performed according to Clinical Laboratory Standards Institute. Results: The following genera of enterobacteria were recovered: Enterobacter (n=11), Citrobacter (n=10), Proteus (n=2), Serratia (n=2), Kluyvera (n=2), Providencia (n=2), Cedecea (n=1), Escherichia (n=1), Edwardsiella (n=1) and Buttiauxella (n=1). As for Vibrio, three species were identified: Vibrio cholerae non-O1/non-O139 (n=4), Vibrio vulnificus (V. vulnificus) (n=1) and Vibrio mimicus (n=1). Vibrio spp. showed minimum inhibitory concentrations values within the susceptibility range established by Clinical Laboratory Standards Institute for almost all antibiotics, except for V. vulnificus, which presented intermediate profile to ampicillin. Conclusions:Enterobacteria do not seem to be the most important pathogens associated with M. amazonicum farming, whereas the recovery of Vibrio spp. from larviculture, with emphasis on Vibrio cholerae and V. vulnificus, deserves special attention due to their role as potentially zoonotic aquaculture-associated pathogens. Furthermore, the intermediate susceptibility of V. vulnificus to ampicillin reflects the importance of monitoring drug use in prawn farming.

  14. Infection of an Insect Vector with a Bacterial Plant Pathogen Increases Its Propensity for Dispersal

    OpenAIRE

    Martini, Xavier; Hoffmann, Mark; Coy, Monique R; Lukasz L Stelinski; Pelz-Stelinski, Kirsten S.

    2015-01-01

    The spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. In sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. However, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. Here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such mo...

  15. Effects of climate change on the persistence and dispersal of foodborne bacterial pathogens in the outdoor environment: A review.

    Science.gov (United States)

    Hellberg, Rosalee S; Chu, Eric

    2016-08-01

    According to the Intergovernmental Panel on Climate Change (IPCC), warming of the climate system is unequivocal. Over the coming century, warming trends such as increased duration and frequency of heat waves and hot extremes are expected in some areas, as well as increased intensity of some storm systems. Climate-induced trends will impact the persistence and dispersal of foodborne pathogens in myriad ways, especially for environmentally ubiquitous and/or zoonotic microorganisms. Animal hosts of foodborne pathogens are also expected to be impacted by climate change through the introduction of increased physiological stress and, in some cases, altered geographic ranges and seasonality. This review article examines the effects of climatic factors, such as temperature, rainfall, drought and wind, on the environmental dispersal and persistence of bacterial foodborne pathogens, namely, Bacillus cereus, Brucella, Campylobacter, Clostridium, Escherichia coli, Listeria monocytogenes, Salmonella, Staphylococcus aureus, Vibrio and Yersinia enterocolitica. These relationships are then used to predict how future climatic changes will impact the activity of these microorganisms in the outdoor environment and associated food safety issues. The development of predictive models that quantify these complex relationships will also be discussed, as well as the potential impacts of climate change on transmission of foodborne disease from animal hosts. PMID:25612827

  16. Pathotypes of Bacterial Spot Pathogen Infecting Capsicum Peppers in Korea.

    Science.gov (United States)

    Wai, Khin Pa Pa; Siddique, Muhammad Irfan; Mo, Hwang-Sung; Yoo, Hee Ju; Byeon, Si-Eun; Jegal, Yoonhyuk; Mekuriaw, Alebel A; Kim, Byung-Soo

    2015-12-01

    Sixty-seven isolates of bacterial spot pathogen (Xanthomonas spp.) collected from six provinces of Korea were tested for the identification of their pathotypes and determination of their distribution throughout Korea in an effort to genetically manage the disease. Near isogenic lines of Early Calwonder (Capsicum annuum) pepper plants carrying Bs1 , Bs2 and Bs3 , and PI235047 (C. pubescens) were used as differential hosts. Race P1 was found to be predominant, followed by race P7, and races P3 and P8 were also observed. This is the first report of races P7 and P8 in Korea. The races P7 and P8 were differentiated from the former races P1 and P3, respectively, on the basis of their ability to elicit hypersensitive reactions to PI235047. PMID:26674555

  17. Pathotypes of Bacterial Spot Pathogen Infecting Capsicum Peppers in Korea

    Directory of Open Access Journals (Sweden)

    Khin Pa Pa Wai

    2015-12-01

    Full Text Available Sixty-seven isolates of bacterial spot pathogen (Xanthomonas spp. collected from six provinces of Korea were tested for the identification of their pathotypes and determination of their distribution throughout Korea in an effort to genetically manage the disease. Near isogenic lines of Early Calwonder (Capsicum annuum pepper plants carrying Bs₁, Bs₂ and Bs₃, and PI235047 (C. pubescens were used as differential hosts. Race P1 was found to be predominant, followed by race P7, and races P3 and P8 were also observed. This is the first report of races P7 and P8 in Korea. The races P7 and P8 were differentiated from the former races P1 and P3, respectively, on the basis of their ability to elicit hypersensitive reactions to PI235047.

  18. Correlation between Detection of a Plasmid and High-Level Virulence of Vibrio nigripulchritudo, a Pathogen of the Shrimp Litopenaeus stylirostris▿

    OpenAIRE

    Reynaud, Yann; Saulnier, Denis; Mazel, Didier; Goarant, Cyrille; Le Roux, Frédérique

    2008-01-01

    Vibrio nigripulchritudo, the etiological agent of Litopenaeus stylirostris summer syndrome, is responsible for mass mortalities of shrimp in New Caledonia. Epidemiological studies led to the suggestion that this disease is caused by an emergent group of pathogenic strains. Genomic subtractive hybridization was carried out between two isolates exhibiting low and high virulence. Our subtraction library was constituted of 521 specific fragments; 55 of these were detected in all virulent isolates...

  19. Effect of poly-ß-hydroxybutyrate on Chinese mitten crab, Eriocheir sinensis, larvae challenged with pathogenic Vibrio anguillarum

    OpenAIRE

    Sui, L; Cai, J.; Sun, H; Wille, M.; Bossier, P.

    2012-01-01

    This study investigated the protective effect of poly-ß-hydroxybutyrate (PHB) on Chinese mitten crab, Eriocheir sinensis, zoea larvae challenged with pathogenic Vibrio anguillarum. PHB was delivered to the crab larvae through rotifer and Artemia bioencapsulation. Zoea 3 larvae were challenged with V. anguillarum at a final concentration of 105 CFU mL-1. PHB-enriched rotifers and Artemia nauplii were added to the culture water 24 h prior to, upon and 24 h after challenge. The results confirmed...

  20. Removal of pathogenic bacterial biofilms by combinations of oxidizing compounds.

    Science.gov (United States)

    Olmedo, Gabriela María; Grillo-Puertas, Mariana; Cerioni, Luciana; Rapisarda, Viviana Andrea; Volentini, Sabrina Inés

    2015-05-01

    Bacterial biofilms are commonly formed on medical devices and food processing surfaces. The antimicrobials used have limited efficacy against the biofilms; therefore, new strategies to prevent and remove these structures are needed. Here, the effectiveness of brief oxidative treatments, based on the combination of sodium hypochlorite (NaClO) and hydrogen peroxide (H2O2) in the presence of copper sulfate (CuSO4), were evaluated against bacterial laboratory strains and clinical isolates, both in planktonic and biofilm states. Simultaneous application of oxidants synergistically inactivated planktonic cells and prevented biofilm formation of laboratory Escherichia coli, Salmonella enterica serovar Typhimurium, Klebsiella pneumoniae, and Staphylococcus aureus strains, as well as clinical isolates of Salmonella enterica subsp. enterica, Klebsiella oxytoca, and uropathogenic E. coli. In addition, preformed biofilms of E. coli C, Salmonella Typhimurium, K. pneumoniae, and Salmonella enterica exposed to treatments were removed by applying 12 mg/L NaClO, 0.1 mmol/L CuSO4, and 350 mmol/L H2O2 for 5 min. Klebsiella oxytoca and Staphylococcus aureus required a 5-fold increase in NaClO concentration, and the E. coli clinical isolate remained unremovable unless treatments were applied on biofilms formed within 24 h instead of 48 h. The application of treatments that last a few minutes using oxidizing compounds at low concentrations represents an interesting disinfection strategy against pathogens associated with medical and industrial settings. PMID:25864510

  1. Comparative analysis of two emerging rice seed bacterial pathogens.

    Science.gov (United States)

    Fory, P A; Triplett, L; Ballen, C; Abello, J F; Duitama, J; Aricapa, M G; Prado, G A; Correa, F; Hamilton, J; Leach, J E; Tohme, J; Mosquera, G M

    2014-05-01

    Seed sterility and grain discoloration limit rice production in Colombia and several Central American countries. In samples of discolored rice seed grown in Colombian fields, the species Burkholderia glumae and B. gladioli were isolated, and field isolates were compared phenotypically. An artificial inoculation assay was used to determine that, although both bacterial species cause symptoms on rice grains, B. glumae is a more aggressive pathogen, causing yield reduction and higher levels of grain sterility. To identify putative virulence genes differing between B. glumae and B. gladioli, four previously sequenced genomes of Asian and U.S. strains of the two pathogens were compared with each other and with two draft genomes of Colombian B. glumae and B. gladioli isolates generated for this study. Whereas previously characterized Burkholderia virulence factors are highly conserved between the two species, B. glumae and B. gladioli strains are predicted to encode distinct groups of genes encoding type VI secretion systems, transcriptional regulators, and membrane-sensing proteins. This study shows that both B. glumae and B. gladioli can threaten grain quality, although only one species affects yield. Furthermore, genotypic differences between the two strains are identified that could contribute to disease phenotypic differences. PMID:24261408

  2. Advances in genetic manipulation of obligate intracellular bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Paul eBeare

    2011-05-01

    Full Text Available Infections by obligate intracellular bacterial pathogens result in significant morbidity and mortality worldwide. These bacteria include Chlamydia spp., which causes millions of cases of sexually transmitted disease and blinding trachoma annually, and members of the α-proteobacterial genera Anaplasma, Ehrlichia, Orientia and Rickettsia, agents of serious human illnesses including epidemic typhus. Coxiella burnetii, the agent of human Q fever, has also been considered a prototypical obligate intracellular bacterium, but recent host cell-free (axenic growth has rescued it from obligatism. The historic genetic intractability of obligate intracellular bacteria has severely limited molecular dissection of their unique lifestyles and virulence factors involved in pathogenesis. Host cell restricted growth is a significant barrier to genetic transformation that can make simple procedures for free-living bacteria, such as cloning, exceedingly difficult. Low transformation efficiency requiring long term culture in host cells to expand small transformant populations is another obstacle. Despite numerous technical limitations, the last decade has witnessed significant gains in genetic manipulation of obligate intracellular bacteria including allelic exchange. Continued development of genetic tools should soon enable routine mutation and complementation strategies for virulence factor discovery and stimulate renewed interest in these refractory pathogens. In this review, we discuss the technical challenges associated with genetic transformation of obligate intracellular bacteria and highlight advances made with individual genera.

  3. A bacterial pathogen uses dimethylsulfoniopropionate as a cue to target heat-stressed corals

    OpenAIRE

    Garren, Melissa; Son, Kwangmin; Raina, Jean-Baptiste; Rusconi, Roberto; Menolascina, Filippo; Shapiro, Orr H.; Tout, Jessica; Bourne, David G; Seymour, Justin R.; Stocker, Roman

    2013-01-01

    Diseases are an emerging threat to ocean ecosystems. Coral reefs, in particular, are experiencing a worldwide decline because of disease and bleaching, which have been exacerbated by rising seawater temperatures. Yet, the ecological mechanisms behind most coral diseases remain unidentified. Here, we demonstrate that a coral pathogen, Vibrio coralliilyticus, uses chemotaxis and chemokinesis to target the mucus of its coral host, Pocillopora damicornis. A primary driver of this response is the ...

  4. Antimicrobial Effects of Quercus Brantii Fruits on Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Issa Sadeghian

    2012-08-01

    Full Text Available Background: In recent years, a number of antibiotics have lost their effectiveness due to the development of resistant strains, mostly through the expression of resistance genes.Objectives: The aim of the present study was to investigate the antimicrobial property of Quercus brantii fruits and compare its effects with some current antibiotics.Materials and Methods: The antimicrobial activities of an ethanol extract of Q. brantii (Oak fruits (brown cortex: B.C and white core: W.C were tested in vitro against eight reference strains of enteric pathogenic bacteria. The antimicrobial activities of the extracts were examined based on the disc diffusion method. The results were evaluated as inhibition zones around the discs impregnated with B.C and W.C extracts at different concentrations (2 to 10 %.Results: The antibacterial effect of the B.C ethanolic extract on Escherichia coli was significant and had a concentration-related effect, although there was no significant effect found on Helicobacter pylori. The W.C ethanolic extract has a high antimicrobial effect on Streptococcus pyogenes; at the same time significant antibacterial activity occurred against H pylori. Comparisons between the antimicrobial activities of these extracts (B.C and W.C and standard antibiotics; gentamicin, colistin, and methicillin, showed that in the most commonly tested bacteria the antibacterial activity of these extracts was even greater than with the antibiotics. Analysis of the extracts components by gas chromatography, showed that tannins and phenolic compounds could be responsible for these antimicrobial activities.Conclusions: The results of this study showed that different parts of Q. brantii have antimicrobial activity against gastrointestinal bacterial pathogens. These antimicrobial activities, in almost all cases, were greater than with standard antibiotics..--------------------------------------------------------------------------------Implication for health

  5. Metabolic responses of clam Ruditapes philippinarum exposed to its pathogen Vibrio tapetis in relation to diet.

    Science.gov (United States)

    Richard, Gaëlle; Guérard, Fabienne; Corporeau, Charlotte; Lambert, Christophe; Paillard, Christine; Pernet, Fabrice

    2016-07-01

    We investigated the effect of brown ring disease (BRD) development and algal diet on energy reserves and activity of enzymes related to energy metabolism, antioxidant system and immunity in Manila clam, Ruditapes philippinarum. We found that algal diet did not impact the metabolic response of clams exposed to Vibrio tapetis. At two days post-injection (dpi), activities of superoxide dismutase and glutathione peroxidase (GPx) decreased whereas activities of nitric oxide synthase (iNOS) and catalase increased in infected clams, although no clinical signs were visible (BRD-). At 7 dpi, activities of several antioxidant and immune-related enzymes were markedly increased in BRD-likely indicating an efficient reactive oxygen species (ROS) scavenging compared to animals which developed clinical signs of BRD (BRD+). Therefore, resistance to BRD clinical signs appearance was associated with higher detoxification of ROS and enhancement of immune response. This study provides new biochemical indicators of disease resistance and a more comprehensive view of the global antioxidant response of clam to BRD development. PMID:26921670

  6. 珠海市海产品中致病性弧菌的污染现状%Pollution situation of pathogenic vibrio in seafood of Zhuhai

    Institute of Scientific and Technical Information of China (English)

    黄辉涛; 魏泉德; 杨春晓; 莫韵韶

    2013-01-01

    Objective]To find out the current pollution situation of pathogenic Vibrio in seafood of Zhuhai,and provide scientific proofs for disease prevention and control.[Method]From January to December,2012,240 samples of seafood were collected from the market,and were tested and analyzed for Vibrio parahemolyticus,Vibrio vulnficus,and Vibrio cholerae.[Results]The detectable rate of Vibrio parahemolyticus is 19.2%,Vibrio vulnficus 15.8%,and Vibrio cholerae 0%.The highest rates are detected from June to September.Among different kinds of seafood,shellfish has the highest detectable rates,with a rate of 40% of Vibrio parahemolyticus and 43.3% Of Vibriovulnficus,market and the hotel was no significant difference in the pollution.[Conclusion]The disease control and health monitoring departments should enhance the monitoring on seafood sold in the markets,and give reasonable diet instructions to citizens so as to persuade them from eating raw or undercooked seafood and thus prevent food poisoning.%目的了解珠海市海产品中致病性弧菌的污染现状,为疾病的预防与控制提供科学的依据。方法于2012年1~12月共采集市售海产品240份,对副溶血性弧菌、创伤弧菌、霍乱弧菌进行检测、分析。结果副溶血性弧菌检出率为19.2%,创伤弧菌检出率为15.8%,霍乱弧菌检出率为0%,5~9月份检出率最高,霍乱弧菌未检出。不同种类的海产品中,贝壳类的检出率最高,其副溶血性弧菌和创伤弧菌的检出率分别高达40%和43.3%,农贸市场和酒店的污染情况无明显差别。结论疾病控制及卫生监督部门应加强市售海产品的卫生监督,合理引导市民的饮食习惯,不生吃或进食未经煮熟的海产品,预防食物中毒的发生。

  7. Inhibition of Luminescence and Virulence in the Black Tiger Prawn (Penaeus monodon) Pathogen Vibrio harveyi by Intercellular Signal Antagonists

    Science.gov (United States)

    Manefield, Michael; Harris, Lachlan; Rice, Scott A.; de Nys, Rocky; Kjelleberg, Staffan

    2000-01-01

    Expression of luminescence in the Penaeus monodon pathogen Vibrio harveyi is regulated by an intercellular quorum sensing mechanism involving the synthesis and detection of two signaling molecules, one of which is N-hydroxy butanoyl-l-homoserine lactone and the other of which is uncharacterized. Indirect evidence has suggested that virulence, associated with a toxic extracellular protein, and luminescence in V. harveyi are coregulated. In this study the effects of an acylated homoserine lactone antagonist produced by the marine alga Delisea pulchra on luminescence and toxin production in a virulent strain of V. harveyi were analyzed. Luminescence and toxin production were both inhibited by the signal antagonist at concentrations that had no impact on growth. Toxin production was found to be prematurely induced in V. harveyi cultures incubated in a 10% conditioned medium. Additionally, a significant reduction in the toxicity of concentrated supernatant extracts from V. harveyi cultures incubated in the presence of the signal antagonist, as measured by in vivo toxicity assays in mice and prawns, was observed. These results suggest that intercellular signaling antagonists have potential utility in the control of V. harveyi prawn infections. PMID:10788385

  8. Ralstonia solanacearum, a widespread bacterial plant pathogen in the post-genomic era

    OpenAIRE

    Peeters, Nemo; Guidot, Alice; Vailleau, Fabienne; Valls i Matheu, Marc

    2013-01-01

    Ralstonia solanacearum is a soil-borne bacterium causing the widespread disease known as bacterial wilt. Ralstonia solanacearum is also the causal agent of Moko disease of banana and brown rot of potato. Since the last R. solanacearum pathogen profile was published 10 years ago, studies concerning this plant pathogen have taken a genomic and post-genomic direction. This was pioneered by the first sequenced and annotated genome for a major plant bacterial pathogen and followed by many more gen...

  9. Trophic network architecture of root-associated bacterial communities determines pathogen invasion and plant health

    OpenAIRE

    Wei, Zhong; Yang, Tianjie; Friman, Ville-Petri; Xu, Yangchun; Shen, Qirong; Jousset, Alexandre

    2015-01-01

    Host-associated bacterial communities can function as an important line of defence against pathogens in animals and plants. Empirical evidence and theoretical predictions suggest that species-rich communities are more resistant to pathogen invasions. Yet, the underlying mechanisms are unclear. Here, we experimentally test how the underlying resource competition networks of resident bacterial communities affect invasion resistance to the plant pathogen Ralstonia solanacearum in microcosms and ...

  10. Insights into Bacteriophage Application in Controlling Vibrio Species

    Science.gov (United States)

    Letchumanan, Vengadesh; Chan, Kok-Gan; Pusparajah, Priyia; Saokaew, Surasak; Duangjai, Acharaporn; Goh, Bey-Hing; Ab Mutalib, Nurul-Syakima; Lee, Learn-Han

    2016-01-01

    Bacterial infections from various organisms including Vibrio sp. pose a serious hazard to humans in many forms from clinical infection to affecting the yield of agriculture and aquaculture via infection of livestock. Vibrio sp. is one of the main foodborne pathogens causing human infection and is also a common cause of losses in the aquaculture industry. Prophylactic and therapeutic usage of antibiotics has become the mainstay of managing this problem, however, this in turn led to the emergence of multidrug resistant strains of bacteria in the environment; which has raised awareness of the critical need for alternative non-antibiotic based methods of preventing and treating bacterial infections. Bacteriophages – viruses that infect and result in the death of bacteria – are currently of great interest as a highly viable alternative to antibiotics. This article provides an insight into bacteriophage application in controlling Vibrio species as well underlining the advantages and drawbacks of phage therapy. PMID:27486446

  11. Assessment of bacterial pathogens in fresh rainwater and airborne particulate matter using Real-Time PCR

    Science.gov (United States)

    Kaushik, Rajni; Balasubramanian, Rajasekhar

    2012-01-01

    Bacterial pathogens in airborne particulate matter (PM) and in rainwater (RW) were detected using a robust and sensitive Real-Time PCR method. Both RW and PM were collected simultaneously in the tropical atmosphere of Singapore, which were then subjected to analysis for the presence of selected bacterial pathogens and potential pathogen of health concern ( Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Aeromonas hydrophila). These pathogens were found to be prevalent in both PM and RW samples with E. coli being the most prevalent potential pathogen in both types of samples. The temporal distribution of these pathogens in PM and RW was found to be similar to each other. Using the proposed microbiological technique, the atmospheric deposition (dry and wet deposition) of bacterial pathogens to lakes and reservoirs can be studied in view of growing concerns about the outbreak of waterborne diseases.

  12. Decreased mortality of Lake Michigan Chinook salmon after bacterial kidney disease challenge: evidence for pathogen-driven selection?

    Science.gov (United States)

    Purcell, Maureen K; Murray, Anthony L; Elz, Anna; Park, Linda K; Marcquenski, Susan V; Winton, James R; Alcorn, Stewart W; Pascho, Ronald J; Elliott, Diane G

    2008-12-01

    In the late 1960s, Chinook salmon Oncorhynchus tshawytscha from the Green River, Washington, were successfully introduced into Lake Michigan. During spring from 1988 to 1992, large fish die-offs affecting Chinook salmon occurred in the lake. Multiple ecological factors probably contributed to the severity of the fish kills, but the only disease agent found regularly was Renibacterium salmoninarum, the causative agent of bacterial kidney disease. In this study, survival after challenge by R. salmoninarum was compared between two Chinook salmon stocks: a Lake Michigan stock from Wisconsin (WI) and the progenitor stock from the Green River. We found that the WI stock had significantly greater survival than the Green River stock. Next, the WI and Green River stocks were exposed to the marine pathogen Listonella anguillarum (formerly Vibrio anguillarum), one of the causative agents of vibriosis; survival after this challenge was significantly poorer for the WI stock than for the Green River stock. A close genetic relationship between the Green River and WI stocks was confirmed by analyzing 13 microsatellite loci. These results collectively suggest that disease susceptibility of Lake Michigan Chinook salmon has diverged from that of the source population, possibly in response to pathogen-driven selection. PMID:19306612

  13. Comparative analysis of glutaredoxin domains from bacterial opportunistic pathogens

    International Nuclear Information System (INIS)

    NMR structures of the glutaredoxin (GLXR) domains from Br. melitensis and Ba. henselae have been determined as part of the SSGCID initiative. Comparison of the domains with known structures reveals overall structural similarity between these proteins and previously determined E. coli GLXR structures, with minor changes associated with the position of helix 1 and with regions that diverge from similar structures found in the closest related human homolog. Glutaredoxin proteins (GLXRs) are essential components of the glutathione system that reductively detoxify substances such as arsenic and peroxides and are important in the synthesis of DNA via ribonucleotide reductases. NMR solution structures of glutaredoxin domains from two Gram-negative opportunistic pathogens, Brucella melitensis and Bartonella henselae, are presented. These domains lack the N-terminal helix that is frequently present in eukaryotic GLXRs. The conserved active-site cysteines adopt canonical proline/tyrosine-stabilized geometries. A difference in the angle of α-helix 2 relative to the β-sheet surface and the presence of an extended loop in the human sequence suggests potential regulatory regions and/or protein–protein interaction motifs. This observation is consistent with mutations in this region that suppress defects in GLXR–ribonucleotide reductase interactions. These differences between the human and bacterial forms are adjacent to the dithiol active site and may permit species-selective drug design

  14. Bacterial biofilm formation, pathogenicity, diagnostics and control: An overview

    Directory of Open Access Journals (Sweden)

    Sawhney Rajesh

    2009-07-01

    Full Text Available Bacterial biofilms are complex, mono- or poly-microbialn communities adhering to biotic or abiotic surfaces. This adaptation has been implicated as a survival strategy. The formation of biofilms is mediated by mechanical, biochemical and genetical factors. The biofilms enhance the virulence of the pathogen and have their potential role in various infections, such as dental caries, cystic fibrosis, osteonecrosis, urinary tract infection and eye infections. A number of diagnostic techniques, viz., bright-field microscopy, epifluorescence microscopy, scanning electron microscopy, confocal laser scanning microscopy and amplicon length heterogeneity polymerase chain reaction, have been employed for detection of these communities. Researchers have worked on applications of catheter lock solutions, a fish protein coating, acid shock treatment, susceptibility to bacteriophages, etc., for biofilm control. However, we need to rearrange our strategies to have thorough insight and concentrate on priority basis to develop new accurate, precise and rapid diagnostic protocols for detection and evaluation of biofilm. Above all, the strict compliance to these techniques is required for accurate diagnosis and control.

  15. Correlation between Detection of a Plasmid and High-Level Virulence of Vibrio nigripulchritudo, a Pathogen of the Shrimp Litopenaeus stylirostris▿

    Science.gov (United States)

    Reynaud, Yann; Saulnier, Denis; Mazel, Didier; Goarant, Cyrille; Le Roux, Frédérique

    2008-01-01

    Vibrio nigripulchritudo, the etiological agent of Litopenaeus stylirostris summer syndrome, is responsible for mass mortalities of shrimp in New Caledonia. Epidemiological studies led to the suggestion that this disease is caused by an emergent group of pathogenic strains. Genomic subtractive hybridization was carried out between two isolates exhibiting low and high virulence. Our subtraction library was constituted of 521 specific fragments; 55 of these were detected in all virulent isolates from our collection (n = 32), and 13 were detected only in the isolates demonstrating the highest pathogenicity (n = 19), suggesting that they could be used as genetic markers for high virulence capacity. Interestingly, 10 of these markers are carried by a replicon of 11.2 kbp that contains sequences highly similar to those of a plasmid detected in Vibrio shilonii, a coral pathogen. The detection of this plasmid was correlated with the highest pathogenicity status of the isolates from our collection. The origin and consequence of this plasmid acquisition are discussed. PMID:18359828

  16. Correlation between detection of a plasmid and high-level virulence of Vibrio nigripulchritudo, a pathogen of the shrimp Litopenaeus stylirostris.

    Science.gov (United States)

    Reynaud, Yann; Saulnier, Denis; Mazel, Didier; Goarant, Cyrille; Le Roux, Frédérique

    2008-05-01

    Vibrio nigripulchritudo, the etiological agent of Litopenaeus stylirostris summer syndrome, is responsible for mass mortalities of shrimp in New Caledonia. Epidemiological studies led to the suggestion that this disease is caused by an emergent group of pathogenic strains. Genomic subtractive hybridization was carried out between two isolates exhibiting low and high virulence. Our subtraction library was constituted of 521 specific fragments; 55 of these were detected in all virulent isolates from our collection (n = 32), and 13 were detected only in the isolates demonstrating the highest pathogenicity (n = 19), suggesting that they could be used as genetic markers for high virulence capacity. Interestingly, 10 of these markers are carried by a replicon of 11.2 kbp that contains sequences highly similar to those of a plasmid detected in Vibrio shilonii, a coral pathogen. The detection of this plasmid was correlated with the highest pathogenicity status of the isolates from our collection. The origin and consequence of this plasmid acquisition are discussed. PMID:18359828

  17. Water relations in the interaction of foliar bacterial pathogens with plants.

    Science.gov (United States)

    Beattie, Gwyn A

    2011-01-01

    This review examines the many ways in which water influences the relations between foliar bacterial pathogens and plants. As a limited resource in aerial plant tissues, water is subject to manipulation by both plants and pathogens. A model is emerging that suggests that plants actively promote localized desiccation at the infection site and thus restrict pathogen growth as one component of defense. Similarly, many foliar pathogens manipulate water relations as one component of pathogenesis. Nonvascular pathogens do this using effectors and other molecules to alter hormonal responses and enhance intercellular watersoaking, whereas vascular pathogens use many mechanisms to cause wilt. Because of water limitations on phyllosphere surfaces, bacterial colonists, including pathogens, benefit from the protective effects of cellular aggregation, synthesis of hygroscopic polymers, and uptake and production of osmoprotective compounds. Moreover, these bacteria employ tactics for scavenging and distributing water to overcome water-driven barriers to nutrient acquisition, movement, and signal exchange on plant surfaces. PMID:21438680

  18. Bacterial respiratory pathogens in children with inherited immune and airway disorders: nasopharyngeal carriage and disease risk

    NARCIS (Netherlands)

    Verhagen, L.M.; Luesink, M.; Warris, A.; Groot, R. de; Hermans, P.W.M.

    2013-01-01

    Children with primary immunodeficiencies, sickle cell disease and cystic fibrosis are at risk to develop invasive bacterial infections caused by respiratory tract pathogens, in particular Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus. This review article evaluates the ro

  19. Complete Genome Sequence of the Bioluminescent Marine Bacterium Vibrio harveyi ATCC 33843 (392 [MAV]).

    Science.gov (United States)

    Wang, Zheng; Hervey, W Judson; Kim, Seongwon; Lin, Baochuan; Vora, Gary J

    2015-01-01

    Vibrio harveyi is a Gram-negative marine γ-proteobacterium that is known to be a formidable pathogen of aquatic animals and is a model organism for the study of bacterial bioluminescence and quorum sensing. In this report, we describe the complete genome sequence of the most studied strain of this species: V. harveyi ATCC 33843 (392 [MAV]). PMID:25635019

  20. Evidence of a new metabolic capacity in an emerging diarrheal pathogen: lessons from the draft genomes of Vibrio fluvialis strains PG41 and I21563

    OpenAIRE

    Khatri, Indu; Mahajan, Sakshi; Dureja, Chetna; Subramanian, Srikrishna; Raychaudhuri, Saumya

    2013-01-01

    Background Vibrio fluvialis is an emerging diarrheal pathogen for which no genome is currently available. In this work, draft genomes of two closely related clinical strains PG41 and I21563 have been explored. Results V. fluvialis strains PG41 and I21563 were sequenced on the Illumina HiSeq 1000 platform to obtain draft genomes of 5.3 Mbp and 4.4 Mbp respectively. Our genome data reveal the presence of genes involved in ethanolamine utilization, which is further experimentally confirmed by gr...

  1. Inhibitory Effect of Lactobacillus reuteri on Some Pathogenic Bacteria Isolated From Women With Bacterial Vaginosis

    Directory of Open Access Journals (Sweden)

    Eslami

    2014-08-01

    Full Text Available Background Considering the high prevalence of bacterial vaginosis and its association with urinary tract infection in women and treatment of gynecologic problems occur when a high recurrence of bacterial vaginosis is often treated with antibiotics. Objectives The purpose of this study was to investigate the inhibitory effect of Lactobacillus reuteri on pathogenic bacteria isolated from women with bacterial vaginosis. Materials and Methods Ninety-six samples were obtained from vaginal discharge of women with bacterial vaginosis by a gynecologist with a Dacron swab and put in sterile tubes containing TSB broth and Thioglycollate broth. Then were immediately sent to the laboratory in cold chain for further assessment. Afterward, culture was transferred on blood agar, EMB, Palcam and differential diagnosis environments. Then cultures were incubated for 24 hours at 37 °C. Lactobacillus reuteri strains were cultured in MRS environment and transferred to laboratory. After purification of pathogenic bacteria, Lactobacillus reuteri inhibitory effect on pathogenic bacteria was evaluated by minimum inhibitory concentration (MIC and antibiogram. Statistical analysis was performed using SPSS software v.16. Results The results of this study demonstrated the inhibitory effect of Lactobacillus reuteri on some pathogenic bacteria that cause bacterial, including Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus agalactiae, Enterococcus, Listeria monocytogenes and E. coli. Microscopic examination of stained smears of most Lactobacillus and pathogenic bacteria showed reduced. The prevalence of abnormal vaginal discharge, history of drug use, contraceptive methods and douching were 61%, 55%, 42% and 13%, respectively. Significant difference was observed between the use and non-use of IUD in women with bacterial. Conclusions Our findings indicated the inhibitory effect of Lactobacillus reuteri on pathogenic bacteria that

  2. Daily variations in pathogenic bacterial populations in a monsoon influenced tropical environment

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A.C.; Naik, S.D.; Gaonkar, C.C.

    and an assessment of the health of such an ecosystem benefits from high resolution observations. Virulent pathogenic Vibrio species are expected more frequently in tropical marine environments, since the virulence gene expression seems to increase at elevated... of the Zuari estuary situated on the central west coast of India (Fig. 1). Subsequently, the samples were diluted as required, spread plated (0.1ml) on Zobell Marine Agar 2216 (Hi-media) and incubated at (30 ± 2 °C), which was the water temperature...

  3. Vibrio lentus protects gnotobiotic sea bass (Dicentrarchus labrax L.) larvae against challenge with Vibrio harveyi.

    Science.gov (United States)

    Schaeck, M; Duchateau, L; Van den Broeck, W; Van Trappen, S; De Vos, P; Coulombet, C; Boon, N; Haesebrouck, F; Decostere, A

    2016-03-15

    Due to the mounting awareness of the risks associated with the use of antibiotics in aquaculture, treatment with probiotics has recently emerged as the preferred environmental-friendly prophylactic approach in marine larviculture. However, the presence of unknown and variable microbiota in fish larvae makes it impossible to disentangle the efficacy of treatment with probiotics. In this respect, the recent development of a germ-free culture model for European sea bass (Dicentrarchus labrax L.) larvae opened the door for more controlled studies on the use of probiotics. In the present study, 206 bacterial isolates, retrieved from sea bass larvae and adults, were screened in vitro for haemolytic activity, bile tolerance and antagonistic activity against six sea bass pathogens. Subsequently, the harmlessness and the protective effect of the putative probiotic candidates against the sea bass pathogen Vibrio harveyi were evaluated in vivo adopting the previously developed germ-free sea bass larval model. An equivalence trial clearly showed that no harmful effect on larval survival was elicited by all three selected probiotic candidates: Bacillus sp. LT3, Vibrio lentus and Vibrio proteolyticus. Survival of Vibrio harveyi challenged larvae treated with V. lentus was superior in comparison with the untreated challenged group, whereas this was not the case for the larvae supplemented with Bacillus sp. LT3 and V. proteolyticus. In this respect, our results unmistakably revealed the protective effect of V. lentus against vibriosis caused by V. harveyi in gnotobiotic sea bass larvae, rendering this study the first in its kind. PMID:26931390

  4. Bacterial contamination of platelet concentrates: pathogen detection and inactivation methods

    Directory of Open Access Journals (Sweden)

    Dana Védy

    2009-04-01

    Full Text Available Whereas the reduction of transfusion related viral transmission has been a priority during the last decade, bacterial infection transmitted by transfusion still remains associated to a high morbidity and mortality, and constitutes the most frequent infectious risk of transfusion. This problem especially concerns platelet concentrates because of their favorable bacterial growth conditions. This review gives an overview of platelet transfusion-related bacterial contamination as well as on the different strategies to reduce this problem by using either bacterial detection or inactivation methods.

  5. New Vibrio species associated to molluscan microbiota: a review

    Directory of Open Access Journals (Sweden)

    JesusLRomalde

    2014-01-01

    Full Text Available The genus Vibrio consists of more than 100 species grouped in 14 clades that are widely distributed in aquatic environments such as estuarine, coastal waters and sediments. A large number of species of this genus are associated with marine organisms like fish, molluscs and crustaceans, in commensal or pathogenic relations. In the last decade, more than 50 new species have been described in the genus Vibrio, due to the introduction of new molecular techniques in bacterial taxonomy, such as multilocus sequence analysis (MLSA or fluorescent amplified fragment length polymorphism (FAFLP. On the other hand, the increasing number of environmental studies has contributed to improve the knowledge about the family Vibrionaceae and its phylogeny. Vibrio crassostreae, V. breoganii, V. celticus are some of the new Vibrio species described as forming part of the molluscan microbiota. Some of them have been associated with mortalities of different molluscan species, seriously affecting their culture and causing high losses in hatcheries as well as in natural beds. For other species, ecological importance has been demonstrated being highly abundant in different marine habitats and geographical regions. The present work provides an updated overview of the recently characterized Vibrio species isolated from molluscs. In addition, their pathogenic potential and/or environmental importance is discussed.

  6. New Vibrio species associated to molluscan microbiota: a review.

    Science.gov (United States)

    Romalde, Jesús L; Dieguez, Ana L; Lasa, Aide; Balboa, Sabela

    2014-01-01

    The genus Vibrio consists of more than 100 species grouped in 14 clades that are widely distributed in aquatic environments such as estuarine, coastal waters, and sediments. A large number of species of this genus are associated with marine organisms like fish, molluscs and crustaceans, in commensal or pathogenic relations. In the last decade, more than 50 new species have been described in the genus Vibrio, due to the introduction of new molecular techniques in bacterial taxonomy, such as multilocus sequence analysis or fluorescent amplified fragment length polymorphism. On the other hand, the increasing number of environmental studies has contributed to improve the knowledge about the family Vibrionaceae and its phylogeny. Vibrio crassostreae, V. breoganii, V. celticus are some of the new Vibrio species described as forming part of the molluscan microbiota. Some of them have been associated with mortalities of different molluscan species, seriously affecting their culture and causing high losses in hatcheries as well as in natural beds. For other species, ecological importance has been demonstrated being highly abundant in different marine habitats and geographical regions. The present work provides an updated overview of the recently characterized Vibrio species isolated from molluscs. In addition, their pathogenic potential and/or environmental importance is discussed. PMID:24427157

  7. Bacterial ‘Cell’ Phones: Do cell phones carry potential pathogens?

    OpenAIRE

    Kiran Chawla; Chiranjay Mukhopadhayay; Bimala Gurung; Priya Bhate; Indira Bairy

    2009-01-01

    Cell phones are important companions for professionals especially health care workers (HCWs) for better communication in hospital. The present study compared the nature of the growth of potentially pathogenic bacterial flora on cell phones in hospital and community. 75% cell phones from both the categories grew at least one potentially pathogenic organism. Cell phones from HCWs grew significantly more potential pathogens like MRSA (20%), Acinetobacter species (5%), Pseudomonas species (2.5%) ...

  8. Ethanolamine utilization in Vibrio alginolyticus

    OpenAIRE

    Khatri Neelam; Khatri Indu; Subramanian Srikrishna; Raychaudhuri Saumya

    2012-01-01

    Abstract Ethanolamine is used as an energy source by phylogenetically diverse bacteria including pathogens, by the concerted action of proteins from the eut-operon. Previous studies have revealed the presence of eutBC genes encoding ethanolamine-ammonia lyase, a key enzyme that breaks ethanolamine into acetaldehyde and ammonia, in about 100 bacterial genomes including members of gamma-proteobacteria. However, ethanolamine utilization has not been reported for any member of the Vibrio genus. O...

  9. Analysis of bacterial communities and bacterial pathogens in a biogas plant by the combination of ethidium monoazide, PCR and Ion Torrent sequencing

    DEFF Research Database (Denmark)

    Luo, Gang; Angelidaki, Irini

    2014-01-01

    The present study investigated the changes of bacterial community composition including bacterial pathogens along a biogas plant, i.e. from the influent, to the biogas reactor and to the post-digester. The effects of post-digestion temperature and time on the changes of bacterial community...... had a significant effect on the changes of bacterial community composition. The changes of bacterial community composition were also reflected in the changes of relative abundance of bacterial pathogens. The richness and relative abundance of bacterial pathogens were reduced after anaerobic digestion...... in the biogas reactor. It was found in batch experiments that bacterial pathogens showed the highest relative abundance and richness after 30days' post-digestion. Streptococcus bovis was found in all the samples. Our results showed that special attention should be paid to the post-digestion since the...

  10. Human-derived probiotic Lactobacillus reuteri demonstrate antimicrobial activities targeting diverse enteric bacterial pathogens.

    Science.gov (United States)

    Spinler, Jennifer K; Taweechotipatr, Malai; Rognerud, Cheryl L; Ou, Ching N; Tumwasorn, Somying; Versalovic, James

    2008-06-01

    Lactobacillus reuteri is a commensal-derived anaerobic probiotic that resides in the human gastrointestinal tract. L. reuteri converts glycerol into a potent broad-spectrum antimicrobial compound, reuterin, which inhibits the growth of gram-positive and gram-negative bacteria. In this study, we compared four human-derived L. reuteri isolates (ATCC 55730, ATCC PTA 6475, ATCC PTA 4659 and ATCC PTA 5289) in their ability to produce reuterin and to inhibit the growth of different enteric pathogens in vitro. Reuterin was produced by each of the four L. reuteri strains and assessed for biological activity. The minimum inhibitory concentration (MIC) of reuterin derived from each strain was determined for the following enteric pathogens: enterohemorrhagic Escherichia coli, enterotoxigenic E. coli, Salmonella enterica, Shigella sonnei and Vibrio cholerae. We also analyzed the relative abilities of L. reuteri to inhibit enteric pathogens in a pathogen overlay assay. The magnitude of reuterin production did not directly correlate with the relative ability of L. reuteri to suppress the proliferation of enteric pathogens. Additional antimicrobial factors may be produced by L. reuteri, and multiple factors may act synergistically with reuterin to inhibit enteric pathogens. PMID:18396068

  11. Dancing with the Stars: How Choreographed Bacterial Interactions Dictate Nososymbiocity and Give Rise to Keystone Pathogens, Accessory Pathogens, and Pathobionts.

    Science.gov (United States)

    Hajishengallis, George; Lamont, Richard J

    2016-06-01

    Many diseases that originate on mucosal membranes ensue from the action of polymicrobial communities of indigenous organisms working in concert to disrupt homeostatic mechanisms. Multilevel physical and chemical communication systems among constituent organisms underlie polymicrobial synergy and dictate the community's pathogenic potential or nososymbiocity, that is, disease arising from living together with a susceptible host. Functional specialization of community participants, often originating from metabolic codependence, has given rise to several newly appreciated designations within the commensal-to-pathogen spectrum. Accessory pathogens, while inherently commensal in a particular microenvironment, nonetheless enhance the colonization or metabolic activity of pathogens. Keystone pathogens (bacterial drivers or alpha-bugs) exert their influence at low abundance by modulating both the composition and levels of community participants and by manipulating host responses. Pathobionts (or bacterial passengers) exploit disrupted host homeostasis to flourish and promote inflammatory disease. In this review we discuss how commensal or pathogenic properties of organisms are not intrinsic features, and have to be considered within the context of both the microbial community in which they reside and the host immune status. PMID:26968354

  12. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira.

    Directory of Open Access Journals (Sweden)

    Derrick E Fouts

    2016-02-01

    Full Text Available Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1 the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2 genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12 autotrophy as a bacterial virulence factor; 3 CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade's refractoriness to gene targeting; 4 finding Leptospira pathogen-specific specialized protein secretion systems; 5 novel virulence-related genes/gene families such as the Virulence Modifying (VM (PF07598 paralogs proteins and pathogen-specific adhesins; 6 discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7 and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately

  13. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira.

    Science.gov (United States)

    Fouts, Derrick E; Matthias, Michael A; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L; Haake, David A; Haft, Daniel H; Hartskeerl, Rudy; Ko, Albert I; Levett, Paul N; Matsunaga, James; Mechaly, Ariel E; Monk, Jonathan M; Nascimento, Ana L T; Nelson, Karen E; Palsson, Bernhard; Peacock, Sharon J; Picardeau, Mathieu; Ricaldi, Jessica N; Thaipandungpanit, Janjira; Wunder, Elsio A; Yang, X Frank; Zhang, Jun-Jie; Vinetz, Joseph M

    2016-02-01

    Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1) the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2) genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12) autotrophy as a bacterial virulence factor; 3) CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade's refractoriness to gene targeting; 4) finding Leptospira pathogen-specific specialized protein secretion systems; 5) novel virulence-related genes/gene families such as the Virulence Modifying (VM) (PF07598 paralogs) proteins and pathogen-specific adhesins; 6) discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7) and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately pathogenic

  14. Soft tissue infections caused by marine bacterial pathogens: epidemiology, diagnosis, and management.

    Science.gov (United States)

    Finkelstein, Renato; Oren, Ilana

    2011-10-01

    Skin and soft tissue infections (SSTIs) are one of the most common infection syndromes and may be caused by a large number of microorganisms. Some principles of aquatic injuries are different than those of land-based trauma. Wounds sustained in marine environment are exposed to a milieu of bacteria rarely encountered in different settings. These include Vibrio spp., Aeromonas spp., Shewanella spp., Erysipelothrix rhusiopathiae, Mycobacterium marinum, Streptococcus iniae, and other microbes. Failure to recognize and treat these uncommon pathogens in a timely manner may result in significant morbidity or death. These infections are frequently contracted as a result of recreational swimming, fishing injuries, or seafood handling. The spectrum of manifestations is wide, varying from cases of mild cellulitis, to severe life-threatening necrotizing fasciitis requiring radical surgery, to sepsis and death. This review will focus on the epidemiology, clinical manifestations, and treatment of SSTIs caused by the most important marine pathogens. PMID:21785929

  15. Surface Proteoglycans as Mediators in Bacterial Pathogens Infections

    Science.gov (United States)

    García, Beatriz; Merayo-Lloves, Jesús; Martin, Carla; Alcalde, Ignacio; Quirós, Luis M.; Vazquez, Fernando

    2016-01-01

    Infectious diseases remain an important global health problem. The interaction of a wide range of pathogen bacteria with host cells from many different tissues is frequently mediated by proteoglycans. These compounds are ubiquitous complex molecules which are not only involved in adherence and colonization, but can also participate in other steps of pathogenesis. To overcome the problem of microbial resistance to antibiotics new therapeutic agents could be developed based on the characteristics of the interaction of pathogens with proteoglycans. PMID:26941735

  16. The Role of Viral and Bacterial Pathogens in Gastrointestinal Cancer

    OpenAIRE

    Selgrad, Michael; Malfertheiner, Peter; Fini, Lucia; Goel, Ajay; Boland, C Richard; Ricciardiello, Luigi

    2008-01-01

    The association of Helicobacter pylori (H. pylori) with gastric cancer is thus far the best understood model to comprehend the causal relationship between a microbial pathogen and cancer in the human gastrointestinal tract. Besides H. pylori, a variety of other pathogens are now being recognized as potential carcinogens in different settings of human cancer. In this context, viral causes of human cancers are central to the issue since these account for 10–20% of cancers worldwide. In the case...

  17. Pathogenicity of Vibrio anguillarum serogroup O1 strains compared to plasmids, outer membrane protein profiles and siderophore production

    DEFF Research Database (Denmark)

    Pedersen, K.; Gram, Lone; Austin, D.A.;

    1997-01-01

    The virulence of 18 strains of Vibrio anguillarum serogroup 01 was compared to plasmid content, expression of siderophores and outer membrane proteins. All strains, irrespective of plasmid content, produced siderophores and inducible outer membrane proteins under iron-limited conditions. Only str...

  18. Bacterial effect of accelerated electrons on several pathogens

    International Nuclear Information System (INIS)

    colibacterillesis and salmonellosis of calves' were developed in RIVU. By widening the application field of developed radiation biotechnology the 'Polyvalent vaccine against pasteurellesis, salmonellosis and colibacterillesis of farm animals' was created in recent years. The mentioned radio vaccines were successfully tested in laboratory and working environment and are widely used in veterinary practice in the farms of the Republic of Uzbekistan [3].For further broadening of the possibility to use the radiation biotechnology and to enrich the native arsenal of veterinary bio medication, it is presently planned to conduct large-scale research on the use of accelerated electrons (AE) to obtain in perspective new preventive materials. Several results of the beginning stage of this research are given in the present report.The suspensions of pathogenic strains of pasteurellesis, salmonellosis and Escherichia Coli strains were exposed to irradiation by accelerated electrons of microtron MT-22C. Taking into account the slightly higher resistance of bacteria against irradiation by accelerated electrons as compared to gamma-irradiation, the doses from 400 to 1100 kRad were used. At this, the special attention was paid to control the distribution of linear density of the current in scanning of AE beam, the distribution of linear density of the current in perpendicular scanning of AE beam and the value of absorbed dose. The studies showed that at AE irradiation by 400 kRad dose the bacterial survival rate is about 10 %, at 500 kRad-2-3 %, 600 kRad- less than 1 %. At the dose of 800 kRad only isolated colonies of bacteria survived. At AE irradiation by 900 kRad- 1.1 MRad dose, there was no increase the growth of bacteria's number. Since these data were obtained at the multiple repetition of results, it can be supposed that the minimal absolute devitalizing AE irradiation dose of bacteria lies in the region 0.9-1.0 MRad. At this, some inter-species and even intra species peculiarities in the

  19. Evaluation of bacterial pathogens in paediatric poliovirus-positive faecal specimens

    Institute of Scientific and Technical Information of China (English)

    Adenike AOOgunshe; Oluwafunmilayo GOyero; Olalekan POlabode

    2009-01-01

    Objective:To evaluate the in vitro inhibitory potential of commonly available antibiotic (discs)and paediatric suspensions against bacterial species from polio-positive faecal specimens.Methods:Commonly available anti-biotic (discs)and oral,paediatric suspensions were screened for in vitro inhibitory activities against bacterial species from infantile polio-positive faecal specimens,using agar disc-diffusion and modified agar well-diffu-sion methods.Results:Isolated bacteria were Bacillus cereus,B.subtilis,Staphylococcus aureus,Streptococcus pneumoniae,Aeromonas hydrophila,Citrobacter aerogenes,Escherichia coli,Enterobacter aerogenes,Klebsiella pneumoniae,Pseudomonas aeruginosa,Proteus mirabilis,Pr.vulgaris,Shigella dysenteriae,Sh.flexneri,Sh. sonnei and Vibrio parahaemolyticus.Overall phenotypic antibiotic susceptibility rates among Gram-positive bac-terial species were between 33.3% (augmentin)and 75.0% (chloramphenicol,erythromycin and gentami-cin);higher susceptibility rates (48.6%-100.0%)were recorded among Gram-negative bacterial species, while between 7.8% /10.1% (metronidazole /ampicillin)and 25.2% /28.1 % (cotrimoxazole /septrin) were recorded towards paediatric antibiotics.Conclusions:Bacterial species from polio-positive fecal speci-mens are minimally susceptible to commonly available oral paediatric antibiotic suspensions in Nigeria.

  20. Grimontia indica AK16(T, sp. nov., isolated from a seawater sample reports the presence of pathogenic genes similar to Vibrio genus.

    Directory of Open Access Journals (Sweden)

    Aditya Singh

    Full Text Available Grimontia indica strain AK16(T sp. nov. is the type strain of G. indica sp. nov. a new species within the genus Grimontia. This strain, whose genome is described here, was isolated from seawater sample collected from southeast coast of Palk Bay, India. G. indica AK16(T is a Gram-negative, facultative aerobic rod shaped bacterium. There are only two other strains in the genus Grimontia one of which, Grimontia hollisae CIP 101886(T, is a reported human pathogen isolated from human stool sample while the other, 'Grimontia marina IMCC5001(T', was isolated from a seawater sample. As compared to the pathogenic strain Grimontia hollisae CIP 101886(T, the strain AK16(T lacks some genes for pathogenesis like the accessory colonization factors AcfA and AcfD, which are required for the colonization of the bacterium in the host body. While it carries some pathogenesis genes like OmpU, which are related to pathogenesis of Vibrio strains. This suggests that the life cycle of AK16(T may include some pathogenic interactions with marine animal(s, or it may be an opportunistic pathogen. Study of the Grimontia genus is important because of the severe pathogenic traits exhibited by a member of the genus with only three species reported in total. The study will provide some vital information which may be useful in future clinical studies on the genus.

  1. Bacteriophage Amplification-Coupled Detection and Identification of Bacterial Pathogens

    Science.gov (United States)

    Cox, Christopher R.; Voorhees, Kent J.

    Current methods of species-specific bacterial detection and identification are complex, time-consuming, and often require expensive specialized equipment and highly trained personnel. Numerous biochemical and genotypic identification methods have been applied to bacterial characterization, but all rely on tedious microbiological culturing practices and/or costly sequencing protocols which render them impractical for deployment as rapid, cost-effective point-of-care or field detection and identification methods. With a view towards addressing these shortcomings, we have exploited the evolutionarily conserved interactions between a bacteriophage (phage) and its bacterial host to develop species-specific detection methods. Phage amplification-coupled matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS) was utilized to rapidly detect phage propagation resulting from species-specific in vitro bacterial infection. This novel signal amplification method allowed for bacterial detection and identification in as little as 2 h, and when combined with disulfide bond reduction methods developed in our laboratory to enhance MALDI-TOF-MS resolution, was observed to lower the limit of detection by several orders of magnitude over conventional spectroscopy and phage typing methods. Phage amplification has been combined with lateral flow immunochromatography (LFI) to develop rapid, easy-to-operate, portable, species-specific point-of-care (POC) detection devices. Prototype LFI detectors have been developed and characterized for Yersinia pestis and Bacillus anthracis, the etiologic agents of plague and anthrax, respectively. Comparable sensitivity and rapidity was observed when phage amplification was adapted to a species-specific handheld LFI detector, thus allowing for rapid, simple, POC bacterial detection and identification while eliminating the need for bacterial culturing or DNA isolation and amplification techniques.

  2. Development and application of the active surveillance of pathogens microarray to monitor bacterial gene flux

    Directory of Open Access Journals (Sweden)

    Hinds Jason

    2008-10-01

    Full Text Available Abstract Background Human and animal health is constantly under threat by emerging pathogens that have recently acquired genetic determinants that enhance their survival, transmissibility and virulence. We describe the construction and development of an Active Surveillance of Pathogens (ASP oligonucleotide microarray, designed to 'actively survey' the genome of a given bacterial pathogen for virulence-associated genes. Results The microarray consists of 4958 reporters from 151 bacterial species and include genes for the identification of individual bacterial species as well as mobile genetic elements (transposons, plasmid and phage, virulence genes and antibiotic resistance genes. The ASP microarray was validated with nineteen bacterial pathogens species, including Francisella tularensis, Clostridium difficile, Staphylococcus aureus, Enterococcus faecium and Stenotrophomonas maltophilia. The ASP microarray identified these bacteria, and provided information on potential antibiotic resistance (eg sufamethoxazole resistance and sulfonamide resistance and virulence determinants including genes likely to be acquired by horizontal gene transfer (e.g. an alpha-haemolysin. Conclusion The ASP microarray has potential in the clinic as a diagnostic tool, as a research tool for both known and emerging pathogens, and as an early warning system for pathogenic bacteria that have been recently modified either naturally or deliberately.

  3. Antibiotic resistance of Vibrio parahaemolyticus and Vibrio vulnificus in various countries: A review.

    Science.gov (United States)

    Elmahdi, Sara; DaSilva, Ligia V; Parveen, Salina

    2016-08-01

    Vibrio parahaemolyticus and Vibrio vulnificus are the leading causes of seafood associated infections and mortality in the United States. The main syndromes caused by these pathogens are gastroenteritis, wound infections, and septicemia. This article reviewed the antibiotic resistance profile of V. parahaemolyticus and V. vulnificus in the United States and other countries including Italy, Brazil, Philippines, Malaysia, Thailand, China, India, Iran, South Africa and Australia. The awareness of antimicrobial resistance of these two pathogens is not as well documented as other foodborne bacterial pathogens. Vibrio spp. are usually susceptible to most antimicrobials of veterinary and human significance. However, many studies reported that V. vulnificus and V. parahaemolyticus showed multiple-antibiotic resistance due to misuse of antibiotics to control infections in aquaculture production. In addition, both environmental and clinical isolates showed similar antibiotic resistance profiles. Most frequently observed antibiotic resistance profiles involved ampicillin, penicillin and tetracycline regardless of the countries. The presence of multiple-antibiotic resistant bacteria in seafood and aquatic environments is a major concern in fish and shellfish farming and human health. PMID:27052711

  4. Isolation and molecular identification of Vibrio spp. by sequencing of 16S rDNA from seafood, meat and meat products in Libya

    Directory of Open Access Journals (Sweden)

    S.M. Azwai

    2016-03-01

    Full Text Available The genus Vibrio includes several food-borne pathogens that cause a spectrum of clinical conditions including septicemia, cholera and milder forms of gastroenteritis. Several Vibrio spp. are commonly associated with food-borne transmission including Vibrio cholerae, Vibrio parahemolyticus, and Vibrio vulnificus. Microbiological analysis for enumeration and isolation of Vibrio spp. were carried out for a total of 93 samples of seafood, meat and meat products from different geographic localities in Libya (Tripoli, Regdalin, Janzour and Tobruk. Vibrio spp. were detected by conventional cultural and molecular method using PCR and sequencing of 16S rDNA. Out of the 93 cultured samples only 48 (51.6% yielded colonies on Thiosulfate Citrate Bile Salt agar (TCBS with culture characteristics of Vibrio spp. More than half (n=27 of processed seafood samples (n=46 yielded colonies on TCBS, while only 44.6% of samples of meat and meat products showed colonies on TCBS. Among cultured seafood samples, the highest bacterial count was recorded in clam with a count of 3.8 х104 CFU\\g. Chicken burger samples showed the highest bacterial count with 6.5 х104 CFU\\g. Molecular analysis of the isolates obtained in this study, showed that 11 samples out of 48 (22.9% were Vibrio spp. Vibrio parahemolyticus was isolated from camel meat for the first time. This study is an initial step to provide a baseline for future molecular research targeting Vibrio spp. foodborne illnesses. This data will be used to provide information on the magnitude of such pathogens in Libyan seafood, meat and meat products.

  5. Isolation and molecular identification of Vibrio spp. by sequencing of 16S rDNA from seafood, meat and meat products in Libya.

    Science.gov (United States)

    Azwai, S M; Alfallani, E A; Abolghait, S K; Garbaj, A M; Naas, H T; Moawad, A A; Gammoudi, F T; Rayes, H M; Barbieri, I; Eldaghayes, I M

    2016-01-01

    The genus Vibrio includes several food-borne pathogens that cause a spectrum of clinical conditions including septicemia, cholera and milder forms of gastroenteritis. Several Vibrio spp. are commonly associated with food-borne transmission including Vibrio cholerae, Vibrio parahemolyticus, and Vibrio vulnificus. Microbiological analysis for enumeration and isolation of Vibrio spp. were carried out for a total of 93 samples of seafood, meat and meat products from different geographic localities in Libya (Tripoli, Regdalin, Janzour and Tobruk). Vibrio spp. were detected by conventional cultural and molecular method using PCR and sequencing of 16S rDNA. Out of the 93 cultured samples only 48 (51.6%) yielded colonies on Thiosulfate Citrate Bile Salt agar (TCBS) with culture characteristics of Vibrio spp. More than half (n=27) of processed seafood samples (n=46) yielded colonies on TCBS, while only 44.6 % of samples of meat and meat products showed colonies on TCBS. Among cultured seafood samples, the highest bacterial count was recorded in clam with a count of 3.8 ×10(4) CFU\\g. Chicken burger samples showed the highest bacterial count with 6.5 ×10(4) CFU\\g. Molecular analysis of the isolates obtained in this study, showed that 11 samples out of 48 (22.9%) were Vibrio spp. Vibrio parahemolyticus was isolated from camel meat for the first time. This study is an initial step to provide a baseline for future molecular research targeting Vibrio spp. foodborne illnesses. This data will be used to provide information on the magnitude of such pathogens in Libyan seafood, meat and meat products. PMID:27004169

  6. Limited functional conservation of a global regulator among related bacterial genera: Lrp in Escherichia, Proteus and Vibrio

    Directory of Open Access Journals (Sweden)

    Martinez-Vaz Betsy M

    2008-04-01

    Full Text Available Abstract Background Bacterial genome sequences are being determined rapidly, but few species are physiologically well characterized. Predicting regulation from genome sequences usually involves extrapolation from better-studied bacteria, using the hypothesis that a conserved regulator, conserved target gene, and predicted regulator-binding site in the target promoter imply conserved regulation between the two species. However many compared organisms are ecologically and physiologically diverse, and the limits of extrapolation have not been well tested. In E. coli K-12 the leucine-responsive regulatory protein (Lrp affects expression of ~400 genes. Proteus mirabilis and Vibrio cholerae have highly-conserved lrp orthologs (98% and 92% identity to E. coli lrp. The functional equivalence of Lrp from these related species was assessed. Results Heterologous Lrp regulated gltB, livK and lrp transcriptional fusions in an E. coli background in the same general way as the native Lrp, though with significant differences in extent. Microarray analysis of these strains revealed that the heterologous Lrp proteins significantly influence only about half of the genes affected by native Lrp. In P. mirabilis, heterologous Lrp restored swarming, though with some pattern differences. P. mirabilis produced substantially more Lrp than E. coli or V. cholerae under some conditions. Lrp regulation of target gene orthologs differed among the three native hosts. Strikingly, while Lrp negatively regulates its own gene in E. coli, and was shown to do so even more strongly in P. mirabilis, Lrp appears to activate its own gene in V. cholerae. Conclusion The overall similarity of regulatory effects of the Lrp orthologs supports the use of extrapolation between related strains for general purposes. However this study also revealed intrinsic differences even between orthologous regulators sharing >90% overall identity, and 100% identity for the DNA-binding helix-turn-helix motif

  7. Hard ticks and their bacterial endosymbionts (or would be pathogens)

    Czech Academy of Sciences Publication Activity Database

    Ahantarig, A.; Trinachartvanit, W.; Baimai, V.; Grubhoffer, Libor

    2013-01-01

    Roč. 58, č. 5 (2013), s. 419-428. ISSN 0015-5632 Institutional support: RVO:60077344 Keywords : Ixodes ricinus * Candidatus Midichloria mitochondrii * Francisella-like endosymbionts * vector Ambylomma americanum * fever group Rickettsiae * Dermacentor andersoni * spotted fever * borne pathogens Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.145, year: 2013

  8. Occurrence of Vibrio Pathotypes in the Final Effluents of Five Wastewater Treatment Plants in Amathole and Chris Hani District Municipalities in South Africa

    Directory of Open Access Journals (Sweden)

    Vuyokazi Nongogo

    2014-08-01

    Full Text Available We assessed the occurrence of Vibrio pathogens in the final effluents of five wastewater treatment plants (WWTPs located in Amathole and Chris Hani District Municipalities in South Africa over a 12 months period between September 2012 and August 2013 using standard membrane filtration technique followed by cultivation on thiosulphate citrate-bile salts-sucrose (TCBS agar. The identities of the presumptive Vibrio isolates were confirmed using polymerase chain reaction (PCR including delineation into V. parahaemolyticus, V. vulnificus and V. fluvialis pathotypes. The counts of Vibrio spp. varied with months in all the study sites and ranged in the order of 101 and 104 CFU/100mL. Vibrio distribution also showed seasonality with high counts being obtained in autumn and spring (p < 0.05. Prevalence of Vibrio spp. among the five WWTPs also differed significantly (p < 0.05. Of the 300 isolates that were confirmed as belonging to the Vibrio genus, 29% (86 were V. fluvialis, 28% (84 were V. vulnificus and 12% (35 were V. parahaemolyticus. The isolation of Vibrio pathogens from the final effluent suggests that this pathogen is in circulation in some pockets of the population and that the WWTPs under study do not efficiently remove bacterial pathogens from the wastewater and consequently are threats to public health.

  9. Environmental parameters influence on the dynamics of total and pathogenic Vibrio parahaemolyticus densities in Crassostrea virginica harvested from Mexico’s Gulf coast

    International Nuclear Information System (INIS)

    Highlights: • V. parahaemolyticus densities in oysters were isolated in spring and winter seasons. • Pathogenic genes abundances varied with environmental parameters seasonal changes. • Water temperature modulated V. parahaemolyticus abundance during reduced salinities. • V. parahaemolyticus with potentially pathogenic genes raises important health issues. - Abstract: The influence of environmental parameters on the total and pathogenic Vibrio parahaemolyticus seasonal densities in American oysters (Crassostrea virginica) was evaluated for 1 year. Harvesting site A yielded the highest mean densities of V. parahaemolyticus tlh+, tdh+/trh−, tdh−/trh+ and tdh+/trh+ during spring season at 2.57, 1.74, 0.36, and −0.40 log10 MPN/g, respectively, and tdh+/orf8+ during winter season (0.90 log10 MPN/g). V. parahaemolyticus tlh+ densities were associated to salinity (R2 = 0.372, P < 0.022), tdh+/trh+ to turbidity (R2 = 0.597, P < 0.035), and orf8+ to temperature, salinity, and pH (R2 = 0.964, P < 0.001). The exposure to salinity and temperature conditions during winter and spring seasons regulated the dynamics of V. parahaemolyticus harboring potentially pathogenic genotypes within the oyster. The adaptive response of V. parahaemolyticus to seasonal environmental changes may lead to an increase in survival and virulence, threatening the seafood safety and increasing the risk of illness

  10. Temperature-Regulated Bleaching and Lysis of the Coral Pocillopora damicornis by the Novel Pathogen Vibrio coralliilyticus

    OpenAIRE

    Ben-Haim, Yael; Zicherman-Keren, Maya; Rosenberg, Eugene

    2003-01-01

    Coral bleaching is the disruption of symbioses between coral animals and their photosynthetic microalgal endosymbionts (zooxanthellae). It has been suggested that large-scale bleaching episodes are linked to global warming. The data presented here demonstrate that Vibrio coralliilyticus is an etiological agent of bleaching of the coral Pocillopora damicornis. This bacterium was present at high levels in bleached P. damicornis but absent from healthy corals. The bacterium was isolated in pure ...

  11. 广州地区海产品和珠江水中致病性弧菌污染状况监测%Investigation of contamination status of Pathogenic Vibrio isolated from seafood and Pearl River water in Guangzhou

    Institute of Scientific and Technical Information of China (English)

    邓志爱; 陈佳旋; 李孝权; 何洁仪; 吴新伟; 陈守义; 杨智聪

    2011-01-01

    目的:了解广州地区海产品和珠江水中致病性弧菌的污染状况,为卫生行政部门制定相关控制措施提供科学依据.方法:霍乱弧菌按WS289-2008附录A和霍乱防治手册(第五版)进行检测,副溶血性弧菌按GB/T4789.7-2008操作,创伤弧菌的检验按国家食源性致病菌监测工作手册中创伤弧菌检验标准操作程序进行.结果:2009年-2010年二年共完成320份样品检测,共检出119株致病菌,检出率为37.19%.其中检出率最高的是副溶血性弧菌,检出率为26.56%,其次为创伤弧菌,检出率为9.06%,O1群霍乱弧菌检出率为1.56%.海产品和珠江水中致病性弧菌污染水平存在季度性差异(P<0.005).结论:应加强对海产品和珠江水中致病性弧菌的监测,尤其是在温暖季节.%Objective:To learn about the contamination status of pathogenic Vibrio isolated from seafood and Pearl River water in Guangzhou area and to provide scientific data for related health administration in making controlling measures. Methods: Vibrio cholerae were isolated and identified according to Diagnostic criteria for cholera WS 289 - 2008 ( Appendix A) and Mannual for cholera prevention and therapy. Vibrio parahaemolyticus were isolated and identified according to National Standards of Microbiological Examination for Vibrio parahaemolyticus ( GB/T4789.7 - 2008 ). The isolation and identification of Vibrio vulnificus were performed according to National Surveillance Mannual for food- borne pathogenic bacteria. Results: 119 strains of pathogenic Vibrio were isolated from all 320 samples, with the detection rate being 37.19%. Among them, Vibrio parahaemolyticus had the most highest detection rate ( 26.56% ), followed by Vibrio vulnificus ( 9.06% ) and Vibrio cholera serogroup O1 ( 1.56% ). Significant differences were observed in the contamination rate among pathogenic Vibrio in different quarter of the year ( P < 0. 005 ).Conclusion: There is high degree of contamination

  12. O antigen modulates insect vector acquisition of the bacterial plant pathogen Xylella fastidiosa.

    Science.gov (United States)

    Rapicavoli, Jeannette N; Kinsinger, Nichola; Perring, Thomas M; Backus, Elaine A; Shugart, Holly J; Walker, Sharon; Roper, M Caroline

    2015-12-01

    Hemipteran insect vectors transmit the majority of plant pathogens. Acquisition of pathogenic bacteria by these piercing/sucking insects requires intimate associations between the bacterial cells and insect surfaces. Lipopolysaccharide (LPS) is the predominant macromolecule displayed on the cell surface of Gram-negative bacteria and thus mediates bacterial interactions with the environment and potential hosts. We hypothesized that bacterial cell surface properties mediated by LPS would be important in modulating vector-pathogen interactions required for acquisition of the bacterial plant pathogen Xylella fastidiosa, the causative agent of Pierce's disease of grapevines. Utilizing a mutant that produces truncated O antigen (the terminal portion of the LPS molecule), we present results that link this LPS structural alteration to a significant decrease in the attachment of X. fastidiosa to blue-green sharpshooter foreguts. Scanning electron microscopy confirmed that this defect in initial attachment compromised subsequent biofilm formation within vector foreguts, thus impairing pathogen acquisition. We also establish a relationship between O antigen truncation and significant changes in the physiochemical properties of the cell, which in turn affect the dynamics of X. fastidiosa adhesion to the vector foregut. Lastly, we couple measurements of the physiochemical properties of the cell with hydrodynamic fluid shear rates to produce a Comsol model that predicts primary areas of bacterial colonization within blue-green sharpshooter foreguts, and we present experimental data that support the model. These results demonstrate that, in addition to reported protein adhesin-ligand interactions, O antigen is crucial for vector-pathogen interactions, specifically in the acquisition of this destructive agricultural pathogen. PMID:26386068

  13. A bacterial pathogen uses dimethylsulfoniopropionate as a cue to target heat-stressed corals.

    Science.gov (United States)

    Garren, Melissa; Son, Kwangmin; Raina, Jean-Baptiste; Rusconi, Roberto; Menolascina, Filippo; Shapiro, Orr H; Tout, Jessica; Bourne, David G; Seymour, Justin R; Stocker, Roman

    2014-05-01

    Diseases are an emerging threat to ocean ecosystems. Coral reefs, in particular, are experiencing a worldwide decline because of disease and bleaching, which have been exacerbated by rising seawater temperatures. Yet, the ecological mechanisms behind most coral diseases remain unidentified. Here, we demonstrate that a coral pathogen, Vibrio coralliilyticus, uses chemotaxis and chemokinesis to target the mucus of its coral host, Pocillopora damicornis. A primary driver of this response is the host metabolite dimethylsulfoniopropionate (DMSP), a key element in the global sulfur cycle and a potent foraging cue throughout the marine food web. Coral mucus is rich in DMSP, and we found that DMSP alone elicits chemotactic responses of comparable intensity to whole mucus. Furthermore, in heat-stressed coral fragments, DMSP concentrations increased fivefold and the pathogen's chemotactic response was correspondingly enhanced. Intriguingly, despite being a rich source of carbon and sulfur, DMSP is not metabolized by the pathogen, suggesting that it is used purely as an infochemical for host location. These results reveal a new role for DMSP in coral disease, demonstrate the importance of chemical signaling and swimming behavior in the recruitment of pathogens to corals and highlight the impact of increased seawater temperatures on disease pathways. PMID:24335830

  14. Staying Alive: Vibrio cholerae's Cycle of Environmental Survival, Transmission, and Dissemination.

    Science.gov (United States)

    Conner, Jenna G; Teschler, Jennifer K; Jones, Christopher J; Yildiz, Fitnat H

    2016-04-01

    Infectious diseases kill nearly 9 million people annually. Bacterial pathogens are responsible for a large proportion of these diseases, and the bacterial agents of pneumonia, diarrhea, and tuberculosis are leading causes of death and disability worldwide. Increasingly, the crucial role of nonhost environments in the life cycle of bacterial pathogens is being recognized. Heightened scrutiny has been given to the biological processes impacting pathogen dissemination and survival in the natural environment, because these processes are essential for the transmission of pathogenic bacteria to new hosts. This chapter focuses on the model environmental pathogen Vibrio cholerae to describe recent advances in our understanding of how pathogens survive between hosts and to highlight the processes necessary to support the cycle of environmental survival, transmission, and dissemination. We describe the physiological and molecular responses of V. cholerae to changing environmental conditions, focusing on its survival in aquatic reservoirs between hosts and its entry into and exit from human hosts. PMID:27227302

  15. Inhibitory effect of Lactobacillus rhamnosus on pathogenic bacteria isolated from women with bacterial vaginosis

    Directory of Open Access Journals (Sweden)

    Gita Eslami

    2014-06-01

    Full Text Available Background: Considering the high prevalence of bacterial vaginosis and its association with urinary tract infection in women and treatment of gynecologic problems occur when a high recurrence of bacterial vaginosis is often treated with antibiotics. The purpose of this study is to investigate the inhibitory effect of Lactobacillus rhamnosus on pathogenic bacteria isolated from women with bacterial vaginosis, respectively.Materials and Methods: 96 samples from women with bacterial vaginosis discharge referred to health centers dependent Shahid Beheshti University in 91-92 were taken by a gynecologist with a dacron swab and put in sterile tubes containing TSB broth and Thioglycollate broth and were immediately sent to the lab location in cold chain for the next stages of investigation. From Thioglycollate and TSB medium was cultured on blood agar and EMB and Palkam and Differential diagnosis environments, and then incubated for 24 h at 37°C. Strains of Lactobacillus rhamnosus were cultured in MRSA environment and were transfered to the lab. After purification of pathogenic bacteria, MIC methods and antibiogram, Lactobacillus rhamnosus inhibitory effect on pathogenic bacteria is checked. Statistical analysis was done by SPSS software v.16.Results: The results of this study show the inhibitory effect of Lactobacillus rhamnosus on some pathogenic bacteria that cause bacterial vaginosis, including Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus agalactiae, Entrococcus, Listeria monocytogenes and E.Coli. Microscopic examination of stained smears of the large number of Lactobacillus and pathogenic bacteria showed reduced. The prevalence of abnormal vaginal discharge, history of drug use means of preventing pregnancy and douching, respectively, 61%, 55%, 42% and 13% respectively. Significant difference was observed between the use and non-use of IUD in women with bacterial vaginosis infection

  16. TLR4-dependent hepcidin expression by myeloid cells in response to bacterial pathogens

    OpenAIRE

    Peyssonnaux, Carole; Zinkernagel, Annelies S.; Datta, Vivekanand; Lauth, Xavier; Johnson, Randall S; Nizet, Victor

    2006-01-01

    Hepcidin is an antimicrobial peptide secreted by the liver during inflammation that plays a central role in mammalian iron homeostasis. Here we demonstrate the endogenous expression of hepcidin by macrophages and neutrophils in vitro and in vivo. These myeloid cell types produced hepcidin in response to bacterial pathogens in a toll-like receptor 4 (TLR4)-dependent fashion. Conversely, bacterial stimulation of macrophages triggered a TLR4-dependent reduction in the iron exporter ferroportin. ...

  17. Pulmonary bacterial pathogens in cystic fibrosis patients and antibiotic therapy: a tool for the health workers

    OpenAIRE

    2008-01-01

    Cystic fibrosis is the most common and best known genetic disease involving a defect in transepithelial Cl- transport by mutations in the CF gene on chromosome 7, which codes for the cystic fibrosis transmembrane conductance regulator protein (CFTR). The most serious symptoms are observed in the lungs, augmenting the risk of bacterial infection. The objective of this review was to describe the bacterial pathogens colonizing patients with cystic fibrosis. A systematic search was conducted usin...

  18. Small RNA Control of Cell-to-Cell Communication in Vibrio Harveyi and Vibrio Cholerae

    Science.gov (United States)

    Svenningsen, Sine Lo

    Quorum sensing is a process of cell-to-cell communication, by which bacteria coordinate gene expression and behavior on a population-wide scale. Quorum sensing is accomplished through production, secretion, and subsequent detection of chemical signaling molecules termed autoinducers. The human pathogen Vibrio cholerae and the marine bioluminescent bacterium Vibrio harveyi incorporate information from multiple autoinducers, and also environmental signals and metabolic cues into their quorum-sensing pathways. At the core of these pathways lie several homologous small regulatory RNA molecules, the Quorum Regulatory RNAs. Small noncoding RNAs have emerged throughout the bacterial and eukaryotic kingdoms as key regulators of behavioral and developmental processes. Here, I review our present understanding of the role of the Qrr small RNAs in integrating quorum-sensing signals and in regulating the individual cells response to this information.

  19. Bovine respiratory disease complex (BRDC): Viral and bacterial pathogens in Serbia

    OpenAIRE

    Kurćubić V.; Đoković R.; Vidanović D.; Šekler M.; Matović K.; Ilić Z.; Stojković J.

    2013-01-01

    Pathogens causing BRDC in Serbia were investigated. Two herds of beef cattle with bovine respiratory disease were included, with twenty diseased calves (10 from each farm) were chosen for isolation of bacteria on artificial culture media and determination by aerobic cultivation. The most common bacterial pathogen was isolated was Pasteurella multocida. Diffusion method of sensitivity to antibiotics (antibiogram), revealed that Enrofloxacin and Floron were m...

  20. Antibacterial potential of Thevetia peruviana leaf extracts against food associated bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Zebenay Gezahegn; Mohd Sayeed Akhtar; Delelegn Woyessa; Yinebeb Tariku

    2015-01-01

    Objective:To isolate and characterize the food associated bacterial strains, and to evaluate the antibacterial activity and minimum inhibitory concentration of various solvents (acetone, chloroform, methanol and petroleum ether) leaf extracts of Thevetia peruviana (T. peruviana) against their respective isolated and standard bacterial strains and also to investigate the presence of various phytochemical constituents in the leaf extracts of test plant. Methods:The food associated bacterial strains were isolated from students' lunch boxes in Tesfa Tewahido Primary School. The antimicrobial activity and minimum inhibitory concentrations were determined by the disc diffusion and serial dilution methods, respectively and phytochemical constituents were also detected in various solvent leaf extracts of T. peruviana. Results:The result showed that all the tested solvent leaf extracts of T. peruviana exhibited antibacterial activity against the tested standard and isolated bacterial strains with zones of inhibition ranged from 10.0 to 17.0 mm. Amongst the tested food borne bacterial pathogens, Salmonella typhimurium was most sensitive towards petroleum ether leaf extracts of T. peruviana while, methanol leaf extracts was relatively least effective against all the tested standard and isolated bacterial strains. Minimum inhibitory concentration of various solvent leaf extracts of T. peruviana ranged from 16.67 to 50.00 mg/mL for all the tested standard and isolated bacterial strains. The phytochemical constituents screening on the leaf extracts of T. peruviana showed the presence of alkaloids, cardiac glycosides, flavonoids, polyphenols, saponins and tannins. Conclusions:The present study suggests that T. peruviana could be used as prospective aspirants against the common food borne bacterial pathogens and also provide a wide array in the development of drugs against common food borne bacterial pathogens.

  1. Detection of a pathogen shift among the pectolytic bacterial pathogens of potato in Washington State

    Science.gov (United States)

    Bacterial tuber soft rot, aerial stem rot and blackleg are significant diseases of potatoes in Washington State. These diseases are caused by Pectobacterium carotovorum subsp. carotovorum, Pectobacterium atrosepticum, and Dickeya chrysanthemi, all characterized by the ability to produce pectolytic ...

  2. Pathogenic Triad in Bacterial Meningitis: Pathogen Invasion, NF-κB Activation, and Leukocyte Transmigration that Occur at the Blood-Brain Barrier

    OpenAIRE

    Wang, Shifu; Peng, Liang; Gai, Zhongtao; Zhang, Lehai; Jong, Ambrose; Cao, Hong; Huang, Sheng-He

    2016-01-01

    Bacterial meningitis remains the leading cause of disabilities worldwide. This life-threatening disease has a high mortality rate despite the availability of antibiotics and improved critical care. The interactions between bacterial surface components and host defense systems that initiate bacterial meningitis have been studied in molecular and cellular detail over the past several decades. Bacterial meningitis commonly exhibits triad hallmark features (THFs): pathogen penetration, nuclear fa...

  3. Draft genome sequence of pathogenic bacteria Vibrio parahaemolyticus strain Ba94C2, associated with acute hepatopancreatic necrosis disease isolate from South America.

    Science.gov (United States)

    Restrepo, Leda; Bayot, Bonny; Betancourt, Irma; Pinzón, Andres

    2016-09-01

    Vibrio parahaemolyticus is a pathogenic bacteria which has been associated to the early mortality syndrome (EMS) also known as hepatopancreatic necrosis disease (AHPND) causing high mortality in shrimp farms. Pathogenic strains contain two homologous genes related to insecticidal toxin genes, PirA and PirB, these toxin genes are located on a plasmid contained within the bacteria. Genomic sequences have allowed the finding of two strains with a divergent structure related to the geographic region from where they were found. The isolates from the geographic collection of Southeast Asia and Mexico show variable regions on the plasmid genome, indicating that even though they are not alike they still conserve the toxin genes. In this paper, we report for the first time, a pathogenic V. parahaemolyticus strain in shrimp from South America that showed symptoms of AHPND. The genomic analysis revealed that this strain of V. parahaemolyticus found in South America appears to be more related to the Southeast Asia as compared to the Mexican strains. This finding is of major importance for the shrimp industry, especially in regards to the urgent need for disease control strategies to avoid large EMS outbreaks and economic loss, and to determine its dispersion in South America. The whole-genome shotgun project of V. parahaemolyticus strain Ba94C2 have been deposited at DDBJ/EMBL/GenBank under the accession PRJNA335761. PMID:27570736

  4. Determination of Bacterial Pathogen in Foods for Export and their Raw Material

    International Nuclear Information System (INIS)

    Chile is a South American country with an important fish and shellfish production. These products are some of the most important items for the economy of the country. From 1998 to 2001, Chile exported $1 137 625 788 of fish and shellfish. Statistics also show that frozen vegetables are fast becoming high on the food export list. During recent years (1998 to 2001) $223 312 248 worth of frozen vegetables were exported to different countries. This study was performed to trace the presence of pathogens in some of these Chilean foods to be exported: 97 samples of salmon and 84 samples of different frozen vegetables (asparagus, peas and corn) were analyzed in order to determine their levels of microbial contamination. Total bacteria counts (mesophilic aerobes bacteria), Escherichia coli, Staphylococcus aureus, Bacillus cereus, Clostridium perfringens, Salmonella spp. and Listeria monocytogenes were tested. Vibrio cholerae was tested only in salmon samples. The analysis of salmon samples showed that the raw material presented a very good quality. However, during the filleting process the fish was contaminated, presenting higher total bacteria counts. Only one of the 48 final product samples presented contamination with a pathogenic bacteria (Listeria monocytogenes (<100 cfu/g)). Frozen vegetable samples (raw material and final products) did not present any of the pathogen bacteria studied. The mesophilic aerobes bacteria counts were reduced during processing due to the effectiveness of the good manufacturing practices and the technological process used. (author)

  5. Antibacterial activity of plant extracts on foodborne bacterial pathogens and food spoilage bacteria

    Science.gov (United States)

    Bacterial foodborne diseases are caused by consumption of foods contaminated with bacteria and/or their toxins. In this study, we evaluated antibacterial properties of twelve different extracts including turmeric, lemon and different kinds of teas against four major pathogenic foodborne bacteria inc...

  6. A bacterial pathogen uses distinct type III secretion systems to alternate between host kingdoms

    Science.gov (United States)

    Plant and animal-pathogenic bacteria utilize phylogenetically distinct type III secretion systems (T3SS) that produce needle-like injectisomes or pili for the delivery of effector proteins into host cells. Pantoea stewartii subsp. stewartii (Pnss), the causative agent of Stewart’s bacterial wilt and...

  7. HYDRAULIC DISRUPTION AND PASSIVE MIGRATION BY A BACTERIAL PATHOGEN IN OAK TREE XYLEM

    Science.gov (United States)

    Xylella fastidiosa (Xf) is a xylem-limited bacterial pathogen that causes leaf scorch symptoms in numerous host plant species in urban, agricultural, and natural ecosystems worldwide. The exact mechanism of hydraulic disruption and systemic colonization of xylem by Xf remains elusive across all hos...

  8. Impact of CRISPR immunity on the emergence and virulence of bacterial pathogens

    OpenAIRE

    Hatoum-Aslan, Asma; Marraffini, Luciano A.

    2013-01-01

    CRISPR-Cas systems protect prokaryotes from viruses and plasmids and function primarily as an adaptive immune system in these organisms. Recent discoveries, however, revealed unexpected roles for CRISPR loci as barriers to horizontal gene transfer and as modulators of gene expression. We review how both of these functions of CRISPR-Cas systems can affect the emergence and virulence of human bacterial pathogens.

  9. Analysis of apple (Malus) responses to bacterial pathogens using an oligo microarray

    Science.gov (United States)

    Fire blight is a devastating disease of apple (Malus x domestica) caused by the bacterial pathogen Erwinia amylovora (Ea). When infiltrated into host leaves, Ea induces reactions similar to a hypersensitive response (HR). Type III (T3SS) associated effectors, especially DspA/E, are suspected to ha...

  10. 'Nothing is permanent but change'- antigenic variation in persistent bacterial pathogens.

    Science.gov (United States)

    Palmer, Guy H; Bankhead, Troy; Lukehart, Sheila A

    2009-12-01

    Pathogens persist in immunocompetent mammalian hosts using various strategies, including evasion of immune effectors by antigenic variation. Among highly antigenically variant bacteria, gene conversion is used to generate novel expressed variants from otherwise silent donor sequences. Recombination using oligonucleotide segments from multiple donors is a combinatorial mechanism that tremendously expands the variant repertoire, allowing thousands of variants to be generated from a relatively small donor pool. Three bacterial pathogens, each encoded by a small genome (Treponema pallidum TprK and Anaplasma marginale Msp2 expression sites and donors are chromosomally encoded. Both T. pallidum and A. marginale generate antigenic variants in vivo in individual hosts and studies at the population level reveal marked strain diversity in the variant repertoire that may underlie pathogen strain structure and the capacity for re-infection and heterologous strain superinfection. Here, we review gene conversion in bacterial antigenic variation and discuss the short- and long-term selective pressures that shape the variant repertoire. PMID:19709057

  11. Long-term effects of ocean warming on vibrios

    Science.gov (United States)

    Pruzzo, C.; Pezzati, E.; Brettar, I.; Reid, P. C.; Colwell, R.; Höfle, M. G.; vezzulli, L.

    2012-12-01

    Vibrios are a major source of human disease, play an important role in the ecology and health of marine animals and are regarded as an abundant fraction of culturable bacteria of the ocean. There has been a considerable global effort to reduce the risk of Vibrio infections and yet in most countries both human and non-human illnesses associated with these bacteria are increasing. The cause of this increase is not known, but since vibrios are strongly thermodependant there is good reason to believe that global warming may have contributed. To investigate this possibility we examined historical samples from the Continuous Plankton Recorder (CPR) archive using advanced molecular analysis and pyrosequencing. For the first time we were able to recover environmental DNA from CPR samples that had been stored for up to ~50 years in a formalin-fixed format, which is suitable for molecular analyses of the associated prokaryotic community. To overcome the problem of DNA degradation due to the sample age and storage in formalin we develop an unbiased index of abundance for Vibrio quantification in CPR samples termed a 'relative Vibrio Abundance Index' (VAI). VAI is defined as the ratio of Vibrio spp. cells to total bacterial cells assessed by Real-Time PCR using genus-specific and universal primers, respectively, producing small amplicons of similar size (~100bp). We assessed VAI index on 55 samples (each representing 10 nautical miles tow equal to 3 m3 of filtered sewater) collected in August by the CPR survey in the North Sea from off the Rhine and Humber estuaries between 1961 to 2005 showing that the genus Vibrio has increased in prevalence in the last 44 years and that this increase is correlated significantly, during the same period, with warming sea surface temperature. In addition, by applying deep sequencing analysis of a subset of these samples we provide evidence that bacteria belonging to the genus Vibrio, including the human pathogen V. cholerae, not only increased

  12. Intracellular phase for an extracellular bacterial pathogen: MgtC shows the way

    Directory of Open Access Journals (Sweden)

    Audrey Bernut

    2015-08-01

    Full Text Available Pseudomonas aeruginosa is an extracellular pathogen known to impair host phagocytic functions. However, our recent results identify MgtC as a novel actor in P. aeruginosa virulence, which plays a role in an intramacrophage phase of this pathogen. In agreement with its intracellular function, P. aeruginosa mgtC gene expression is strongly induced when the bacteria reside within macrophages. MgtC was previously known as a horizontally-acquired virulence factor important for multiplication inside macrophages in several intracellular bacterial pathogens. MgtC thus provides a singular example of a virulence determinant that subverts macrophages both in intracellular and extracellular pathogens. Moreover, we demonstrate that P. aeru-ginosa MgtC is required for optimal growth in Mg2+ deprived medium, a property shared by MgtC factors from intracellular pathogens and, under Mg2+ limitation, P. aeruginosaMgtC prevents biofilm formation. We propose that MgtC has a similar function in intracellular and extracellular pathogens, which contributes to macrophage resistance and fine-tune adaptation to the host in relation to the different bacterial lifestyles. MgtC thus appears as an attractive target for antivirulence strategies and our work provides a natural peptide as MgtC antagonist, which paves the way for the development of MgtC inhibitors.

  13. Minimum Inhibitory Concentration Analysis of Nerium oleander against Bacterial Pathogens

    Institute of Scientific and Technical Information of China (English)

    M Abu Hena Mostofa Jamal; Shahedur Rahman; Md Azizul Islam; Md Rezaul Karim; Md Samsul Alam; Md Ziaur Rahman

    2012-01-01

    Objective: In this present study, it is tried to find out the antimicrobial effect and Minimum Inhibitory Concentration (MIC) of Nerium oleander against Bacillus subtilis (IFO 3026), Sarcina lutea (IFO 3232), Escherichia coli (IFO 3007) and Klebsiella Pneumoniae (ATTC 10031). Methods:Powered leaves were prepared and used for extraction with various solvents, viz, the petroleum ether, and chloroform extract of the oleander. All the solvent extracts were evaporated to dryness. Using the disc diffusion method, the bacterial growth were inhibited, Results: Among the solvent extracts tested, petroleum ether extract inhibited the growth of all the tested bacteria having various degrees of inhibition zones. Highest inhibitory activity was observed against E. coli (1.9 cm) and minimum inhibitory concentration was observed 2μg/ml also against E. coli. Both results were observed in case of petroleum ether extract. Petroleum ether extract also showed inhibitory zones of 1.8 cm, 1.4 cm and 1.5cm against B. subtilis, S. lutea and K. pneumoniae. On the other hand chloroform extract was observed to have inhibition zones of 1.2 cm, 1.6 cm, 1.8 cm and 1.5 cm against B. subtilis, S. lutea, E. coli and K. pneumoniae respectively. Conclusions: The study demonstrated that the petroleum ether extract of N. oleander is potentially good source of antibacterial agents. Further evaluation is necessary to identify the specific bioactive compounds, their mode of action and their nontoxic nature in vivo condition.

  14. Bacterial-induced cell reprogramming to stem cell-like cells: new premise in host-pathogen interactions

    OpenAIRE

    Hess, Samuel; Rambukkana, Anura

    2014-01-01

    Bacterial pathogens employ a myriad of strategies to alter host tissue cell functions for bacterial advantage during infection. Recent advances revealed a fusion of infection biology with stem cell biology by demonstrating developmental reprogramming of lineage committed host glial cells to progenitor/stem cell-like cells by an intracellular bacterial pathogen Mycobacterium leprae. Acquisition of migratory and immunomodulatory properties of such reprogrammed cells provides an added advantage ...

  15. Development of a Selective Medium for the Fungal Pathogen Fusarium graminearum Using Toxoflavin Produced by the Bacterial Pathogen Burkholderia glumae

    Directory of Open Access Journals (Sweden)

    Boknam Jung

    2013-12-01

    Full Text Available The ascomycete fungus Fusarium graminearum is a major causal agent for Fusarium head blight in cereals and produces mycotoxins such as trichothecenes and zearalenone. Isolation of the fungal strains from air or cereals can be hampered by various other airborne fungal pathogens and saprophytic fungi. In this study, we developed a selective medium specific to F. graminearum using toxoflavin produced by the bacterial pathogen Burkholderia glumae. F. graminearum was resistant to toxoflavin, while other fungi were sensitive to this toxin. Supplementing toxoflavin into medium enhanced the isolation of F. graminearum from rice grains by suppressing the growth of saprophytic fungal species. In addition, a medium with or without toxoflavin exposed to wheat fields for 1 h had 84% or 25%, respectively, of colonies identified as F. graminearum. This selection medium provides an efficient tool for isolating F. graminearum, and can be adopted by research groups working on genetics and disease forecasting.

  16. Infection of an Insect Vector with a Bacterial Plant Pathogen Increases Its Propensity for Dispersal.

    Science.gov (United States)

    Martini, Xavier; Hoffmann, Mark; Coy, Monique R; Stelinski, Lukasz L; Pelz-Stelinski, Kirsten S

    2015-01-01

    The spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. In sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. However, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. Here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such movement of vectors is likely manipulated by a bacterial plant pathogen. We investigated how Candidatus Liberibacter asiaticus (CLas) affects dispersal behavior, flight capacity, and the sexual attraction of its vector, the Asian citrus psyllid (Diaphorina citri Kuwayama). CLas is the putative causal agent of huanglongbing (HLB), which is a disease that threatens the viability of commercial citrus production worldwide. When D. citri developed on CLas-infected plants, short distance dispersal of male D. citri was greater compared to counterparts reared on uninfected plants. Flight by CLas-infected D. citri was initiated earlier and long flight events were more common than by uninfected psyllids, as measured by a flight mill apparatus. Additionally, CLas titers were higher among psyllids that performed long flights than psyllid that performed short flights. Finally, attractiveness of female D. citri that developed on infected plants to male conspecifics increased proportionally with increasing CLas bacterial titers measured within female psyllids. Our study indicates that the phytopathogen, CLas, may manipulate movement and mate selection behavior of their vectors, which is a possible evolved mechanism to promote their own spread. These results have global implications for both current HLB models of disease spread and control strategies. PMID:26083763

  17. Infection of an Insect Vector with a Bacterial Plant Pathogen Increases Its Propensity for Dispersal.

    Directory of Open Access Journals (Sweden)

    Xavier Martini

    Full Text Available The spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. In sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. However, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. Here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such movement of vectors is likely manipulated by a bacterial plant pathogen. We investigated how Candidatus Liberibacter asiaticus (CLas affects dispersal behavior, flight capacity, and the sexual attraction of its vector, the Asian citrus psyllid (Diaphorina citri Kuwayama. CLas is the putative causal agent of huanglongbing (HLB, which is a disease that threatens the viability of commercial citrus production worldwide. When D. citri developed on CLas-infected plants, short distance dispersal of male D. citri was greater compared to counterparts reared on uninfected plants. Flight by CLas-infected D. citri was initiated earlier and long flight events were more common than by uninfected psyllids, as measured by a flight mill apparatus. Additionally, CLas titers were higher among psyllids that performed long flights than psyllid that performed short flights. Finally, attractiveness of female D. citri that developed on infected plants to male conspecifics increased proportionally with increasing CLas bacterial titers measured within female psyllids. Our study indicates that the phytopathogen, CLas, may manipulate movement and mate selection behavior of their vectors, which is a possible evolved mechanism to promote their own spread. These results have global implications for both current HLB models of disease spread and control strategies.

  18. Survival of the Fittest: How Bacterial Pathogens Utilize Bile To Enhance Infection.

    Science.gov (United States)

    Sistrunk, Jeticia R; Nickerson, Kourtney P; Chanin, Rachael B; Rasko, David A; Faherty, Christina S

    2016-10-01

    Bacterial pathogens have coevolved with humans in order to efficiently infect, replicate within, and be transmitted to new hosts to ensure survival and a continual infection cycle. For enteric pathogens, the ability to adapt to numerous host factors under the harsh conditions of the gastrointestinal tract is critical for establishing infection. One such host factor readily encountered by enteric bacteria is bile, an innately antimicrobial detergent-like compound essential for digestion and nutrient absorption. Not only have enteric pathogens evolved to resist the bactericidal conditions of bile, but these bacteria also utilize bile as a signal to enhance virulence regulation for efficient infection. This review provides a comprehensive and up-to-date analysis of bile-related research with enteric pathogens. From common responses to the unique expression of specific virulence factors, each pathogen has overcome significant challenges to establish infection in the gastrointestinal tract. Utilization of bile as a signal to modulate virulence factor expression has led to important insights for our understanding of virulence mechanisms for many pathogens. Further research on enteric pathogens exposed to this in vivo signal will benefit therapeutic and vaccine development and ultimately enhance our success at combating such elite pathogens. PMID:27464994

  19. Host response to respiratory bacterial pathogens as identified by integrated analysis of human gene expression data.

    Directory of Open Access Journals (Sweden)

    Steven B Smith

    Full Text Available Respiratory bacterial pathogens are one of the leading causes of infectious death in the world and a major health concern complicated by the rise of multi-antibiotic resistant strains. Therapeutics that modulate host genes essential for pathogen infectivity could potentially avoid multi-drug resistance and provide a wider scope of treatment options. Here, we perform an integrative analysis of published human gene expression data generated under challenges from the gram-negative and Gram-positive bacteria pathogens, Pseudomonas aeruginosa and Streptococcus pneumoniae, respectively. We applied a previously described differential gene and pathway enrichment analysis pipeline to publicly available host mRNA GEO datasets resulting from exposure to bacterial infection. We found 72 canonical human pathways common between four GEO datasets, representing P. aeruginosa and S. pneumoniae. Although the majority of these pathways are known to be involved with immune response, we found several interesting new interactions such as the SUMO1 pathway that might have a role in bacterial infections. Furthermore, 36 host-bacterial pathways were also shared with our previous results for respiratory virus host gene expression. Based on our pathway analysis we propose several drug-repurposing opportunities supported by the literature.

  20. 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.

  1. Selection of Vibrio harveyi-resistant Litopenaeus vannamei via a three-round challenge selection with a pathogenic strain of V. harveyi.

    Science.gov (United States)

    Huang, Hai-Hong; Liu, Xiao-Lin; Xiang, Jian-Hai; Wang, Ping

    2013-08-01

    To obtain Vibrio harveyi-resistant Litopenaeus vannamei shrimp used for study on immune response of shrimp avoid vibriosis, a three-round challenge selection procedure was applied. In this procedure, resistant shrimp were selected gradually via three rounds challenge experiment with a pathogenic strain of V. harveyi at a median and controllable lethal dose of 96-h LD50 (the median lethal dose). After this procedure, the cumulative mortality of selected shrimp during 96 h after injection of V. harveyi at 2.0 × 10(6) cfu shrimp(-1) significantly decreased from 93.3% to 26.7%, the hours of beginning of death and the hours of attaining of the maximum cumulative mortality of shrimp prolonged from 4 h and 10 h to 8 h and 24 h, respectively. The LD50 of 6 h, 12 h, 24 h, 48 h and 96 h of selected shrimp significantly increased to 1.4 ± 0.1 × 10(7) (p < 0.01), 5.5 ± 0.4 × 10(6) (p < 0.01), 3.1 ± 0.2 × 10(6) (p < 0.01), 2.7 ± 0.1 × 10(6) (p < 0.01) and 2.7 ± 0.1 × 10(6) cfu shrimp(-1) (p < 0.01), about 15.9, 15.3, 9.4, 10.0 and 10.4 times of that of normal shrimp, respectively. In conclusion, the resistance of shrimp to Vibrio significantly increased after the three-round challenge selection procedure. PMID:23665547

  2. In vitro anti- bacterial activity of leaves extracts of Albizia lebbeck Benth against some selected pathogens

    Institute of Scientific and Technical Information of China (English)

    Mohammed Nazneen Bobby; Edward Gnanaraj Wesely; MarimuthuAntonisamy Johnson

    2012-01-01

    Objective: To screen the anti-bacterial activity of Albizia lebbeck (A. lebbeck) Benth leaves extract against the selected bacterial pathogens viz., Bacillus subtilis (MTCC441), Escherichia coli (MTCC443), Klebsiella pneumonia (MTCC 109), Proteus vulgaris (MTCC742), Pseudomonas aeruginosa (MTCC741), Salmonella typhii (MTCC733) and Staphylococus aureus (MTCC96).Methods:The leaves extracts of A. lebbeck was tested against bacteria by the agar disc diffusion method. Results: Results of the present study indicated that different extracts of A. lebbeck showed inhibitory effects against the pathogens. The present study results demonstrated that methanolic extracts of A. lebbeck conferred the widest spectrum activities that inhibited the growth of all studied pathogens with the maximum zone of inhibition. The methanolic extracts ofA. lebbeck illustrated the highest zone of inhibition against the pathogens Bacillus subtilis (16 mm), Escherichia coli (22 mm), Klebsiella pneumonia (11 mm), Proteus vulgaris (18 mm), Pseudomonas aeruginosa (22 mm), Salmonella typhii (23 mm) and Staphylococus aureus (17 mm). The ethyl acetate extracts demonstrated maximum zone of inhibition against Escherichia coli (26 mm), Pseudomonas aeruginosa (22 mm) and Klebsiella pneumonia (16 mm). Conclusions: It is expected that this study would direct to the establishment of some active compounds that could be used to formulate new and more potent anti-bacterial drugs of natural origin.

  3. Radiation Sensitivity of some Food Borne Bacterial Pathogens in Animal Foods and Minced Meat

    International Nuclear Information System (INIS)

    Bacteriological examination of 100 samples of animal food stuffs (fish meal and bone and meat meal; as models of dry food materials) and 50 samples of minced meat (as a model of moist food materials) revealed the isolation of different bacterial pathogens; Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Proteus spp., Staph. aureus and Salmonella species, in a decreasing order of occurrence. In the experiment; the dry food stuffs were sterilized in autoclave and the minced meat was sterilized by gamma irradiation at 10 kGy. The efficacy of gamma irradiation against the inoculated bacterial isolates (E coli 0157: H7, Salmonella enteritidis and Staph. aureus) in animal food stuffs and minced meat was investigated. Irradiated samples were stored at room temperature (25 degree C) for 2 weeks. The food borne pathogens used in this study showed a difference in radiation sensitivity. E. coli 0157: H7, Staphylococcus aureus and Salmonella enteritidis were eradicated at 1, 2 and 3 kGy, respectively. Also, inoculated pathogens in minced meat were more sensitive to ionizing radiation than dry animal food stuffs. It could be concluded that low doses of gamma irradiation are effective means of inactivating pathogenic bacteria. This radiation sensitivity is related to the bacterial isolates and the evaluated growth

  4. Development of Quorum-Based Anti-Virulence Therapeutics Targeting Gram-Negative Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Wen Shan Yew

    2013-08-01

    Full Text Available Quorum sensing is a cell density-dependent signaling phenomenon used by bacteria for coordination of population-wide phenotypes, such as expression of virulence genes, antibiotic resistance and biofilm formation. Lately, disruption of bacterial communication has emerged as an anti-virulence strategy with enormous therapeutic potential given the increasing incidences of drug resistance in pathogenic bacteria. The quorum quenching therapeutic approach promises a lower risk of resistance development, since interference with virulence generally does not affect the growth and fitness of the bacteria and, hence, does not exert an associated selection pressure for drug-resistant strains. With better understanding of bacterial communication networks and mechanisms, many quorum quenching methods have been developed against various clinically significant bacterial pathogens. In particular, Gram-negative bacteria are an important group of pathogens, because, collectively, they are responsible for the majority of hospital-acquired infections. Here, we discuss the current understanding of existing quorum sensing mechanisms and present important inhibitory strategies that have been developed against this group of pathogenic bacteria.

  5. Titanium dioxide nanoparticles enhance mortality of fish exposed to bacterial pathogens

    International Nuclear Information System (INIS)

    Nano-TiO2 is immunotoxic to fish and reduces the bactericidal function of fish neutrophils. Here, fathead minnows (Pimephales promelas) were exposed to low and high environmentally relevant concentration of nano-TiO2 (2 ng g−1 and 10 μg g−1 body weight, respectively), and were challenged with common fish bacterial pathogens, Aeromonas hydrophila or Edwardsiella ictaluri. Pre-exposure to nano-TiO2 significantly increased fish mortality during bacterial challenge. Nano-TiO2 concentrated in the kidney and spleen. Phagocytosis assay demonstrated that nano-TiO2 has the ability to diminish neutrophil phagocytosis of A. hydrophila. Fish injected with TiO2 nanoparticles displayed significant histopathology when compared to control fish. The interplay between nanoparticle exposure, immune system, histopathology, and infectious disease pathogenesis in any animal model has not been described before. By modulating fish immune responses and interfering with resistance to bacterial pathogens, manufactured nano-TiO2 has the potential to affect fish survival in a disease outbreak. - Highlights: • First data on the effect of nano-TiO2 pre-exposure on responses to bacterial pathogens. • Interplay between nano-TiO2, immune system, histopathology, and bacteria is described. • Nano-TiO2 has the potential to affect fish population survival in a disease outbreak. - By modulating fish immune responses and interfering with resistance to bacterial pathogens, internalized environmentally relevant concentrations of nano-TiO2 have potential to increase mortality of fish exposed to infectious disease challenge

  6. The type III secretion system apparatus determines the intracellular niche of bacterial pathogens.

    Science.gov (United States)

    Du, Juan; Reeves, Analise Z; Klein, Jessica A; Twedt, Donna J; Knodler, Leigh A; Lesser, Cammie F

    2016-04-26

    Upon entry into host cells, intracellular bacterial pathogens establish a variety of replicative niches. Although some remodel phagosomes, others rapidly escape into the cytosol of infected cells. Little is currently known regarding how professional intracytoplasmic pathogens, including Shigella, mediate phagosomal escape. Shigella, like many other Gram-negative bacterial pathogens, uses a type III secretion system to deliver multiple proteins, referred to as effectors, into host cells. Here, using an innovative reductionist-based approach, we demonstrate that the introduction of a functional Shigella type III secretion system, but none of its effectors, into a laboratory strain of Escherichia coli is sufficient to promote the efficient vacuole lysis and escape of the modified bacteria into the cytosol of epithelial cells. This establishes for the first time, to our knowledge, a direct physiologic role for the Shigella type III secretion apparatus (T3SA) in mediating phagosomal escape. Furthermore, although protein components of the T3SA share a moderate degree of structural and functional conservation across bacterial species, we show that vacuole lysis is not a common feature of T3SA, as an effectorless strain of Yersinia remains confined to phagosomes. Additionally, by exploiting the functional interchangeability of the translocator components of the T3SA of Shigella, Salmonella, and Chromobacterium, we demonstrate that a single protein component of the T3SA translocon-Shigella IpaC, Salmonella SipC, or Chromobacterium CipC-determines the fate of intracellular pathogens within both epithelial cells and macrophages. Thus, these findings have identified a likely paradigm by which the replicative niche of many intracellular bacterial pathogens is established. PMID:27078095

  7. Capture and concentration of viral and bacterial foodborne pathogens using apolipoprotein H.

    Science.gov (United States)

    Almand, Erin A; Goulter, Rebecca M; Jaykus, Lee-Ann

    2016-09-01

    The need for improved pathogen separation and concentration methods to reduce time-to-detection for foodborne pathogens is well recognized. Apolipoprotein H (ApoH) is an acute phase human plasma protein that has been previously shown to interact with viruses, lipopolysaccharides (LPS) and bacterial proteins. The purpose of this study was to determine if ApoH was capable of binding and efficiently capturing two representative human norovirus strains (GI.1 and GII.4), a cultivable surrogate, and four bacterial pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica serovar Enteritidis, and Staphylococcus aureus). Experiments were carried out using an ApoH-conjugated magnetic bead-based capture followed by pathogen detection using nucleic acid amplification. For all three viruses studied, >10% capture efficiency (microflora. A complementary plate-based capture assay showed that ApoH bound to a variety of human norovirus virus-like particles. ApoH has the potential to be a broadly reactive ligand for separating and concentrating representative foodborne pathogens, both bacteria and viruses. PMID:27439140

  8. Genomic survey of pathogenicity determinants and VNTR markers in the cassava bacterial pathogen Xanthomonas axonopodis pv. Manihotis strain CIO151.

    Directory of Open Access Journals (Sweden)

    Mario L Arrieta-Ortiz

    Full Text Available Xanthomonas axonopodis pv. manihotis (Xam is the causal agent of bacterial blight of cassava, which is among the main components of human diet in Africa and South America. Current information about the molecular pathogenicity factors involved in the infection process of this organism is limited. Previous studies in other bacteria in this genus suggest that advanced draft genome sequences are valuable resources for molecular studies on their interaction with plants and could provide valuable tools for diagnostics and detection. Here we have generated the first manually annotated high-quality draft genome sequence of Xam strain CIO151. Its genomic structure is similar to that of other xanthomonads, especially Xanthomonas euvesicatoria and Xanthomonas citri pv. citri species. Several putative pathogenicity factors were identified, including type III effectors, cell wall-degrading enzymes and clusters encoding protein secretion systems. Specific characteristics in this genome include changes in the xanthomonadin cluster that could explain the lack of typical yellow color in all strains of this pathovar and the presence of 50 regions in the genome with atypical nucleotide composition. The genome sequence was used to predict and evaluate 22 variable number of tandem repeat (VNTR loci that were subsequently demonstrated as polymorphic in representative Xam strains. Our results demonstrate that Xanthomonas axonopodis pv. manihotis strain CIO151 possesses ten clusters of pathogenicity factors conserved within the genus Xanthomonas. We report 126 genes that are potentially unique to Xam, as well as potential horizontal transfer events in the history of the genome. The relation of these regions with virulence and pathogenicity could explain several aspects of the biology of this pathogen, including its ability to colonize both vascular and non-vascular tissues of cassava plants. A set of 16 robust, polymorphic VNTR loci will be useful to develop a multi

  9. Benfang Lei’s research on heme acquisition in Gram-positive pathogens and bacterial pathogenesis

    Directory of Open Access Journals (Sweden)

    Benfang Lei

    2010-09-01

    Full Text Available Benfang Lei’s laboratory conducts research on pathogenesis of human pathogen Group A Streptococcus (GAS and horse pathogen Streptococcus equi (S. equi. His current research focuses on heme acquisition in Gram-positive pathogens and molecular mechanism of GAS and S. equi pathogenesis. Heme is an important source of essential iron for bacterial pathogens. Benfang Lei and colleagues identified the first cell surface heme-binding protein in Gram-positive pathogens and the heme acquisition system in GAS, demonstrated direct heme transfer from one protein to another, demonstrated an experimental pathway of heme acquisition by the Staphylococcus aureus Isd system, elucidated the activated heme transfer mechanism, and obtained evidence for a chemical mechanism of direct axial ligand displacement during the Shp-to-HtsA heme transfer reaction. These findings have considerably contributed to the progress that has been made over recent years in understanding the heme acquisition process in Gram-positive pathogens. Pathogenesis of GAS is mediated by an abundance of extracellular proteins, and pathogenic role and functional mechanism are not known for many of these virulence factors. Lei laboratory identified a secreted protein of GAS as a CovRS-regulated virulence factor that is a protective antigen and is critical for GAS spreading in the skin and systemic dissemination. These studies may lead to development of novel strategies to prevent and treat GAS infections.

  10. Benfang Lei’s research on heme acquisition in Gram-positive pathogens and bacterial pathogenesis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Benfang Lei’s laboratory conducts research on pathogenesis of human pathogen Group A Streptococcus (GAS)and horse pathogen Streptococcus equi(S.equi). His current research focuses on heme acquisition in Gram-positive pathogens and molecular mechanism of GAS and S.equi pathogenesis.Heme is an important source of essential iron for bacterial pathogens.Benfang Lei and colleagues identified the first cell surface heme-binding protein in Gram-positive pathogens and the heme acquisition system in GAS,demonstrated direct heme transfer from one protein to another,demonstrated an experimental pathway of heme acquisition by the Staphylococcus aureus Isd system,elucidated the activated heme transfer mechanism,and obtained evidence for a chemical mechanism of direct axial ligand displacement during the Shp-to-HtsA heme transfer reaction.These findings have considerably contributed to the progress that has been made over recent years in understanding the heme acquisition process in Grampositive pathogens.Pathogenesis of GAS is mediated by an abundance of extracellular proteins,and pathogenic role and functional mechanism are not known for many of these virulence factors.Lei laboratory identified a secreted protein of GAS as a CovRS-regulated virulence factor that is a protective antigen and is critical for GAS spreading in the skin and systemic dissemination.These studies may lead to development of novel strategies to prevent and treat GAS infections.

  11. Vibrio Cholerae

    OpenAIRE

    Sri Amelia

    2006-01-01

    Vibrio cholerae adalah salah satu bakteri yang masuk dalam family Vibrionaceae selain dari Aeromonas dan Plesiomonas, dan merupakan bagian dari genus Vibrio. Bakteri ini pertama kali ditemukan oleh Robert Koch pada tahun 1884 dan sangat penting dalam dunia kedokteran karena menyebabkan penyakit kolera, oleh Sri Amelia

  12. In Vitro Antibacterial Spectrum of Sodium Selenite against Selected Human Pathogenic Bacterial Strains

    Directory of Open Access Journals (Sweden)

    Mohammad Firoz Alam

    2016-01-01

    Full Text Available The objective of this investigation was to predict the antibacterial properties of sodium selenite against selected human pathogens. A group of six human bacterial pathogens including Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella planticola were utilized for screening. The spectrum of activity was qualified based on zone of inhibition. Our study demonstrated that sodium selenite exhibits a strong spectrum of activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Klebsiella planticola. The spectrum of activity was compared with standard ciprofloxacin disc (5 μg/disc and observed to have satisfactory effect.

  13. Nucleic Acid-based Detection of Bacterial Pathogens Using Integrated Microfluidic Platform Systems

    Directory of Open Access Journals (Sweden)

    Carl A. Batt

    2009-05-01

    Full Text Available The advent of nucleic acid-based pathogen detection methods offers increased sensitivity and specificity over traditional microbiological techniques, driving the development of portable, integrated biosensors. The miniaturization and automation of integrated detection systems presents a significant advantage for rapid, portable field-based testing. In this review, we highlight current developments and directions in nucleic acid-based micro total analysis systems for the detection of bacterial pathogens. Recent progress in the miniaturization of microfluidic processing steps for cell capture, DNA extraction and purification, polymerase chain reaction, and product detection are detailed. Discussions include strategies and challenges for implementation of an integrated portable platform.

  14. Detection and investigation of foodborne bacterial pathogens in Ningbo%宁波地区食品中致病菌污染物检测与调查

    Institute of Scientific and Technical Information of China (English)

    盛冬萍; 谢益君; 陈米娜; 徐景野

    2013-01-01

    Objective objective To understand the presence,contamination and cross contamination of foodborne bacterial pathogens in Ningbo city,provide basis for foodborne disease control,and trace the source of foodborne disease.Methods Strains were detected directly or after enrichment with biochemistry and API method,and subtyped with serum agglutination method.Antibiotic resistance and relative genes were detected with K-B method and PCR method respectively.Results 2 331 (7 species and 12 types) strains were detected from 6 812 food samples and the detection rate is 34.22% (2 331/6 812).The prevalent pathogens were Vibrio parahaemolyticus,and the detection rate was significantly different from the other types (P < 0.005).Vibrio parahaemolyticus could be classified into 10 sero-groups,and O6 and O5 were proved as the prevalent sero-groups.Most of the pathogens were sensitive to antibiotics.Three strains of Aeromonas were found multi-resistant with aacc resistance gene.Conclusion Various distribution was proved in foodborne bacteria in Ningbo.Contamination of foodborne pathogens was a major factor of foodborne diseases.Vibrio parahaemolyticus was the prevalent pathogenic bacteria.Most of the pathogens were sensitive to antibiotics.Bacteria with aacc resistance gene were found,which should raise concerns to control the spread of the resistant strains through rational administration of antibiotics and resistance surveillance.%目的 了解宁波地区食品中携带或污染的致病菌,为控制食源性疾病提供依据.方法 致病菌检测采用直接分离与增菌分离相结合的方法;细菌鉴定采用生化筛检和API等方法;血清分型采用诊断血清凝集法;药敏试验采用K-B法;采用PCR检测耐药基因.结果 从6 812份食品标本中检出致病菌7类12种,共2 331株,检出率为34.22%,以副溶血性弧菌检出率最高,与其他病原菌检出率比较差异有统计学意义(P<0.005).主要流行株

  15. Search for MicroRNAs Expressed by Intracellular Bacterial Pathogens in Infected Mammalian Cells

    Science.gov (United States)

    Furuse, Yuki; Finethy, Ryan; Saka, Hector A.; Xet-Mull, Ana M.; Sisk, Dana M.; Smith, Kristen L. Jurcic; Lee, Sunhee; Coers, Jörn; Valdivia, Raphael H.; Tobin, David M.; Cullen, Bryan R.

    2014-01-01

    MicroRNAs are expressed by all multicellular organisms and play a critical role as post-transcriptional regulators of gene expression. Moreover, different microRNA species are known to influence the progression of a range of different diseases, including cancer and microbial infections. A number of different human viruses also encode microRNAs that can attenuate cellular innate immune responses and promote viral replication, and a fungal pathogen that infects plants has recently been shown to express microRNAs in infected cells that repress host cell immune responses and promote fungal pathogenesis. Here, we have used deep sequencing of total expressed small RNAs, as well as small RNAs associated with the cellular RNA-induced silencing complex RISC, to search for microRNAs that are potentially expressed by intracellular bacterial pathogens and translocated into infected animal cells. In the case of Legionella and Chlamydia and the two mycobacterial species M. smegmatis and M. tuberculosis, we failed to detect any bacterial small RNAs that had the characteristics expected for authentic microRNAs, although large numbers of small RNAs of bacterial origin could be recovered. However, a third mycobacterial species, M. marinum, did express an ∼23-nt small RNA that was bound by RISC and derived from an RNA stem-loop with the characteristics expected for a pre-microRNA. While intracellular expression of this candidate bacterial microRNA was too low to effectively repress target mRNA species in infected cultured cells in vitro, artificial overexpression of this potential bacterial pre-microRNA did result in the efficient repression of a target mRNA. This bacterial small RNA therefore represents the first candidate microRNA of bacterial origin. PMID:25184567

  16. Search for microRNAs expressed by intracellular bacterial pathogens in infected mammalian cells.

    Directory of Open Access Journals (Sweden)

    Yuki Furuse

    Full Text Available MicroRNAs are expressed by all multicellular organisms and play a critical role as post-transcriptional regulators of gene expression. Moreover, different microRNA species are known to influence the progression of a range of different diseases, including cancer and microbial infections. A number of different human viruses also encode microRNAs that can attenuate cellular innate immune responses and promote viral replication, and a fungal pathogen that infects plants has recently been shown to express microRNAs in infected cells that repress host cell immune responses and promote fungal pathogenesis. Here, we have used deep sequencing of total expressed small RNAs, as well as small RNAs associated with the cellular RNA-induced silencing complex RISC, to search for microRNAs that are potentially expressed by intracellular bacterial pathogens and translocated into infected animal cells. In the case of Legionella and Chlamydia and the two mycobacterial species M. smegmatis and M. tuberculosis, we failed to detect any bacterial small RNAs that had the characteristics expected for authentic microRNAs, although large numbers of small RNAs of bacterial origin could be recovered. However, a third mycobacterial species, M. marinum, did express an ∼ 23-nt small RNA that was bound by RISC and derived from an RNA stem-loop with the characteristics expected for a pre-microRNA. While intracellular expression of this candidate bacterial microRNA was too low to effectively repress target mRNA species in infected cultured cells in vitro, artificial overexpression of this potential bacterial pre-microRNA did result in the efficient repression of a target mRNA. This bacterial small RNA therefore represents the first candidate microRNA of bacterial origin.

  17. Impact of transgenic potatoes expressing anti-bacterial agents on bacterial endophytes is comparable with the effects of plant genotype, soil type and pathogen infection

    NARCIS (Netherlands)

    Rasche, F.; Velvis, H.; Zachow, C.; Berg, G.; Elsas, van J.D.; Sessitsch, A.

    2006-01-01

    1. Blackleg and soft rot disease of potatoes Solanum tuberosum L., mainly caused by the bacterial pathogen Erwinia carotovora ssp. atrospetica (Eca), lead to enormous yield losses world-wide. Genetically modified (GM) potatoes producing anti-bacterial agents, such as cecropin/attacin and T4 lysozyme

  18. Genetic diversity of citrus bacterial canker pathogens preserved in herbarium specimens

    OpenAIRE

    Li, Wenbin; Song, Qijian; Brlansky, Ronald H.; Hartung, John S.

    2007-01-01

    Citrus bacterial canker (CBC) caused by Xanthomonas axonopodis pv. citri (Xac) was first documented in India and Java in the mid 19th century. Since that time, the known distribution of the disease has steadily increased. Concurrent with the dispersion of the pathogen, the diversity of described strains continues to increase, with novel strains appearing in Saudi Arabia, Iran, and Florida in the last decade. Herbarium specimens of infected plants provide an historical record documenting both ...

  19. An Alternative Efficient Procedure for Purification of the Obligate Intracellular Fish Bacterial Pathogen Piscirickettsia salmonis

    OpenAIRE

    Henríquez, Vitalia; Rojas, María Verónica; Marshall, Sergio H.

    2003-01-01

    Piscirickettsia salmonis is an obligate intracellular bacterial pathogen of salmonid fish and the etiological agent of the aggressive disease salmonid rickettsial syndrome. Today, this disease, also known as piscirickettsiosis, is the cause of high mortality in net pen-reared salmonids in southern Chile. Although the bacteria can be grown in tissue culture cells, genetic analysis of the organism has been hindered because of the difficulty in obtaining P. salmonis DNA free from contaminating h...

  20. Fluorescence in situ hybridization for the tissue detection of bacterial pathogens associated with porcine infections

    DEFF Research Database (Denmark)

    Jensen, Henrik Elvang; Jensen, Louise Kruse; Barington, Kristiane;

    2015-01-01

    sequences within intact cells. FISH allows direct histological localization of the bacteria in the tissue and thereby a correlation between the infection and the histopathological changes present. This chapter presents protocols for FISH identification of bacterial pathogens in fixed deparaffinized tissue......Fluorescence in situ hybridization (FISH) is an efficient technique for the identification of specific bacteria in tissue of both experimental and spontaneous infections. The method detects specific sequences of nucleic acids by hybridization of fluorescently labeled probes to complementary target...

  1. Fluorescence In Situ Hybridization for the Tissue Detection of Bacterial Pathogens Associated with Porcine Infections

    DEFF Research Database (Denmark)

    Elvang Jensen, Henrik; Jensen, Louise Kruse; Barington, Kristiane;

    2015-01-01

    sequences within intact cells. FISH allows direct histological localization of the bacteria in the tissue and thereby a correlation between the infection and the histopathological changes present. This chapter presents protocols for FISH identification of bacterial pathogens in fixed deparaffinized tissue......Fluorescence in situ hybridization (FISH) is an efficient technique for the identification of specific bacteria in tissue of both experimental and spontaneous infections. The method detects specific sequences of nucleic acids by hybridization of fluorescently labeled probes to complementary target...

  2. Interactions among Strategies Associated with Bacterial Infection: Pathogenicity, Epidemicity, and Antibiotic Resistance†

    OpenAIRE

    Martínez, José L.; Baquero, Fernando

    2002-01-01

    Infections have been the major cause of disease throughout the history of human populations. With the introduction of antibiotics, it was thought that this problem should disappear. However, bacteria have been able to evolve to become antibiotic resistant. Nowadays, a proficient pathogen must be virulent, epidemic, and resistant to antibiotics. Analysis of the interplay among these features of bacterial populations is needed to predict the future of infectious diseases. In this regard, we hav...

  3. Inducible Resistance of Fish Bacterial Pathogens to the Antimicrobial Peptide Cecropin B▿

    OpenAIRE

    Sallum, Ulysses W.; Chen, Thomas T

    2008-01-01

    Cecropin B is a cationic antimicrobial peptide originally isolated from the diapausing pupae of the giant silk moth, Hylphora cecropia. Cecropin B elicits its antimicrobial effects through disruption of the anionic cell membranes of gram-negative bacteria. Previous work by our laboratory demonstrated that a constitutively expressed cecropin B transgene conferred enhanced resistance to bacterial infection in medaka. The development of antibiotic resistance by pathogenic bacteria is a growing p...

  4. Effects of Benzalkonium Chloride on Planktonic Growth and Biofilm Formation by Animal Bacterial Pathogens

    OpenAIRE

    Ebrahimi, Azizollah; Hemati, Majid; Shabanpour, Ziba; Habibian Dehkordi, Saeed; BAHADORAN, Shahab; Lotfalian, Sharareh; Khubani, Shahin

    2015-01-01

    Background: Resistance toward quaternary ammonium compounds (QACs) is widespread among a diverse range of microorganisms and is facilitated by several mechanisms such as biofilm formation. Objectives: In this study, the effects of benzalkonium chloride on planktonic growth and biofilm formation by some field isolates of animal bacterial pathogens were investigated. Materials and Methods: Forty clinical isolates of Escherichia coli, Salmonella serotypes, Staphylococcus aureus and Streptococcus...

  5. Convergent use of RhoGAP toxins by eukaryotic parasites and bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Dominique Colinet

    2007-12-01

    Full Text Available Inactivation of host Rho GTPases is a widespread strategy employed by bacterial pathogens to manipulate mammalian cellular functions and avoid immune defenses. Some bacterial toxins mimic eukaryotic Rho GTPase-activating proteins (GAPs to inactivate mammalian GTPases, probably as a result of evolutionary convergence. An intriguing question remains whether eukaryotic pathogens or parasites may use endogenous GAPs as immune-suppressive toxins to target the same key genes as bacterial pathogens. Interestingly, a RhoGAP domain-containing protein, LbGAP, was recently characterized from the parasitoid wasp Leptopilina boulardi, and shown to protect parasitoid eggs from the immune response of Drosophila host larvae. We demonstrate here that LbGAP has structural characteristics of eukaryotic RhoGAPs but that it acts similarly to bacterial RhoGAP toxins in mammals. First, we show by immunocytochemistry that LbGAP enters Drosophila immune cells, plasmatocytes and lamellocytes, and that morphological changes in lamellocytes are correlated with the quantity of LbGAP they contain. Demonstration that LbGAP displays a GAP activity and specifically interacts with the active, GTP-bound form of the two Drosophila Rho GTPases Rac1 and Rac2, both required for successful encapsulation of Leptopilina eggs, was then achieved using biochemical tests, yeast two-hybrid analysis, and GST pull-down assays. In addition, we show that the overall structure of LbGAP is similar to that of eukaryotic RhoGAP domains, and we identify distinct residues involved in its interaction with Rac GTPases. Altogether, these results show that eukaryotic parasites can use endogenous RhoGAPs as virulence factors and that despite their differences in sequence and structure, eukaryotic and bacterial RhoGAP toxins are similarly used to target the same immune pathways in insects and mammals.

  6. Pathogenicity of some bacterial species isolated from the bee digestive tract

    Directory of Open Access Journals (Sweden)

    Dugalić-Vrndić Nada

    2010-01-01

    Full Text Available The aim of this paper was to examine the pathogenicity of most commonly isolated bacteria from the digestive tract of bees. Bees from 150 colonies (n=3000 were examined and 19 bacterial species were isolated, which are either permanent or temporary inhabitants of the digestive tract. Pathogenic activity of the most commonly isolated species (Enterobacter aerogenes, Klebsiella ozaenae, Klebsiella pneumonie, Citrobacter freundii, Enterobacter cloacae and Enterobacter agglomerans was examined on seven-day-old chicken embryos and tissue of MDBK cells. Bacterial inoculation of the examined bacteria was conducted in the alantoic cavity of chicken embryos in the quantity of 0.5 mL. Control noninoculated and inoculated embryos were incubated at 38oC with about 60% relative humidity. All six bacterial species manifested pathogenic activity on chicken embryos and caused their death within 2-4 days and changes such as lagging in embryo development, bleeding and unpleasant smell. The bacteria examined in MDBK cell lines of bovine kidney tissue did not manifest cytopathogenic effect and the structure of control tissue was normal.

  7. Bacteriocin from Bacillus subtilis as a novel drug against diabetic foot ulcer bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Baby Joseph; Berlina Dhas; Vimalin Hena; Justin Raj

    2013-01-01

    Objective:To isolate and identify Bacillus subtilis (B. subtilis) from soil and to characterize and partially purify the bacteriocin. To evaluate the antimicrobial activity against four diabetic foot ulcer bacterial pathogens. Methods:Genotypic identification was done based on Bergey’s manual of systemic bacteriology. Antimicrobial susceptibility test was done by Kirby-Bauer disc diffusion method. Colonies were identified by colony morphology and biochemical characterization and also compared with MTCC 121 strain. Further identification was done by 16S rRNA sequencing. Inhibitory activities of partially purified bacteriocin on all the DFU isolates were done by agar well diffusion method. The strain was identified to produce bacteriocin by stab overlay assay. Bacteriocin was extracted by organic solvent extraction using chloroform, further purified by HPLC and physical, and chemical characterization was performed. Results: The four isolates showed high level of resistance to amoxyclav and sensitivity to ciprofloxacin. HPLC purification revealed that the extracts are bacteriocin. The phylogenetic tree analysis results showed that the isolate was 99%related to B. subtilis BSF01. The results reveled activity to all the four isolates and high level of activity was seen in case of Klebsiella sp. Conclusions:Partially purified bacteriocin was found to have antimicrobial activity against the four diabetic foot ulcer bacterial pathogens, which can thus be applied as a better drug molecule on further studies. The strain B. subtilis are found to be safe for use and these antimicrobial peptides can be used as an antimicrobial in humans to treat DFU bacterial pathogens.

  8. Insights into the emergent bacterial pathogen Cronobacter spp., generated by multilocus sequence typing and analysis

    Directory of Open Access Journals (Sweden)

    StephenForsythe

    2012-11-01

    Full Text Available Cronobacter spp. (previously known as Enterobacter sakazakii is a bacterial pathogen affecting all age groups, with particularly severe clinical complications in neonates and infants. One recognised route of infection being the consumption of contaminated infant formula. As a recently recognised bacterial pathogen of considerable importance and regulatory control, appropriate detection and identification schemes are required. The application of multilocus sequence typing (MLST and analysis (MLSA of the seven alleles atpD, fusA, glnS, gltB, gyrB, infB and ppsA (concatenated length 3036 base pairs has led to considerable advances in our understanding of the genus. This approach is supported by both the reliability of DNA sequencing over subjective phenotyping and the establishment of a MLST database which has open access and is also curated; http://www.pubMLST.org/cronobacter. MLST has been used to describe the diversity of the newly recognised genus, instrumental in the formal recognition of new Cronobacter species (C. universalis and C. condimenti and revealed the high clonality of strains and the association of clonal complex 4 with neonatal meningitis cases. Clearly the MLST approach has considerable benefits over the use of non-DNA sequence based methods of analysis for newly emergent bacterial pathogens. The application of MLST and MLSA has dramatically enabled us to better understand this opportunistic bacterium which can cause irreparable damage to a newborn baby’s brain, and has contributed to improved control measures to protect neonatal health.

  9. Exposure to viral and bacterial pathogens among Soay sheep (Ovis aries) of the St Kilda archipelago.

    Science.gov (United States)

    Graham, A L; Nussey, D H; Lloyd-Smith, J O; Longbottom, D; Maley, M; Pemberton, J M; Pilkington, J G; Prager, K C; Smith, L; Watt, K A; Wilson, K; McNEILLY, T N; Brülisauer, F

    2016-07-01

    We assessed evidence of exposure to viruses and bacteria in an unmanaged and long-isolated population of Soay sheep (Ovis aries) inhabiting Hirta, in the St Kilda archipelago, 65 km west of Benbecula in the Outer Hebrides of Scotland. The sheep harbour many metazoan and protozoan parasites but their exposure to viral and bacterial pathogens is unknown. We tested for herpes viral DNA in leucocytes and found that 21 of 42 tested sheep were infected with ovine herpesvirus 2 (OHV-2). We also tested 750 plasma samples collected between 1997 and 2010 for evidence of exposure to seven other viral and bacterial agents common in domestic Scottish sheep. We found evidence of exposure to Leptospira spp., with overall seroprevalence of 6·5%. However, serological evidence indicated that the population had not been exposed to border disease, parainfluenza, maedi-visna, or orf viruses, nor to Chlamydia abortus. Some sheep tested positive for antibodies against Mycobacterium avium subsp. paratuberculosis (MAP) but, in the absence of retrospective faecal samples, the presence of this infection could not be confirmed. The roles of importation, the pathogen-host interaction, nematode co-infection and local transmission warrant future investigation, to elucidate the transmission ecology and fitness effects of the few viral and bacterial pathogens on Hirta. PMID:26829883

  10. Diet and environment shape fecal bacterial microbiota composition and enteric pathogen load of grizzly bears.

    Directory of Open Access Journals (Sweden)

    Clarissa Schwab

    Full Text Available BACKGROUND: Diet and environment impact the composition of mammalian intestinal microbiota; dietary or health disturbances trigger alterations in intestinal microbiota composition and render the host susceptible to enteric pathogens. To date no long term monitoring data exist on the fecal microbiota and pathogen load of carnivores either in natural environments or in captivity. This study investigates fecal microbiota composition and the presence of pathogenic Escherichia coli and toxigenic clostridia in wild and captive grizzly bears (Ursus arctos and relates these to food resources consumed by bears. METHODOLOGY/PRINCIPAL FINDINGS: Feces were obtained from animals of two wild populations and from two captive animals during an active bear season. Wild animals consumed a diverse diet composed of plant material, animal prey and insects. Captive animals were fed a regular granulated diet with a supplement of fruits and vegetables. Bacterial populations were analyzed using quantitative PCR. Fecal microbiota composition fluctuated in wild and in captive animals. The abundance of Clostridium clusters I and XI, and of C. perfringens correlated to regular diet protein intake. Enteroaggregative E. coli were consistently present in all populations. The C. sordellii phospholipase C was identified in three samples of wild animals and for the first time in Ursids. CONCLUSION: This is the first longitudinal study monitoring the fecal microbiota of wild carnivores and comparing it to that of captive individuals of the same species. Location and diet affected fecal bacterial populations as well as the presence of enteric pathogens.

  11. A transcriptional regulator linking quorum sensing and chitin induction to render Vibrio cholerae naturally transformable

    OpenAIRE

    Lo Scrudato, Mirella; Blokesch, Melanie

    2013-01-01

    The human pathogen Vibrio cholerae is an aquatic bacterium associated with zooplankton and their chitinous exoskeletons. On chitinous surfaces, V. cholerae initiates a developmental programme, known as natural competence, to mediate transformation, which is a mode of horizontal gene transfer. Competence facilitates the uptake of free DNA and recombination into the bacterial genome. Recent studies have indicated that chitin surfaces are required, but not sufficient to induce competence. Two ad...

  12. Effect of gamma radiation on shellstock oysters. Extension of shelf-life and reduction in bacterial numbers, with particular reference to Vibrio vulnificus

    International Nuclear Information System (INIS)

    Shellstock oysters from Apalachicola Bay, Florida, United States of America, were irradiated at the nation's first commercial food irradiator, Vindicator, Inc. in Mulberry, Florida, with four doses, and analysed for their shelf-life and bacterial levels. A 2-3 log cycle reduction in bacterial numbers was observed at all the doses immediately after irradiation. The shelf-life was limited in that the D50 values were found to be 30, 25, 7 and 6 days at 0.5, 1, 2 and 3 kGy, respectively. The D20 values were calculated as 17, 9, 4 and 4 days at 0.5, 1, 2 and 3 kGy, respectively. Even though the bacterial numbers were significantly lower in the irradiated oysters, the shelf-life was reduced markedly at doses higher than 1 kGy. The irradiated shellstock did not demonstrate any extension in shelf-life, above that of the non-irradiated controls; in fact, they experienced a reduction in shelf-life and there was a growing back of the surviving organisms, which reached levels that were higher than those observed in the controls. Vibrio vulnificus demonstrated high radiosensitivity, with D10 values of 0.062 and 0.037 kGy for the virulent and avirulent forms, respectively. Preliminary data indicate that the viable but non-culturable form of V. vulnificus is more radioresistant than the corresponding viable and culturable forms, but this needs further elucidation. Also, current research is directed at analysing the effects of the shell to meat ratio of the oysters, and how this affects their radioresistance. Furthermore, oysters from different locations have different shell to meat weight ratios, and this can influence the efficiency of radiation treatment. (author)

  13. Pathogenic Leptospira species express surface-exposed proteins belonging to the bacterial immunoglobulin superfamily.

    Science.gov (United States)

    Matsunaga, James; Barocchi, Michele A; Croda, Julio; Young, Tracy A; Sanchez, Yolanda; Siqueira, Isadora; Bolin, Carole A; Reis, Mitermayer G; Riley, Lee W; Haake, David A; Ko, Albert I

    2003-08-01

    Proteins with bacterial immunoglobulin-like (Big) domains, such as the Yersinia pseudotuberculosis invasin and Escherichia coli intimin, are surface-expressed proteins that mediate host mammalian cell invasion or attachment. Here, we report the identification and characterization of a new family of Big domain proteins, referred to as Lig (leptospiral Ig-like) proteins, in pathogenic Leptospira. Screening of L. interrogans and L. kirschneri expression libraries with sera from leptospirosis patients identified 13 lambda phage clones that encode tandem repeats of the 90 amino acid Big domain. Two lig genes, designated ligA and ligB, and one pseudogene, ligC, were identified. The ligA and ligB genes encode amino-terminal lipoprotein signal peptides followed by 10 or 11 Big domain repeats and, in the case of ligB, a unique carboxy-terminal non-repeat domain. The organization of ligC is similar to that of ligB but contains mutations that disrupt the reading frame. The lig sequences are present in pathogenic but not saprophytic Leptospira species. LigA and LigB are expressed by a variety of virulent leptospiral strains. Loss of Lig protein and RNA transcript expression is correlated with the observed loss of virulence during culture attenuation of pathogenic strains. High-pressure freeze substitution followed by immunocytochemical electron microscopy confirmed that the Lig proteins were localized to the bacterial surface. Immunoblot studies with patient sera found that the Lig proteins are a major antigen recognized during the acute host infection. These observations demonstrate that the Lig proteins are a newly identified surface protein of pathogenic Leptospira, which by analogy to other bacterial immunoglobulin superfamily virulence factors, may play a role in host cell attachment and invasion during leptospiral pathogenesis. PMID:12890019

  14. Chlorhexidine Digluconate Effects on Planktonic Growth and Biofilm Formation in Some Field Isolates of Animal Bacterial Pathogens

    OpenAIRE

    Ebrahimi, Azizollah; Hemati, Majid; Habibian Dehkordi, Saeed; Bahadoran, Shahab; Khoshnood, Sheida; Khubani, Shahin; Dokht Faraj, Mahdi; Hakimi Alni, Reza

    2014-01-01

    Background: To study chlorhexidine digluconate disinfectant effects on planktonic growth and biofilm formation in some bacterial field isolates from animals. Objectives: The current study investigated chlorhexidine digluconate effects on planktonic growth and biofilm formation in some field isolates of veterinary bacterial pathogens. Materials and Methods: Forty clinical isolates of Escherichia coli, Salmonella serotypes, Staphylococcus. aureus and Streptococcus agalactiae (10 isolates for ea...

  15. Inhibitory Effect of Camptothecin against Rice Bacterial Brown Stripe Pathogen Acidovorax avenae subsp. avenae RS-2.

    Science.gov (United States)

    Dong, Qiaolin; Luo, Ju; Qiu, Wen; Cai, Li; Anjum, Syed Ishtiaq; Li, Bin; Hou, Mingsheng; Xie, Guanlin; Sun, Guochang

    2016-01-01

    Camptothecin (CPT) has anticancer, antiviral, and antifungal properties. However, there is a dearth of information about antibacterial activity of CPT. Therefore, in this study, we investigated the inhibitory effect of CPT on Acidovorax avenae subsp. avenae strain RS-2, the pathogen of rice bacterial brown stripe, by measuring cell growth, DNA damage, cell membrane integrity, the expression of secretion systems, and topoisomerase-related genes, as well as the secretion of effector protein Hcp. Results indicated that CPT solutions at 0.05, 0.25, and 0.50 mg/mL inhibited the growth of strain RS-2 in vitro, while the inhibitory efficiency increased with an increase in CPT concentration, pH, and incubation time. Furthermore, CPT treatment affected bacterial growth and replication by causing membrane damage, which was evidenced by transmission electron microscopic observation and live/dead cell staining. In addition, quantitative real-time PCR analysis indicated that CPT treatment caused differential expression of eight secretion system-related genes and one topoisomerase-related gene, while the up-regulated expression of hcp could be justified by the increased secretion of Hcp based on the ELISA test. Overall, this study indicated that CPT has the potential to control the bacterial brown stripe pathogen of rice. PMID:27472315

  16. Comparison of individual and pooled sampling methods for detecting bacterial pathogens of fish

    Science.gov (United States)

    Mumford, Sonia; Patterson, Chris; Evered, J.; Brunson, Ray; Levine, J.; Winton, J.

    2005-01-01

    Examination of finfish populations for viral and bacterial pathogens is an important component of fish disease control programs worldwide. Two methods are commonly used for collecting tissue samples for bacteriological culture, the currently accepted standards for detection of bacterial fish pathogens. The method specified in the Office International des Epizooties Manual of Diagnostic Tests for Aquatic Animals permits combining renal and splenic tissues from as many as 5 fish into pooled samples. The American Fisheries Society (AFS) Blue Book/US Fish and Wildlife Service (USFWS) Inspection Manual specifies the use of a bacteriological loop for collecting samples from the kidney of individual fish. An alternative would be to more fully utilize the pooled samples taken for virology. If implemented, this approach would provide substantial savings in labor and materials. To compare the relative performance of the AFS/USFWS method and this alternative approach, cultures of Yersinia ruckeri were used to establish low-level infections in groups of rainbow trout (Oncorhynchus mykiss) that were sampled by both methods. Yersinia ruckeri was cultured from 22 of 37 groups by at least 1 method. The loop method yielded 18 positive groups, with 1 group positive in the loop samples but negative in the pooled samples. The pooled samples produced 21 positive groups, with 4 groups positive in the pooled samples but negative in the loop samples. There was statistically significant agreement (Spearman coefficient 0.80, P sampling methods to permit detection of low-level bacterial infections of rainbow trout.

  17. A Comparison between Transcriptome Sequencing and 16S Metagenomics for Detection of Bacterial Pathogens in Wildlife.

    Directory of Open Access Journals (Sweden)

    Maria Razzauti

    Full Text Available Rodents are major reservoirs of pathogens responsible for numerous zoonotic diseases in humans and livestock. Assessing their microbial diversity at both the individual and population level is crucial for monitoring endemic infections and revealing microbial association patterns within reservoirs. Recently, NGS approaches have been employed to characterize microbial communities of different ecosystems. Yet, their relative efficacy has not been assessed. Here, we compared two NGS approaches, RNA-Sequencing (RNA-Seq and 16S-metagenomics, assessing their ability to survey neglected zoonotic bacteria in rodent populations.We first extracted nucleic acids from the spleens of 190 voles collected in France. RNA extracts were pooled, randomly retro-transcribed, then RNA-Seq was performed using HiSeq. Assembled bacterial sequences were assigned to the closest taxon registered in GenBank. DNA extracts were analyzed via a 16S-metagenomics approach using two sequencers: the 454 GS-FLX and the MiSeq. The V4 region of the gene coding for 16S rRNA was amplified for each sample using barcoded universal primers. Amplicons were multiplexed and processed on the distinct sequencers. The resulting datasets were de-multiplexed, and each read was processed through a pipeline to be taxonomically classified using the Ribosomal Database Project. Altogether, 45 pathogenic bacterial genera were detected. The bacteria identified by RNA-Seq were comparable to those detected by 16S-metagenomics approach processed with MiSeq (16S-MiSeq. In contrast, 21 of these pathogens went unnoticed when the 16S-metagenomics approach was processed via 454-pyrosequencing (16S-454. In addition, the 16S-metagenomics approaches revealed a high level of coinfection in bank voles.We concluded that RNA-Seq and 16S-MiSeq are equally sensitive in detecting bacteria. Although only the 16S-MiSeq method enabled identification of bacteria in each individual reservoir, with subsequent derivation of

  18. Animals devoid of pulmonary system as infection models in the study of lung bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Yamilé eLópez Hernández

    2015-02-01

    Full Text Available Biological disease models can be difficult and costly to develop and use on a routine basis. Particularly, in vivo lung infection models performed to study lung pathologies use to be laborious, demand a great time and commonly are associated with ethical issues. When infections in experimental animals are used, they need to be refined, defined, and validated for their intended purpose. Therefore, alternative and easy to handle models of experimental infections are still needed to test the virulence of bacterial lung pathogens. Because non-mammalian models have less ethical and cost constraints as a subjects for experimentation, in some cases would be appropriated to include these models as a valuate tools to explore host-pathogen interactions. Numerous scientific data have been argued to the more extensive use of several kinds of alternative models, such as, the vertebrate zebrafish (Danio rerio, and non-vertebrate insects and nematodes (e.g. Caenorhabditis elegans in the study of diverse infectious agents that affect humans. Here we review the use of these vertebrate and non-vertebrate models in the study of bacterial agents, which are considered the principal causes of lung injury. Curiously none of these animals have a respiratory system as in air-breathing vertebrates, where respiration takes place in lungs. Despite this fact, with the present review we sought to provide elements in favour of the use of these alternative animal models of infection to reveal the molecular signatures of host-pathogen interactions.

  19. Animals devoid of pulmonary system as infection models in the study of lung bacterial pathogens.

    Science.gov (United States)

    López Hernández, Yamilé; Yero, Daniel; Pinos-Rodríguez, Juan M; Gibert, Isidre

    2015-01-01

    Biological disease models can be difficult and costly to develop and use on a routine basis. Particularly, in vivo lung infection models performed to study lung pathologies use to be laborious, demand a great time and commonly are associated with ethical issues. When infections in experimental animals are used, they need to be refined, defined, and validated for their intended purpose. Therefore, alternative and easy to handle models of experimental infections are still needed to test the virulence of bacterial lung pathogens. Because non-mammalian models have less ethical and cost constraints as a subjects for experimentation, in some cases would be appropriated to include these models as valuable tools to explore host-pathogen interactions. Numerous scientific data have been argued to the more extensive use of several kinds of alternative models, such as, the vertebrate zebrafish (Danio rerio), and non-vertebrate insects and nematodes (e.g., Caenorhabditis elegans) in the study of diverse infectious agents that affect humans. Here, we review the use of these vertebrate and non-vertebrate models in the study of bacterial agents, which are considered the principal causes of lung injury. Curiously none of these animals have a respiratory system as in air-breathing vertebrates, where respiration takes place in lungs. Despite this fact, with the present review we sought to provide elements in favor of the use of these alternative animal models of infection to reveal the molecular signatures of host-pathogen interactions. PMID:25699030

  20. Molecular Epidemiologic Typing Systems of Bacterial Pathogens: Current Issues and Perpectives

    Directory of Open Access Journals (Sweden)

    Marc J Struelens

    1998-09-01

    Full Text Available The epidemiologic typing of bacterial pathogens can be applied to answer a number of different questions: in case of outbreak, what is the extent and mode of transmission of epidemic clone(s ? In case of long-term surveillance, what is the prevalence over time and the geographic spread of epidemic and endemic clones in the population? A number of molecular typing methods can be used to classify bacteria based on genomic diversity into groups of closely-related isolates (presumed to arise from a common ancestor in the same chain of transmission and divergent, epidemiologically-unrelated isolates (arising from independent sources of infection. Ribotyping, IS-RFLP fingerprinting, macrorestriction analysis of chromosomal DNA and PCR-fingerprinting using arbitrary sequence or repeat element primers are useful methods for outbreak investigations and regional surveillance. Library typing systems based on multilocus sequence-based analysis and strain-specific probe hybridization schemes are in development for the international surveillance of major pathogens like Mycobacterium tuberculosis. Accurate epidemiological interpretation of data obtained with molecular typing systems still requires additional research on the evolution rate of polymorphic loci in bacterial pathogens.

  1. Exposure to the paralytic shellfish toxin producer Alexandrium catenella increases the susceptibility of the oyster Crassostrea gigas to pathogenic vibrios.

    OpenAIRE

    Celina Abi-Khalil; Carmen Lopez-Joven; Eric Abadie; Veronique Savar; Zouher Amzil; Mohamed Laabir; Jean-Luc Rolland

    2016-01-01

    International audience The multifactorial etiology of massive Crassostrea gigas summer mortalities results from complex interactions between oysters, opportunistic pathogens and environmental factors. In a field survey conducted in 2014 in the Mediterranean Thau Lagoon (France), we evidenced that the development of the toxic dinoflagellate Alexandrium catenella, which produces paralytic shellfish toxins (PSTs), was concomitant with the accumulation of PSTs in oyster flesh and the occurrenc...

  2. Identification and Characterization of Bacterial Vaginosis-Associated Pathogens Using a Comprehensive Cervical-Vaginal Epithelial Coculture Assay

    OpenAIRE

    Eade, Colleen R.; Diaz, Camila; Wood, Matthew P.; Anastos, Kathryn; Patterson, Bruce K.; Gupta, Phalguni; Cole, Amy L.; Cole, Alexander M.

    2012-01-01

    Bacterial vaginosis (BV) is the most commonly treated female reproductive tract affliction, characterized by the displacement of healthy lactobacilli by an overgrowth of pathogenic bacteria. BV can contribute to pathogenic inflammation, preterm birth, and susceptibility to sexually transmitted infections. As the bacteria responsible for BV pathogenicity and their interactions with host immunity are not understood, we sought to evaluate the effects of BV-associated bacteria on reproductive epi...

  3. Interactions of Seedborne Bacterial Pathogens with Host and Non-Host Plants in Relation to Seed Infestation and Seedling Transmission

    OpenAIRE

    Bhabesh Dutta; Ronald Gitaitis; Samuel Smith; David Langston

    2014-01-01

    The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same...

  4. Identification of polyvalent protective immunogens from outer membrane proteins in Vibrio parahaemolyticus to protect fish against bacterial infection.

    Science.gov (United States)

    Peng, Bo; Ye, Jin-Zhou; Han, Yi; Zeng, Li; Zhang, Jian-Ying; Li, Hui

    2016-07-01

    Vaccination is one of the most effective and economic way to prevent infectious diseases in aquaculture. The development of effective vaccines, however, is still limited, especially for polyvalent vaccines, which are against multiple species. With this regard, identification of polyvalent protective immunogens, serving as polyvalent vaccines, became a key step in vaccine development. In the current study, 17 outer membrane proteins from Vibrio parahaemolyticus were identified as immunogens. Further, four of the 17 proteins including VP2309, VP0887, VPA0548 and VP1019 were characterized as efficiently protective immunogens against V. parahaemolyticus' infection through passive and active immunizations in zebrafish. Importantly, these four proteins showed cross-protective capability against infections by Aeromonas hydrophila or/and Pseudomonas fluorescens, which shared similar epitopes with V. parahaemolyticus in homology of these proteins. Further investigation showed that the expression level of the four protective immunogens elevated in response to fish plasma in a dose-dependent manner. These results indicate that the four protective immunogens are polyvalent vaccine candidates in aquaculture. PMID:27071519

  5. Factors related to occurrence and distribution of selected bacterial and protozoan pathogens in Pennsylvania streams

    Science.gov (United States)

    Duris, Joseph W.; Reif, Andrew G.; Donna A. Crouse; Isaacs, Natasha M.

    2013-01-01

    The occurrence and distribution of fecal indicator bacteria (FIB) and bacterial and protozoan pathogens are controlled by diverse factors. To investigate these factors in Pennsylvania streams, 217 samples were collected quarterly from a 27-station water-quality monitoring network from July 2007 through August 2009. Samples were analyzed for concentrations of Escherichia coli (EC) and enterococci (ENT) indicator bacteria, concentrations of Cryptosporidium oocysts and Giardia cysts, and the presence of four genes related to pathogenic types of EC (eaeA, stx2, stx1, rfbO157) plus three microbial source tracking (MST) gene markers that are also associated with pathogenic ENT and EC (esp, LTIIa, STII). Water samples were concurrently analyzed for basic water chemistry, physical measures of water quality, nutrients, metals, and a suite of 79 organic compounds that included hormones, pharmaceuticals, and antibiotics. For each sample location, stream discharge was measured by using standardized methods at the time of sample collection, and ancillary sample site information, such as land use and geological characteristics, was compiled. Samples exceeding recreational water quality criteria were more likely to contain all measured pathogen genes but notCryptosporidium or Giardia (oo)cysts. FIB and Giardia density and frequency of eaeA gene occurrence were significantly related to season. When discharge at a sampling location was high (>75th percentile of daily mean discharge), there were greater densities of FIB and Giardia, and the stx2, rfbO157, STII, and esp genes were found more frequently than at other discharge conditions. Giardia occurrence was likely related to nonpoint sources, which are highly influential during seasonal overland transport resulting from snowmelt and elevated precipitation in late winter and spring in Pennsylvania. When MST markers of human, swine, or bovine origin were present, samples more frequently carried the eaeA, stx2

  6. Monitoring of Vibrio harveyi quorum sensing activity in real time during infection of brine shrimp larvae.

    Science.gov (United States)

    Defoirdt, Tom; Sorgeloos, Patrick

    2012-12-01

    Quorum sensing, bacterial cell-to-cell communication, has been linked to the virulence of pathogenic bacteria. Indeed, in vitro experiments have shown that many bacterial pathogens regulate the expression of virulence genes by this cell-to-cell communication process. Moreover, signal molecules have been detected in samples retrieved from infected hosts and quorum sensing disruption has been reported to result in reduced virulence in different host-pathogen systems. However, data on in vivo quorum sensing activity of pathogens during infection of a host are currently lacking. We previously reported that quorum sensing regulates the virulence of Vibrio harveyi in a standardised model system with gnotobiotic brine shrimp (Artemia franciscana) larvae. Here, we monitored quorum sensing activity in Vibrio harveyi during infection of the shrimp, using bioluminescence as a read-out. We found that wild-type Vibrio harveyi shows a strong increase in quorum sensing activity early during infection. In this respect, the bacteria behave remarkably similar in different larvae, despite the fact that only half of them survive the infection. Interestingly, when expressed per bacterial cell, Vibrio harveyi showed around 200-fold higher maximal quorum sensing-regulated bioluminescence when associated with larvae than in the culture water. Finally, the in vivo quorum sensing activity of mutants defective in the production of one of the three signal molecules is consistent with their virulence, with no detectable in vivo quorum sensing activity in AI-2- and CAI-1-deficient mutants. These results indicate that AI-2 and CAI-1 are the dominant signals during infection of brine shrimp. PMID:22673627

  7. Fecal indicators and bacterial pathogens in bottled water from Dhaka, Bangladesh

    Directory of Open Access Journals (Sweden)

    W. Ahmed

    2013-01-01

    Full Text Available Forty-six bottled water samples representing 16 brands from Dhaka, Bangladesh were tested for the numbers of total coliforms, fecal indicator bacteria (i.e., thermotolerant Escherichia coli and Enterococcus spp. and potential bacterial pathogens (i.e., Aeromonas hydrophil, Pseudomonas aeruginos, Salmonella spp., and Shigella spp.. Among the 16 brands tested, 14 (86%, ten (63% and seven (44% were positive for total coliforms, E. coil and Enterococcus spp., respectively. Additionally, a further nine (56%, eight (50%, six (37%, and four (25% brands were PCR positive for A. hydrophila lip, P. aeruginosa ETA, Salmonella spp. invA, and Shigella spp. ipaH genes, respectively. The numbers of bacterial pathogens in bottled water samples ranged from 28 ± 12 to 600 ± 45 (A. hydrophila lip gene, 180 ± 40 to 900 ± 200 (Salmonella spp. invA gene, 180 ± 40 to 1,300 ± 400 (P. aeruginosa ETA gene genomic units per L of water. Shigella spp. ipaH gene was not quantifiable. Discrepancies were observed in terms of the occurrence of fecal indicators and bacterial pathogens. No correlations were observed between fecal indicators numbers and presence/absence of A. hydrophila lip (p = 0.245, Salmonella spp. invA (p = 0.433, Shigella spp. ipaH gene (p = 0.078, and P. aeruginosa ETA (p = 0.059 genes. Our results suggest that microbiological quality of bottled waters sold in Dhaka, Bangladesh is highly variable. To protect public health, stringent quality control is recommended for the bottled water industry in Bangladesh.

  8. Quorum-sensing blockade as a strategy for enhancing host defences against bacterial pathogens

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2007-01-01

    Conventional antibiotics target the growth and the basal life processes of bacteria leading to growth arrest and cell death. The selective force that is inherently linked to this mode of action eventually selects out antibiotic-resistant variants. The most obvious alternative to antibiotic...... rise to a new 'drug target rush'. Recently, QS has been shown to be involved in the development of tolerance to various antimicrobial treatments and immune modulation. The regulation of virulence via QS confers a strategic advantage over host defences. Consequently, a drug capable of blocking QS is...... likely to increase the susceptibility of the infecting organism to host defences and its clearance from the host. The use of QS signal blockers to attenuate bacterial pathogenicity, rather than bacterial growth, is therefore highly attractive, particularly with respect to the emergence of multi...

  9. Quorum-Sensing Blockade As A Strategy for Enhancing Host Defences Against Bacterial Pathogens

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2007-01-01

    Conventional antibiotics target the growth and the basal life processes of bacteria leading to growth arrest and cell death. The selective force that is inherently linked to this mode of action eventually selects out antibiotic-resistant variants. The most obvious alternative to antibiotic...... rise to a new 'drug target rush'. Recently, QS has been shown to be involved in the development of tolerance to various antimicrobial treatments and immune modulation. The regulation of virulence via QS confers a strategic advantage over host defences. Consequently, a drug capable of blocking QS is...... likely to increase the susceptibility of the infecting organism to host defences and its clearance from the host. The use of QS signal blockers to attenuate bacterial pathogenicity, rather than bacterial growth, is therefore highly attractive, particularly with respect to the emergence of multi...

  10. Bioinhibition of diarrhogenic Gram-positive bacterial patho-gens by potential indigenous probiotics

    Institute of Scientific and Technical Information of China (English)

    Adenike A.O.Ogunshe

    2008-01-01

    High level infant mortality rates and onset of drug resistance has led into the possible development of indige-nous probiotics as alternative bacteriotherapy in the control of infantile bacterial diarrhoea.This study was to determine the in vitro inhibitory potential of four probiotic candidates obtained from Nigerian indigenous fer-mented foods and beverages and from faecal specimens of healthy infants on infantile Gram-positive diarrhogen-ic bacterial pathogens.Potential probiotic candidates,AAOOL4,L.reuteri AAOOCH1,L.plantarum AAOO25 NN and L.delbrueckii AAOOT20 were assayed for in vitro bactericidal effects on diarrhogenic bacte-rial test strains-Bacillus cereus 25S,B.cereus 32S,B.licheniformis 26S and B.licheniformis 39S.All the test strains inoculated into an industrial infant weaning food already seeded with the probiotic strains were sig-nificantly inhibited within 96 hours. L. acidophilus AAOOL4, L. reuteri AAOOCH1 , L. plantarum AAOO25 NN and L.delbrueckii AAOOT20 had in vitro bactericidal effects on bacteri isolates implicated in in-fantile diarrhoea,indicating the probiotic potential of the candidates.

  11. Coronatine inhibits stomatal closure and delays hypersensitive response cell death induced by nonhost bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Seonghee Lee

    2013-02-01

    Full Text Available Pseudomonas syringae is the most widespread bacterial pathogen in plants. Several strains of P. syringae produce a phytotoxin, coronatine (COR, which acts as a jasmonic acid mimic and inhibits plant defense responses and contributes to disease symptom development. In this study, we found that COR inhibits early defense responses during nonhost disease resistance. Stomatal closure induced by a nonhost pathogen, P. syringae pv. tabaci, was disrupted by COR in tomato epidermal peels. In addition, nonhost HR cell death triggered by P. syringae pv. tabaci on tomato was remarkably delayed when COR was supplemented along with P. syringae pv. tabaci inoculation. Using isochorismate synthase (ICS-silenced tomato plants and transcript profiles of genes in SA- and JA-related defense pathways, we show that COR suppresses SA-mediated defense during nonhost resistance.

  12. Glycosaminoglycan binding facilitates entry of a bacterial pathogen into central nervous systems.

    Science.gov (United States)

    Chang, Yung-Chi; Wang, Zhipeng; Flax, Lindsay A; Xu, Ding; Esko, Jeffrey D; Nizet, Victor; Baron, Miriam J

    2011-06-01

    Certain microbes invade brain microvascular endothelial cells (BMECs) to breach the blood-brain barrier (BBB) and establish central nervous system (CNS) infection. Here we use the leading meningitis pathogen group B Streptococcus (GBS) together with insect and mammalian infection models to probe a potential role of glycosaminoglycan (GAG) interactions in the pathogenesis of CNS entry. Site-directed mutagenesis of a GAG-binding domain of the surface GBS alpha C protein impeded GBS penetration of the Drosophila BBB in vivo and diminished GBS adherence to and invasion of human BMECs in vitro. Conversely, genetic impairment of GAG expression in flies or mice reduced GBS dissemination into the brain. These complementary approaches identify a role for bacterial-GAG interactions in the pathogenesis of CNS infection. Our results also highlight how the simpler yet genetically conserved Drosophila GAG pathways can provide a model organism to screen candidate molecules that can interrupt pathogen-GAG interactions for future therapeutic applications. PMID:21731486

  13. Glycosaminoglycan binding facilitates entry of a bacterial pathogen into central nervous systems.

    Directory of Open Access Journals (Sweden)

    Yung-Chi Chang

    2011-06-01

    Full Text Available Certain microbes invade brain microvascular endothelial cells (BMECs to breach the blood-brain barrier (BBB and establish central nervous system (CNS infection. Here we use the leading meningitis pathogen group B Streptococcus (GBS together with insect and mammalian infection models to probe a potential role of glycosaminoglycan (GAG interactions in the pathogenesis of CNS entry. Site-directed mutagenesis of a GAG-binding domain of the surface GBS alpha C protein impeded GBS penetration of the Drosophila BBB in vivo and diminished GBS adherence to and invasion of human BMECs in vitro. Conversely, genetic impairment of GAG expression in flies or mice reduced GBS dissemination into the brain. These complementary approaches identify a role for bacterial-GAG interactions in the pathogenesis of CNS infection. Our results also highlight how the simpler yet genetically conserved Drosophila GAG pathways can provide a model organism to screen candidate molecules that can interrupt pathogen-GAG interactions for future therapeutic applications.

  14. Isolation of bacterial fish pathogen Aeromonas hydrophila and therapeutic effects of medicinal plants on its invasion

    Directory of Open Access Journals (Sweden)

    Md. Tareq-Uz-Zaman

    2014-04-01

    Full Text Available Aeromonas hydrophila, a bacterial pathogen, was isolated form Pangasius hypophthalmus. For pathogenicity test, different doses were injected intramuscularly in Barbonymus gonionotus. Crude extracts were prepared from various parts Azadirachta indica, Curcuma longa, C. zedoaria, and Callotropis gigentia and applied to B. gonionotus for 7 days. Bath treatment was done up to their tolerance level and well ventilation was confirmed for aeration and 50% water was exchanged daily. Minimum inhibitory dose was detected as 7 mg/ml. High inhibitory effect was observed in case of A. indica and mixed extract of A. indica and C. gigentia. Both A. indica and C. gigentia showed the best result with 90-95% recovery of infected fish at a dose of 7 mg/l. C. zedoaria showed moderate to weak effect with 50-60% recovery at the same dose. The present study showed that medicinal plants would be an effective control measure against A. hydrophila.

  15. Genomic Epidemiology: Whole-Genome-Sequencing–Powered Surveillance and Outbreak Investigation of Foodborne Bacterial Pathogens

    DEFF Research Database (Denmark)

    Deng, Xiangyu; den Bakker, Henk C.; Hendriksen, Rene S.

    2016-01-01

    As we are approaching the twentieth anniversary of PulseNet, a network of public health and regulatory laboratories that has changed the landscape of foodborne illness surveillance through molecular subtyping, public health microbiology is undergoing another transformation brought about by so......-called next-generation sequencing (NGS) technologies that have made whole-genome sequencing (WGS) of foodborne bacterial pathogens a realistic and superior alternative to traditional subtyping methods. Routine, real-time, and widespread application of WGS in food safety and public health is on the horizon...

  16. 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

  17. 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

  18. 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

  19. Toxicity of nitric oxide and peroxynitrite to bacterial pathogens of fish.

    Science.gov (United States)

    Campos-Pérez, J J; Ellis, A E; Secombes, C J

    2000-11-14

    The inhibitory effect of the nitric oxide (NO) donor S-nitroso-acetyl-penicillamine (SNAP) and the NO and O2- donor 3-morpholino-sydnonimine hydrochloride (SIN-1) was tested in a cell-free assay. Strains of the bacterial fish pathogens Aeromonas salmonicida, Renibacterium salmoninarum and Yersinia ruckeri were exposed to different concentrations of the NO donors for 24 h. The results showed that NO possesses inhibitory properties, while peroxynitrite had no effect. However, when SIN-1 was used in combination with superoxide dismutase (SOD) alone or with catalase, an inhibitory effect comparable to that caused by SNAP was seen. The implications of these results are discussed. PMID:11145451

  20. Investigating the Antimicrobial Bioactivity of Cyano bacterial Extracts on Some Plant and Human Pathogens

    International Nuclear Information System (INIS)

    The search for broad spectrum antimicrobial agents against microbial pathogens, as the available bioactive compounds, has decreasing efficacy and the multidrug resistance trait is spreading among pathogens. Accordingly, the study was carried out to investigate the antimicrobial bioactivity of extracts derived from a cyano bacterial strain from Egypt. The solvents used were diethyl ether, chloroform and methanol. The antimicrobial bioassay of the lipophilic fraction dissolved in diethyl ether of Synechococcus spp. (isolated from Wadi El-Natroun, Egypt) showed the highest broad spectrum bioactivity as it inhibited the growth of both plant and human pathogens. The extract was also effective on the filamentous plant pathogenic fungi Aspergillus flavus and Aspergillus niger. The effects of incubation periods, growth media and pH values on both growth and antimicrobial activity of Synechococcus spp. were investigated. Chu medium was the medium that gave the highest growth followed by BG11 medium then Oscillatoria medium and all these three media showed antibacterial activities but only BG11 showed both antibacterial and antifungal activities after 18 days of incubation. The pH value 10 proved to be the best for growth and antimicrobial activities of Synechococcus spp. in BG11 medium

  1. mADP-RTs: Versatile virulence factors from bacterial pathogens of plants and mammals

    Directory of Open Access Journals (Sweden)

    Lennart eWirthmueller

    2012-06-01

    Full Text Available Mono ADP-ribosyltransferases (mADP-RTs are a family of enzymes that cleave NAD+ and covalently attach the ADP-ribosyl moiety to target proteins. mADP-RTs are well established as important virulence factors of bacteria that infect mammals. Cholera toxin, pertussis toxin and diphteria toxin are three of the best-known examples of mADP-RTs. They modify host target proteins in order to promote infection and/or killing of the host cell. Despite low sequence similarity at the primary amino acid level, mADP-RTs share a conserved core catalytic fold and structural biology has made important contributions to elucidating how mADP-RTs modify mammalian host targets. Recently, mADP-RTs were shown to be present in plant pathogenic bacteria, suggesting that mADP-RTs are also important virulence factors of plant pathogens. Crystal structures of plant pathogenic bacterial mADP-RTs are also now available. Here we review the structure/function of mADP-RTs from pathogens of mammals and plants, highlighting both commonalities and differences.

  2. Autecology of Vibrio vulnificus and Vibrio parahaemolyticus in tropical waters

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, S.; Lugo, T.; Hazen, T.C. [Univ. of Puerto Rico, Rio Piedras (Puerto Rico)

    1988-12-31

    Water and shellfish samples collected from estuaries, mangroves, and beaches along the coast of Puerto Rico were examined for Vibrio vulnificus and Vibrio parahaemolyticus. An array of water quality parameters were also measured simultaneous with bacteria sampling. Both species of vibrio were associated with estuary and mangrove locations, and neither was isolated from sandy beaches. Densities of V. vulnificus were negatively correlated with salinity, 10--15 ppt being optimal. V. parahaemolyticus was isolated from sites with salinities between 20 and 35 ppt, the highest densities occurring at 20 ppt. Densities of Vibrio spp. and V. parahaemolyticus for a tropical estuary surpassed those reported for temperate estuaries by several orders of magnitude. Both densities of total Vibrio spp. and V. parahaemolyticus in the water were directly related to densities of fecal coliforms, unlike V. vulnificus. The incidence of ONPG(+) strains among sucrose({minus}) Vibrio spp. served as an indicator of the frequency of V. vulnificus in this group. More than 63% of the V. vulnificus isolated were pathogenic. V. vulnificus and V. parahaemolyticus occupy clearly separate niches within the tropical estuarine-marine ecosystem.

  3. Immunological evaluation of Vibrio alginolyticus, Vibrio harveyi, Vibrio vulnificus and infectious spleen and kidney necrosis virus (ISKNV) combined-vaccine efficacy in Epinephelus coioides.

    Science.gov (United States)

    Huang, Zhijian; Tang, Jingjing; Li, Mei; Fu, Yacheng; Dong, Chuanfu; Zhong, Jiang F; He, Jianguo

    2012-11-15

    Combined vaccines are immunological products intended for immunization against multifactorial infectious diseases caused by different types or variants of pathogens. In this study, the effectiveness of Vibrio alginolyticus (Va), Vibrio harveyi (Vh), Vibrio vulnificus (Vv) and infectious spleen and kidney necrosis virus (ISKNV), an iridovirus, combined-vaccine (Vibrio and ISKNV combined vaccines, VICV), Va+Vh+Vv inactive vaccine (VIV) and ISKNV whole cell inactive vaccine (IWCIV) in Epinephelus coioides were evaluated using various immunological parameters including antibody titer, serum lysozyme activity (LA), respiratory burst (RB) activity, bactericidal activity (BA) and relative percentage survival (RPS). E. coioides immunized with VICV and challenged with Va+Vh+Vv+ISKNV had an RPS of 80%. The RPS was 73.3% in E. coioides immunized with VIV and challenged with Va+Vh+Vv. E. coioides immunized with IWCIV and challenged with ISKNV had an RPS of 69.6%. Serum LA in the vaccinated group was significantly higher than the control group on days 21 and 28 post-vaccination (P0.05). After immunization with VICV, BA values of blood leucocytes and head kidney cells increased significantly more than spleen cells. BA value of blood leucocytes was higher than that in head kidney cells. There were distinct difference between BA values in head kidney cells and in spleen cells (P<0.05) as well as between BA value of blood leucocytes and head kidney cells (P<0.01). E. coioides vaccinated with VICV have significantly higher antibody levels than control groupers (P<0.01). Our study suggests that the VICV candidate can effectively protect groupers against multiple bacterial and viral pathogens. PMID:23010220

  4. Structure of the beta 2 homodimer of bacterial luciferase from Vibrio harveyi: X-ray analysis of a kinetic protein folding trap.

    Science.gov (United States)

    Thoden, J. B.; Holden, H. M.; Fisher, A. J.; Sinclair, J. F.; Wesenberg, G.; Baldwin, T. O.; Rayment, I.

    1997-01-01

    Luciferase, as isolated from Vibrio harveyi, is an alpha beta heterodimer. When allowed to fold in the absence of the alpha subunit, either in vitro or in vivo, the beta subunit of enzyme will form a kinetically stable homodimer that does not unfold even after prolonged incubation in 5 M urea at pH 7.0 and 18 degrees C. This form of the beta subunit, arising via kinetic partitioning on the folding pathway, appears to constitute a kinetically trapped alternative to the heterodimeric enzyme (Sinclair JF, Ziegler MM, Baldwin TO. 1994. Kinetic partitioning during protein folding yields multiple native states. Nature Struct Biol 1: 320-326). Here we describe the X-ray crystal structure of the beta 2 homodimer of luciferase from V. harveyi determined and refined at 1.95 A resolution. Crystals employed in the investigational belonged to the orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions of a = 58.8 A, b = 62.0 A, and c = 218.2 A and contained one dimer per asymmetric unit. Like that observed in the functional luciferase alpha beta heterodimer, the major tertiary structural motif of each beta subunit consists of an (alpha/beta)8 barrel (Fisher AJ, Raushel FM, Baldwin TO, Rayment I. 1995. Three-dimensional structure of bacterial luciferase from Vibrio harveyi at 2.4 A resolution. Biochemistry 34: 6581-6586). The root-mean-square deviation of the alpha-carbon coordinates between the beta subunits of the hetero- and homodimers is 0.7 A. This high resolution X-ray analysis demonstrated that "domain" or "loop" swapping has not occurred upon formation of the beta 2 homodimer and thus the stability of the beta 2 species to denaturation cannot be explained in such simple terms. In fact, the subunit:subunit interfaces observed in both the beta 2 homodimer and alpha beta heterodimer are remarkably similar in hydrogen-bonding patterns and buried surface areas. PMID:9007973

  5. Comparison of the sulfonamide inhibition profiles of the α-, β- and γ-carbonic anhydrases from the pathogenic bacterium Vibrio cholerae.

    Science.gov (United States)

    Del Prete, Sonia; Vullo, Daniela; De Luca, Viviana; Carginale, Vincenzo; Osman, Sameh M; AlOthman, Zeid; Supuran, Claudiu T; Capasso, Clemente

    2016-04-15

    Carbonic anhydrases (CA, EC 4.2.1.1) are ubiquitous metalloenzymes, which catalyze the conversion of carbon dioxide (CO2) to bicarbonate (HCO3(-)) and protons (H(+)). In prokaryotes, the existence of genes encoding for α-, β- and γ-classes suggests that these enzymes play an important role in the prokaryotic physiology. It has been demonstrated, in fact, that their inhibition in vivo leads to growth impairment or growth defects of the microorganism. Ultimately, we started to investigate the biochemical properties and the inhibitory profiles of the α- and β-CAs identified in the genome of Vibrio cholerae, which is the causative agent of cholera. The genome of this pathogen encodes for CAs belonging to α, β and γ classes. Here, we report a sulfonamide inhibition study of the γ-CA (named VchCAγ) comparing it with data obtained for the α- and β-CA enzymes. VchCAγ activity (kcat=7.39 × 10(5)s(-1)) was significantly higher than the other γ-CAs. The inhibition study with a panel of sulfonamides and one sulfamate led to the detection of a large number of nanomolar VchCAγ inhibitors, including simple aromatic/heterocyclic sulfonamides (compounds 2-9, 11, 13-15, 24) as well as EZA, DZA, BRZ, BZA, TPM, ZNS, SLP, IND (KIs in the range of 66.2-95.3 nM). As it was proven that bicarbonate is a virulence factor of this bacterium and since ethoxzolamide was shown to inhibit this virulence in vivo, we propose that VchCA, VchCAβ and VchCAγ may be a target for antibiotic development, exploiting a mechanism of action rarely considered up until now, i.e., interference with bicarbonate supply as a virulence factor. PMID:26972117

  6. Determination of Profiles of Salmonella and Pathogenic Vibrio SPP. in Black Tiger Shrimp for Export by Introduction of Quality Assured Microbiological Assays

    International Nuclear Information System (INIS)

    Studies were conducted on contamination by Salmonella and pathogenic Vibrio spp. in samples of aquaculture black tiger shrimp, the water supply (canal water which is supplied as raw pond water before treatment), pond water, feed materials, and fresh and frozen shrimp. Salmonella was detected in samples of the water supply, pond water, feed materials, fresh shrimp at farm, fresh shrimp from wholesale market and frozen shrimp destined for export at levels of 13.95%, 1.53%, 1.14%, 3.17%, 30.4% and 0.21% respectively. V. cholerae non 01 was found in one sample of water from a culture pond of 131 tested (0.8%). V. parahaemolyticus was found in samples of canal water, pond water, fresh black tiger shrimp collected at farms, fresh black tiger shrimp collected at wholesale shrimp markets and frozen black tiger shrimp destined for export at levels of 2.3%, 5.3%, 14.3%, 48 % and 0.2% respectively. The strains identified as V. parahaemolyticus were examined for the presence or absence of the TDH and TRH. The incidence of TDH (KP+) was 2.67% (seven of 262 strains) and of TRH (urease reaction) was 1.15% (three of 262 strains). Salmonella and V. parahaemolyticus were found in a high percentage in fresh black tiger shrimp collected from wholesale shrimp markets. These shrimp are used as raw material for domestic consumption and for processing for exported shrimp products. Therefore GMP and/or Hazard Analysis Critical Control Point (HACCP) system for shrimp distributors/producers should be applied. (author)

  7. Co-transcriptomic Analysis by RNA Sequencing to Simultaneously Measure Regulated Gene Expression in Host and Bacterial Pathogen

    KAUST Repository

    Ravasi, Timothy

    2016-01-24

    Intramacrophage pathogens subvert antimicrobial defence pathways using various mechanisms, including the targeting of host TLR-mediated transcriptional responses. Conversely, TLR-inducible host defence mechanisms subject intramacrophage pathogens to stress, thus altering pathogen gene expression programs. Important biological insights can thus be gained through the analysis of gene expression changes in both the host and the pathogen during an infection. Traditionally, research methods have involved the use of qPCR, microarrays and/or RNA sequencing to identify transcriptional changes in either the host or the pathogen. Here we describe the application of RNA sequencing using samples obtained from in vitro infection assays to simultaneously quantify both host and bacterial pathogen gene expression changes, as well as general approaches that can be undertaken to interpret the RNA sequencing data that is generated. These methods can be used to provide insights into host TLR-regulated transcriptional responses to microbial challenge, as well as pathogen subversion mechanisms against such responses.

  8. Antibiotic sensitivity pattern of bacterial pathogens in the intensive care unit of Fatmawati Hospital, Indonesia

    Institute of Scientific and Technical Information of China (English)

    Maksum Radji; Siti Fauziah; Nurgani Aribinuko

    2011-01-01

    Objective: To evaluate the sensitivity pattern of bacterial pathogens in the intensive care unit (ICU) of a tertiary care of Fatmawati Hospital Jakarta Indonesia. Methods: A cross sectional retrospective study of bacterial pathogen was carried out on a total of 722 patients that were admitted to the ICU of Fatmawati Hospital Jakarta Indonesia during January 2009 to March 2010. All bacteria were identified by standard microbiologic methods, and their antibiotic susceptibility testing was performed using disk diffusion method. Results: Specimens were collected from 385 patients who were given antimicrobial treatment, of which 249 (64.68%) were cultured positive and 136 (35.32%) were negative. The most predominant isolate was Pseudomonas aeruginosa (P. aeruginosa) (26.5%) followed by Klebsiella pneumoniae (K. pneumoniae) (15.3%) and Staphylococcus epidermidis (14.9%). P. aeruginosa isolates showed high rate of resistance to cephalexin (95.3%), cefotaxime (64.1%), and ceftriaxone (60.9%). Amikacin was the most effective (84.4%) antibiotic against P. aeruginosa followed by imipenem (81.2%), and meropenem (75.0%). K. pneumoniae showed resistance to cephalexin (86.5%), ceftriaxone (75.7%), ceftazidime (73.0%), cefpirome (73.0%) and cefotaxime (67.9%), respectively. Conclusions: Most bacteria isolated from ICU of Fatmawati Hospital Jakarta Indonesia were resistant to the third generation of cephalosporins, and quinolone antibiotics. Regular surveillance of antibiotic susceptibility patterns is very important for setting orders to guide the clinician in choosing empirical or directed therapy of infected patients.

  9. Population structure of the bacterial pathogen Xylella fastidiosa among street trees in Washington D.C.

    Science.gov (United States)

    Harris, Jordan Lee; Balci, Yilmaz

    2015-01-01

    Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship. PMID:25815838

  10. Studies on antimicrobial and antifungal activities of ziziphus mauritiana human clinical bacterial and fungal pathogens

    International Nuclear Information System (INIS)

    The antimicrobial and antifungal activities of crude extracts of Ziziphus mauritiana leaves were investigated against six selected bacterial (Staphylococcus aureus, Micrococcus luteus, Escherichia coli, Pseudomonas aeruginosa, Enterobacter, Klebsiella pneumoniae) and one fungal pathogen (Aspel-gillus niger). The crude extract was further fractionated in butanol, choloroform, n-hexane and methanol. Agar well diffusion and agar dilution assay were employed for determination of zones of inhibition and MICs, respectively, whereas MBC was determined using broth dilution test. The butanol fraction presented encouraging antimicrobial activity (15.0%0.02), while methanol (7.03:1:0.05) and chloroform (7.0%0,05) fractions emerged with significantly low susceptibility. The n-hexane fraction was recorded as almost inactive (0%0) against all bacterial pathogens. Unlike the antibacterial activities, all fractions possessed momentous antifungal activities except the methanol fraction (0%0). The n-hexane fraction showed widest zone of inhibition (11:1:0.05) followed by butanol (8.0%0.02) and chloroform (7.0%0.02). (author)

  11. Screening of Quercus infectoria gall extracts as anti-bacterial agents against dental pathogens

    Directory of Open Access Journals (Sweden)

    Vermani Archa

    2009-01-01

    Full Text Available Background and Objectives: A number of bacteria have now become antibiotic-resistant. This increases the importance of ayurvedic drugs. We report, here, the activity of different extracts (petroleum ether, chloroform, methanol and water of Quercus infectoria galls against dental pathogens - Streptococcus mutans, Streptococcus salivarius, Staphylococcus aureus, Lactobacillus acidophilus (designated and Streptococcus sanguis (isolated. Materials and Methods: The cup-plate method was used in anti-bacterial activity of the extracts at concentration of 200 mg/ml against dental pathogens. Minimum inhibitory concentration (MIC values of most effective extracts against the most susceptible bacteria were determined using a two-fold serial micro dilution method. Results: Methanolic extract showed maximum anti-bacterial activity against all the bacteria. The most susceptible bacteria were S. sanguis followed by S. aureus, S. mutans, S. salivarius and L. acidophilus. The MIC values showed that methanolic extract was more effective than water extract. Conclusion: The plant has the potential to generate herbal metabolites. The crude extracts demonstrating anti-dental caries activity could result in the discovery of new chemical classes of antibiotics. These chemical classes of antibiotics could serve as selective agents for the maintenance of human health and provide bio-chemical tools for the study of infectious diseases.

  12. Nucleic Acid-Based Detection and Identification of Bacterial and Fungal Plant Pathogens - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Kingsley, Mark T.

    2001-03-13

    The threat to American interests from terrorists is not limited to attacks against humans. Terrorists might seek to inflict damage to the U.S. economy by attacking our agricultural sector. Infection of commodity crops by bacterial or fungal crop pathogens could adversely impact U.S. agriculture, either directly from damage to crops or indirectly from damage to our ability to export crops suspected of contamination. Recognizing a terrorist attack against U.S. agriculture, to be able to prosecute the terrorists, is among the responsibilities of the members of Hazardous Material Response Unit (HMRU) of the Federal Bureau of Investigation (FBI). Nucleic acid analysis of plant pathogen strains by the use of polymerase chain reaction (PCR) amplification techniques is a powerful method for determining the exact identity of pathogens, as well as their possible region of origin. This type of analysis, however, requires that PCR assays be developed specific to each particular pathogen strain, and analysis protocols developed that are specific to the particular instrument used for detection. The objectives of the work described here were threefold: 1) to assess the potential terrorist threat to U.S. agricultural crops, 2) to determine whether suitable assays exist to monitor that threat, and 3) where assays are needed for priority plant pathogen threats, to modify or develop those assays for use by specialists at the HMRU. The assessment of potential threat to U.S. commodity crops and the availability of assays for those threats were described in detail in the Technical Requirements Document (9) and will be summarized in this report. This report addresses development of specific assays identified in the Technical Requirements Document, and offers recommendations for future development to ensure that HMRU specialists will be prepared with the PCR assays they need to protect against the threat of economic terrorism.

  13. Metabolic pathways of Pseudomonas aeruginosa involved in competition with respiratory bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Marie eBeaume

    2015-04-01

    Full Text Available Background: Chronic airway infection by Pseudomonas aeruginosa considerably contributes to lung tissue destruction and impairment of pulmonary function in cystic-fibrosis (CF patients. Complex interplays between P. aeruginosa and other co-colonizing pathogens including Staphylococcus aureus, Burkholderia spp and Klebsiella pneumoniae may be crucial for pathogenesis and disease progression.Methods: We generated a library of PA14 transposon insertion mutants to identify P. aeruginosa genes required for exploitative and direct competitions with S. aureus, B. cenocepacia, and K. pneumoniae. Results: Whereas wild type PA14 inhibited S. aureus growth, two transposon insertions located in pqsC and carB, resulted in reduced growth inhibition. PqsC is involved in the synthesis of 4-hydroxy-2-alkylquinolines (HAQs, a family of molecules having antibacterial properties, while carB is a key gene in pyrimidine biosynthesis. The carB mutant was also unable to grow in the presence of B. cepacia and K. pneumoniae but not E. coli and S. epidermidis. We further identified a transposon insertion in purF, encoding a key enzyme of purine metabolism. This mutant displayed a severe growth deficiency in the presence of Gram-negative but not of Gram-positive bacteria. We identified a beneficial interaction in a bioA transposon mutant, unable to grow on rich medium. This growth defect could be restored either by addition of biotin or by co-culturing the mutant in the presence of K. pneumoniae or E. coli.Conclusions: Complex interactions take place between the various bacterial species colonizing CF-lungs. This work identified both detrimental and beneficial interactions occurring between P. aeruginosa and three other respiratory pathogens involving several major metabolic pathways. Manipulating these pathways could be used to interfere with bacterial interactions and influence the colonization by respiratory pathogens.

  14. DgcA, a diguanylate cyclase from Xanthomonas oryzae pv. oryzae regulates bacterial pathogenicity on rice

    Science.gov (United States)

    Su, Jianmei; Zou, Xia; Huang, Liangbo; Bai, Tenglong; Liu, Shu; Yuan, Meng; Chou, Shan-Ho; He, Ya-Wen; Wang, Haihong; He, Jin

    2016-01-01

    Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice blight disease as well as a serious phytopathogen worldwide. It is also one of the model organisms for studying bacteria-plant interactions. Current progress in bacterial signal transduction pathways has identified cyclic di-GMP as a major second messenger molecule in controlling Xanthomonas pathogenicity. However, it still remains largely unclear how c-di-GMP regulates the secretion of bacterial virulence factors in Xoo. In this study, we focused on the important roles played by DgcA (XOO3988), one of our previously identified diguanylate cyclases in Xoo, through further investigating the phenotypes of several dgcA-related mutants, namely, the dgcA-knockout mutant ΔdgcA, the dgcA overexpression strain OdgcA, the dgcA complemented strain CdgcA and the wild-type strain. The results showed that dgcA negatively affected virulence, EPS production, bacterial autoaggregation and motility, but positively triggered biofilm formation via modulating the intracellular c-di-GMP levels. RNA-seq data further identified 349 differentially expressed genes controlled by DgcA, providing a foundation for a more solid understanding of the signal transduction pathways in Xoo. Collectively, the present study highlights DgcA as a major regulator of Xoo virulence, and can serve as a potential target for preventing rice blight diseases. PMID:27193392

  15. DgcA, a diguanylate cyclase from Xanthomonas oryzae pv. oryzae regulates bacterial pathogenicity on rice.

    Science.gov (United States)

    Su, Jianmei; Zou, Xia; Huang, Liangbo; Bai, Tenglong; Liu, Shu; Yuan, Meng; Chou, Shan-Ho; He, Ya-Wen; Wang, Haihong; He, Jin

    2016-01-01

    Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice blight disease as well as a serious phytopathogen worldwide. It is also one of the model organisms for studying bacteria-plant interactions. Current progress in bacterial signal transduction pathways has identified cyclic di-GMP as a major second messenger molecule in controlling Xanthomonas pathogenicity. However, it still remains largely unclear how c-di-GMP regulates the secretion of bacterial virulence factors in Xoo. In this study, we focused on the important roles played by DgcA (XOO3988), one of our previously identified diguanylate cyclases in Xoo, through further investigating the phenotypes of several dgcA-related mutants, namely, the dgcA-knockout mutant ΔdgcA, the dgcA overexpression strain OdgcA, the dgcA complemented strain CdgcA and the wild-type strain. The results showed that dgcA negatively affected virulence, EPS production, bacterial autoaggregation and motility, but positively triggered biofilm formation via modulating the intracellular c-di-GMP levels. RNA-seq data further identified 349 differentially expressed genes controlled by DgcA, providing a foundation for a more solid understanding of the signal transduction pathways in Xoo. Collectively, the present study highlights DgcA as a major regulator of Xoo virulence, and can serve as a potential target for preventing rice blight diseases. PMID:27193392

  16. A human pathogenic bacterial infection model using the two-spotted cricket, Gryllus bimaculatus.

    Science.gov (United States)

    Kochi, Yuto; Miyashita, Atsushi; Tsuchiya, Kohsuke; Mitsuyama, Masao; Sekimizu, Kazuhisa; Kaito, Chikara

    2016-08-01

    Invertebrate animal species that can withstand temperatures as high as 37°C, the human body temperature, are limited. In the present study, we utilized the two-spotted cricket, Gryllus bimaculatus, which lives in tropical and subtropical regions, as an animal model of human pathogenic bacterial infection. Injection of Pseudomonas aeruginosa or Staphylococcus aureus into the hemolymph killed crickets. Injected P. aeruginosa or S. aureus proliferated in the hemolymph until the cricket died. The ability of these pathogenic bacteria to kill the crickets was blocked by the administration of antibiotics. S. aureus gene-knockout mutants of virulence factors, including cvfA, agr and srtA, exhibited decreased killing ability compared with the parent strain. The dose at which 50% of crickets were killed by P. aeruginosa or S. aureus was not decreased at 37°C compared with that at 27°C. Injection of Listeria monocytogenes, which upregulates toxin expression at 37°C, killed crickets, and the dose at which 50% of crickets were killed was decreased at 37°C compared with that at 27°C. These findings suggest that the two-spotted cricket is a useful model animal for evaluating the virulence properties of various human pathogenic bacteria at variable temperature including 37°C. PMID:27377894

  17. A Novel Bacterial Pathogen of Biomphalaria glabrata: A Potential Weapon for Schistosomiasis Control?

    Science.gov (United States)

    Duval, David; Galinier, Richard; Mouahid, Gabriel; Toulza, Eve; Allienne, Jean François; Portela, Julien; Calvayrac, Christophe; Rognon, Anne; Arancibia, Nathalie; Mitta, Guillaume; Théron, André; Gourbal, Benjamin

    2015-01-01

    Background Schistosomiasis is the second-most widespread tropical parasitic disease after malaria. Various research strategies and treatment programs for achieving the objective of eradicating schistosomiasis within a decade have been recommended and supported by the World Health Organization. One of these approaches is based on the control of snail vectors in endemic areas. Previous field studies have shown that competitor or predator introduction can reduce snail numbers, but no systematic investigation has ever been conducted to identify snail microbial pathogens and evaluate their molluscicidal effects. Methodology/Principal findings In populations of Biomphalaria glabrata snails experiencing high mortalities, white nodules were visible on snail bodies. Infectious agents were isolated from such nodules. Only one type of bacteria, identified as a new species of Paenibacillus named Candidatus Paenibacillus glabratella, was found, and was shown to be closely related to P. alvei through 16S and Rpob DNA analysis. Histopathological examination showed extensive bacterial infiltration leading to overall tissue disorganization. Exposure of healthy snails to Paenibacillus-infected snails caused massive mortality. Moreover, eggs laid by infected snails were also infected, decreasing hatching but without apparent effects on spawning. Embryonic lethality was correlated with the presence of pathogenic bacteria in eggs. Conclusions/Significance This is the first account of a novel Paenibacillus strain, Ca. Paenibacillus glabratella, as a snail microbial pathogen. Since this strain affects both adult and embryonic stages and causes significant mortality, it may hold promise as a biocontrol agent to limit schistosomiasis transmission in the field. PMID:25719489

  18. CHEMICALLY FABRICATED SILVER NANOPARTICLES ENHANCES THE ACTIVITY OF ANTIBIOTICS AGAINST SELECTED HUMAN BACTERIAL PATHOGENS

    Directory of Open Access Journals (Sweden)

    S. Thangapandiyan and P. Prema*

    2012-05-01

    Full Text Available Due to the outbreak of infectious diseases caused by different pathogenic bacteria and the development of antibiotic resistance, the pharmaceutical companies and the researchers are now searching for new unconventional antibacterial agents. Nanotechnology represents a modern and innovative approach to develop new formulations based on metallic nanoparticles with antimicrobial properties. The potential bioactivity of chemically fabricated silver nanoparticles has been extensively studied. However, the antibacterial activity of silver nanoparticles individually or in combination with different antibiotics has not been demonstrated. In the present investigations, the effect of silver nanoparticles on the antibacterial activity of different antibiotics was evaluated against selected human bacterial pathogens such as Staphylococcus aureus, Streptococcus epidermis, Escherichia coli, Pseudomonas aeruginosa, and Bacillus cereus by disc diffusion method. In the presence of sub - inhibitory concentration of silver nanoparticles (100µL/disc, the antibacterial activities of all antibiotics are increased from 1 mm to 10 mm. The maximum fold increase was noticed for vancomycin against Pseudomonas aeruginosa (66.67%, Escherichia coli (62.50%, and Staphylococcus aureus (46% followed by rifampicin against Bacillus cereus (66.67% and kanamycin against Streptococcus epidermis (25%. These results signify that the silver nanoparticles showed potential antibacterial action of ß-lactams, glycopeptides, aminoglycosides, sulphonamides suggesting a possible utilization of silver nanocompounds in combination therapy against selected pathogens used in the experiment.

  19. The bacterial pathogen Xylella fastidiosa affects the leaf ionome of plant hosts during infection.

    Science.gov (United States)

    De La Fuente, Leonardo; Parker, Jennifer K; Oliver, Jonathan E; Granger, Shea; Brannen, Phillip M; van Santen, Edzard; Cobine, Paul A

    2013-01-01

    Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition) were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen. PMID:23667547

  20. A Catalytic DNA Activated by a Specific Strain of Bacterial Pathogen.

    Science.gov (United States)

    Shen, Zhifa; Wu, Zaisheng; Chang, Dingran; Zhang, Wenqing; Tram, Kha; Lee, Christine; Kim, Peter; Salena, Bruno J; Li, Yingfu

    2016-02-01

    Pathogenic strains of bacteria are known to cause various infectious diseases and there is a growing demand for molecular probes that can selectively recognize them. Here we report a special DNAzyme (catalytic DNA), RFD-CD1, that shows exquisite specificity for a pathogenic strain of Clostridium difficile (C. difficile). RFD-CD1 was derived by an in vitro selection approach where a random-sequence DNA library was allowed to react with an unpurified molecular mixture derived from this strain of C. difficle, coupled with a subtractive selection strategy to eliminate cross-reactivities to unintended C. difficile strains and other bacteria species. RFD-CD1 is activated by a truncated version of TcdC, a transcription factor, that is unique to the targeted strain of C. difficle. Our study demonstrates for the first time that in vitro selection offers an effective approach for deriving functional nucleic acid probes that are capable of achieving strain-specific recognition of bacterial pathogens. PMID:26676768

  1. USER Friendly Cloning Coupled with Chitin-Based Natural Transformation Enables Rapid Mutagenesis of Vibrio vulnificus▿ †

    OpenAIRE

    Paul A. Gulig; Tucker, Matthew S.; Thiaville, Patrick C.; Joseph, Jennifer L.; Brown, Roslyn N.

    2009-01-01

    Vibrio vulnificus is a bacterial contaminant of shellfish and causes highly lethal sepsis and destructive wound infections. A definitive identification of virulence factors using the molecular version of Koch's postulates has been hindered because of difficulties in performing molecular genetic analysis of this opportunistic pathogen. For example, conjugation is required to introduce plasmid DNA, and allelic exchange suicide vectors that rely on sucrose sensitivity for counterselection are no...

  2. Essential roles for platelets during neutrophil-dependent or lymphocyte-mediated defense against bacterial pathogens.

    Science.gov (United States)

    Wang, Zheng; Zhao, Qi; Zhang, Dongxia; Sun, Chengming; Bao, Cuixia; Yi, Maoli; Xing, Li; Luo, Deyan

    2016-09-01

    Emerging evidence from animal models suggests that platelets may participate in a wide variety of processes including the immune response against infection. More than 200 whole blood samples from patients and healthy controls were run in the System XE-5000 analyzer, and plasma fractions were separated for the following tests by ELISA, Luminex and light scattering. We describe two mechanisms by which platelets may contribute to immune function against various bacterial pathogens based on increased mean platelet volume in gram-positive bacterial infections and increased platelet counts in gram-negative bacterial infections. Gram-negative bacteria activate platelets to recruit neutrophils, which participate in the immune response against infection. During this process, fractalkine, macrophage inflammatory protein-1β, interleukin-17A, tumor necrosis factor-α and platelet-activating factor were higher in patients infected with Escherichia coli; additionally, giant platelets were observed under the microscope. Meanwhile, we found that platelets played a different role in gram-positive bacterial infections. Specifically, they could actively adhere to gram-positive bacteria in circulation and transfer them to immune sites to promote antibacterial lymphocyte expansion. During this process, complement C3 and factor XI were more highly expressed in patients infected with Staphylococcus aureus; additionally, we detected more small platelets under the microscope. Platelets participate in the immune response against both gram-negative and gram-positive bacteria, although the mechanisms differ. These results will help us understand the complex roles of platelets during infections, and direct our use of antibiotics based on clinical platelet data. PMID:26588444

  3. Internalization of bacterial pathogens in tomatoes and their control by selected chemicals.

    Science.gov (United States)

    Ibarra-Sánchez, L S; Alvarado-Casillas, S; Rodríguez-García, M O; Martínez-Gonzáles, N E; Castillo, A

    2004-07-01

    The effect of different washing or sanitizing agents was compared for preventing or reducing surface and internal contamination of tomatoes by Salmonella Typhimurium and Escherichia coli O157:H7. The tomatoes were inoculated by dipping them in a bacterial suspension containing approximately 6.0 log CFU/ml of each pathogen and then rinsing them with tap water, hypochlorite solution (250 mg/liter), or lactic acid solution (2%, wt/vol). All treatments were applied by dipping or spraying, and solutions were applied at 5, 25, 35, and 55 degrees C. With the exception of the lactic acid dip at 5 degrees C, all treatments reduced both pathogens on the surfaces of the tomatoes by at least 2.9 cycles. No significantly different results were obtained (P > 0.05) with the dipping and spraying techniques. For internalized pathogens, the mean counts for tomatoes treated with water alone or with chlorine ranged from 0.8 to 2.1 log CFU/g. In contrast, after lactic acid spray treatment, all core samples of tomatoes tested negative for Salmonella Typhimurium and, except for one sample with a low but detectable count, all samples tested negative for E. coli O157:H7 with a plate count method. When the absence of pathogens was verified by an enrichment method, Salmonella was not recovered from any samples, whereas two of four samples tested positive for E. coli O157:H7 even though the counts were negative. Few cells of internalized pathogens were able to survive in the center of the tomato during storage at room temperature (25 to 28 degrees C). The average superficial pH of tomatoes treated with tap water, chlorine, or lactic acid was 4.9 to 5.2, 4.1 to 4.3, and 2.5, respectively (P lactic acid sprays may be a more effective alternative for decontaminating tomato surfaces. The use of warm (55 degrees C) sprays could reduce pathogen internalization during washing. PMID:15270485

  4. Bacterial pathogens implicated in causing urinary tract infection (uti and their antimicrobial susceptibility pattern in Ethiopia

    Directory of Open Access Journals (Sweden)

    Theodros Getachew

    2010-01-01

    Full Text Available Introduction: Urinary Tract Infection (UTI is one of the most common infectious disease ranking next to upper respiratory tract infection is the cause of morbidity and mortality in human. They are mostly caused by bacteria. However, studies conducted in Ethiopia are few and are not extensive. Therefore, studying bacterial pathogens causing UTI and their drug susceptibility patterns is of a highest priority. Material & Methods: A total of 3228 urine samples were collected from 2004 to 2009. Fresh midstream urine samples were aseptically collected in sterile containers. Each sample was cultured onto 5% sheep blood agar and CLED agar plates using a calibrated loop, delivering 1ul of the sample. This was incubated at 37° C aerobically overnight. Bacterial isolates were identified using standard biochemical tests and antimicrobial susceptibility pattern was determined using the Kirby ¿ Bauer¿s disk diffusion method followed CLSI guidelines. Result & discussion: From a total of 3228 urine samples significant bacterial growth was obtained from 651 samples. The gram positive and negative bacteria accounted 17.7 % and 80.2% respectively, the rest 2.2 % are yeasts. The majority 475(72.9 of the isolates were from women while the remaining 176 (27.1 were from men. A wide spectrum of uropathogens was isolated, of which 359 (55.1 % were Escherichia coli, 107 (16.4 % Klebsiella species, 66 (10.1 % streptococcus species, 49(7.5% staphylococcus species, 14 (2.2 % citrobacter species, 14 (2.2 % candida species, 13 (2 % enterobacter species, 11 (1.7 % pseudomonas and the rest 2.8% are 5 proteus species, 5 salmonella species, 4 acinetobacter species and 4 M. morganii. Resistance rate to Gram-negative bacilli were 96 % to amoxicilline-clavulanic acid, 66.9 % to tetracycline, 61.4 % to ampicillin, 64.7 % to trimethoprimsulfamethoxazole, 37.6 % to chloramphenicol, 34 % to norfloxacine and 22.4 % to ceftriaxone. Among Gram-positive, 45.1 % were resistant to

  5. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff

    OpenAIRE

    Miller, Melissa A.; Byrne, Barbara A.; Jang, Spencer S.; Dodd, Erin M.; Dorfmeier, Elene; Harris, Michael D.; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A.; Miller, Woutrina A.

    2009-01-01

    Although protected for nearly a century, California's sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile...

  6. Exploration of Phage-Host Interactions in Fish Pathogen Vibrio anguillarum and Anti-Phage Defense Strategies

    DEFF Research Database (Denmark)

    Tan, Demeng

    repress ompK expression. It was demonstrated that QS controls the choice of anti-phage defense strategies in the V. anguillarum strain PF430-3, suggesting the presence of dynamic, temporary adaptations to phage infection pressure, while still securing the ability to produce a functional OmpK receptor. In...... bacterial pathogenicity development. Therefore, successful application of phage therapy in the treatment of vibriosis requires a detailed understanding of phage-host interactions, especially with regards to anti-phage defense mechanisms in the host. Part I. As a first approach, 24 V. anguillarum and 13...... conclusion, this thesis provides a first insight into the dynamic vibriophage-host interactions, indicating the complexity of phage therapy in the treatment of vibriosis, regarding the evolution of anti-phage defense mechanisms, gene regulation, quorum sensing, biofilm formation, as well as pathogenesis...

  7. Genomic Epidemiology: Whole-Genome-Sequencing-Powered Surveillance and Outbreak Investigation of Foodborne Bacterial Pathogens.

    Science.gov (United States)

    Deng, Xiangyu; den Bakker, Henk C; Hendriksen, Rene S

    2016-01-01

    As we are approaching the twentieth anniversary of PulseNet, a network of public health and regulatory laboratories that has changed the landscape of foodborne illness surveillance through molecular subtyping, public health microbiology is undergoing another transformation brought about by so-called next-generation sequencing (NGS) technologies that have made whole-genome sequencing (WGS) of foodborne bacterial pathogens a realistic and superior alternative to traditional subtyping methods. Routine, real-time, and widespread application of WGS in food safety and public health is on the horizon. Technological, operational, and policy challenges are still present and being addressed by an international and multidisciplinary community of researchers, public health practitioners, and other stakeholders. PMID:26772415

  8. Isolation and characterization of a new species of Vibrio-Vibrio olivaceus sp.nov. from diseased flounder (Paralichthys olivaceus temminck et schlegel)

    Institute of Scientific and Technical Information of China (English)

    Fang Hai; Zhang Xiao-jun; Chen Cuizhen; Zhan Wenbin; Jin Xiaomin

    2005-01-01

    One kind of pathogenic bacteria was isolated from diseased (or dead) flounder (Paralichthys olivaceus L.) which expressed bacterial septicaemia. The phenotyic information of the 10 pure cultures was studied extensively, including morphological characteristics, colony characteristics in different media, physiological and biochemical characteristics, and the mol%G+C ratio of the DNA for representative strain. The results showed that the isolates belonged to a new species of Vibrio. In addition, the representative strains have been re-checked by China Center for Type Culture Collection (CCTCC), the results were the same as ours, the examined strains were also regarded as a new species of Vibrio, and designated as Vibrio olivaceus sp.nov. by its isolated fish (Paralichthys olivaceus) based on its biological properties following Rules of International Code of Nomenclature of Bacteria. In the same time, we conducted studies on the serum homology of isolates, pathogenicity of isolates by experimental infection. The results showed that all the isolates were of serologic similarity and the isolates have strong pathogenicity to flounder. Inspection to pure cultures and isolates from liver of moribund fish from infection experiment by fluorescent antibody technique showed the feasibility of fluorescent antibody technique as an auxiliary method of examination.

  9. Reactive oxygen species generated by a heat shock protein (Hsp) inducing product contributes to Hsp70 production and Hsp70-mediated protective immunity in Artemia franciscana against pathogenic vibrios.

    Science.gov (United States)

    Baruah, Kartik; Norouzitallab, Parisa; Linayati, Linayati; Sorgeloos, Patrick; Bossier, Peter

    2014-10-01

    The cytoprotective role of heat shock protein (Hsp70) described in a variety of animal disease models, including vibriosis in farmed aquatic animals, suggests that new protective strategies relying upon the use of compounds that selectively turn on Hsp genes could be developed. The product Tex-OE® (hereafter referred to as Hspi), an extract from the skin of the prickly pear fruit, Opuntia ficus indica, was previously shown to trigger Hsp70 synthesis in a non-stressful situation in a variety of animals, including in a gnotobiotically (germ-free) cultured brine shrimp Artemia franciscana model system. This model system offers great potential for carrying out high-throughput, live-animal screens of compounds that have health benefit effects. By using this model system, we aimed to disclose the underlying cause behind the induction of Hsp70 by Hspi in the shrimp host, and to determine whether the product affects the shrimp in inducing resistance towards pathogenic vibrios. We provide unequivocal evidences indicating that during the pretreatment period with Hspi, there is an initial release of reactive oxygen species (hydrogen peroxide and/or superoxide anion), generated by the added product, in the rearing water and associated with the host. The reactive molecules generated are the triggering factors responsible for causing Hsp70 induction within Artemia. We have also shown that Hspi acts prophylactically at an optimum dose regimen to confer protection against pathogenic vibrios. This salutary effect was associated with upregulation of two important immune genes, prophenoloxidase and transglutaminase of the innate immune system. These findings suggest that inducers of stress protein (e.g. Hsp70) are potentially important modulator of immune responses and might be exploited to confer protection to cultured shrimp against Vibrio infection. PMID:24950414

  10. Artificial bacterial biomimetic nanoparticles synergize pathogen-associated molecular patterns for vaccine efficacy.

    Science.gov (United States)

    Siefert, Alyssa L; Caplan, Michael J; Fahmy, Tarek M

    2016-08-01

    Antigen-presenting cells (APCs) sense microorganisms via pathogen-associated molecular patterns (PAMPs) by both extra- and intracellular Toll-like Receptors (TLRs), initiating immune responses against invading pathogens. Bacterial PAMPs include extracellular lipopolysaccharides and intracellular unmethylated CpG-rich oligodeoxynucleotides (CpG). We hypothesized that a biomimetic approach involving antigen-loaded nanoparticles (NP) displaying Monophosphoryl Lipid A (MPLA) and encapsulating CpG may function as an effective "artificial bacterial" biomimetic vaccine platform. This hypothesis was tested in vitro and in vivo using NP assembled from biodegradable poly(lactic-co-glycolic acid) (PLGA) polymer, surface-modified with MPLA, and loaded with CpG and model antigen Ovalbumin (OVA). First, CpG potency, characterized by cytokine profiles, titers, and antigen-specific T cell responses, was enhanced when CpG was encapsulated in NP compared to equivalent concentrations of surface-presented CpG, highlighting the importance of biomimetic presentation of PAMPs. Second, NP synergized surface-bound MPLA with encapsulated CpG in vitro and in vivo, inducing greater pro-inflammatory, antigen-specific T helper 1 (Th1)-skewed cellular and antibody-mediated responses compared to single PAMPs or soluble PAMP combinations. Importantly, NP co-presentation of CpG and MPLA was critical for CD8(+) T cell responses, as vaccination with a mixture of NP presenting either CpG or MPLA failed to induce cellular immunity. This work demonstrates a rational methodology for combining TLR ligands in a context-dependent manner for synergistic nanoparticulate vaccines. PMID:27162077

  11. Antibiotic sensitivity pattern of bacterial pathogens in the intensive care unit of Fatmawati Hospital,Indonesia

    Institute of Scientific and Technical Information of China (English)

    Maksum; Radji; Siti; Fauziah; Nurgani; Aribinuko

    2011-01-01

    Objective:To evaluate the sensitivity pattern of bacterial pathogens in the intensive care unit(ICU) of a tertiary care of Falmawati Hospital Jakarta Indonesia.Methods:A cross sectional retrospective study of bacterial pathogen was carried out on a total of 722 patients that were admitted to the ICU of Fatmawati Hospital Jakarta Indonesia during January 2009 to March 2010. All bacteria were identified by standard microbiologic methods,and(heir antibiotic susceptibility testing was performed using disk diffusion method.Results:Specimens were collected from 385 patients who were given antimicrobial treatment,of which 249(64.68%) were cultured positive and 136(35.32%) were negative.The most predominant isolate was Pseudomonas aeruginosa(P.aeruginosa)(26.5%) followed by Klebsiella pneumoniae(K.pneumoniae)(15.3%) and Staphylococcus epidermidis(14.9%).P.aeruginosa isolates showed high rate of resistance to cephalexin(95.3%),cefotaxime(64.1%),and ceftriaxone(60.9%).Amikacin was the most effective(84.4%) antibiotic against P.aeruginosa followed by imipenem(81.2%),and meropenem(75.0%).K.pneumoniae showed resistance to cephalexin(86.5%),ceftriaxone(75.7%),ceftazidime(73.0%),cefpirome(73.0%) and cefotaxime(67.9%),respectively.Conclusions:Most bacteria isolated from ICU of Fatmawati Hospital Jakarta Indonesia were resistant to the third generation of cephalosporins,and quinolone antibiotics.Regular surveillance of antibiotic susceptibility pallerns is very important for setting orders to guide the clinician in choosing empirical or directed therapy of infected patients.

  12. Disruption of Cell-to-Cell Signaling Does Not Abolish the Antagonism of Phaeobacter gallaeciensis toward the Fish Pathogen Vibrio anguillarum in Algal Systems

    DEFF Research Database (Denmark)

    Prol García, María Jesús; D'Alvise, Paul; Gram, Lone

    2013-01-01

    Quorum sensing (QS) regulates Phaeobacter gallaeciensis antagonism in broth systems; however, we demonstrate here that QS is not important for antagonism in algal cultures. QS mutants reduced Vibrio anguillarum to the same extent as the wild type. Consequently, a combination of probiotic Phaeobac......Quorum sensing (QS) regulates Phaeobacter gallaeciensis antagonism in broth systems; however, we demonstrate here that QS is not important for antagonism in algal cultures. QS mutants reduced Vibrio anguillarum to the same extent as the wild type. Consequently, a combination of probiotic...

  13. The emergence of Vibrio pathogens in Europe: ecology, evolution, and pathogenesis (Paris, 11-12th March 2015)

    DEFF Research Database (Denmark)

    LeRoux, Frederique; Wegner, K. Mathias; Baker-Austin, Craig;

    2015-01-01

    Global change has caused a worldwide increase in reports of Vibrio-associated diseases with ecosystem-wide impacts on humans and marine animals. In Europe, higher prevalence of human infections followed regional climatic trends with outbreaks occurring during episodes of unusually warm weather. S...... federative questions that meet societal needs. Here we report the proceedings of the first European workshop dedicated to these specific goals of the Vibrio research community by connecting current knowledge to societal issues related to ocean health and food security....

  14. Bacterial rRNA-Targeted Reverse Transcription-PCR Used To Identify Pathogens Responsible for Fever with Neutropenia▿

    OpenAIRE

    Sakaguchi, Sachi; Saito, Masahiro; Tsuji, Hirokazu; Asahara, Takashi; Takata, Oto; Fujimura, Junya; NAGATA, Satoru; Nomoto, Koji; Shimizu, Toshiaki

    2010-01-01

    The purpose of this study was to evaluate the clinical utility of bacterial rRNA-targeted reverse transcription-quantitative PCR (BrRNA RT-qPCR) assays for identifying the bacterial pathogens that cause fever with neutropenia in pediatric cancer patients, by comparing the bacterial detection rate of this technique with that of blood culture. One milliliter of blood was collected from pediatric patients who developed fever with neutropenia following cancer chemotherapy. BrRNA RT-qPCR was perfo...

  15. Localization of adhesins on the surface of a pathogenic bacterial envelope through atomic force microscopy

    Science.gov (United States)

    Arnal, L.; Longo, G.; Stupar, P.; Castez, M. F.; Cattelan, N.; Salvarezza, R. C.; Yantorno, O. M.; Kasas, S.; Vela, M. E.

    2015-10-01

    Bacterial adhesion is the first and a significant step in establishing infection. This adhesion normally occurs in the presence of flow of fluids. Therefore, bacterial adhesins must be able to provide high strength interactions with their target surface in order to maintain the adhered bacteria under hydromechanical stressing conditions. In the case of B. pertussis, a Gram-negative bacterium responsible for pertussis, a highly contagious human respiratory tract infection, an important protein participating in the adhesion process is a 220 kDa adhesin named filamentous haemagglutinin (FHA), an outer membrane and also secreted protein that contains recognition domains to adhere to ciliated respiratory epithelial cells and macrophages. In this work, we obtained information on the cell-surface localization and distribution of the B. pertussis adhesin FHA using an antibody-functionalized AFM tip. Through the analysis of specific molecular recognition events we built a map of the spatial distribution of the adhesin which revealed a non-homogeneous pattern. Moreover, our experiments showed a force induced reorganization of the adhesin on the surface of the cells, which could explain a reinforced adhesive response under external forces. This single-molecule information contributes to the understanding of basic molecular mechanisms used by bacterial pathogens to cause infectious disease and to gain insights into the structural features by which adhesins can act as force sensors under mechanical shear conditions.Bacterial adhesion is the first and a significant step in establishing infection. This adhesion normally occurs in the presence of flow of fluids. Therefore, bacterial adhesins must be able to provide high strength interactions with their target surface in order to maintain the adhered bacteria under hydromechanical stressing conditions. In the case of B. pertussis, a Gram-negative bacterium responsible for pertussis, a highly contagious human respiratory tract

  16. Interactions of seedborne bacterial pathogens with host and non-host plants in relation to seed infestation and seedling transmission.

    Directory of Open Access Journals (Sweden)

    Bhabesh Dutta

    Full Text Available The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1 × 10(6 colony forming units (CFUs/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion. Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating, respectively and they were not significantly different (P = 0.67. The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03. None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be

  17. Interactions of seedborne bacterial pathogens with host and non-host plants in relation to seed infestation and seedling transmission.

    Science.gov (United States)

    Dutta, Bhabesh; Gitaitis, Ronald; Smith, Samuel; Langston, David

    2014-01-01

    The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1 × 10(6) colony forming units (CFUs)/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion). Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO) assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67). The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03). None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be colonized by

  18. 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.

  19. Hyperglycemia Impairs Neutrophil-Mediated Bacterial Clearance in Mice Infected with the Lyme Disease Pathogen

    Science.gov (United States)

    Javid, Ashkan; Zlotnikov, Nataliya; Pětrošová, Helena; Tang, Tian Tian; Zhang, Yang; Bansal, Anil K.; Ebady, Rhodaba; Parikh, Maitry; Ahmed, Mijhgan; Sun, Chunxiang; Newbigging, Susan; Kim, Yae Ram; Santana Sosa, Marianna; Glogauer, Michael

    2016-01-01

    Insulin-insufficient type 1 diabetes is associated with attenuated bactericidal function of neutrophils, which are key mediators of innate immune responses to microbes as well as pathological inflammatory processes. Neutrophils are central to immune responses to the Lyme pathogen Borrelia burgdorferi. The effect of hyperglycemia on host susceptibility to and outcomes of B. burgdorferi infection has not been examined. The present study investigated the impact of sustained obesity-independent hyperglycemia in mice on bacterial clearance, inflammatory pathology and neutrophil responses to B. burgdorferi. Hyperglycemia was associated with reduced arthritis incidence but more widespread tissue colonization and reduced clearance of bacterial DNA in multiple tissues including brain, heart, liver, lung and knee joint. B. burgdorferi uptake and killing were impaired in neutrophils isolated from hyperglycemic mice. Thus, attenuated neutrophil function in insulin-insufficient hyperglycemia was associated with reduced B. burgdorferi clearance in target organs. These data suggest that investigating the effects of comorbid conditions such as diabetes on outcomes of B. burgdorferi infections in humans may be warranted. PMID:27340827

  20. Hyperglycemia Impairs Neutrophil-Mediated Bacterial Clearance in Mice Infected with the Lyme Disease Pathogen.

    Directory of Open Access Journals (Sweden)

    Ashkan Javid

    Full Text Available Insulin-insufficient type 1 diabetes is associated with attenuated bactericidal function of neutrophils, which are key mediators of innate immune responses to microbes as well as pathological inflammatory processes. Neutrophils are central to immune responses to the Lyme pathogen Borrelia burgdorferi. The effect of hyperglycemia on host susceptibility to and outcomes of B. burgdorferi infection has not been examined. The present study investigated the impact of sustained obesity-independent hyperglycemia in mice on bacterial clearance, inflammatory pathology and neutrophil responses to B. burgdorferi. Hyperglycemia was associated with reduced arthritis incidence but more widespread tissue colonization and reduced clearance of bacterial DNA in multiple tissues including brain, heart, liver, lung and knee joint. B. burgdorferi uptake and killing were impaired in neutrophils isolated from hyperglycemic mice. Thus, attenuated neutrophil function in insulin-insufficient hyperglycemia was associated with reduced B. burgdorferi clearance in target organs. These data suggest that investigating the effects of comorbid conditions such as diabetes on outcomes of B. burgdorferi infections in humans may be warranted.

  1. Lytic bacteriophages in Veterinary Medicine: a therapeutic option against bacterial pathogens?

    Directory of Open Access Journals (Sweden)

    C Borie

    2014-01-01

    Full Text Available The high prevalence of certain bacterial diseases in animals and their economic impact at the productive and public health levels, have directed attention towards the search for new methods of control and prevention, alternative or complementary, that aim to mitigate their adverse effects. This scenario is further complicated by the permanent and rising presence of pathogenic bacteria that are resistant to many antibiotics, limiting the choice of control strategies. In the continuous search for new therapies, there is a renewed interest on the application of bacteriophages, viruses that kill bacteria, as potential antimicrobial agents. Phage therapy in animal production, pets and experimental models of human infection have been discussed in veterinary medicine for 3 decades, with encouraging results in terms of reducing mortality, the severity of the clinical state and bacterial counts at tissue level. These benefits have been achieved thanks to increased knowledge of the biology of phages, better technology that allows their purification and their inherent advantages in terms of their safety for animals. Currently, phage research continues to open new horizons for both the medical industry and the food industry, considering the use of phages in the stages of "farm to fork", with promising results if used as an intervention in animals since their arrival to the slaughter house.

  2. Bacterial pathogen gene regulation: a DNA-structure-centred view of a protein-dominated domain.

    Science.gov (United States)

    Dorman, Charles J; Colgan, Aoife; Dorman, Matthew J

    2016-07-01

    The mechanisms used by bacterial pathogens to regulate the expression of their genes, especially their virulence genes, have been the subject of intense investigation for several decades. Whole genome sequencing projects, together with more targeted studies, have identified hundreds of DNA-binding proteins that contribute to the patterns of gene expression observed during infection as well as providing important insights into the nature of the gene products whose expression is being controlled by these proteins. Themes that have emerged include the importance of horizontal gene transfer to the evolution of pathogens, the need to impose regulatory discipline upon these imported genes and the important roles played by factors normally associated with the organization of genome architecture as regulatory principles in the control of virulence gene expression. Among these architectural elements is the structure of DNA itself, its variable nature at a topological rather than just at a base-sequence level and its ability to play an active (as well as a passive) part in the gene regulation process. PMID:27252403

  3. Terminal reassortment drives the quantum evolution of type III effectors in bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    John Stavrinides

    2006-10-01

    Full Text Available Many bacterial pathogens employ a type III secretion system to deliver type III secreted effectors (T3SEs into host cells, where they interact directly with host substrates to modulate defense pathways and promote disease. This interaction creates intense selective pressures on these secreted effectors, necessitating rapid evolution to overcome host surveillance systems and defenses. Using computational and evolutionary approaches, we have identified numerous mosaic and truncated T3SEs among animal and plant pathogens. We propose that these secreted virulence genes have evolved through a shuffling process we have called "terminal reassortment." In terminal reassortment, existing T3SE termini are mobilized within the genome, creating random genetic fusions that result in chimeric genes. Up to 32% of T3SE families in species with relatively large and well-characterized T3SE repertoires show evidence of terminal reassortment, as compared to only 7% of non-T3SE families. Terminal reassortment may permit the near instantaneous evolution of new T3SEs and appears responsible for major modifications to effector activity and function. Because this process plays a more significant role in the evolution of T3SEs than non-effectors, it provides insight into the evolutionary origins of T3SEs and may also help explain the rapid emergence of new infectious agents.

  4. Caenorhabditis elegans bacterial pathogen resistant bus-4 mutants produce altered mucins.

    Directory of Open Access Journals (Sweden)

    Lisa M Parsons

    Full Text Available Caenorabditis elegans bus-4 glycosyltransferase mutants are resistant to infection by Microbacterium nematophilum, Yersinia pestis and Yersinia pseudotuberculosis and have altered susceptibility to two Leucobacter species Verde1 and Verde2. Our objective in this study was to define the glycosylation changes leading to this phenotype to better understand how these changes lead to pathogen resistance. We performed MALDI-TOF MS, tandem MS and GC/MS experiments to reveal fine structural detail for the bus-4 N- and O-glycan pools. We observed dramatic changes in O-glycans and moderate ones in N-glycan pools compared to the parent strain. Ce core-I glycans, the nematode's mucin glycan equivalent, were doubled in abundance, halved in charge and bore shifts in terminal substitutions. The fucosyl O-glycans, Ce core-II and neutral fucosyl forms, were also increased in abundance as were fucosyl N-glycans. Quantitative expression analysis revealed that two mucins, let-653 and osm-8, were upregulated nearly 40 fold and also revealed was a dramatic increase in GDP-Man 4,6 dehydratease expression. We performed detailed lectin binding studies that showed changes in glycoconjugates in the surface coat, cuticle surface and intestine. The combined changes in cell surface glycoconjugate distribution, increased abundance and altered properties of mucin provide an environment where likely the above pathogens are not exposed to normal glycoconjugate dependent cues leading to barriers to these bacterial infections.

  5. The many forms of a pleomorphic bacterial pathogen – The developmental network of Legionella pneumophila

    Directory of Open Access Journals (Sweden)

    Peter eRobertson

    2014-12-01

    Full Text Available Legionella pneumophila is a natural intracellular bacterial parasite of free-living freshwater protozoa and an accidental human pathogen that causes Legionnaires’ disease. L. pneumophila differentiates, and does it in style. Recent experimental data on L. pneumophila’s differentiation point at the existence of a complex network that involves many developmental forms. We intend readers to: (i understand the biological relevance of L. pneumophila’s forms found in freshwater and their potential to transmit Legionnaires’ disease, and (ii learn that the common depiction of L. pneumophila’s differentiation as a biphasic developmental cycle that alternates between a replicative and a transmissive form is but an oversimplification of the actual process. Our specific objectives are to provide updates on the molecular factors that regulate L. pneumophila’s differentiation (section 2, and describe the developmental network of L. pneumophila (section 3, which for clarity’s sake we have dissected into five separate developmental cycles. Finally, since each developmental form seems to contribute differently to the human pathogenic process and the transmission of Legionnaires’ disease, readers are presented with a challenge to develop novel methods to detect the various L. pneumophila forms present in water (section 4, as a means to improve our assessment of risk and more effectively prevent legionellosis outbreaks.

  6. Viral and bacterial pathogens identification in children hospitalised for severe pneumonia and parapneumonic empyema

    Directory of Open Access Journals (Sweden)

    Jean-Noël Telles

    2012-05-01

    Full Text Available Pneumonia is caused by respiratory bacteria and/or viruses. Little is known if co-infections are an aggravating factor in hospitalised children with severe pneumonia. We studied the impact of respiratory pathogens on the severity of pneumonia. Between 2007 and 2009, 52 children hospitalised with a well-documented diagnosis of communityacquired pneumonia (CAP, with or without parapneumonic empyema (PPE, were enrolled in the study. The patients were classified into 2 groups: CAP + PPE (n = 28 and CAP (n = 24. The identification of respiratory viruses and bacteria in nasopharyngeal aspirates and pleural effusion samples were performed using conventional bacterial techniques and molecular assays. Using real-time multiplex PCR and antigen detection, Streptococcus pneumoniae was the main agent identified in 76% of the cases by molecular tests and BinaxNOW® in pleural fluid. A total of 8% of pleural fluid samples remained undiagnosed. In nasopharyngeal aspirates, rhinovirus, parainfluenza viruses, human metapneumovirus, and respiratory syncytial virus were detected in both CAP and CAP + PPE populations; however, the percentage of viral co-detection was significantly higher in nasopharyngeal aspirates from CAP + PPE patients (35% compared with CAP patients (5%. In conclusion, viral co-detection was observed mainly in patients with more severe pneumonia. Molecular biology assays improved the pathogens detection in pneumonia and confirmed the S. pneumoniae detection by BinaxNOW® in pleural effusion samples. Interestingly, the main S. pneumoniae serotypes found in PPE are not the ones targeted by the heptavalent pneumococcal conjugate vaccine.

  7. A single natural nucleotide mutation alters bacterial pathogen host-tropism

    Science.gov (United States)

    Ward, Melissa J.; Selva, Laura; Guinane, Caitriona M.; González-Muñoz, Beatriz M.; Tristan, Anne; Foster, Simon J; Fitzgerald, J. Ross; Penadés, José R.

    2015-01-01

    The capacity of microbial pathogens to alter their host-tropism leading to epidemics in distinct host-species populations is a global public and veterinary health concern. In order to investigate the molecular basis of a bacterial host-switching event in a tractable host-species, we traced the evolutionary trajectory of the common rabbit clone of Staphylococcus aureus. We report that it evolved through a likely human-to-rabbit host jump over 40 years ago, and that only a single natural nucleotide mutation was required and sufficient to convert a human-specific S. aureus strain into one which could infect rabbits. Related mutations were identified at the same locus in other rabbit strains of distinct clonal origin, consistent with convergent evolution. This first report of a single mutation that was sufficient to alter the host-tropism of a micro-organism during its evolution highlights the capacity of some pathogens to readily expand into novel host-species populations. PMID:25685890

  8. Molecular evidence for bacterial pathogens in Ixodes ricinus ticks infesting Shetland ponies.

    Science.gov (United States)

    Skotarczak, Bogumiła; Wodecka, Beata; Rymaszewska, Anna; Adamska, Małgorzata

    2016-06-01

    Ixodes ricinus has the potential to transmit zoonotic pathogens to humans and domestic animals. The feeding I. ricinus (n = 1737) collected from 49 Shetland ponies and questing ones from vegetation (n = 371) were tested for the presence and differentiation of the bacterial species. DNA of I. ricinus ticks was examined with PCR and sequencing analysis to identify species of Borrelia burgdorferi sensu lato (Bbsl), Anaplasma phagocytophilum and Rickettsia spp. Altogether, 24.3 % I. ricinus of the infested horses and 12.4 % ticks from vegetation carried at least one pathogen species. Horse-feeding ticks (19.2 %) were significantly more frequently infected with Borrelia spp. than questing ticks (4.8 %). Among Bbsl species, in I. ricinus infesting ponies, B. garinii, B. afzelii, B. burgdorferi sensu stricto, B. valaisiana and B. lusitanie and one species, B. miyamotoi related to relapsing fever group, were detected. The 73 flaB gene sequences of Borrelia obtained from feeding I. ricinus have been deposited in GenBank. Among Rickettsia species, two were identified: R. helvetica which was dominant and R. monacensis. Infections with more than one pathogenic species, involving mostly Bbsl and R. helvetica were detected in 6.3 % of infected ticks collected from horses. Shetland ponies may play an important role in the epidemiological cycle of Bbsl and probably could contribute to the natural cycle of A. phagocytophilum and R. helvetica as host for infected ticks. The awareness about these infectious agents in ticks from ponies might be an important criterion for the risk assessment of human diseases, especially as these animals are maintained for recreational purposes. PMID:26920921

  9. Modular microfluidic system fabricated in thermoplastics for the strain-specific detection of bacterial pathogens.

    Science.gov (United States)

    Chen, Yi-Wen; Wang, Hong; Hupert, Mateusz; Witek, Makgorzata; Dharmasiri, Udara; Pingle, Maneesh R; Barany, Francis; Soper, Steven A

    2012-09-21

    The recent outbreaks of a lethal E. coli strain in Germany have aroused renewed interest in developing rapid, specific and accurate systems for detecting and characterizing bacterial pathogens in suspected contaminated food and/or water supplies. To address this need, we have designed, fabricated and tested an integrated modular-based microfluidic system and the accompanying assay for the strain-specific identification of bacterial pathogens. The system can carry out the entire molecular processing pipeline in a single disposable fluidic cartridge and detect single nucleotide variations in selected genes to allow for the identification of the bacterial species, even its strain with high specificity. The unique aspect of this fluidic cartridge is its modular format with task-specific modules interconnected to a fluidic motherboard to permit the selection of the target material. In addition, to minimize the amount of finishing steps for assembling the fluidic cartridge, many of the functional components were produced during the polymer molding step used to create the fluidic network. The operation of the cartridge was provided by electronic, mechanical, optical and hydraulic controls located off-chip and packaged into a small footprint instrument (1 ft(3)). The fluidic cartridge was capable of performing cell enrichment, cell lysis, solid-phase extraction (SPE) of genomic DNA, continuous flow (CF) PCR, CF ligase detection reaction (LDR) and universal DNA array readout. The cartridge was comprised of modules situated on a fluidic motherboard; the motherboard was made from polycarbonate, PC, and used for cell lysis, SPE, CF PCR and CF LDR. The modules were task-specific units and performed universal zip-code array readout or affinity enrichment of the target cells with both made from poly(methylmethacrylate), PMMA. Two genes, uidA and sipB/C, were used to discriminate between E. coli and Salmonella, and evaluated as a model system. Results showed that the fluidic

  10. Pharmacodynamic evaluation of commonly prescribed oral antibiotics against respiratory bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Pignatari Antonio CC

    2011-10-01

    Full Text Available Abstract Background Upper and lower respiratory tract infections (RTIs account for a substantial portion of outpatient antibiotic utilization. However, the pharmacodynamic activity of commonly used oral antibiotic regimens has not been studied against clinically relevant pathogens. The objective of this study was to assess the probability of achieving the requisite pharmacodynamic exposure for oral antibacterial regimens commonly prescribed for RTIs in adults against bacterial isolates frequently involved in these processes (S. pneumoniae, H. influenzae, and M. catharralis. Methods Using a 5000-subject Monte Carlo simulation, the cumulative fractions of response (CFR, (i.e., probabilities of achieving requisite pharmacodynamic targets for the most commonly prescribed oral antibiotic regimens, as determined by a structured survey of medical prescription patterns, were assessed against local respiratory bacterial isolates from adults in São Paulo collected during the same time period. Minimal inhibitory concentration (MIC of 230 isolates of Streptococcus pneumoniae (103, Haemophilus influenzae (98, and Moraxella catharralis (29 from a previous local surveillance were used. Results The most commonly prescribed antibiotic regimens were azithromycin 500 mg QD, amoxicillin 500 mg TID, and levofloxacin 500 mg QD, accounting for 58% of the prescriptions. Varied doses of these agents, plus gatifloxacin, amoxicillin-clavulanate, moxifloxacin, and cefaclor made up the remaining regimens. Utilizing aggressive pharmacodynamic exposure targets, the only regimens to achieve greater than 90% CFR against all three pathogens were amoxicillin/amoxicillin-clavulanate 500 mg TID (> 91%, gatifloxacin 400 mg QD (100%, and moxifloxacin 400 mg QD (100%. Considering S. pneumoniae isolates alone, azithromycin 1000 mg QD also achieved greater than 90% CFR (91.3%. Conclusions The only regimens to achieve high CFR against all three pathogen populations in both scenarios

  11. Simultaneous Detection of Bacterial Fish Pathogens, Edwardsiella ictaluri, Flavobacterium columnnare and Aeromonas Hydrophila by Multiplex-PCR

    Science.gov (United States)

    Edwardsiella ictaluri, Flavobacterium columnare and Aeromonas hydrophila are three major bacterial pathogens of fish that cause diseases with significant economic impact on the aquaculture industry world-wide. Rapid detection of multiple infections with these bacteria in the same host is important f...

  12. Complete Genome Sequence of Japanese Erwinia Strain Ejp617, a Bacterial Shoot Blight Pathogen of Pear ▿

    OpenAIRE

    Park, Duck Hwan; Thapa, Shree Prasad; Choi, Beom-Soon; Kim, Won-Sik; Hur, Jang Hyun; Cho, Jun Mo; Lim, Jong-Sung; Choi, Ik-Young; Lim, Chun Keun

    2010-01-01

    The Japanese Erwinia strain Ejp617 is a plant pathogen that causes bacterial shoot blight of pear in Japan. Here, we report the complete genome sequence of strain Ejp617 isolated from Nashi pears in Japan to provide further valuable insight among related Erwinia species.

  13. Disruption of Cell-to-Cell Signaling Does Not Abolish the Antagonism of Phaeobacter gallaeciensis toward the Fish Pathogen Vibrio anguillarum in Algal Systems

    OpenAIRE

    Prol García, M. J.; D'Alvise, P. W.; Gram, L

    2013-01-01

    Quorum sensing (QS) regulates Phaeobacter gallaeciensis antagonism in broth systems; however, we demonstrate here that QS is not important for antagonism in algal cultures. QS mutants reduced Vibrio anguillarum to the same extent as the wild type. Consequently, a combination of probiotic Phaeobacter and QS inhibitors is a feasible strategy for aquaculture disease control.

  14. A Single Residue Change in Vibrio harveyi Hemolysin Results in the Loss of Phospholipase and Hemolytic Activities and Pathogenicity for Turbot (Scophthalmus maximus)▿

    Science.gov (United States)

    Sun, Boguang; Zhang, Xiao-Hua; Tang, Xuexi; Wang, Shushan; Zhong, Yingbin; Chen, Jixiang; Austin, Brian

    2007-01-01

    Vibrio harveyi hemolysin, an important virulence determinant in fish pathogenesis, was further characterized, and the enzyme was identified as a phospholipase B by gas chromatography. Site-directed mutagenesis revealed that a specific residue, Ser153, was critical for its enzymatic activity and for its virulence in fish. PMID:17220231

  15. Survey on antimicrobial resistance patterns in Vibrio vulnificus and Vibrio cholerae non-O1/non-O139 in Germany reveals carbapenemase-producing Vibrio cholerae in coastal waters

    OpenAIRE

    Bier, Nadja; Schwartz, Keike; Guerra, Beatriz; Strauch, Eckhard

    2015-01-01

    An increase in the occurrence of potentially pathogenic Vibrio species is expected for waters in Northern Europe as a consequence of global warming. In this context, a higher incidence of Vibrio infections is predicted for the future and forecasts suggest that people visiting and living at the Baltic Sea are at particular risk. This study aimed to investigate antimicrobial resistance patterns among Vibrio vulnificus and Vibrio cholerae non-O1/non-O139 isolates that could pose a public health ...

  16. Detection of pathogenic gram negative bacteria using infrared thermography

    Science.gov (United States)

    Lahiri, B. B.; Divya, M. P.; Bagavathiappan, S.; Thomas, Sabu; Philip, John

    2012-11-01

    Detection of viable bacteria is of prime importance in all fields of microbiology and biotechnology. Conventional methods of enumerating bacteria are often time consuming and labor-intensive. All living organisms generate heat due to metabolic activities and hence, measurement of heat energy is a viable tool for detection and quantification of bacteria. In this article, we employ a non-contact and real time method - infrared thermography (IRT) for measurement of temperature variations in four clinically significant gram negative pathogenic bacteria, viz. Vibrio cholerae, Vibrio mimicus, Proteus mirabilis and Pseudomonas aeruginosa. We observe that, the energy content, defined as the ratio of heat generated by bacterial metabolic activities to the heat lost from the liquid medium to the surrounding, vary linearly with the bacterial concentration in all the four pathogenic bacteria. The amount of energy content observed in different species is attributed to their metabolisms and morphologies that affect the convection velocity and hence heat transport in the medium.

  17. Isolation and molecular identification of Vibrio spp. by sequencing of 16S rDNA from seafood, meat and meat products in Libya

    OpenAIRE

    S. M. Azwai; Alfallani, E.A.; S.K. Abolghait; Garbaj, A.M.; Naas, H.T.; Moawad, A.A.; F.T. Gammoudi; Rayes, H.M.; Barbieri, I.; Eldaghayes, I.M.

    2016-01-01

    The genus Vibrio includes several food-borne pathogens that cause a spectrum of clinical conditions including septicemia, cholera and milder forms of gastroenteritis. Several Vibrio spp. are commonly associated with food-borne transmission including Vibrio cholerae, Vibrio parahemolyticus, and Vibrio vulnificus. Microbiological analysis for enumeration and isolation of Vibrio spp. were carried out for a total of 93 samples of seafood, meat and meat products from different geographic localitie...

  18. A Bacterial Pathogen Displaying Temperature-Enhanced Virulence of the Microalga Emiliania huxleyi

    Science.gov (United States)

    Mayers, Teaghan J.; Bramucci, Anna R.; Yakimovich, Kurt M.; Case, Rebecca J.

    2016-01-01

    recently been shown to have acquired resistance against EhVs at elevated temperature, bacterial pathogens with temperature-dependent virulence, such as R11, may become much more important in the ecology of E. huxleyi in a warming climate. PMID:27379036

  19. A Bacterial Pathogen Displaying Temperature-Enhanced Virulence of the Microalga Emiliania huxleyi.

    Science.gov (United States)

    Mayers, Teaghan J; Bramucci, Anna R; Yakimovich, Kurt M; Case, Rebecca J

    2016-01-01

    shown to have acquired resistance against EhVs at elevated temperature, bacterial pathogens with temperature-dependent virulence, such as R11, may become much more important in the ecology of E. huxleyi in a warming climate. PMID:27379036

  20. Infection in a dish: high-throughput analyses of bacterial pathogenesis.

    OpenAIRE

    Kurz, C. Léopold; Ewbank, Jonathan,

    2007-01-01

    Diverse aspects of host-pathogen interactions have been studied using non-mammalian hosts such as Dictyostelium discoideum, Caenorhabditis elegans, Drosophila melanogaster and Danio rerio for more than 20 years. Over the past two years, the use of these model hosts to dissect bacterial virulence mechanisms has been expanded to include the important human pathogens Vibrio cholerae and Yersinia pestis. Innovative approaches using these alternative hosts have also been developed, enabling the is...

  1. Pathogen-induced conditioning of the primary xylem vessels - a prerequisite for the formation of bacterial emboli by Pectobacterium atrosepticum.

    Science.gov (United States)

    Gorshkov, V Y; Daminova, A G; Mikshina, P V; Petrova, O E; Ageeva, M V; Salnikov, V V; Gorshkova, T A; Gogolev, Y V

    2016-07-01

    Representatives of Pectobacterium genus are some of the most harmful phytopathogens in the world. In the present study, we have elucidated novel aspects of plant-Pectobacterium atrosepticum interactions. This bacterium was recently demonstrated to form specific 'multicellular' structures - bacterial emboli in the xylem vessels of infected plants. In our work, we showed that the process of formation of these structures includes the pathogen-induced reactions of the plant. The colonisation of the plant by P. atrosepticum is coupled with the release of a pectic polysaccharide, rhamnogalacturonan I, into the vessel lumen from the plant cell wall. This polysaccharide gives rise to a gel that serves as a matrix for bacterial emboli. P. atrosepticum-caused infection involves an increase of reactive oxygen species (ROS) levels in the vessels, creating the conditions for the scission of polysaccharides and modification of plant cell wall composition. Both the release of rhamnogalacturonan I and the increase in ROS precede colonisation of the vessels by bacteria and occur only in the primary xylem vessels, the same as the subsequent formation of bacterial emboli. Since the appearance of rhamnogalacturonan I and increase in ROS levels do not hamper the bacterial cells and form a basis for the assembly of bacterial emboli, these reactions may be regarded as part of the susceptible response of the plant. Bacterial emboli thus represent the products of host-pathogen integration, since the formation of these structures requires the action of both partners. PMID:26992469

  2. Community structure of actively growing bacterial populations in plant pathogen suppressive soil

    NARCIS (Netherlands)

    Hjort, K.; Lembke, A.; Speksnijder, A.G.C.L.; Smalla, K.; Jansson, J.K.

    2007-01-01

    The bacterial community in soil was screened by using various molecular approaches for bacterial populations that were activated upon addition of different supplements. Plasmodiophora brassicae spores, chitin, sodium acetate, and cabbage plants were added to activate specific bacterial populations a

  3. Development and application of an oligonucleotide microarray and real-time quantitative PCR for detection of wastewater bacterial pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dae-Young [National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario, L7R 4A6 (Canada)], E-mail: daeyoung.lee@ec.gc.ca; Lauder, Heather; Cruwys, Heather; Falletta, Patricia [National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario, L7R 4A6 (Canada); Beaudette, Lee A. [Environmental Science and Technology Centre, Environment Canada, 335 River Road South, Ottawa, Ontario, K1A 0H3 (Canada)], E-mail: lee.beaudette@ec.gc.ca

    2008-07-15

    Conventional microbial water quality test methods are well known for their technical limitations, such as lack of direct pathogen detection capacity and low throughput capability. The microarray assay has recently emerged as a promising alternative for environmental pathogen monitoring. In this study, bacterial pathogens were detected in municipal wastewater using a microarray equipped with short oligonucleotide probes targeting 16S rRNA sequences. To date, 62 probes have been designed against 38 species, 4 genera, and 1 family of pathogens. The detection sensitivity of the microarray for a waterborne pathogen Aeromonas hydrophila was determined to be approximately 1.0% of the total DNA, or approximately 10{sup 3}A. hydrophila cells per sample. The efficacy of the DNA microarray was verified in a parallel study where pathogen genes and E. coli cells were enumerated using real-time quantitative PCR (qPCR) and standard membrane filter techniques, respectively. The microarray and qPCR successfully detected multiple wastewater pathogen species at different stages of the disinfection process (i.e. secondary effluents vs. disinfected final effluents) and at two treatment plants employing different disinfection methods (i.e. chlorination vs. UV irradiation). This result demonstrates the effectiveness of the DNA microarray as a semi-quantitative, high throughput pathogen monitoring tool for municipal wastewater.

  4. Development and application of an oligonucleotide microarray and real-time quantitative PCR for detection of wastewater bacterial pathogens

    International Nuclear Information System (INIS)

    Conventional microbial water quality test methods are well known for their technical limitations, such as lack of direct pathogen detection capacity and low throughput capability. The microarray assay has recently emerged as a promising alternative for environmental pathogen monitoring. In this study, bacterial pathogens were detected in municipal wastewater using a microarray equipped with short oligonucleotide probes targeting 16S rRNA sequences. To date, 62 probes have been designed against 38 species, 4 genera, and 1 family of pathogens. The detection sensitivity of the microarray for a waterborne pathogen Aeromonas hydrophila was determined to be approximately 1.0% of the total DNA, or approximately 103A. hydrophila cells per sample. The efficacy of the DNA microarray was verified in a parallel study where pathogen genes and E. coli cells were enumerated using real-time quantitative PCR (qPCR) and standard membrane filter techniques, respectively. The microarray and qPCR successfully detected multiple wastewater pathogen species at different stages of the disinfection process (i.e. secondary effluents vs. disinfected final effluents) and at two treatment plants employing different disinfection methods (i.e. chlorination vs. UV irradiation). This result demonstrates the effectiveness of the DNA microarray as a semi-quantitative, high throughput pathogen monitoring tool for municipal wastewater

  5. Development and application of an oligonucleotide microarray and real-time quantitative PCR for detection of wastewater bacterial pathogens.

    Science.gov (United States)

    Lee, Dae-Young; Lauder, Heather; Cruwys, Heather; Falletta, Patricia; Beaudette, Lee A

    2008-07-15

    Conventional microbial water quality test methods are well known for their technical limitations, such as lack of direct pathogen detection capacity and low throughput capability. The microarray assay has recently emerged as a promising alternative for environmental pathogen monitoring. In this study, bacterial pathogens were detected in municipal wastewater using a microarray equipped with short oligonucleotide probes targeting 16S rRNA sequences. To date, 62 probes have been designed against 38 species, 4 genera, and 1 family of pathogens. The detection sensitivity of the microarray for a waterborne pathogen Aeromonas hydrophila was determined to be approximately 1.0% of the total DNA, or approximately 10(3)A. hydrophila cells per sample. The efficacy of the DNA microarray was verified in a parallel study where pathogen genes and E. coli cells were enumerated using real-time quantitative PCR (qPCR) and standard membrane filter techniques, respectively. The microarray and qPCR successfully detected multiple wastewater pathogen species at different stages of the disinfection process (i.e. secondary effluents vs. disinfected final effluents) and at two treatment plants employing different disinfection methods (i.e. chlorination vs. UV irradiation). This result demonstrates the effectiveness of the DNA microarray as a semi-quantitative, high throughput pathogen monitoring tool for municipal wastewater. PMID:18423816

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

    Science.gov (United States)

    Narusaka, Mari; Minami, Taichi; Iwabuchi, Chikako; Hamasaki, Takashi; Takasaki, Satoko; Kawamura, Kimito; Narusaka, Yoshihiro

    2015-01-01

    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. PMID:25565273

  7. 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.

  8. Cultivation and qPCR Detection of Pathogenic and Antibiotic-Resistant Bacterial Establishment in Naive Broiler Houses.

    Science.gov (United States)

    Brooks, J P; McLaughlin, M R; Adeli, A; Miles, D M

    2016-05-01

    Conventional commercial broiler production involves the rearing of more than 20,000 broilers in a single confined space for approximately 6.5 wk. This environment is known for harboring pathogens and antibiotic-resistant bacteria, but studies have focused on previously established houses with mature litter microbial populations. In the current study, a set of three naive houses were followed from inception through 11 broiler flocks and monitored for ambient climatic conditions, bacterial pathogens, and antibiotic resistance. Within the first 3 wk of the first flock cycle, 100% of litter samples were positive for and , whereas was cultivation negative but PCR positive. Antibiotic resistance genes were ubiquitously distributed throughout the litter within the first flock, approaching 10 to 10 genomic units g. Preflock litter levels were approximately 10 CFU g for heterotrophic plate count bacteria, whereas midflock levels were >10 colony forming units (CFU) g; other indicators demonstrated similar increases. The influence of intrahouse sample location was minor. In all likelihood, given that preflock levels were negative for pathogens and antibiotic resistance genes and 4 to 5 Log lower than flock levels for indicators, incoming birds most likely provided the colonizing microbiome, although other sources were not ruled out. Most bacterial groups experienced a cyclical pattern of litter contamination seen in other studies, whereas microbial stabilization required approximately four flocks. This study represents a first-of-its-kind view into the time required for bacterial pathogens and antibiotic resistance to colonize and establish in naive broiler houses. PMID:27136163

  9. Specific DNA probes for the identification of the fish pathogen, Renibacterium salmoninarum.

    Science.gov (United States)

    León, G; Martinez, M A; Etchegaray, J P; Vera, M I; Figueroa, J; Krauskopf, M

    1994-03-01

    To obtain specific DNA probes for the identification of the fish pathogen, Renibacterium salmoninarum, a discriminatory recombinant DNA library was constructed using selective fragments of the bacterial genome. Three renibacterial clones, pMAM29, pMAM46 and pMAM77, containing 149, 73, and 154 bp respectively, were isolated and characterized. The specificity of the probes was confirmed by dot-blot and Southern hybridization analyses. Bacterial hybridization experiments revealed that pMAM29 discriminates the R. salmoninarum genome from that of other fish pathogens such as Aeromonas salmonicida, Yersinia ruckeri, Flexibacter columnaris, Lactobacillus piscicola, Vibrio ordalii, Vibrio anguillarum and Aeromonas hydrophila. Thus, this probe may provide a new means to diagnose bacterial kidney disease in asymptomatic fish and ova. PMID:24420936

  10. Glucose- but Not Rice-Based Oral Rehydration Therapy Enhances the Production of Virulence Determinants in the Human Pathogen Vibrio cholerae

    OpenAIRE

    Kühn, Juliane; Finger, Flavio; Bertuzzo, Enrico; Borgeaud, Sandrine; Gatto, Marino; Rinaldo, Andrea; Blokesch, Melanie

    2014-01-01

    Despite major attempts to prevent cholera transmission, millions of people worldwide still must address this devastating disease. Cholera research has so far mainly focused on the causative agent, the bacterium Vibrio cholerae, or on disease treatment, but rarely were results from both fields interconnected. Indeed, the treatment of this severe diarrheal disease is mostly accomplished by oral rehydration therapy (ORT), whereby water and electrolytes are replenished. Commonly distributed oral ...

  11. Cross-species induction of luminescence in the quorum-sensing bacterium Vibrio harveyi.

    Science.gov (United States)

    Bassler, B L; Greenberg, E P; Stevens, A M

    1997-01-01

    Different species of bacteria were tested for production of extracellular autoinducer-like activities that could stimulate the expression of the luminescence genes in Vibrio harveyi. Several species of bacteria, including the pathogens Vibrio cholerae and Vibrio parahaemolyticus, were found to produce such activities. Possible physiological roles for the two V. harveyi detection-response systems and their joint regulation are discussed. PMID:9190823

  12. Purification and Characterization of a Rabbit Serum Factor That Kills Listeria Species and Other Foodborne Bacterial Pathogens.

    Science.gov (United States)

    Kothary, Mahendra H; Franco, Augusto A; Tall, Ben D; Gopinath, Gopal R; Datta, Atin R

    2016-08-01

    In an in-vitro assay, rabbit serum, but not human serum, killed Listeria monocytogenes, a foodborne pathogen. The aim of our study was to purify and partially characterize this killing factor. Listericidin was purified from rabbit serum by a single-step ion-exchange chromatography with DEAE-Sephadex A-50 and its antimicrobial activity was assessed by a microdilution method. Listericidin is a protein with a molecular weight of 9 kDa and an isoelectric point of 8.1. It kills L. monocytogenes at 4°C, 25°C, and 37°C, and its activity is resistant to heat (boiling) and acidic conditions (pH <2). Listericidin's activity is inhibited by sodium chloride and various growth media, is sensitive to proteolytic enzymes and is enhanced by calcium chloride, and is neutralized by monoclonal antibodies to human complement C3a. However, the listericidin reacts weakly with these antibodies in an ELISA. The first 33 N-terminal residues of listericidin (SVQLTEKRMDKVGQYTNKELRKXXEDGMRDNPM) have homology to various complement C3a components. Listericidin also kills other Listeria spp., Vibrio spp., Salmonella spp., Escherichia spp., Cronobacter spp., and Bacillus spp. The listericidin peptide purified in a single-step chromatography is pH and heat stable, and has a broad antimicrobial spectrum against major foodborne pathogens in addition to L. monocytogenes. PMID:27455064

  13. Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains

    Institute of Scientific and Technical Information of China (English)

    Rabia Naz; Asghari Bano

    2012-01-01

    Objective: To investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis. Methods:Agar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts. Results:Methanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth. Conclusions: The efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.

  14. Antimicrobial potential of Halophilic actinomycetes against multi drug resistant (MDR) ventilator associated pneumonia causing bacterial pathogens.

    Science.gov (United States)

    Aslam, Sana; Sajid, Imran

    2016-03-01

    A collection of forty halophilic actinomycetes isolated from water and mud samples of the saline lake at Kalar Kahar, salt range, Pakistan, was screened to investigate their antimicrobial potential against multi drug resistant (MDR) ventilator associated pneumonia causing bacterial pathogens. The isolates exhibited significant tolerance to alkaline conditions and grew well at pH 9-11. The taxonomic status of the isolated strains was determined by morphological, biochemical and physiological characterization and by 16s rRNA gene sequencing. The results revealed that majority of the isolates (90%) belong to the genus Streptomyces. Most of the isolates exhibited remarkable antimicrobial activity up to 20mm zone of inhibition against MDR ventilator associated pneumonia causing bacteria including Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Klebsiella pneumoniae, Escherichia coli, Enterobacter and Acinetobacter spp. Additionally the isolates showed moderate to high cytotoxicity in the range of 40 to 80% larval mortality against Artemia salina in a micro well cytotoxicity assay. The chemical screening or the so called metabolic fingerprinting of the methanolic extracts of each isolate, by thin layer chromatography (TLC) using various staining reagents and by high performance liquid chromatography (HPLC-UV), indicated an impressive diversity of the compounds produced by these strains. The study reveals that these halophilic actinomycetes are a promising source of bioactive compounds. The preparative scale fermentation, isolation, purification and structure elucidation of the compounds produced by them may yield novel antimicrobial or chemotherapeutic agents. PMID:27087086

  15. Microfluidic system for the identification of bacterial pathogens causing urinary tract infections

    Science.gov (United States)

    Becker, Holger; Hlawatsch, Nadine; Haraldsson, Tommy; van der Wijngaart, Wouter; Lind, Anders; Malhotra-Kumar, Surbi; Turlej-Rogacka, Agata; Goossens, Herman

    2015-03-01

    Urinary tract infections (UTIs) are among the most common bacterial infections and pose a significant healthcare burden. The growing trend in antibiotic resistance makes it mandatory to develop diagnostic kits which allow not only the determination of a pathogen but also the antibiotic resistances. We have developed a microfluidic cartridge which takes a direct urine sample, extracts the DNA, performs an amplification using batch-PCR and flows the sample over a microarray which is printed into a microchannel for fluorescence detection. The cartridge is injection-molded out of COP and contains a set of two-component injection-molded rotary valves to switch between input and to isolate the PCR chamber during thermocycling. The hybridization probes were spotted directly onto a functionalized section of the outlet microchannel. We have been able to successfully perform PCR of E.coli in urine in this chip and perform a fluorescence detection of PCR products. An upgraded design of the cartridge contains the buffers and reagents in blisters stored on the chip.

  16. Antibacterial potential of silver nanoparticles against isolated urinary tract infectious bacterial pathogens

    Science.gov (United States)

    Jacob Inbaneson, Samuel; Ravikumar, Sundaram; Manikandan, Nachiappan

    2011-12-01

    The silver nanoparticles were synthesized by chemical reduction method and the nanoparticles were characterized using ultraviolet-visible (UV-Vis) absorption spectroscopy and X-ray diffraction (XRD) studies. The synthesized silver nanoparticles were investigated to evaluate the antibacterial activity against urinary tract infectious (UTIs) bacterial pathogens. Thirty-two bacteria were isolated from mid urine samples of 25 male and 25 female patients from Thondi, Ramanathapuram District, Tamil Nadu, India and identified by conventional methods. Escherichia coli was predominant (47%) followed by Pseudomonas aeruginosa (22%), Klebsiella pneumoniae (19%), Enterobacter sp. (6%), Proteus morganii (3%) and Staphylococcus aureus (3%). The antibacterial activity of silver nanoparticles was evaluated by disc diffusion assay. P. aeruginosa showed maximum sensitivity (11 ± 0.58 mm) followed by Enterobacter sp. (8 ± 0.49 mm) at a concentration of 20 μg disc-1 and the sensitivity was highly comparable with the positive control kanamycin and tetracycline. K. pneumoniae, E. coli, P. morganii and S. aureus showed no sensitivity against all the tested concentrations of silver nanoparticles. The results provided evidence that, the silver nanoparticles might indeed be the potential sources to treat urinary tract infections caused by P. aeruginosa and Enterobacter sp.

  17. Secreted and immunogenic proteins produced by the honeybee bacterial pathogen, Paenibacillus larvae.

    Science.gov (United States)

    Antúnez, Karina; Anido, Matilde; Evans, Jay D; Zunino, Pablo

    2010-03-24

    American Foulbrood is a severe disease affecting larvae of honeybee Apis mellifera, causing significant decrease in the honeybee population, beekeeping industries and agricultural production. In spite of its importance, little is known about the virulence factors secreted by Paenibacillus larvae during larval infection. The aim of the present work was to perform a first approach to the identification and characterization of P. larvae secretome. P. larvae secreted proteins were analyzed by SDS-PAGE and identified by MALDI-TOF. Protein toxicity was evaluated using an experimental model based on feeding of A. mellifera larvae and immunogenicity was evaluated by Western blot, using an antiserum raised against cells and spores of P. larvae. Ten different proteins were identified among P. larvae secreted proteins, including proteins involved in transcription, metabolism, translation, cell envelope, transport, protein folding, degradation of polysaccharides and motility. Although most of these proteins are cytosolic, many of them have been previously detected in the extracellular medium of different Bacillus spp. cultures and have been related to virulence. The secreted proteins resulted highly toxic and immunogenic when larvae were exposed using an experimental model. This is the first description of proteins secreted by the honeybee pathogen P. larvae. This information may be relevant for the elucidation of bacterial pathogenesis mechanisms. PMID:19781868

  18. The impact of hypoxia on intestinal epithelial cell functions: consequences for invasion by bacterial pathogens.

    Science.gov (United States)

    Zeitouni, Nathalie E; Chotikatum, Sucheera; von Köckritz-Blickwede, Maren; Naim, Hassan Y

    2016-12-01

    The maintenance of oxygen homeostasis in human tissues is mediated by several cellular adaptations in response to low-oxygen stress, called hypoxia. A decrease in tissue oxygen levels is initially counteracted by increasing local blood flow to overcome diminished oxygenation and avoid hypoxic stress. However, studies have shown that the physiological oxygen concentrations in several tissues are much lower than atmospheric (normoxic) conditions, and the oxygen supply is finely regulated in individual cell types. The gastrointestinal tract has been described to subsist in a state of physiologically low oxygen level and is thus depicted as a tissue in the state of constant low-grade inflammation. The intestinal epithelial cell layer plays a vital role in the immune response to inflammation and infections that occur within the intestinal tissue and is involved in many of the adaptation responses to hypoxic stress. This is especially relevant in the context of inflammatory disorders, such as inflammatory bowel disease (IBD). Therefore, this review aims to describe the intestinal epithelial cellular response to hypoxia and the consequences for host interactions with invading gastrointestinal bacterial pathogens. PMID:27002817

  19. The Vibrio parahaemolyticus-infecting bacteriophage qdvp001: genome sequence and endolysin with a modular structure.

    Science.gov (United States)

    Wang, Weiyu; Li, Mengzhe; Lin, Hong; Wang, Jingxue; Mao, Xiangzhao

    2016-10-01

    Vibrio parahaemolyticus, a marine pathogen, is a causative agent of gastroenteritis in humans after consumption of contaminated seafood. In recent years, infections with V. parahaemolyticus have become an increasingly frequent factor in microbial food poisoning; therefore, it is urgent to figure out ways to control Vibrio parahaemolyticus. Endolysins, lytic enzymes encoded by bacteriophages, have been regarded as a therapeutic alternative to antibiotics in control of bacterial growth and have been successfully utilized in various areas. Here, we report the full genome sequence of the novel phage qdvp001, which lyses Vibrio parahaemolyticus 17802. The qdvp001 genome consists of a 134,742-bp DNA with a G+C content of 35.35 % and 227 putative open reading frames. Analysis revealed that the qdvp001 open reading frames encoded various putative functional proteins with a putative endolysin gene (ORF 60). No holin genes were identified in qdvp001. ORF 60 was cloned and expressed. The results showed that the purified endolysin Lysqdvp001 had a high hydrolytic activity toward Vibrio parahaemolyticus and a broader spectrum compared to that of the parental bacteriophage qdvp001. Thus, purified endolysin Lysqdvp001 has a potential to be used as an antibacterial agent in the future. PMID:27376376

  20. Parallel quorum sensing signaling pathways in Vibrio cholerae.

    Science.gov (United States)

    Jung, Sarah A; Hawver, Lisa A; Ng, Wai-Leung

    2016-05-01

    Quorum sensing (QS) is a microbial signaling process for monitoring population density and complexity. Communication among bacterial cells via QS relies on the production, secretion, and detection of small molecules called autoinducers. Many bacteria have evolved their QS systems with different network architectures to incorporate information from multiple signals. In the human pathogen Vibrio cholerae, at least four parallel signaling pathways converge to control the activity of a single regulator to modulate its QS response. By integrating multiple signal inputs, it is believed that Vibrio species can survey intra-species, intra-genus, and inter-species populations and program their gene expression accordingly. Our recent studies suggest that this "many-to-one" circuitry is also important for maintaining the integrity of the input-output relationship of the system and minimizes premature commitment to QS due to signal perturbation. Here we discuss the implications of this specific parallel network setup for V. cholerae intercellular communication and how this system arrangement affects our approach to manipulate the QS response of this clinically important pathogen. PMID:26545759

  1. Structured literature review of responses of cattle to viral and bacterial pathogens causing bovine respiratory disease complex.

    Science.gov (United States)

    Grissett, G P; White, B J; Larson, R L

    2015-01-01

    Bovine respiratory disease (BRD) is an economically important disease of cattle and continues to be an intensely studied topic. However, literature summarizing the time between pathogen exposure and clinical signs, shedding, and seroconversion is minimal. A structured literature review of the published literature was performed to determine cattle responses (time from pathogen exposure to clinical signs, shedding, and seroconversion) in challenge models using common BRD viral and bacterial pathogens. After review a descriptive analysis of published studies using common BRD pathogen challenge studies was performed. Inclusion criteria were single pathogen challenge studies with no treatment or vaccination evaluating outcomes of interest: clinical signs, shedding, and seroconversion. Pathogens of interest included: bovine viral diarrhea virus (BVDV), bovine herpesvirus type 1 (BHV-1), parainfluenza-3 virus, bovine respiratory syncytial virus, Mannheimia haemolytica, Mycoplasma bovis, Pastuerella multocida, and Histophilus somni. Thirty-five studies and 64 trials were included for analysis. The median days to the resolution of clinical signs after BVDV challenge was 15 and shedding was not detected on day 12 postchallenge. Resolution of BHV-1 shedding resolved on day 12 and clinical signs on day 12 postchallenge. Bovine respiratory syncytial virus ceased shedding on day 9 and median time to resolution of clinical signs was on day 12 postchallenge. M. haemolytica resolved clinical signs 8 days postchallenge. This literature review and descriptive analysis can serve as a resource to assist in designing challenge model studies and potentially aid in estimation of duration of clinical disease and shedding after natural pathogen exposure. PMID:25929158

  2. The ttpC Gene Is Contained in Two of Three TonB Systems in the Human Pathogen Vibrio vulnificus, but Only One Is Active in Iron Transport and Virulence

    OpenAIRE

    Kustusch, Ryan J.; Kuehl, Carole J.; Crosa, Jorge H.

    2012-01-01

    The TonB system of proteins is required for the energy-dependent active transport of iron-bound substrates across the outer membrane of Gram-negative bacteria. We have identified three TonB systems within the human pathogen Vibrio vulnificus. The TonB1 system contains the TonB1, ExbD1, and ExbB1 proteins, whereas both the TtpC2-TonB2 and TtpC3-TonB3 systems contain an additional fourth protein, TtpC. Here we report that TtpC3, although highly related to TtpC2, is inactive in iron transport, w...

  3. In-vitro Antibacterial Efficacy of Solvent Extracts of Leaves of Bauhinia racemosa Lam. (Caesalpiniaceae Against Enteric Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    S. B. Dahikar

    2011-01-01

    Full Text Available Phytochemical screening of the plant leaves reveals the presence of carbohydrates, alkaloids, flavonoids, steroids, and tannins. Petroleum ether extract, chloroform extract, ethyl acetate extract and methanol extracts of leaves of Bauhinia racemosa Linn. were prepared and antibacterial activity were studied by disc diffusion method against certain enteric bacterial pathogens such as Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, Enterobacter aerogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Salmonella typhi, Staphylococcus epidermidis and Proteus vulgaris. The Methanol extracts had wide range of antibacterial activity against enteric bacterial pathogens than the petroleum ether extract, where as ethyl acetate extract were slightly higher antibacterial activity than chloroform extract. Antibacterial activity of various extract of leaves of Bauhinia racemosa was carried in attempt to develop a new pharmaceutical drug from natural origin for prevention of enteric infection.

  4. Prophage-Mediated Dynamics of ‘Candidatus Liberibacter asiaticus’ Populations, the Destructive Bacterial Pathogens of Citrus Huanglongbing

    OpenAIRE

    Lijuan Zhou; Powell, Charles A.; Wenbin Li; Mike Irey; Yongping Duan

    2013-01-01

    Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus' (Las) Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB), a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by s...

  5. Molecular Interactions between the Citrus Bacterial Pathogen Candidatus Liberbacter asiaticus and Its Insect Vector the Asian Citrus Psyllid Diaphorina citri

    OpenAIRE

    Wang, Linling; Killiny, Nabil

    2014-01-01

    Huanglongbing (HLB), the most serious disease of citrus, is attributed in the United States to Candidatus Liberibacter asiaticus (CLas), a gram-negative, phloem-restricted α-proteobacterium transmitted by the Asian citrus psyllid (Diaphorina citri). Despite the fact that the psyllid is well recognized as the vector of CLas, to the best of our knowledge, little research has so far been conducted on molecular interactions between CLas and the psyllid. Many gram-negative bacterial pathogens have...

  6. Prophage-Mediated Dynamics of ‘Candidatus Liberibacter asiaticus’ Populations, the Destructive Bacterial Pathogens of Citrus Huanglongbing

    OpenAIRE

    Zhou, Lijuan; Powell, Charles A.; Li, Wenbin; Irey, Mike; Duan, Yongping

    2013-01-01

    Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus’ (Las) Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB), a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by s...

  7. Arabidopsis Clade I TGA Factors Regulate Apoplastic Defences against the Bacterial Pathogen Pseudomonas syringae through Endoplasmic Reticulum-Based Processes

    OpenAIRE

    Wang, Lipu; Fobert, Pierre R.

    2013-01-01

    During the plant immune response, large-scale transcriptional reprogramming is modulated by numerous transcription (co) factors. The Arabidopsis basic leucine zipper transcription factors TGA1 and TGA4, which comprise the clade I TGA factors, have been shown to positively contribute to disease resistance against virulent strains of the bacterial pathogen Pseudomonas syringae . Despite physically interacting with the key immune regulator, NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), f...

  8. Prevalence of bacterial respiratory pathogens in the nasopharynx in breast-fed versus formula-fed infants.

    OpenAIRE

    Kaleida, P H; Nativio, D G; Chao, H P; Cowden, S N

    1993-01-01

    In several studies, breast-feeding has been associated with decreased frequency or duration of otitis media episodes. If a causal relationship exists, the mechanism of protection of breast-feeding has not been established. We hypothesized that infants who are breast-fed, compared with infants who are formula-fed, have a lower prevalence of nasopharyngeal colonization with the bacterial respiratory pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Streptococcu...

  9. Exploration and conservation of bacterial genetic resources as bacteriocin producing inhibitory microorganisms to pathogen bacteria in livestock

    OpenAIRE

    2013-01-01

    Exploration and conservation of microorganisms producing bacteriocin was done as the primary study towards the collection of potential bacteria and its application in improving livestock health condition and inhibit food borne pathogens. Diferent kinds of samples such as beef cattle rectal swab, rumen fluids, cow’s milk, chicken gut content, goat’s milk were collected at Bogor cattle slaughter houses, poultry slaughter houses, dairy cattle and goat farms. A total of 452 bacterial isolates con...

  10. Development and efficacy of an attenuated Vibrio harveyi vaccine candidate with cross protectivity against Vibrio alginolyticus.

    Science.gov (United States)

    Hu, Yong-hua; Deng, Tian; Sun, Bo-guang; Sun, Li

    2012-06-01

    Vibrio harveyi is a Gram-negative bacterial pathogen that can infect a wide range of marine animals. In previous studies, we have reported a virulent V. harveyi strain, T4D. In the present study, an attenuated mutant of T4D, T4DM, was obtained by selection of rifampicin resistance. Compared to the wild type, T4DM was different in whole-cell protein profile and much slower in growth rate when cultured in stress conditions caused by iron depletion. Virulence analysis showed that compared to T4D, T4DM exhibited a dramatically increased median lethal dose, impaired tissue dissemination capacity, defective hemolytic activity, and significantly reduced resistance against the killing effect of host serum. To examine the potential of T4DM as a live attenuated vaccine, Japanese flounder (Paralichthys olivaceus) were vaccinated with T4DM via intraperitoneal injection or immersion. The results showed that at one and two months post-vaccination, fish administered with T4DM via both approaches, in particular that of immersion, were effectively protected against not only V. harveyi but also Vibrio alginolyticus, another important fish pathogen. Microbiological analysis showed that following immersion vaccination, T4DM was recovered from the internal organs of the vaccinated fish in a time-dependent manner within the first 6 days post-vaccination. Serum antibodies against V. harveyi and V. alginolyticus were detected in T4DM-vaccinated fish, and, compared to serum from control fish, serum from T4DM-vaccinated fish was significantly enhanced in bactericidal activity. These results indicate that T4DM is an attenuated strain with residual infectivity and that T4DM can induce effective cross-species protection against both V. harveyi and V. alginolyticus when used as a live immersion vaccine. PMID:22484605

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

    Directory of Open Access Journals (Sweden)

    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

  12. 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

  13. Isolation of TDA-producing Phaeobacter strains from sea bass larval rearing units and their probiotic effect against pathogenic Vibrio spp. in Artemia cultures

    DEFF Research Database (Denmark)

    Grotkjær, Torben; Bentzon-Tilia, Mikkel; D'Alvise, Paul;

    2016-01-01

    V. harveyi, which is the major bacterial pathogen in crustaceans and Mediterranean sea bass larvae cultures. Concomitantly, they significantly improved survival of V. harveyi-infected brine shrimp. 16S rRNA gene sequence homology identified the antagonists as Phaeobacter sp., and in silico DNA...

  14. Vibrio-Infektionen durch Lebensmittel und Meerwasser. Das Netzwerk VibrioNet stellt sich vor

    OpenAIRE

    Alter, T.; Appel, Bernd; Bartelt, E.; Dieckmann, Ralf; Eichhorn, C.; Erler, R.; Frank, Christina; Gerdts, G.; Gunzer, Florian; Hühn, S.; Neifer, Janina; Oberheitmann, B.; Strauch, Eckhard

    2011-01-01

    Vibrionen sind salzliebende Bakterien, die in Oberflächen- und Küstengewässern sowie Meerestieren weltweit verbreitet sind. In vielen Ländern stellen pathogene Vibrio-Spezies eine der Hauptursachen von bakteriell verursachten Durchfallerkrankungen dar, die durch den Verzehr von kontaminierten Meeresfrüchten und Fischprodukten und durch verseuchtes Trinkwasser hervorgerufen werden. Vibrio-Infektionen könnten auch in unseren Breiten aufgrund der globalen Klimaerwärmung und der Zunahme des weltw...

  15. Vibrio parahaemolyticus, enterotoxigenic Escherichia coli, enterohemorrhagic Escherichia coli and Vibrio cholerae

    OpenAIRE

    Takeda, Yoshifumi

    2011-01-01

    This review highlighted the following: (i) pathogenic mechanism of the thermostable direct hemolysin produced by Vibrio parahaemolyticus, especially on its cardiotoxicity, (ii) heat-labile and heat-stable enterotoxins produced by enterotoxigenic Escherichia coli, especially structure–activity relationship of heat-stable enterotoxin, (iii) RNA N-glycosidase activity of Vero toxins (VT1 and VT2) produced by enterohemorrhagic Escherichia coli O157:H7, (iv) discovery of Vibrio cholerae O139, (v) ...

  16. Cloning of Vibrio cholerae outer membrane protein W in Pichia pastoris

    OpenAIRE

    Javad Alizadeh; Reza Ranjbar; Mehdi Kamali; Nima Farhadi; Amin Davari; Nourkhoda Sadeghifard

    2013-01-01

    Background and Objective The outer membrane protein W (ompW) of Vibrio cholerae is involved in stimulating the immune response via induction of protective immunity. It also plays an important role in bacterial pathogenesis by increasing the adaptability of pathogenic strains. In this study we aimed to clone V. cholerae ompW gene in the strain X-33 of Pichia pastoris. Materials and Methods A gene encoding ompW was cloned into the Ppicza vector downstream of alcohol oxidase promoter. Then recom...

  17. Bacterial pathogens and their antimicrobial susceptibility in Otukpo Benue state of Nigeria

    Institute of Scientific and Technical Information of China (English)

    Okwori EE; Nwadioha SI; Nwokedi EOP; Odimayo M; Jombo GTA

    2011-01-01

    Objective:To isolate bacterial pathogens and test for their antibiotic susceptibility. Methods:A total of 20 000 samples from 9 different clinical sites were processed in the laboratory between 1987 to 2000. The specimens were inoculated on the appropriate media for the isolation of the bacteria. Biochemical and serology tests were carried out on the organisms to confirm the type of bacteria isolated. Antibiotic susceptibility test was also carried out on each of the bacteria isolated. Results:A total of 18 520 bacteria were isolated from the specimens. The specimens were from nine different clinical sites, i.e. wound accounted for 22.84%, urine 31.67%, blood 12.38%, genital 7.70%, sputum 6.81%, stool 6.28%, cerebrospinal fluid 5.98%, aspirates 3.85%and ear/throat swabs were 2.49%. Gram negative bacteria accounted for 76%of isolates. The main species were Pseudomonas 2 238 (12.08%), Escherichia coli (E. coli) 2 073 (11.19%) and Staphylococcus aureus (S. aureus) which accounted for 2 511 (13.56%) of the total isolates. S. aureus showed 70%and 65%resistance to penicillin and ampicillin, respectively. Surprisingly, 40%of the organism was resistant to cloxacillin. E. coli showed 47%and 42%resistance to ampicillin and gentamicin, respectively. 49%of Salmonella typhi was resistant to chloramphenicol while 37%of Neisseria meningitidis was resistant to penicillin. Conclusions: The rate of bacteria isolated from the clinical specimens is high and antibiotic sensitivity pattern of the organisms vary from one antibiotic to the other.

  18. Iron Limitation Triggers Early Egress by the Intracellular Bacterial Pathogen Legionella pneumophila.

    Science.gov (United States)

    O'Connor, Tamara J; Zheng, Huaixin; VanRheenen, Susan M; Ghosh, Soma; Cianciotto, Nicholas P; Isberg, Ralph R

    2016-08-01

    Legionella pneumophila is an intracellular bacterial pathogen that replicates in alveolar macrophages, causing a severe form of pneumonia. Intracellular growth of the bacterium depends on its ability to sequester iron from the host cell. In the L. pneumophila strain 130b, one mechanism used to acquire this essential nutrient is the siderophore legiobactin. Iron-bound legiobactin is imported by the transport protein LbtU. Here, we describe the role of LbtP, a paralog of LbtU, in iron acquisition in the L. pneumophila strain Philadelphia-1. Similar to LbtU, LbtP is a siderophore transport protein and is required for robust growth under iron-limiting conditions. Despite their similar functions, however, LbtU and LbtP do not contribute equally to iron acquisition. The Philadelphia-1 strain lacking LbtP is more sensitive to iron deprivation in vitro Moreover, LbtP is important for L. pneumophila growth within macrophages while LbtU is dispensable. These results demonstrate that LbtP plays a dominant role over LbtU in iron acquisition. In contrast, loss of both LbtP and LbtU does not impair L. pneumophila growth in the amoebal host Acanthamoeba castellanii, demonstrating a host-specific requirement for the activities of these two transporters in iron acquisition. The growth defect of the ΔlbtP mutant in macrophages is not due to alterations in growth kinetics. Instead, the absence of LbtP limits L. pneumophila replication and causes bacteria to prematurely exit the host cell. These results demonstrate the existence of a preprogrammed exit strategy in response to iron limitation that allows L. pneumophila to abandon the host cell when nutrients are exhausted. PMID:27185787

  19. Prophage-mediated dynamics of 'Candidatus Liberibacter asiaticus' populations, the destructive bacterial pathogens of citrus huanglongbing.

    Directory of Open Access Journals (Sweden)

    Lijuan Zhou

    Full Text Available Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus' (Las Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB, a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by screening clone libraries of infected citrus, periwinkle and psyllids. Among them, Types A and B share highly conserved sequences and localize within the two prophages, FP1 and FP2, respectively. Although Types B and C were abundant in all three libraries, Type A was much more abundant in the libraries from the Las-infected psyllids than from the Las-infected plants, and Type D was only identified in libraries from the infected host plants but not from the infected psyllids. Sequence analysis of these variants revealed that the variations may result from recombination and rearrangement events. Conventional PCR results using type-specific molecular markers indicated that A, B, C and D are the four most abundant types in Las-infected citrus and periwinkle. However, only three types, A, B and C are abundant in Las-infected psyllids. Typing results for Las-infected citrus field samples indicated that mixed populations of Las bacteria present in Floridian isolates, but only the Type D population was correlated with the blotchy mottle symptom. Extended cloning and sequencing of the Type D region revealed a third prophage/phage in the Las genome, which may derive from the recombination of FP1 and FP2. Dramatic variations in these prophage regions were also found among the global Las isolates. These results are the first to demonstrate the prophage/phage-mediated dynamics of Las populations in plant and insect hosts, and their correlation with insect transmission and

  20. Comparing wastewater chemicals, indicator bacteria concentrations, and bacterial pathogen genes as fecal pollution indicators

    Science.gov (United States)

    Haack, S.K.; Duris, J.W.; Fogarty, L.R.; Kolpin, D.W.; Focazio, M.J.; Furlong, E.T.; Meyer, M.T.

    2009-01-01

    The objective of this study was to compare fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli [EC], and enterococci [ENT]) concentrations with a wide array of typical organic wastewater chemicals and selected bacterial genes as indicators of fecal pollution in water samples collected at or near 18 surface water drinking water intakes. Genes tested included esp (indicating human-pathogenic ENT) and nine genes associated with various animal sources of shiga-toxin-producing EC (STEC). Fecal pollution was indicated by genes and/or chemicals for 14 of the 18 tested samples, with little relation to FIB standards. Of 13 samples with genes (indicating varying animal sources of STEC) were detected in eight. Only the EC eaeA gene was positively correlated with FIB concentrations. Human-source fecal pollution was indicated by the esp gene and the human pharmaceutical carbamazepine in one of the nine samples that met all FIB recreational water quality standards. Escherichia coli rfbO157 and stx2c genes, which are typically associated with cattle sources and are of potential human health significance, were detected in one sample in the absence of tested chemicals. Chemical and gene-based indicators of fecal contamination may be present even when FIB standards are met, and some may, unlike FIB, indicate potential sources. Application of multiple water quality indicators with variable environmental persistence and fate may yield greater confidence in fecal pollution assessment and may inform remediation decisions. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  1. A membrane-bound matrix-metalloproteinase from Nicotiana tabacum cv. BY-2 is induced by bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Wahner Verena

    2009-06-01

    Full Text Available Abstract Background Plant matrix metalloproteinases (MMP are conserved proteolytic enzymes found in a wide range of monocotyledonous and dicotyledonous plant species. Acting on the plant extracellular matrix, they play crucial roles in many aspects of plant physiology including growth, development and the response to stresses such as pathogen attack. Results We have identified the first tobacco MMP, designated NtMMP1, and have isolated the corresponding cDNA sequence from the tobacco suspension cell line BY-2. The overall domain structure of NtMMP1 is similar to known MMP sequences, although certain features suggest it may be constitutively active rather than dependent on proteolytic processing. The protein appears to be expressed in two forms with different molecular masses, both of which are enzymatically active as determined by casein zymography. Exchanging the catalytic domain of NtMMP1 with green fluorescent protein (GFP facilitated subcellular localization by confocal laser scanning microscopy, showing the protein is normally inserted into the plasma membrane. The NtMMP1 gene is expressed constitutively at a low level but can be induced by exposure to bacterial pathogens. Conclusion Our biochemical analysis of NtMMP1 together with bioinformatic data on the primary sequence indicate that NtMMP1 is a constitutively-active protease. Given its induction in response to bacterial pathogens and its localization in the plasma membrane, we propose a role in pathogen defense at the cell periphery.

  2. Biofilm formation and phenotypic variation enhance predation-driven persistence of Vibrio cholerae

    DEFF Research Database (Denmark)

    Matz, Carsten; McDougald, D.; Moreno, A.M.;

    2005-01-01

    Persistence of the opportunistic bacterial pathogen Vibrio cholerae in aquatic environments is the principal cause for seasonal occurrence of cholera epidemics. This causality has been explained by postulating that V. cholerae forms biofilms in association with animate and inanimate surfaces....... Alternatively, it has been proposed that bacterial pathogens are an integral part of the natural microbial food web and thus their survival is constrained by protozoan predation. Here, we report that both explanations are interrelated. our data show that biofilms are the protective agent enabling V. cholerae to...... survive protozoan grazing while their planktonic counterparts are eliminated. Grazing on planktonic V. cholerae was found to select for the biofilm-enhancing rugose phase variant, which is adapted to the surf ace-associated niche by the production of exopolymers. Interestingly, grazing resistance in V...

  3. Influence of phenolic compounds of Kangra tea [Camellia sinensis (L O Kuntze] on bacterial pathogens and indigenous bacterial probiotics of Western Himalayas

    Directory of Open Access Journals (Sweden)

    Aditi Sourabh

    2013-09-01

    Full Text Available Phenolic compounds of nutraceutical importance viz., catechins (C, (--epicatechin (EC, (--epigallocatechin (EGC, (--epigallocatechin-3-gallate (EGCG and (--epicatechin-3-gallate (ECG were estimated in fresh green tea shoots of Camellia sinensis (L O Kuntze cultivar. The total polyphenols and total catechins were in the range of 219.90 to 317.81 and 140.83 to 271.39 g/kg, respectively in monthly samples of tea. The values of C, EC, EGC, EGCG and ECG in tea powders as analyzed through high performance liquid chromatography (HPLC were in the range of 1.560 to 3.661, 13.338 to 27.766, 26.515 to 39.597, 62.903 to 102.168 and 18.969 to 39.469 mg/g, respectively. Effect of tea extracts and standard flavanols against five pathogenic bacteria viz., Listeria monocytogenes (MTCC-839, Pseudomonas aeruginosa (MTCC-741, Bacillus cereus (MTCC-1272, Staphylococcus aureus (MTCC-96 and Escherichia coli (MTCC-443, and eleven indigenous potential bacterial probiotics belonging to genera Enterococcus, Bacillus and Lactobacillus spp. obtained from fermented foods of Western Himalayas, was investigated. EGCG, ECG and EGC exhibited antibacterial activity but, C and EC did not show this activity. Tea extracts having high concentrations of EGCG and ECG were more potent in antibacterial action against bacterial pathogens. Tea extracts and standard flavan-3-ols augmented viability of potential probiotics in an order of EGCG > EGC > ECG > EC > C. Tea extracts and standard flavanols had no antibacterial activity against Escherichia coli (MTCC-443 but, in combination with probiotic culture supernatants, this activity was seen. The Kangra tea thus, exerts antibacterial effect on bacterial pathogens through EGCG, ECG and EGC constituents while stimulatory effect on growth of indigenous potential probiotics.

  4. Induced release of a plant-defense volatile 'deceptively' attracts insect vectors to plants infected with a bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    Rajinder S Mann

    Full Text Available Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las, affects host preference behavior of its psyllid (Diaphorina citri Kuwayama vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of

  5. Glucose- but Not Rice-Based Oral Rehydration Therapy Enhances the Production of Virulence Determinants in the Human Pathogen Vibrio cholerae

    Science.gov (United States)

    Kühn, Juliane; Finger, Flavio; Bertuzzo, Enrico; Borgeaud, Sandrine; Gatto, Marino; Rinaldo, Andrea; Blokesch, Melanie

    2014-01-01

    Despite major attempts to prevent cholera transmission, millions of people worldwide still must address this devastating disease. Cholera research has so far mainly focused on the causative agent, the bacterium Vibrio cholerae, or on disease treatment, but rarely were results from both fields interconnected. Indeed, the treatment of this severe diarrheal disease is mostly accomplished by oral rehydration therapy (ORT), whereby water and electrolytes are replenished. Commonly distributed oral rehydration salts also contain glucose. Here, we analyzed the effects of glucose and alternative carbon sources on the production of virulence determinants in the causative agent of cholera, the bacterium Vibrio cholerae during in vitro experimentation. We demonstrate that virulence gene expression and the production of cholera toxin are enhanced in the presence of glucose or similarly transported sugars in a ToxR-, TcpP- and ToxT-dependent manner. The virulence genes were significantly less expressed if alternative non-PTS carbon sources, including rice-based starch, were utilized. Notably, even though glucose-based ORT is commonly used, field studies indicated that rice-based ORT performs better. We therefore used a spatially explicit epidemiological model to demonstrate that the better performing rice-based ORT could have a significant impact on epidemic progression based on the recent outbreak of cholera in Haiti. Our results strongly support a change of carbon source for the treatment of cholera, especially in epidemic settings. PMID:25474211

  6. Age-related presence of selected viral and bacterial pathogens in paraffin-embedded lung samples of dogs with pneumonia.

    Science.gov (United States)

    Wöhrer, Daniela; Spergser, Joachim; Bagrinovschi, Gabriela; Möstl, Karin; Weissenböck, Herbert

    2016-03-01

    The aim of this retrospective study was to detect selected pathogens in pneumonic lung tissue of dogs of different age groups by immunohistochemistry (IHC), in situ hybridisation (ISH) or polymerase chain reaction (PCR) in order to get information about their involvement in pneumonia formation. In archived formalin-fixed and paraffin wax-embedded lung samples from 68 cases with the clinical and histologic diagnosis of pneumonia the histological pattern of pneumonia was re-evaluated and the samples were further investigated for the following infectious agents: canine distemper virus (CDV), canine adenovirus type 2 (CAV-2), canine respiratory coronavirus (CRCoV), Bordetella (B.) bronchiseptica, Pasteurella (P.) multocida, Mycoplasma spp., and Pneumocystis spp. In 47.1% of the samples at least one of the featured respiratory pathogens was detected. In 31.3% of these positive samples more than one pathogen could be found. The correct detection of CDV had been achieved in ten out of eleven positive cases (90.9%) upon initial investigation, but the presence of bacterial pathogens, like B. bronchiseptica (10 cases) and P. multocida (17 cases) had been missed in all but one case. While CDV and CRCoV infections were exclusively found in dogs younger than one year, the vast majority of infections with P. multocida and B. bronchiseptica were both common either in dogs younger than 4 months or older than one year. Thus, this retrospective approach yielded valuable data on the presence, absence and prevalence of certain respiratory pathogens in dogs with pneumonia. PMID:26919147

  7. Prevalence of swine viral and bacterial pathogens in rodents and stray cats captured around pig farms in Korea.

    Science.gov (United States)

    Truong, Quang Lam; Seo, Tae Won; Yoon, Byung-Il; Kim, Hyeon-Cheol; Han, Jeong Hee; Hahn, Tae-Wook

    2013-12-30

    In 2008, 102 rodents and 24 stray cats from the areas around 9 pig farms in northeast South Korea were used to determine the prevalence of the following selected swine pathogens: ten viral pathogens [porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), rotavirus, classical swine fever virus (CSFV), porcine circovirus type 2 (PCV2), encephalomyocarditis virus (EMCV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine parvovirus (PPV), pseudorabies virus (PRV) and Japanese encephalitis virus (JEV)] and four bacterial pathogens (Brucella, Leptospira, Salmonella and Lawsonia intracellularis). In total, 1,260 tissue samples from 102 rodents and 24 stray cats were examined by specific PCR and RT-PCR assays, including tissue samples of the brain, tonsils, lungs, heart, liver, kidneys, spleen, small intestine, large intestine and mesenteric lymph nodes. The percentages of PCR-positive rodents for the porcine pathogens were as follows: 63.7% for Leptospira, 39.2% for Brucella, 6.8% for Salmonella, 15.7% for L. intracellularis, 14.7% for PCV2 and 3.9% for EMCV. The percentages of PCR-positive stray cats for the swine pathogens were as follows: 62.5% for Leptospira, 25% for Brucella, 12.5% for Salmonella, 12.5% for L. intracellularis and 4.2% for PEDV. These results may be helpful for developing control measures to prevent the spread of infectious diseases of pigs. PMID:23892461

  8. Phage–host interplay: examples from tailed phages and Gram-negative bacterial pathogens

    OpenAIRE

    Chaturongakul, Soraya; Ounjai, Puey

    2014-01-01

    Complex interactions between bacteriophages and their bacterial hosts play significant roles in shaping the structure of environmental microbial communities, not only by genetic transduction but also by modification of bacterial gene expression patterns. Survival of phages solely depends on their ability to infect their bacterial hosts, most importantly during phage entry. Successful dynamic adaptation of bacteriophages when facing selective pressures, such as host adaptation and resistance, ...

  9. Phage-host interplay: examples from tailed phages and Gram-negative bacterial pathogens

    OpenAIRE

    PueyOunjai; SorayaChaturongakul

    2014-01-01

    Complex interactions between bacteriophages and their bacterial hosts play significant roles in shaping the structure of environmental microbial communities, not only by genetic transduction but also by modification of bacterial gene expression patterns. Survival of phages solely depends on their ability to infect their bacterial hosts, most importantly during phage entry. Successful dynamic adaptation of bacteriophages when facing selective pressures, such as host adaptation and resistance, ...

  10. Quantitative PCR monitoring of antibiotic resistance genes and bacterial pathogens in three European artificial groundwater recharge systems.

    Science.gov (United States)

    Böckelmann, Uta; Dörries, Hans-Henno; Ayuso-Gabella, M Neus; Salgot de Marçay, Miquel; Tandoi, Valter; Levantesi, Caterina; Masciopinto, Costantino; Van Houtte, Emmanuel; Szewzyk, Ulrich; Wintgens, Thomas; Grohmann, Elisabeth

    2009-01-01

    Aquifer recharge presents advantages for integrated water management in the anthropic cycle, namely, advanced treatment of reclaimed water and additional dilution of pollutants due to mixing with natural groundwater. Nevertheless, this practice represents a health and environmental hazard because of the presence of pathogenic microorganisms and chemical contaminants. To assess the quality of water extracted from recharged aquifers, the groundwater recharge systems in Torreele, Belgium, Sabadell, Spain, and Nardò, Italy, were investigated for fecal-contamination indicators, bacterial pathogens, and antibiotic resistance genes over the period of 1 year. Real-time quantitative PCR assays for Helicobacter pylori, Yersinia enterocolitica, and Mycobacterium avium subsp. paratuberculosis, human pathogens with long-time survival capacity in water, and for the resistance genes ermB, mecA, blaSHV-5, ampC, tetO, and vanA were adapted or developed for water samples differing in pollutant content. The resistance genes and pathogen concentrations were determined at five or six sampling points for each recharge system. In drinking and irrigation water, none of the pathogens were detected. tetO and ermB were found frequently in reclaimed water from Sabadell and Nardò. mecA was detected only once in reclaimed water from Sabadell. The three aquifer recharge systems demonstrated different capacities for removal of fecal contaminators and antibiotic resistance genes. Ultrafiltration and reverse osmosis in the Torreele plant proved to be very efficient barriers for the elimination of both contaminant types, whereas aquifer passage followed by UV treatment and chlorination at Sabadell and the fractured and permeable aquifer at Nardò posed only partial barriers for bacterial contaminants. PMID:19011075

  11. ``Black Holes" and Bacterial Pathogenicity: A Large Genomic Deletion that Enhances the Virulence of Shigella spp. and Enteroinvasive Escherichia coli

    Science.gov (United States)

    Maurelli, Anthony T.; Fernandez, Reinaldo E.; Bloch, Craig A.; Rode, Christopher K.; Fasano, Alessio

    1998-03-01

    Plasmids, bacteriophages, and pathogenicity islands are genomic additions that contribute to the evolution of bacterial pathogens. For example, Shigella spp., the causative agents of bacillary dysentery, differ from the closely related commensal Escherichia coli in the presence of a plasmid in Shigella that encodes virulence functions. However, pathogenic bacteria also may lack properties that are characteristic of nonpathogens. Lysine decarboxylate (LDC) activity is present in ≈ 90% of E. coli strains but is uniformly absent in Shigella strains. When the gene for LDC, cadA, was introduced into Shigella flexneri 2a, virulence became attenuated, and enterotoxin activity was inhibited greatly. The enterotoxin inhibitor was identified as cadaverine, a product of the reaction catalyzed by LDC. Comparison of the S. flexneri 2a and laboratory E. coli K-12 genomes in the region of cadA revealed a large deletion in Shigella. Representative strains of Shigella spp. and enteroinvasive E. coli displayed similar deletions of cadA. Our results suggest that, as Shigella spp. evolved from E. coli to become pathogens, they not only acquired virulence genes on a plasmid but also shed genes via deletions. The formation of these ``black holes,'' deletions of genes that are detrimental to a pathogenic lifestyle, provides an evolutionary pathway that enables a pathogen to enhance virulence. Furthermore, the demonstration that cadaverine can inhibit enterotoxin activity may lead to more general models about toxin activity or entry into cells and suggests an avenue for antitoxin therapy. Thus, understanding the role of black holes in pathogen evolution may yield clues to new treatments of infectious diseases.

  12. Common strategies for antigenic variation by bacterial, fungal and protozoan pathogens

    OpenAIRE

    Deitsch, Kirk W.; Lukehart, Sheila A.; Stringer, James R.

    2009-01-01

    The complex relationships between infectious organisms and their hosts often reflect the continuing struggle of the pathogen to proliferate and spread to new hosts, and the need of the infected individual to control and potentially eradicate the infecting population. In the case of mammals and the pathogens that infect them, a veritable “arms race” has ensued. A highly adapted immune system has evolved to control the proliferation of infectious organisms and the pathogens have developed corre...

  13. Diet and Environment Shape Fecal Bacterial Microbiota Composition and Enteric Pathogen Load of Grizzly Bears

    OpenAIRE

    Schwab, Clarissa; Cristescu, Bogdan; Northrup, Joseph M.; Stenhouse, Gordon B.; Gänzle, Michael

    2011-01-01

    Background Diet and environment impact the composition of mammalian intestinal microbiota; dietary or health disturbances trigger alterations in intestinal microbiota composition and render the host susceptible to enteric pathogens. To date no long term monitoring data exist on the fecal microbiota and pathogen load of carnivores either in natural environments or in captivity. This study investigates fecal microbiota composition and the presence of pathogenic Escherichia coli and toxigenic cl...

  14. Nasopharyngeal vs. adenoid cultures in children undergoing adenoidectomy: prevalence of bacterial pathogens, their interactions and risk factors.

    Science.gov (United States)

    Korona-Glowniak, I; Niedzielski, A; Kosikowska, U; Grzegorczyk, A; Malm, A

    2015-03-01

    Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus colonization of the adenoids and nasopharynx in 103 preschool children who underwent adenoidectomy for recurrent upper respiratory tract infections was examined. Bacterial interactions and risk factors for bacterial colonization of the nasopharynx and adenoids, separately, were analysed statistically. The prevalence of simultaneous isolation from both anatomical sites was 45·6% for S. pneumoniae, 29·1% for H. influenzae, 15·5% for M. catarrhalis and 18·4% for S. aureus. Three pathogens were significantly more frequent together from adenoid samples; nasopharyngeal swabs more often yielded a single organism, but without statistical significance. M. catarrhalis and S. aureus significantly more frequently co-existed with S. pneumoniae and H. influenzae than with each other and a positive association of S. pneumoniae and H. influenzae in adenoid samples was evident. Several differences between risk factors for nasopharyngeal and adenoid colonization by the individual pathogens were observed. We conclude that the adenoids and nasopharynx appear to differ substantially in colonization by pathogenic microbes but occurrence of H. influenzae and S. pneumoniae in the nasopharynx could be predictive of upper respiratory tract infections. PMID:25703401

  15. Adhesion of Vibrio cholerae to Granular Starches

    OpenAIRE

    Gancz, Hanan; Niderman-Meyer, Orly; Broza, Meir; Kashi, Yechezkel; Shimoni, Eyal

    2005-01-01

    Cholera is a severe diarrheal disease caused by specific serogroups of Vibrio cholerae that are pathogenic to humans. Cholera can become epidemic and deadly without adequate medical care. Appropriate rehydration therapy can reduce the mortality rate from as much as 50% of the affected individuals to

  16. Bioactive Potential of Peppermint Extract Against Some Human Bacterial and Fungal Pathogens

    OpenAIRE

    Farzaei; Azizi,, F; Arji; Rostami

    2015-01-01

    Background Bacterial and fungal infections are an emerging public health concern, especially in the context of nosocomial infections. This study discusses the use of peppermint (Mentha piperita L.) methanolic extract against bacterial strains such as Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus and fungal species such as Trichophyton mentagrophytes, Trichophyton verrucosum, and Candida albicans. Object...

  17. Genome Sequence of the Banana Pathogen Dickeya zeae Strain MS1, Which Causes Bacterial Soft Rot

    OpenAIRE

    Zhang, Jing-Xin; Lin, Bi-Run; Shen, Hui-Fang; Pu, Xiao-Ming

    2013-01-01

    We report a draft genome sequence of Dickeya zeae strain MS1, which is the causative agent of banana soft rot in China, and we show several of its specific properties compared with those of other D. zeae strains. Genome sequencing provides a tool for understanding the genomic determination of the pathogenicity and phylogeny placement of this pathogen.

  18. Draft Genome Sequence of Nocardia jinanensis, an Opportunistic Bacterial Pathogen That Causes Cellulitis

    Science.gov (United States)

    Chakrabortti, Alolika; Li, Jinming

    2016-01-01

    The draft genome sequence of Nocardia jinanensis, an opportunistic pathogen that can cause skin infections, reveals genes that may contribute to the lifestyle and pathogenicity of N. jinanensis. The genome also reveals the biosynthetic capacity of N. jinanensis in producing mycolic acids, siderophores, and other polyketide and nonribosomal peptide-derived secondary metabolites. PMID:27445366

  19. Cytotoxic chromosomal targeting by CRISPR/Cas systems can reshape bacterial genomes and expel or remodel pathogenicity islands.

    Directory of Open Access Journals (Sweden)

    Reuben B Vercoe

    2013-04-01

    Full Text Available In prokaryotes, clustered regularly interspaced short palindromic repeats (CRISPRs and their associated (Cas proteins constitute a defence system against bacteriophages and plasmids. CRISPR/Cas systems acquire short spacer sequences from foreign genetic elements and incorporate these into their CRISPR arrays, generating a memory of past invaders. Defence is provided by short non-coding RNAs that guide Cas proteins to cleave complementary nucleic acids. While most spacers are acquired from phages and plasmids, there are examples of spacers that match genes elsewhere in the host bacterial chromosome. In Pectobacterium atrosepticum the type I-F CRISPR/Cas system has acquired a self-complementary spacer that perfectly matches a protospacer target in a horizontally acquired island (HAI2 involved in plant pathogenicity. Given the paucity of experimental data about CRISPR/Cas-mediated chromosomal targeting, we examined this process by developing a tightly controlled system. Chromosomal targeting was highly toxic via targeting of DNA and resulted in growth inhibition and cellular filamentation. The toxic phenotype was avoided by mutations in the cas operon, the CRISPR repeats, the protospacer target, and protospacer-adjacent motif (PAM beside the target. Indeed, the natural self-targeting spacer was non-toxic due to a single nucleotide mutation adjacent to the target in the PAM sequence. Furthermore, we show that chromosomal targeting can result in large-scale genomic alterations, including the remodelling or deletion of entire pre-existing pathogenicity islands. These features can be engineered for the targeted deletion of large regions of bacterial chromosomes. In conclusion, in DNA-targeting CRISPR/Cas systems, chromosomal interference is deleterious by causing DNA damage and providing a strong selective pressure for genome alterations, which may have consequences for bacterial evolution and pathogenicity.

  20. Small RNA target genes and regulatory connections in the Vibrio cholerae quorum sensing system

    DEFF Research Database (Denmark)

    Hammer, Brian K; Svenningsen, Sine Lo

    2011-01-01

    The two-component quorum sensing (QS) system, first described in the marine bacterium Vibrio harveyi and evolutionarily conserved among members of the genus Vibrio, has been best studied in the human pathogen Vibrio cholerae (1, 2). In the V. cholerae QS system, the response to the accumulation of...

  1. 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

    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...... 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...

  2. A study on the pathogenic characteristics and traceability of Vibrio cholera strains circulated in Hubei province in 2012%2012年湖北省霍乱的病原学研究及溯源分析

    Institute of Scientific and Technical Information of China (English)

    张婷; 杨红梅; 程均福; 吕静; 刘公平; 李国明

    2013-01-01

      目的分析2012年湖北省霍乱流行的病原学特征,应用脉冲场凝胶电泳分析各疫情菌株之间的遗传相关性,查找霍乱传染来源,为制定防治措施提供依据。方法对35株霍乱弧菌菌株进行常规生化鉴定和毒素基因检验,以及药敏试验,采用脉冲场凝胶电泳( PFGE)技术获得电泳酶切指纹图谱并对图谱进行聚类分析。结果35株霍乱弧菌经检验均为霍乱 O139群,产毒株占71.42%,霍乱弧菌耐药结果显示四环素、复方新诺明、利福平耐药率分别为57.14%、88.57%、80.00%。 PFGE电泳图谱条带总相似率为80%~100%,具有一定的同源性。三起疫情中相同地区的大部分菌株都聚为一类,同源性为100%,提示为相同菌株感染所致;仅来源于荆州地区甲鱼中分离的菌株单独为一类与其他菌株不同。结论2012年湖北省霍乱弧菌的优势菌株为O139群,大部分产毒。药敏结果显示,菌株对四环素、复方新诺明、利福平大部分耐药;对亚胺培南、头孢曲松高度敏感;疫情中相同地区的大部分菌株聚为一类属于同一来源,不同地区的菌株有一定的变异,几起疫情暴发均与聚餐有关,所以注意食物卫生,从甲鱼中分离的菌株不产毒,提示甲鱼可能并不是疫情的主要毒株来源,应密切关注海、水产品的监测情况。%Objective To investigate the pathogenic characteristics of Vibrio cholera strains isola-ted from Hubei province in 2012 , and to identify the source of infection by analyzing their genetic correla-tions.Methods The biochemical identification , toxin gene detection and drug susceptibility test were car-ried out to analyze a total of 35 Vibrio cholera strains isolated from three epidemic areas .Comparison of ge-nomic DNA fingerprints and cluster analysis among isolates of Vibrio cholera was conducted by using pulsed-field gel electrophoresis ( PFGE

  3. In vitro activities of lomefloxacin and temafloxacin against pathogens causing diarrhea.

    OpenAIRE

    Segreti, J; Nelson, J A; Goodman, L J; Kaplan, R L; Trenholme, G M

    1989-01-01

    The in vitro activities of temafloxacin (A63004) and lomefloxacin (SC-47111; NY-198) were compared with those of seven other antibiotics against 146 isolates of bacterial enteric pathogens, including Campylobacter jejuni and Campylobacter coli. Ciprofloxacin was the most active drug against the Salmonella, Shigella, Yersinia, and Vibrio spp. tested. Lomefloxacin, temafloxacin, and difloxacin were the most active drugs tested against Campylobacter spp. (MIC for 90% of strains, 0.125 to 0.25 mi...

  4. Perforin-2 Protects Host Cells and Mice by Restricting the Vacuole to Cytosol Transitioning of a Bacterial Pathogen.

    Science.gov (United States)

    McCormack, Ryan; Bahnan, Wael; Shrestha, Niraj; Boucher, Justin; Barreto, Marcella; Barrera, Carlos M; Dauer, Edward A; Freitag, Nancy E; Khan, Wasif N; Podack, Eckhard R; Schesser, Kurt

    2016-04-01

    The host-encoded Perforin-2 (encoded by the macrophage-expressed gene 1,Mpeg1), which possesses a pore-forming MACPF domain, reduces the viability of bacterial pathogens that reside within membrane-bound compartments. Here, it is shown that Perforin-2 also restricts the proliferation of the intracytosolic pathogenListeria monocytogenes Within a few hours of systemic infection, the massive proliferation ofL. monocytogenesinPerforin-2(-/-)mice leads to a rapid appearance of acute disease symptoms. We go on to show in culturedPerforin-2(-/-)cells that the vacuole-to-cytosol transitioning ofL. monocytogenesis greatly accelerated. Unexpectedly, we found that inPerforin-2(-/-)macrophages,Listeria-containing vacuoles quickly (≤15 min) acidify, and that this was coincident with greater virulence gene expression, likely accounting for the more rapid translocation ofL. monocytogenesto its replicative niche in the cytosol. This hypothesis was supported by our finding that aL. monocytogenesstrain expressing virulence factors at a constitutively high level replicated equally well inPerforin-2(+/+)andPerforin-2(-/-)macrophages. Our findings suggest that the protective role of Perforin-2 against listeriosis is based on it limiting the intracellular replication of the pathogen. This cellular activity of Perforin-2 may derive from it regulating the acidification ofListeria-containing vacuoles, thereby depriving the pathogen of favorable intracellular conditions that promote its virulence gene activity. PMID:26831467

  5. In Vitro Activity of Gepotidacin, a Novel Triazaacenaphthylene Bacterial Topoisomerase Inhibitor, against a Broad Spectrum of Bacterial Pathogens.

    Science.gov (United States)

    Biedenbach, D J; Bouchillon, S K; Hackel, M; Miller, L A; Scangarella-Oman, N E; Jakielaszek, C; Sahm, D F

    2016-01-01

    Gepotidacin inhibits bacterial DNA replication through a mode different from that of fluoroquinolones. Gepotidacin and comparators were tested by broth and agar dilution against clinical isolates. The in vitro activities of gepotidacin were comparable against methicillin-susceptible and -resistant Staphylococcus aureus (MSSA and MRSA, respectively) isolates (MIC90, 0.5 μg/ml). The gepotidacin MIC90s were as follows (in micrograms per milliliter) for the indicated bacteria: Streptococcus pyogenes, 0.25; Escherichia coli, 2; Moraxella catarrhalis, ≤0.06; Streptococcus pneumoniae (0.25), Haemophilus influenzae, 1; Clostridium perfringens, 0.5; and Shigella spp., 1, including levofloxacin-resistant subsets. Gepotidacin warrants further investigation for clinical development. PMID:26729499

  6. Biological activity of some bacterial isolates against soil borne pathogenic fungi

    International Nuclear Information System (INIS)

    The antagonistic activity of three bacterial isolates namely Micro bacterium terregens, Cellulosimicrobium cellulans and Bacillus amyloliquefaciens was evaluated through direct confrontation method and filtrates culture against the growth of Fusarium solani, Fusarium oxysporum, Rhizoctonia solani and Phytophthra cactorum. All bacterial isolates showed the inhibition of the mycelia growth of the isolated fungi as resulting to confrontation methods except R. solani with C. cellulans that showed no inhibitory effect and energized the low activity with B. amyloliquefaciens. Culture filtrate of different bacterial isolates after different incubation periods revealed that the highest antifungal activity between 3-10 days

  7. The Role of Vibrios in Diseases of Corals.

    Science.gov (United States)

    Munn, Colin B

    2015-08-01

    The tissue, skeleton, and secreted mucus of corals supports a highly dynamic and diverse community of microbes, which play a major role in the health status of corals such as the provision of essential nutrients or the metabolism of waste products. However, members of the Vibrio genus are prominent as causative agents of disease in corals. The aim of this chapter is to review our understanding of the spectrum of disease effects displayed by coral-associated vibrios, with a particular emphasis on the few species where detailed studies of pathogenicity have been conducted. The role of Vibrio shilonii in seasonal bleaching of Oculina patagonica and the development of the coral probiotic hypothesis is reviewed, pointing to unanswered questions about this phenomenon. Detailed consideration is given to studies of V. coralliilyticus and related pathogens and changes in the dominance of vibrios associated with coral bleaching. Other Vibrio-associated disease syndromes discussed include yellow band/blotch disease and tissue necrosis in temperate gorgonian corals. The review includes analysis of the role of enzymes, resistance to oxidative stress, and quorum sensing in virulence of coral-associated vibrios. The review concludes that we should probably regard most-possibly all-vibrios as "opportunistic" pathogens which, under certain environmental conditions, are capable of overwhelming the defense mechanisms of appropriate hosts, leading to rapid growth and tissue destruction. PMID:26350314

  8. Characterization and experimental infection of Vibrio harveyi isolated from diseased Asian seabass (Lates calcarifer

    Directory of Open Access Journals (Sweden)

    Ransangan, J.

    2012-06-01

    Full Text Available Aims: Vibrio harveyi causes vibriosis to Asian seabass (Lates calcarifer. The disease spreads rapidly among fish stocked in the same cage. It causes high mortality especially in weak and small sized fish stocked at high density in poorly managed net cage. Study to determine the virulence levels of the bacterial pathogen in various aquaculture animals is a key to prevent vibriosis in marine aquaculture. Methodology and Result: Isolation of bacteria from diseased Asian seabass was done using tryptic soy agar (TSAand thiosulphate citrate bile sucrose agar (TCBS plates. Virulence of two strains of Vibrio harveyi (VHJR4 and VHJR7was tested against clinically healthy aquaculture animals. The analysis revealed that the two bacterial strains differ in pathogenicity. The V. harveyi strain VHJR7 was virulent to Asian seabass at 1.40 x 104 c.f.u. g-1, humpback grouper(Cromileptis altivelis at LD50 8.33 x 103 c.f.u. g-1 and black tiger shrimp (Penaeus monodon at LD50 3.26 x 104 c.f.u. g-1,respectively. The V. harveyi strain VHJR4 was not virulent to Asian seabass and humpback grouper but it caused mortality to black tiger shrimp at LD50 1.32 x 106 c.f.u. g-1. Phenotypically, the two strains shared most of the biochemical features except that the V. harveyi strain VHJR7 was a urease positive and grew at 8.5 % NaCl, and at 10 °C. The percentage similarity of nucleotide sequences of 16S rDNA in V. harveyi VHJR4 and V. harveyi VHJR7 was higher (99% but reduced at 95 % in hemolysin gene. Conclusion, significance and impact of study: Pathogenic strain of V. harveyi causes mortality and affects aquaculture production of Asian seabass. Hence, vaccine development against the bacterial pathogen is urgently needed for sustainability of Asian seabass aquaculture in Malaysia.

  9. Characterization of abalone Haliotis tuberculata-Vibrio harveyi interactions in gill primary cultures.

    Science.gov (United States)

    Pichon, Delphine; Cudennec, Benoit; Huchette, Sylvain; Djediat, Chakib; Renault, Tristan; Paillard, Christine; Auzoux-Bordenave, Stéphanie

    2013-10-01

    The decline of European abalone Haliotis tuberculata populations has been associated with various pathogens including bacteria of the genus Vibrio. Following the summer mortality outbreaks reported in France between 1998 and 2000, Vibrio harveyi strains were isolated from moribund abalones, allowing in vivo and in vitro studies on the interactions between abalone H. tuberculata and V. harveyi. This work reports the development of primary cell cultures from abalone gill tissue, a target tissue for bacterial colonisation, and their use for in vitro study of host cell-V. harveyi interactions. Gill cells originated from four-day-old explant primary cultures were successfully sub-cultured in multi-well plates and maintained in vitro for up to 24 days. Cytological parameters, cell morphology and viability were monitored over time using flow cytometry analysis and semi-quantitative assay (XTT). Then, gill cell cultures were used to investigate in vitro the interactions with V. harveyi. The effects of two bacterial strains were evaluated on gill cells: a pathogenic bacterial strain ORM4 which is responsible for abalone mortalities and LMG7890 which is a non-pathogenic strain. Cellular responses of gill cells exposed to increasing concentrations of bacteria were evaluated by measuring mitochondrial activity (XTT assay) and phenoloxidase activity, an enzyme which is strongly involved in immune response. The ability of gill cells to phagocyte GFP-tagged V. harveyi was evaluated by flow cytometry and gill cells-V. harveyi interactions were characterized using fluorescence microscopy and transmission electron microscopy. During phagocytosis process we evidenced that V. harveyi bacteria induced significant changes in gill cells metabolism and immune response. Together, the results showed that primary cell cultures from abalone gills are suitable for in vitro study of host-pathogen interactions, providing complementary assays to in vivo experiments. PMID:23756730

  10. Effect of clove oil on plant pathogenic bacteria and bacterial wilt of tomato and geranium

    Science.gov (United States)

    We determined the antibacterial activity of clove oil against seven different genera of plant pathogenic bacteria including Gram-negative Agrobacterium tumefaciens, Erwinia carotovora pv. carotovora, Pseudomonas syringae pv. syringae, Ralstonia solanacearum, and Xanthomonas campestris pv. pelargonii...

  11. Tomato pathogen genome may offer clues about bacterial evolution at the dawn of agriculture

    OpenAIRE

    Sutphin, Michael D.

    2008-01-01

    The availability of new genome sequencing technology has prompted a Virginia Tech plant scientist Boris Vinatzer to test an intriguing hypothesis about how agriculture's early beginnings may have impacted the evolution of plant pathogens.

  12. Within-host evolution decreases virulence in an opportunistic bacterial pathogen

    OpenAIRE

    Mikonranta, Lauri; Mappes, Johanna; Laakso, Jouni; Ketola, Tarmo

    2015-01-01

    Abstract Background Pathogens evolve in a close antagonistic relationship with their hosts. The conventional theory proposes that evolution of virulence is highly dependent on the efficiency of direct host-to-host transmission. Many opportunistic pathogens, however, are not strictly dependent on the hosts due to their ability to reproduce in the free-living environment. Therefore it is likely that conflicting selection pressures for grow...

  13. A randomized trial of chlorhexidine gluconate on oral bacterial pathogens in mechanically ventilated patients

    OpenAIRE

    Scannapieco, Frank A.; Yu, Jihnhee; Raghavendran, Krishnan; Vacanti, Angela; Owens, Susan I; Wood, Kenneth; Mylotte, Joseph M.

    2009-01-01

    Introduction Dental plaque biofilms are colonized by respiratory pathogens in mechanically-ventilated intensive care unit patients. Thus, improvements in oral hygiene in these patients may prevent ventilator-associated pneumonia. The goal of this study was to determine the minimum frequency (once or twice a day) for 0.12% chlorhexidine gluconate application necessary to reduce oral colonization by pathogens in 175 intubated patients in a trauma intensive care unit. Methods A randomized, doubl...

  14. 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...

  15. 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...

  16. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira

    OpenAIRE

    Fouts, Derrick E.; Matthias, Michael A.; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E.; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L.; Haake, David A.; Haft, Daniel H.; Hartskeerl, Rudy; Ko, Albert I.; Levett, Paul N

    2016-01-01

    Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field....

  17. Anti-bacterial effects of the essential oil of Teucrium polium L. on human pathogenic bacteria

    OpenAIRE

    Mohammad Mohammad; Hassan Salari; Armita Farahmand

    2013-01-01

    Background: Pathogenic bacteria are important causes of disease in humans and agricultural products contamination. Side effects of chemical preservatives necessitate research on the use of a special blend of natural oils to prevent the growth of bacteria. The aim of this study was elucidating the antibacterial effect of the essential oil of Teucrium polium on human pathogenic bacteria in the Kerman province. Materials and Methods: In order to investigate the chemical composition and antiba...

  18. Transcriptome Analysis and Discovery of Genes Involved in Immune Pathways from Coelomocytes of Sea Cucumber (Apostichopus japonicus) after Vibrio splendidus Challenge.

    Science.gov (United States)

    Gao, Qiong; Liao, Meijie; Wang, Yingeng; Li, Bin; Zhang, Zheng; Rong, Xiaojun; Chen, Guiping; Wang, Lan

    2015-01-01

    Vibrio splendidus is identified as one of the major pathogenic factors for the skin ulceration syndrome in sea cucumber (Apostichopus japonicus), which has vastly limited the development of the sea cucumber culture industry. In order to screen the immune genes involving Vibrio splendidus challenge in sea cucumber and explore the molecular mechanism of this process, the related transcriptome and gene expression profiling of resistant and susceptible biotypes of sea cucumber with Vibrio splendidus challenge were collected for analysis. A total of 319,455,942 trimmed reads were obtained, which were assembled into 186,658 contigs. After that, 89,891 representative contigs (without isoform) were clustered. The analysis of the gene expression profiling identified 358 differentially expression genes (DEGs) in the bacterial-resistant group, and 102 DEGs in the bacterial-susceptible group, compared with that in control group. According to the reported references and annotation information from BLAST, GO and KEGG, 30 putative bacterial-resistant genes and 19 putative bacterial-susceptible genes were identified from DEGs. The qRT-PCR results were consistent with the RNA-Seq results. Furthermore, many DGEs were involved in immune signaling related pathways, such as Endocytosis, Lysosome, MAPK, Chemokine and the ERBB signaling pathway. PMID:26193268

  19. Transcriptome Analysis and Discovery of Genes Involved in Immune Pathways from Coelomocytes of Sea Cucumber (Apostichopus japonicus after Vibrio splendidus Challenge

    Directory of Open Access Journals (Sweden)

    Qiong Gao

    2015-07-01

    Full Text Available Vibrio splendidus is identified as one of the major pathogenic factors for the skin ulceration syndrome in sea cucumber (Apostichopus japonicus, which has vastly limited the development of the sea cucumber culture industry. In order to screen the immune genes involving Vibrio splendidus challenge in sea cucumber and explore the molecular mechanism of this process, the related transcriptome and gene expression profiling of resistant and susceptible biotypes of sea cucumber with Vibrio splendidus challenge were collected for analysis. A total of 319,455,942 trimmed reads were obtained, which were assembled into 186,658 contigs. After that, 89,891 representative contigs (without isoform were clustered. The analysis of the gene expression profiling identified 358 differentially expression genes (DEGs in the bacterial-resistant group, and 102 DEGs in the bacterial-susceptible group, compared with that in control group. According to the reported references and annotation information from BLAST, GO and KEGG, 30 putative bacterial-resistant genes and 19 putative bacterial-susceptible genes were identified from DEGs. The qRT-PCR results were consistent with the RNA-Seq results. Furthermore, many DGEs were involved in immune signaling related pathways, such as Endocytosis, Lysosome, MAPK, Chemokine and the ERBB signaling pathway.

  20. Distinct immune responses of juvenile and adult oysters (Crassostrea gigas) to viral and bacterial infections.

    Science.gov (United States)

    Green, Timothy J; Vergnes, Agnes; Montagnani, Caroline; de Lorgeril, Julien

    2016-01-01

    Since 2008, massive mortality events of Pacific oysters (Crassostrea gigas) have been reported worldwide and these disease events are often associated with Ostreid herpesvirus type 1 (OsHV-1). Epidemiological field studies have also reported oyster age and other pathogens of the Vibrio genus are contributing factors to this syndrome. We undertook a controlled laboratory experiment to simultaneously investigate survival and immunological response of juvenile and adult C. gigas at different time-points post-infection with OsHV-1, Vibrio tasmaniensis LGP32 and V. aestuarianus. Our data corroborates epidemiological studies that juveniles are more susceptible to OsHV-1, whereas adults are more susceptible to Vibrio. We measured the expression of 102 immune-genes by high-throughput RT-qPCR, which revealed oysters have different transcriptional responses to OsHV-1 and Vibrio. The transcriptional response in the early stages of OsHV-1 infection involved genes related to apoptosis and the interferon-pathway. Transcriptional response to Vibrio infection involved antimicrobial peptides, heat shock proteins and galectins. Interestingly, oysters in the later stages of OsHV-1 infection had a transcriptional response that resembled an antibacterial response, which is suggestive of the oyster's microbiome causing secondary infections (dysbiosis-driven pathology). This study provides molecular evidence that oysters can mount distinct immune response to viral and bacterial pathogens and these responses differ depending on the age of the host. PMID:27439510

  1. Triclosan Resistance in a Bacterial Fish Pathogen, Aeromonas salmonicida subsp. salmonicida, is Mediated by an Enoyl Reductase, FabV.

    Science.gov (United States)

    Khan, Raees; Lee, Myung Hwan; Joo, Hae-Jin; Jung, Yong-Hoon; Ahmad, Shabir; Choi, Jin-Hee; Lee, Seon-Woo

    2015-04-01

    Triclosan, the widely used biocide, specifically targets enoyl-acyl carrier protein reductase (ENR) in the bacterial fatty acid synthesis system. Although the fish pathogen Aeromonas salmonicida subsp. salmonicida exhibits triclosan resistance, the nature of this resistance has not been elucidated. Here, we aimed to characterize the triclosan resistance of A. salmonicida subsp. salmonicida causing furunculosis. The fosmid library of triclosan-resistant A. salmonicida subsp. salmonicida was constructed to select a fosmid clone showing triclosan resistance. With the fosmid clone showing triclosan resistance, a subsequent secondary library search resulted in the selection of subclone pTSR-1. DNA sequence analysis of pTSR-1 revealed the presence of a chromosomal-borne fabV-encoding ENR homolog. The ENR of A. salmonicida (FabVas) exhibited significant homology with previously known FabV, including the catalytic domain YX(8)K. fabVas introduction into E. coli dramatically increased its resistance to triclosan. Heterologous expression of FabVas might functionally replace the triclosan-sensitive FabI in vivo to confer E. coli with triclosan resistance. A genome-wide search for fabVas homologs revealed the presence of an additional fabV gene (fabVas2) paralog in A. salmonicida strains and the fabVas orthologs from other gram-negative fish pathogens. Both of the potential FabV ENRs expressed similarly with or without triclosan supplement. This is the first report about the presence of two potential FabV ENRs in a single pathogenic bacterium. Our result suggests that triclosan-resistant ENRs are widely distributed in various bacteria in nature, and the wide use of this biocide can spread these triclosan-tolerant ENRs among fish pathogens and other pathogenic bacteria. PMID:25370725

  2. A Type VI Secretion System Is Involved in Pseudomonas fluorescens Bacterial Competition

    OpenAIRE

    Victorien Decoin; Corinne Barbey; Dorian Bergeau; Xavier Latour; Feuilloley, Marc G. J.; Nicole Orange; Annabelle Merieau

    2014-01-01

    Protein secretion systems are crucial mediators of bacterial interactions with other organisms. Among them, the type VI secretion system (T6SS) is widespread in Gram-negative bacteria and appears to inject toxins into competitor bacteria and/or eukaryotic cells. Major human pathogens, such as Vibrio cholerae, Burkholderia and Pseudomonas aeruginosa, express T6SSs. Bacteria prevent self-intoxication by their own T6SS toxins by producing immunity proteins, which interact with the cognate toxins...

  3. Rapid proliferation of Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio cholerae during freshwater flash floods in French Mediterranean coastal lagoons.

    Science.gov (United States)

    Esteves, Kevin; Hervio-Heath, Dominique; Mosser, Thomas; Rodier, Claire; Tournoud, Marie-George; Jumas-Bilak, Estelle; Colwell, Rita R; Monfort, Patrick

    2015-11-01

    Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio cholerae of the non-O1/non-O139 serotype are present in coastal lagoons of southern France. In these Mediterranean regions, the rivers have long low-flow periods followed by short-duration or flash floods during and after heavy intense rainstorms, particularly at the end of the summer and in autumn. These floods bring large volumes of freshwater into the lagoons, reducing their salinity. Water temperatures recorded during sampling (15 to 24°C) were favorable for the presence and multiplication of vibrios. In autumn 2011, before heavy rainfalls and flash floods, salinities ranged from 31.4 to 36.1‰ and concentrations of V. parahaemolyticus, V. vulnificus, and V. cholerae varied from 0 to 1.5 × 10(3) most probable number (MPN)/liter, 0.7 to 2.1 × 10(3) MPN/liter, and 0 to 93 MPN/liter, respectively. Following heavy rainstorms that generated severe flash flooding and heavy discharge of freshwater, salinity decreased, reaching 2.2 to 16.4‰ within 15 days, depending on the site, with a concomitant increase in Vibrio concentration to ca. 10(4) MPN/liter. The highest concentrations were reached with salinities between 10 and 20‰ for V. parahaemolyticus, 10 and 15‰ for V. vulnificus, and 5 and 12‰ for V. cholerae. Thus, an abrupt decrease in salinity caused by heavy rainfall and major flooding favored growth of human-pathogenic Vibrio spp. and their proliferation in the Languedocian lagoons. Based on these results, it is recommended that temperature and salinity monitoring be done to predict the presence of these Vibrio spp. in shellfish-harvesting areas of the lagoons. PMID:26319881

  4. Biodiversity of Vibrios

    OpenAIRE

    Fabiano L. Thompson; Iida, Tetsuya; Swings, Jean

    2004-01-01

    Vibrios are ubiquitous and abundant in the aquatic environment. A high abundance of vibrios is also detected in tissues and/or organs of various marine algae and animals, e.g., abalones, bivalves, corals, fish, shrimp, sponges, squid, and zooplankton. Vibrios harbour a wealth of diverse genomes as revealed by different genomic techniques including amplified fragment length polymorphism, multilocus sequence typing, repetetive extragenic palindrome PCR, ribotyping, and whole-genome sequencing. ...

  5. ToxR interferes with CRP-dependent transcriptional activation of ompT in Vibrio cholerae

    OpenAIRE

    Li, Caiyi C.; Merrell, D. Scott; Camilli, Andrew; Kaper*, James B.

    2002-01-01

    In pathogenic Vibrio cholerae, the transmembrane DNA-binding protein ToxR co-ordinates the expression of over 20 genes, including those encoding important virulence factors such as cholera toxin and the toxin-co-regulated pilus. The outer membrane protein OmpT is the only member of the ToxR regulon known to be repressed by ToxR. In this study, we examined the environmental conditions that regulate OmpT expression and demonstrated that ompT transcription is upregulated 14-fold when the bacteri...

  6. Ingestion of a marked bacterial pathogen of cotton conclusively demonstrates feeding by first instar southern green stink bug (Hemiptera: Pentatomidae).

    Science.gov (United States)

    Esquivel, J F; Medrano, E G

    2014-02-01

    Long-held dogma dictates that first instars of Nezara viridula (L.) do not feed, yet recent observations of stylet activity within a food source suggest otherwise. As a cosmopolitan pest of cotton and other high-value cash crops, confirmation of feeding by first instars may ultimately influence the knowledge on biology and management strategies for this pest. To determine whether first instars feed, newly hatched nymphs were provided sterile green beans (control) or beans infected with a rifampicin-resistant marked bacterial pathogen (Pantoea agglomerans (Ewing and Fife)) of cotton. Insects were exposed to beans for 2 d, and feeding was confirmed based on detection of marked bacteria ingested by the insect. Normal bacterial flora was detected in all insects; however, control insects did not possess the marked bacteria. Of the first instars surviving on infected beans, ≍65% possessed the marked bacteria internally. Furthermore, the frequency of insects with marked bacteria was higher in insects collected directly from the bean surface than those that were off the bean at time of collection. Densities of innate and marked bacteria were comparable (both ranging from 10(1) to 10(3)), suggesting that the marked bacteria did not exclude preexisting bacterial flora. Marked bacteria were also detected in a subset of second instars, indicating marked bacteria were retained through the molting process after ingesting bacteria as first instars. Our findings conclusively demonstrate feeding by first instars and redefine the long-held perspective of nonfeeding by first instars. These findings may necessitate changes to crop protection strategies against feeding and vectoring of plant pathogens by N. viridula. PMID:24342007

  7. Modulation of Inducible Nitric Oxide Synthase Expression by the Attaching and Effacing Bacterial Pathogen Citrobacter rodentium in Infected Mice

    Science.gov (United States)

    Vallance, Bruce A.; Deng, Wanyin; De Grado, Myriam; Chan, Crystal; Jacobson, Kevan; Finlay, B. Brett

    2002-01-01

    Citrobacter rodentium belongs to the attaching and effacing family of enteric bacterial pathogens that includes both enteropathogenic and enterohemorrhagic Escherichia coli. These bacteria infect their hosts by colonizing the intestinal mucosal surface and intimately attaching to underlying epithelial cells. The abilities of these pathogens to exploit the cytoskeleton and signaling pathways of host cells are well documented, but their interactions with the host's antimicrobial defenses, such as inducible nitric oxide synthase (iNOS), are poorly understood. To address this issue, we infected mice with C. rodentium and found that iNOS mRNA expression in the colon significantly increased during infection. Immunostaining identified epithelial cells as the major source for immunoreactive iNOS. Finding that nitric oxide (NO) donors were bacteriostatic for C. rodentium in vitro, we examined whether iNOS expression contributed to host defense by infecting iNOS-deficient mice. Loss of iNOS expression caused a small but significant delay in bacterial clearance without affecting tissue pathology. Finally, immunofluorescence staining was used to determine if iNOS expression was localized to infected cells by staining for the C. rodentium virulence factor, translocated intimin receptor (Tir), as well as iNOS. Interestingly, while more than 85% of uninfected epithelial cells expressed iNOS, fewer than 15% of infected (Tir-positive) cells expressed detectable iNOS. These results demonstrate that both iNOS and intestinal epithelial cells play an active role in host defense during C. rodentium infection. However, the selective expression of iNOS by uninfected but not infected cells suggests that this pathogen has developed mechanisms to locally limit its exposure to host-derived NO. PMID:12379723

  8. Plasmid- and chromosome-encoded siderophore anguibactin systems found in marine vibrios: biosynthesis, transport and evolution.

    Science.gov (United States)

    Naka, Hiroaki; Liu, Moqing; Actis, Luis A; Crosa, Jorge H

    2013-08-01

    Vibrio anguillarum is a marine pathogen that causes vibriosis, a hemorrhagic septicemia in aquatic invertebrate as well as vertebrate animals. The siderophore anguibactin system is one of the most important virulence factors of this bacterium. Most of the anguibactin biosynthesis and transport genes are located in the 65-kb pJM1 virulence plasmid although some of them are found in the chromosome of this fish pathogen. Over 30 years of research unveiled the role numerous chromosomal and pJM1 genes play in the synthesis of anguibactin and the transport of cognate ferric complexes into the bacterial cell. Furthermore, these studies showed that pJM1-carrying strains might be originated from pJM1-less strains producing the chromosome-mediated siderophore vanchrobactin. Additionally, we recently identified a chromosome-mediated anguibactin system in V. harveyi suggesting the possible evolutional origin of the V. anguillarum anguibactin system. In this review, we present our current understanding of the mechanisms and evolution hypothesis of the anguibactin system that might have occurred in these pathogenic vibrios. PMID:23660776

  9. Cis-encoded noncoding antisense RNAs in streptococci and other low GC Gram (+ bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Kyu Hong eCho

    2015-03-01

    Full Text Available Due to recent advances of bioinformatics and high throughput sequencing technology, discovery of regulatory noncoding RNAs in bacteria has been increased to a great extent. Based on this bandwagon, many studies searching for trans-acting small noncoding RNAs in streptococci have been performed intensively, especially in the important human pathogen, group A and B streptococci. However, studies for cis-encoded noncoding antisense RNAs in streptococci have been scarce. A recent study shows antisense RNAs are involved in virulence gene regulation in group B streptococcus, S. agalactiae. This suggests antisense RNAs could have important roles in the pathogenesis of streptococcal pathogens. In this review, we describe recent discoveries of chromosomal cis-encoded antisense RNAs in streptococcal pathogens and other low GC Gram (+ bacteria to provide a guide for future studies.

  10. Removal of two waterborne pathogenic bacterial strains by activated carbon particles prior to and after charge modification.

    Science.gov (United States)

    Busscher, Henk J; Dijkstra, Rene J B; Engels, Eefje; Langworthy, Don E; Collias, Dimitris I; Bjorkquist, David W; Mitchell, Michael D; Van der Mei, Henny C

    2006-11-01

    Waterborne diseases constitute a threat to public health despite costly treatment measures aimed at removing pathogenic microorganisms from potable water supplies. This paper compared the removal of Raoultella terrigena ATCC 33257 and Escherichia coli ATCC 25922 by negatively and positively charged types of activated carbon particles. Both strains display bimodal negative zeta-potential distributions in stabilized water. Carbon particles were suspended to an equivalent external geometric surface area of 700 cm2 in 250 mL of a bacterial suspension, with shaking. Samples were taken after different durations for plate counting. Initial removal rates were less elevated for the positively charged carbon particle than expected, yielding the conclusion that bacterial adhesion under shaking is mass-transport limited. After 360 min, however, the log-reduction of the more negatively charged R. terrigena in suspension was largest for the positively charged carbon particles as compared with the negatively charged ones, although conditioning in ultrapure or tap water of positively charged carbon particles for 21 days eliminated the favorable effect of the positive charge due to counterion adsorption from the water. Removal of the less negatively charged E. coli was less affected by aging of the (positively charged) carbon particles, confirming the role of electrostatic interactions in bacterial removal by activated carbon particles. The microporous, negatively charged coconut carbon performed less than the mesoporous, positively charged carbon particle prior to conditioning but did not suffer from loss of effect after conditioning in ultrapure or tap water. PMID:17144313

  11. Antimicrobial peptide melittin against Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen in rice.

    Science.gov (United States)

    Shi, Wei; Li, Caiyun; Li, Man; Zong, Xicui; Han, Dongju; Chen, Yuqing

    2016-06-01

    Xanthomonas oryzae pv. oryzae is a destructive bacterial disease of rice, and the development of an environmentally safe bactericide is urgently needed. Antimicrobial peptides, as antibacterial sources, may play important roles in bactericide development. In the present study, we found that the antimicrobial peptide melittin had the desired antibacterial activity against X. oryzae pv. oryzae. The antibacterial mechanism was investigated by examining its effects on cell membranes, energy metabolism, and nucleic acid, and protein synthesis. The antibacterial effects arose from its ability to interact with the bacterial cell wall and disrupt the cytoplasmic membrane by making holes and channels, resulting in the leakage of the cytoplasmic content. Additionally, melittin is able to permeabilize bacterial membranes and reach the cytoplasm, indicating that there are multiple mechanisms of antimicrobial action. DNA/RNA binding assay suggests that melittin may inhibit macromolecular biosynthesis by binding intracellular targets, such as DNA or RNA, and that those two modes eventually lead to bacterial cell death. Melittin can inhibit X. oryzae pv. oryzae from spreading, alleviating the disease symptoms, which indicated that melittin may have potential applications in plant protection. PMID:26948237

  12. CONTROL OF BACTERIAL SOFT ROT AND FOODBORNE HUMAN PATHOGENS ON FRESH FRUITS AND VEGETABLES

    Science.gov (United States)

    Production and sale of fresh fruits and vegetables in the U.S. has increased very sharply over the two decades. This chapter will address two most important problems now facing the fresh produce industry; one is to reduce the losses caused by bacterial soft rot and the other to reduce the safety ri...

  13. Stress, Sublethal Injury, Resuscitation and Virulence of Bacterial Foodborne Pathogens: A Review

    Science.gov (United States)

    Environmental stress and food preservation methods (e.g., heating, chilling, acidity, and alkalinity) are known to induce adaptive responses within the bacterial cell. Microorganisms that survive a given stress often gain resistance to that stress or other stresses via cross-protection. The physio...

  14. Bacteriophage remediation of bacterial pathogens in aquaculture: a review of the technology

    Science.gov (United States)

    Bacteriophages have been proposed as an alternative to antibiotic usage and several studies on their application in aquaculture have been reported. This review highlights progress to date on phage therapies for the following fish and shellfish diseases and associated pathogens: hemorrhagic septicem...

  15. Draft genome sequence of Erwinia tracheiphila, an economically important bacterial pathogen of cucurbits

    Science.gov (United States)

    Erwinia tracheiphila is one of the most economically important pathogen of cucumbers, melons, squashes, pumpkins, and gourds, in the Northeastern and Midwestern United States, yet the molecular pathology remains uninvestigated. Here we report the first draft genome sequence of an E. tracheiphila str...

  16. Ingestion of food pellets containing Escherichia coli overexpressing the heat-shock protein DnaK protects Penaeus vannamei (Boone) against Vibrio harveyi (Baumann) infection.

    Science.gov (United States)

    Sinnasamy, S; Mat Noordin, N; MacRae, T H; Ikhwanuddin Bin Abdullah, M; Bossier, P; Bin Abdul Wahid, M E; Noriaki, A; Sung, Y Y

    2016-05-01

    Feeding aquatic animals with bacterial encapsulated heat-shock proteins (Hsps) is potentially a new method to combat vibriosis, an important disease affecting aquatic animals used in aquaculture. Food pellets comprised of shrimp and containing Escherichia coli overexpressing either DnaK-DnaJ-GrpE, the prokaryotic equivalents of Hsp70-Hsp40-Hsp20, or only DnaK were fed to juveniles of the white leg shrimp Penaeus vannamei, and protection against pathogenic Vibrio harveyi was determined. Maintaining pellets at different temperatures for varying lengths of time reduced the number of live adhering E. coli, as did contact with sea water, demonstrating that storage and immersion adversely affected bacterial survival and attachment to pellets. Feeding P. vannamei with E. coli did not compromise their survival, indicating that the bacteria were not pathogenic to shrimp. Feeding P. vannamei with pellets containing bacteria overproducing DnaK (approximately 60 cells g(-1) pellets) boosted P. vannamei survival twofold against V. harveyi, suggesting that DnaK plays a role in Vibrio tolerance. Pellets containing DnaK were effective in providing protection to P. vannamei for up to 2 weeks before loss of viability and that DnaK encapsulated by these bacteria enhanced shrimp resistance against Vibrio infection. PMID:26132358

  17. Short Communication - In vitro screening of mucus and solvent extracts of Eisenia foetida against human bacterial and fungal pathogens.

    Science.gov (United States)

    Andleeb, Saiqa; Ejaz, Mubashir; Awan, Uzma Azeem; Ali, Shaukat; Kiyani, Ayesha; Shafique, Irsa; Zafar, Atiya

    2016-05-01

    Earthworms are macro invertebrate and have been widely used as therapeutic drugs for thousands of years. In the current research, experiments viz., the antibacterial, antifungal and antioxidant activity of mucus and solvent extracts of Eisenia foetida were conducted to investigate for the first time in Pakistan against human infectious pathogens. Antimicrobial activity of E. foetida against human pathogens underwent investigation through an agar disc diffusion method while an ABTS•+ free radical scavenging method assessed the antioxidant activity. The percentage of bacterial and fungal growth was analyzed statistically with One-Way Analysis of Variance (ANOVA). Results showed that the mucus IV of E. foetida produced a strong potent antibacterial and antifungal activity. Pseudomonas aeruginosa exhibited the highest inhibition zone (33.67±1.53 mm), followed by Klebsiella pneumonia (30.33±1.53mm), Penicillium notatum (30±0.051), Escherichia coli (29±1 mm), Candida albicans (28.33±0.54 mm), Staphylococcus aureus (27±1mm), Serratia marcescens (25.33±0.58 mm), Aspergillus flavus (25.33±0.58 mm), Staphylococcus epidermidis (24.33±0.58 mm), Streptococcus pyogenes (21.67±1.53 mm), and Aspergillus niger (20.67±0.53 mm). Mucus IV of E. foetida also showed the highest antioxidant activity (99%). The results clearly indicate that the mucus and solvent extracts contain effective antimicrobial properties and bioactive compounds to inhibit the growth of infectious pathogens. We conclude that mucus extracts of earthworm have significant level of antimicrobial and antioxidant activities and in future could be potentially used against various infectious pathogens. PMID:27166541

  18. Incidence and persistence of zoonotic bacterial and protozoan pathogens in a beef cattle feedlot runoff control vegetative treatment system.

    Science.gov (United States)

    Berry, Elaine D; Woodbury, Bryan L; Nienaber, John A; Eigenberg, Roger A; Thurston, Jeanette A; Wells, James E

    2007-01-01

    Determining the survival of zoonotic pathogens in livestock manure and runoff is critical for understanding the environmental and public health risks associated with these wastes. The occurrence and persistence of the bacterial pathogens Escherichia coli O157:H7 and Campylobacter spp. in a passive beef cattle feedlot runoff control-vegetative treatment system were examined over a 26-mo period. Incidence of the protozoans Cryptosporidium spp. and Giardia spp. was also assessed. The control system utilizes a shallow basin to collect liquid runoff and accumulate eroded solids from the pen surfaces; when an adequate liquid volume is attained, the liquid is discharged from the basin onto a 4.5-ha vegetative treatment area (VTA) of bromegrass which is harvested as hay. Basin discharge transported E. coli O157, Campylobacter spp., and generic E. coli into the VTA soil, but without additional discharge from the basin, the pathogen prevalences decreased over time. Similarly, the VTA soil concentrations of generic E. coli initially decreased rapidly, but lower residual populations persisted. Isolation of Cryptosporidium oocysts and Giardia cysts from VTA samples was infrequent, indicating differences in sedimentation and/or transport in comparison to bacteria. Isolation of generic E. coli from freshly cut hay from VTA regions that received basin discharge (12 of 30 vs. 1 of 30 control samples) provided evidence for the risk of contamination; however, neither E. coli O157 or Campylobacter spp. were recovered from the hay following baling. This work indicates that the runoff control system is effective for reducing environmental risk by containing and removing pathogens from feedlot runoff. PMID:17965390

  19. Roles of thermostable direct hemolysin (TDH and TDH-related hemolysin (TRH in Vibrio parahaemolyticus

    Directory of Open Access Journals (Sweden)

    Pendru eRaghunath

    2015-01-01

    Full Text Available Vibrio parahaemolyticus is the leading cause of seafood borne bacterial gastroenteritis in the world, often associated with the consumption of raw or undercooked seafood. However, not all strains of V. parahaemolyticus are pathogenic. The thermostable direct haemolysin (TDH or TDH-related haemolysin (TRH encoded by tdh and trh genes, respectively are considered major virulence factors in V. parahaemolyticus. However, about 10% of clinical strains do not contain tdh and/or trh. Environmental isolates of V. parahaemolyticus lacking tdh and/or trh are also highly cytotoxic to human gastrointestinal cells. Even in the absence of these hemolysins, V. parahaemolyticus remains pathogenic indicating other virulence factors exist. This mini review aims at discussing the possible roles of tdh and trh genes in clinical and environmental isolates of V. parahaemolyticus.

  20. Inhibition of Vibrio anguillarum by Pseudomonas fluorescens AH2, a possible probiotic treatment of fish

    DEFF Research Database (Denmark)

    Gram, Lone; Melchiorsen, Jette; Spanggaard, Bettina; Huber, I.; Nielsen, T.F.

    1999-01-01

    To study the possible use of probiotics in fish farming, we evaluated the in vitro and in vivo antagonism of antibacterial strain Pseudomonas fluorescens strain AH2 against the fish- pathogenic bacterium Vibrio anguillarum. As iron is important in virulence and bacterial interactions, the effect of....... fluorescens AH2 inhibited the growth of V. anguillarum during coculture, independently of the iron concentration, when the initial count of the antagonist was 100 to 1,000 times greater that of the fish pathogen. These in vitro results were successfully repeated in vivo. A probiotic effect in vivo was tested...... probiotic treatment resulted in a 46% reduction of calculated accumulated mortality; accumulated mortality was 25% after 7 days at 12 degrees C in the probiotic-treated fish, whereas mortality was 47% in fish not treated with the probiont...

  1. Inhibition of Vibrio anguillarum by Pseudomonas fluorescens AH2, a possible probiotic treatment of fish

    DEFF Research Database (Denmark)

    Gram, Lone; Melchiorsen, Jette; Spanggaard, Bettina;

    1999-01-01

    To study the possible use of probiotics in fish farming, we evaluated the in vitro and in vivo antagonism of antibacterial strain Pseudomonas fluorescens strain AH2 against the fish- pathogenic bacterium Vibrio anguillarum. As iron is important in virulence and bacterial interactions, the effect of...... P.fluorescens AH2 was studied under iron-rich and iron-limited conditions. Sterile-filtered culture supernatants from iron- limited P. fluorescens AH2 inhibited the growth of V. anguillarum, whereas sterile-filtered supernatants from iron- replete cultures of P. fluorescens AH2 did not. P....... fluorescens AH2 inhibited the growth of V. anguillarum during coculture, independently of the iron concentration, when the initial count of the antagonist was 100 to 1,000 times greater that of the fish pathogen. These in vitro results were successfully repeated in vivo. A probiotic effect in vivo was tested...

  2. Inactivation of Vibrio anguillarum by Attached and Planktonic Roseobacter Cells▿

    OpenAIRE

    D'Alvise, Paul W.; Melchiorsen, Jette; Porsby, Cisse H.; Nielsen, Kristian F.; Gram, Lone

    2010-01-01

    The purpose of the present study was to investigate the inhibition of Vibrio by Roseobacter in a combined liquid-surface system. Exposure of Vibrio anguillarum to surface-attached roseobacters (107 CFU/cm2) resulted in significant reduction or complete killing of the pathogen inoculated at 102 to 104 CFU/ml. The effect was likely associated with the production of tropodithietic acid (TDA), as a TDA-negative mutant did not affect survival or growth of V. anguillarum.

  3. Inactivation of Vibrio anguillarum by attached and planktonic Roseobacter cells

    DEFF Research Database (Denmark)

    D'Alvise, Paul; Melchiorsen, Jette; Porsby, Cisse Hedegaard;

    2010-01-01

    The purpose of the present study was to investigate inhibition of Vibrio by Roseobacter in a combined liquid-surface system. Exposure of Vibrio anguillarum to surface-attached roseobacters (10e7 cfu/cm2) resulted in significant reduction or complete killing of the pathogen inoculated at 10e2 – 10...... cfu/ml. The effect was likely associated with production of tropodithietic acid (TDA), as a TDA-negative mutant did not affect survival or growth of V. anguillarum....

  4. Antimicrobial peptide melittin against Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen in rice

    OpenAIRE

    SHI, Wei; Li, Caiyun; Li, Man; Zong, Xicui; Han, Dongju; Chen, Yuqing

    2016-01-01

    Xanthomonas oryzae pv. oryzae is a destructive bacterial disease of rice, and the development of an environmentally safe bactericide is urgently needed. Antimicrobial peptides, as antibacterial sources, may play important roles in bactericide development. In the present study, we found that the antimicrobial peptide melittin had the desired antibacterial activity against X. oryzae pv. oryzae. The antibacterial mechanism was investigated by examining its effects on cell membranes, energy metab...

  5. The erratic antibiotic susceptibility patterns of bacterial pathogens causing urinary tract infections

    OpenAIRE

    Ahmed, Iftkhar; Sajed, Muhammad; Sultan, Aneesa; MURTAZA, Iram; Yousaf, Sohail; Maqsood, Bushra; Vanhara, Petr; Anees, Mariam

    2015-01-01

    Increasing trend of antibiotic resistance and expression of Extended Spectrum Beta Lactamases (ESBLs) are serious threats for public health as they render the treatment ineffective. Present study was designed to elucidate the antibiotic-susceptibility patterns of ESBL and non-ESBL producing E. coli and K. pneumoniae causing urinary tract infections so that the ineffective antibiotics could be removed from the line of treatment. The bacterial isolates obtained from the urine of patients visiti...

  6. Surface Proteins of Streptococcus agalactiae and Related Proteins in Other Bacterial Pathogens.

    OpenAIRE

    Lindahl, Gunnar; Stålhammar-Carlemalm, Margaretha; Areschoug, Thomas

    2005-01-01

    Streptococcus agalactiae (group B Streptococcus) is the major cause of invasive bacterial disease, including meningitis, in the neonatal period. Although prophylactic measures have contributed to a substantial reduction in the number of infections, development of a vaccine remains an important goal. While much work in this field has focused on the S. agalactiae polysaccharide capsule, which is an important virulence factor that elicits protective immunity, surface proteins have received incre...

  7. Molecular basis of in-vivo biofilm formation by bacterial pathogens

    OpenAIRE

    Joo, Hwang-Soo; Otto, Michael

    2012-01-01

    Bacterial biofilms are involved in a multitude of serious chronic infections. In recent years, modeling biofilm infection in vitro led to the identification of microbial determinants governing biofilm development. However, we lack information as to whether biofilm formation mechanisms identified in vitro have relevance for biofilm-associated infection. Here, we discuss the molecular basis of biofilm formation using staphylococci and Pseudomonas aeruginosa to illustrate key points, as their bi...

  8. Bacterial meningitis exposure during an international flight: lessons for communicable pathogens.

    Science.gov (United States)

    Riley, Lyrad K

    2006-07-01

    Air transport of infectious patients presents challenges for screening, post-exposure follow-up of fellow passengers, and international coordination issues. This report illustrates how an index case may not receive a clear diagnosis until days after the flight of interest, complicating treatment and fellow passenger tracking. This patient was diagnosed with meningococcal meningitis after a transatlantic flight with over 200 other passengers. In such cases, prompt initiation of public health measures and rapid coordination between various agencies may be required to limit outbreaks. Similar concerns will likely complicate intentional pathogen exposures; however, there may also be additional challenges related to unfamiliar pathogens and legal or political limitations to information sharing. For meningococcal disease, published guidelines exist to assist in determining which passengers and health-care workers meet criteria for antimicrobial chemoprophylaxis. PMID:16856365

  9. Development of multiplex PCR assay for simultaneous detection of five bacterial fish pathogens.

    Science.gov (United States)

    Altinok, Ilhan; Capkin, Erol; Kayis, Sevki

    2008-10-15

    A multiplex polymerase chain reaction (PCR) method was designed for the simultaneous detection of the five major fish pathogens, Aeromonas hydrophila, Aeromonas salmonicida subsp. salmonicida, Flavobacterium columnare, Renibacterium salmoninarum, and Yersinia ruckeri. Each of the five pairs of oligonucleotide primers exclusively amplified the targeted gene of the specific microorganism. The detection limits of the multiplex PCR was in the range of 2, 1, 1, 3, and 1CFU for A. hydrophila, A. salmonicida, F. columnare, R. salmoninarum, and Y. ruckeri, respectively. Multiplex PCR did not produce any nonspecific amplification products when tested against 23 related species of bacteria. The multiplex PCR assay was useful for the detection of the bacteria in naturally infected fish. This assay is a sensitive and specific and reproducible diagnostic tool for the simultaneous detection of five pathogenic bacteria that cause disease in fish. Therefore, it could be a useful alternative to the conventional culture based method. PMID:18499358

  10. Comparison of subgingival bacterial sampling with oral lavage for detection and quantification of periodontal pathogens by real-time polymerase chain reaction

    OpenAIRE

    Boutaga, Khalil; Savelkoul, Paul H. M.; Winkel, Edwin G.; van Winkelhoff, Arie J.

    2007-01-01

    Background: Saliva has been studied for the presence of subgingival pathogens in periodontitis patients. With the anaerobic culture technique, the discrepancy between salivary recovery and subgingival presence has been significant, which makes this approach not suitable for practical use in the microbial diagnosis of periodontitis patients. The real-time polymerase chain reaction (PCR) technique represents a very sensitive technique to detect and quantify bacterial pathogens. The aim of the s...

  11. Multilocus Sequence Analysis of the Marine Bacterial Genus Tenacibaculum Suggests Parallel Evolution of Fish Pathogenicity and Endemic Colonization of Aquaculture Systems

    OpenAIRE

    Habib, Christophe; Houel, Armel; Lunazzi, Aurélie; Bernardet, Jean-François; Olsen, Anne Berit; Nilsen, Hanne; Toranzo, Alicia E.; Castro, Nuria; Nicolas, Pierre; Duchaud, Eric

    2014-01-01

    The genus Tenacibaculum, a member of the family Flavobacteriaceae, is an abundant component of marine bacterial ecosystems that also hosts several fish pathogens, some of which are of serious concern for marine aquaculture. Here, we applied multilocus sequence analysis (MLSA) to 114 representatives of most known species in the genus and of the worldwide diversity of the major fish pathogen Tenacibaculum maritimum. Recombination hampers precise phylogenetic reconstruction, but the data indicat...

  12. Nanomaterial-based sensors for detection of foodborne bacterial pathogens and toxins as well as pork adulteration in meat products

    OpenAIRE

    Stephen Inbaraj, B; Chen, B H

    2016-01-01

    Food safety draws considerable attention in the modern pace of the world owing to rapid-changing food recipes and food habits. Foodborne illnesses associated with pathogens, toxins, and other contaminants pose serious threat to human health. Besides, a large amount of money is spent on both analyses and control measures, which causes significant loss to the food industry. Conventional detection methods for bacterial pathogens and toxins are time consuming and laborious, requiring certain soph...

  13. 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...

  14. Phytoextracts-Synthesized Silver Nanoparticles Inhibit Bacterial Fish Pathogen Aeromonas hydrophila

    OpenAIRE

    Mahanty, Arabinda; Mishra, Snehasish; Bosu, Ranadhir; Maurya, UK; Netam, Surya Prakash; Sarkar, Biplab

    2013-01-01

    Fish disease is a major stumbling block towards sustainable growth of the fisheries sector. Aeromonas hydrophila, which is a major infectious aquatic pathogen is reportedly the causative agent of ulcers, fin-rot, tail-rot, hemorrhagic septicemia in fish, and has reportedly developed resistance against many of the available antibiotics. In this context, the inhibitory function of silver nanoparticles (AgNPs) against A. hydrophila was studied to evaluate its possible application in aquaculture ...

  15. Compact multi-channel surface plasmon resonance sensor for rapid detection of bacterial pathogens

    Czech Academy of Sciences Publication Activity Database

    Vala, Milan; Šípová, Hana; Špringer, Tomáš; Chadt, Karel; Piliarik, Marek; Homola, Jiří

    Vol. XConference on Optical Chemical Sensors and Biosensors. Praha : Institute of Photonics and Electronics AS CR, v.v.i, 2010 - (Homola, J.). s. 214-214 ISBN 978-80-86269-20-7. [EUROPT(R)ODE X – X.Conference on Optical Chemical Sensors and Biosensors. 28.03.2010-31.3.2010, Praha] Institutional research plan: CEZ:AV0Z20670512 Keywords : surface plasmon resonance * biosensor * detection of pathogens Subject RIV: JB - Sensors, Measurment, Regulation

  16. Glycosaminoglycan Binding Facilitates Entry of a Bacterial Pathogen into Central Nervous Systems

    OpenAIRE

    Chang, Yung-Chi; Wang, Zhipeng; Flax, Lindsay A.; Xu, Ding; Esko, Jeffrey D.; Nizet, Victor; Baron, Miriam J.

    2011-01-01

    Certain microbes invade brain microvascular endothelial cells (BMECs) to breach the blood-brain barrier (BBB) and establish central nervous system (CNS) infection. Here we use the leading meningitis pathogen group B Streptococcus (GBS) together with insect and mammalian infection models to probe a potential role of glycosaminoglycan (GAG) interactions in the pathogenesis of CNS entry. Site-directed mutagenesis of a GAG-binding domain of the surface GBS alpha C protein impeded GBS penetration ...

  17. Inhibition of Growth of Highly Resistant Bacterial and Fungal Pathogens by a Natural Product

    OpenAIRE

    Hafidh, Rand R; Abdulamir, Ahmed S; Vern, Law Se; Abu Bakar, Fatimah; Abas, Faridah; Jahanshiri, Fatemeh; Sekawi, Zamberi

    2011-01-01

    The continuous escalation of resistant bacteria against a wide range of antibiotics necessitates discovering novel unconventional sources of antibiotics. B. oleracea L (red cabbage) is health-promoting food with proven anticancer and anti-inflammatory activities. However, it has not been researched adequately for its antimicrobial activity on potential resistant pathogens. The methanol crude extract of B. oleracea L. was investigated for a possible anti-microbial activity. The screening metho...

  18. The water cycle, a potential source of the bacterial pathogen Bacillus cereus

    OpenAIRE

    Julien Brillard; Dupont, Christian M. S.; Odile Berge; Claire Dargaignaratz; Stéphanie Oriol-Gagnier; Claude Doussan; Véronique Broussolle; Marina Gillon; Thierry Clavel; Annette Bérard

    2015-01-01

    The behaviour of the sporulating soil-dwelling Bacillus cereus sensu lato (B. cereus sl) which includes foodborne pathogenic strains has been extensively studied in relation to its various animal hosts. The aim of this environmental study was to investigate the water compartments (rain and soil water, as well as groundwater) closely linked to the primary B. cereus sl reservoir, for which available data are limited. B. cereus sl was present, primarily as spores, in all of the tested compartmen...

  19. A Bacterial Virulence Protein Promotes Pathogenicity by Inhibiting the Bacterium's Own F1Fo ATP Synthase

    OpenAIRE

    Lee, Eun-Jin; Pontes, Mauricio H.; Groisman, Eduardo A.

    2013-01-01

    Several intracellular pathogens including Salmonella enterica and Mycobacterium tuberculosis require the virulence protein MgtC to survive within macrophages and to cause a lethal infection in mice. We now report that, unlike secreted virulence factors that target the host vacuolar ATPase to withstand phagosomal acidity, the MgtC protein acts on Salmonella's own F1Fo ATP synthase. This complex couples proton translocation to ATP synthesis/ hydrolysis and is required for virulence. We establis...

  20. A sophisticated network of signaling pathways regulates stomatal defenses to bacterial pathogens.

    Science.gov (United States)

    Arnaud, Dominique; Hwang, Ildoo

    2015-04-01

    Guard cells are specialized cells forming stomatal pores at the leaf surface for gas exchanges between the plant and the atmosphere. Stomata have been shown to play an important role in plant defense as a part of the innate immune response. Plants actively close their stomata upon contact with microbes, thereby preventing pathogen entry into the leaves and the subsequent colonization of host tissues. In this review, we present current knowledge of molecular mechanisms and signaling pathways implicated in stomatal defenses, with particular emphasis on plant-bacteria interactions. Stomatal defense responses begin from the perception of pathogen-associated molecular patterns (PAMPs) and activate a signaling cascade involving the production of secondary messengers such as reactive oxygen species, nitric oxide, and calcium for the regulation of plasma membrane ion channels. The analyses on downstream molecular mechanisms implicated in PAMP-triggered stomatal closure have revealed extensive interplays among the components regulating hormonal signaling pathways. We also discuss the strategies deployed by pathogenic bacteria to counteract stomatal immunity through the example of the phytotoxin coronatine. PMID:25661059