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TheScientificWorldJournal 2012Salmonella and Vibrio species were isolated and identified from Litopenaeus vannamei cultured in shrimp farms. Shrimp samples showed occurrence of 3.3% of Salmonella and...
Salmonella and Vibrio species were isolated and identified from Litopenaeus vannamei cultured in shrimp farms. Shrimp samples showed occurrence of 3.3% of Salmonella and 48.3% of Vibrio. The isolates were also screened for antibiotic resistance to oxolinic acid, sulphonamides, tetracycline, sulfamethoxazole/trimethoprim, norfloxacin, ampicillin, doxycycline hydrochloride, erythromycin, chloramphenicol, and nitrofurantoin. Salmonella enterica serovar Corvallis isolated from shrimp showed individual and multiple antibiotic resistance patterns. Five Vibrio species having individual and multiple antibiotic resistance were also identified. They were Vibrio cholerae (18.3%), V. mimicus (16.7%), V. parahaemolyticus (10%), V. vulnificus (6.7%), and V. alginolyticus (1.7%). Farm owners should be concerned about the presence of these pathogenic bacteria which also contributes to human health risk and should adopt best management practices for responsible aquaculture to ensure the quality of shrimp.
Topics: Animals; Aquaculture; Crustacea; Drug Resistance, Microbial; Microbial Sensitivity Tests; Salmonella; Vibrio
PubMed: 22619583
DOI: 10.1100/2012/130136 -
PloS One 2012Historically, marine invertebrates have been a prolific source of unique natural products, with a diverse array of biological activities. Recent studies of...
Historically, marine invertebrates have been a prolific source of unique natural products, with a diverse array of biological activities. Recent studies of invertebrate-associated microbial communities are revealing microorganisms as the true producers of many of these compounds. Inspired by the human microbiome project, which has highlighted the human intestine as a unique microenvironment in terms of microbial diversity, we elected to examine the bacterial communities of fish intestines (which we have termed the fish microbiome) as a new source of microbial and biosynthetic diversity for natural products discovery. To test the hypothesis that the fish microbiome contains microorganisms with unique capacity for biosynthesizing natural products, we examined six species of fish through a combination of dissection and culture-dependent evaluation of intestinal microbial communities. Using isolation media designed to enrich for marine Actinobacteria, we have found three main clades that show taxonomic divergence from known strains, several of which are previously uncultured. Extracts from these strains exhibit a wide range of activities against both gram-positive and gram-negative human pathogens, as well as several fish pathogens. Exploration of one of these extracts has identified the novel bioactive lipid sebastenoic acid as an anti-microbial agent, with activity against Staphylococcus aureus, Bacillus subtilis, Enterococcus faecium, and Vibrio mimicus.
Topics: Animals; Bacteria; Biodiversity; Biological Products; Culture Techniques; Drug Discovery; Fishes; Intestines; Metagenome; Oceans and Seas; Phylogeny
PubMed: 22574119
DOI: 10.1371/journal.pone.0035398 -
Journal of Food Protection Apr 2012We report a cluster of severe diarrheal disease caused by Vibrio mimicus infection among four persons who had consumed leftover crayfish the day after a private crayfish...
We report a cluster of severe diarrheal disease caused by Vibrio mimicus infection among four persons who had consumed leftover crayfish the day after a private crayfish boil. Gastrointestinal illness caused by Vibrio mimicus has not been reported previously in Washington State. Three cases were laboratory confirmed by stool culture; using PCR, isolates were found to have ctx genes that encode cholera toxin (CT). Two of the cases were hospitalized under intensive care with a cholera-like illness. The illnesses were most likely caused by cross-contamination of cooked crayfish with uncooked crayfish; however, V. mimicus was not isolated nor were CT genes detected by PCR in leftover samples of frozen crayfish. Clinicians should be aware that V. mimicus can produce CT and that V. mimicus infection can cause severe illness.
Topics: Adolescent; Animals; Astacoidea; Diarrhea; Female; Food Contamination; Food Handling; Hospitalization; Humans; Male; Middle Aged; Polymerase Chain Reaction; Shellfish; Vibrio Infections; Vibrio mimicus; Washington
PubMed: 22488068
DOI: 10.4315/0362-028X.JFP-11-410 -
Biomedical and Environmental Sciences :... Dec 2011To understand the genetic structures and variations of the superintegron (SI) in Vibrio cholerae isolated in the seventh cholera pandemic.
OBJECTIVE
To understand the genetic structures and variations of the superintegron (SI) in Vibrio cholerae isolated in the seventh cholera pandemic.
METHODS
Polymerase chain reaction scanning and fragment sequencing were used. Sixty toxigenic V. cholerae O1 El Tor strains isolated between 1961 and 2008 were analyzed.
RESULTS
Some variations were found, including insertions, replacements, and deletions. Most of the deletions were probably the result of recombination between V. cholerae repeat sequences. The majority of the variations clustered together. The SIs of the strains isolated in the 1960s and 1970s showed more diversity, whereas SI cassette variations in strains isolated in the 1990s and after were lower, with ∼24 kb signature sequence deletion. This indicates the predominant SI in the host during the epidemic in the 1990s and after. The insertion cassettes suggested the mobilization from the SIs of other V. cholerae serogroups and Vibrio mimicus.
CONCLUSION
The study revealed that structural variations of SIs were obvious in the strains isolated in epidemics in different decades, whereas the divergence was based on syntenic structure of SIs in these El Tor strains. Also, the continuing cassette flows in the SIs of the host strains during the seventh cholera pandemics were displayed.
Topics: Cholera; Chromosomes, Bacterial; Cluster Analysis; DNA, Bacterial; Electrophoresis, Gel, Pulsed-Field; Gene Deletion; Gene Flow; Genetic Variation; Humans; Integrons; Mutagenesis, Insertional; Open Reading Frames; Polymerase Chain Reaction; Tandem Repeat Sequences; Vibrio cholerae O1
PubMed: 22365393
DOI: 10.3967/0895-3988.2011.06.001 -
Microbiology and Immunology Jan 2012A sensitive rRNA-targeted reverse transcription-quantitative polymerase chain reaction (RT-qPCR) method was developed for detection of Vibrio cholerae/mimicus, V....
Development of a sensitive rRNA-targeted reverse transcription-quantitative polymerase chain reaction for detection of Vibrio cholerae/mimicus, V. parahaemolyticus/alginolyticus and Campylobacter jejuni/coli.
A sensitive rRNA-targeted reverse transcription-quantitative polymerase chain reaction (RT-qPCR) method was developed for detection of Vibrio cholerae/mimicus, V. parahaemolyticus/alginolyticus and Campylobacter jejuni/coli by using specific primers. Counts of the enteric pathogens spiked in human stools were quantified at the lower detection limit of 10(3) cells/g stool by RT-qPCR, in marked contrast with conventional quantitative polymerase chain reaction (qPCR) at the detection limit of 10(5) to 10(6) cells/g stool. The bacterial counts determined by RT-qPCR were almost equivalent to those determined by the culture method and fluorescence in situ hybridization (FISH) during the course of in vitro culture. Bacterial rRNA in the stools was stable for at least 4 weeks when the stools were kept as the suspensions in RNA-stabilizing agent, RNAlater®, even at 37(o) C. These data suggested that the rapid and high sensitive rRNA-targeted RT-qPCR was applicable for the accurate quantification of viable enteric pathogens, such as V. cholerae/mimicus, V. parahaemolyticus/alginolyticus and C. jejuni/coli.
Topics: Bacterial Load; Campylobacter coli; Campylobacter jejuni; DNA Primers; Feces; Genes, rRNA; Humans; In Situ Hybridization, Fluorescence; RNA, Bacterial; RNA, Ribosomal, 16S; Reverse Transcriptase Polymerase Chain Reaction; Sensitivity and Specificity; Specimen Handling; Vibrio cholerae; Vibrio mimicus; Vibrio parahaemolyticus
PubMed: 22146006
DOI: 10.1111/j.1348-0421.2011.00405.x -
PloS One 2011Vibrio mimicus, the species most similar to V. cholerae, is a microbe present in the natural environmental and sometimes causes diarrhea and internal infections in...
Vibrio mimicus, the species most similar to V. cholerae, is a microbe present in the natural environmental and sometimes causes diarrhea and internal infections in humans. It shows similar phenotypes to V. cholerae but differs in some biochemical characteristics. The molecular mechanisms underlying the differences in biochemical metabolism between V. mimicus and V. cholerae are currently unclear. Several V. mimicus isolates have been found that carry cholera toxin genes (ctxAB) and cause cholera-like diarrhea in humans. Here, the genome of the V. mimicus isolate SX-4, which carries an intact CTX element, was sequenced and annotated. Analysis of its genome, together with those of other Vibrio species, revealed extensive differences within the Vibrionaceae. Common mutations in gene clusters involved in three biochemical metabolism pathways that are used for discrimination between V. mimicus and V. cholerae were found in V. mimicus strains. We also constructed detailed genomic structures and evolution maps for the general types of genomic drift associated with pathogenic characters in polysaccharides, CTX elements and toxin co-regulated pilus (TCP) gene clusters. Overall, the whole-genome sequencing of the V. mimicus strain carrying the cholera toxin gene provides detailed information for understanding genomic differences among Vibrio spp. V. mimicus has a large number of diverse gene and nucleotide differences from its nearest neighbor, V. cholerae. The observed mutations in the characteristic metabolism pathways may indicate different adaptations to different niches for these species and may be caused by ancient events in evolution before the divergence of V. cholerae and V. mimicus. Horizontal transfers of virulence-related genes from an uncommon clone of V. cholerae, rather than the seventh pandemic strains, have generated the pathogenic V. mimicus strain carrying cholera toxin genes.
Topics: Alleles; Base Sequence; DNA, Circular; Evolution, Molecular; Fermentation; Gene Deletion; Gene Transfer, Horizontal; Genes, Bacterial; Genomic Islands; Metabolic Networks and Pathways; Molecular Sequence Data; Mutation; Phylogeny; Sequence Analysis, DNA; Species Specificity; Sucrose; Vibrio cholerae; Vibrio mimicus; Virulence
PubMed: 21731695
DOI: 10.1371/journal.pone.0021299 -
Journal of Food Protection Jun 2011Three species--Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus--account for the majority of vibrio infections in humans. Rapid and accurate...
Three species--Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus--account for the majority of vibrio infections in humans. Rapid and accurate identification of Vibrio species has been problematic because phenotypic characteristics are variable within species. Additionally, biochemical identification and confirmation require 2 or more days to complete. Rapid and sensitive molecular techniques for the detection of vibrio pathogens would be useful for the surveillance and management of outbreaks. To facilitate the identification of human-pathogenic species, we designed and validated a highly sensitive, specific, and robust multiplex real-time PCR assay to identify V. cholerae, V. parahaemolyticus, and V. vulnificus using a four-dye configuration in a convenient lyophilized format. Multiple Vibrio strains were sequenced to verify candidate target TaqMan sites. Several individual assays within the multiplex contain multiple primers or probes to ensure detection of polymorphic variants. V. cholerae, V. parahaemolyticus, and V. vulnificus were detected either individually or in mixtures at ≤30 genomic copies. V. cholerae was specifically detected in the presence or absence of Vibrio mimicus. The Vibrio multiplex assay showed 100% specificity to all targets analyzed and no detection of nearest neighbor strains. Each assay exhibited 100% ± 10% efficiency. Multiplex real-time PCR can simplify pathogen detection and reduce costs per test since three species can be analyzed in a single reaction tube. Rapid and accurate detection of pathogenic vibrios in shellfish or seawater samples will improve the microbiological safety of seafood for consumers.
Topics: Consumer Product Safety; Food Contamination; Humans; Polymerase Chain Reaction; Reproducibility of Results; Seafood; Sensitivity and Specificity; Species Specificity; Vibrio; Vibrio cholerae; Vibrio parahaemolyticus; Vibrio vulnificus
PubMed: 21669071
DOI: 10.4315/0362-028X.JFP-10-511 -
Microbiology and Immunology Oct 2010The present authors have previously reported that Vibrio mimicus expresses 77-kDa and 80-kDa outer membrane proteins in response to iron-limited conditions, and that the...
The present authors have previously reported that Vibrio mimicus expresses 77-kDa and 80-kDa outer membrane proteins in response to iron-limited conditions, and that the 77-kDa protein serves as the receptor for ferriaerobactin. In this study, it was found that V. mimicus can use heme and hemoglobin as iron sources. FURTA was then applied to V. mimicus 7PT to obtain candidate gene fragments involved in utilization of heme and hemoglobin. One FURTA-positive clone was shown to contain a partial gene, whose predicted amino acid sequence correlated with the N-terminal amino acid sequence determined for the 80-kDa outer membrane protein and also shared homology with heme/hemoglobin receptors of Gram-negative bacteria. Based on this information, the entire gene (named mhuA), and a gene upstream of mhuA (named mhuB) encoding a LysR family of transcriptional activator, were cloned and analyzed. RNA analysis indicated that mhuA and mhuB are each transcribed from individual Fur-regulated promoters. Moreover, RNA analysis of an mhuB deletion mutant and a promoter reporter assay coupled with β-galactosidase suggested that MhuB could function as an activator for mhuA transcription. Finally, the role of MhuA as the heme/hemoglobin receptor was confirmed by construction of an mhuA deletion mutant and its complemented strain followed by growth assay.
Topics: Amino Acid Sequence; Bacterial Outer Membrane Proteins; Base Sequence; Cloning, Molecular; Genes, Bacterial; Heme; Hemoglobins; Iron; Molecular Sequence Data; Transcription, Genetic; Vibrio mimicus
PubMed: 21118298
DOI: 10.1111/j.1348-0421.2010.00256.x -
BMC Microbiology Nov 2010Vibrios, which include more than 100 species, are ubiquitous in marine and estuarine environments, and several of them e.g. Vibrio cholerae, V. parahaemolyticus, V....
BACKGROUND
Vibrios, which include more than 100 species, are ubiquitous in marine and estuarine environments, and several of them e.g. Vibrio cholerae, V. parahaemolyticus, V. vulnificus and V. mimicus, are pathogens for humans. Pathogenic V. parahaemolyticus strains possess two sets of genes for type III secretion system (T3SS), T3SS1 and T3SS2. The latter are critical for virulence of the organism and be classified into two distinct phylogroups, T3SS2α and T3SS2β, which are reportedly also found in pathogenic V. cholerae non-O1/non-O139 serogroup strains. However, whether T3SS2-related genes are present in other Vibrio species remains unclear.
RESULTS
We therefore examined the distribution of the genes for T3SS2 in vibrios other than V. parahaemolyticus by using a PCR assay targeting both T3SS2α and T3SS2β genes. Among the 32 Vibrio species tested in our study, several T3SS2-related genes were detected in three species, V. cholerae, V. mimicus and V. hollisae, and most of the essential genes for type III secretion were present in T3SS2-positive V. cholerae and V. mimicus strains. Moreover, both V. mimicus strains possessing T3SS2α and T3SS2β were identified. The gene organization of the T3SS2 gene clusters in V. mimicus strains was fundamentally similar to that of V. parahaemolyticus and V. cholerae in both T3SS2α- and T3SS2β-possessing strains.
CONCLUSIONS
This study is the first reported evidence of the presence of T3SS2 gene clusters in V. mimicus strains. This finding thus provides a new insight into the pathogenicity of the V. mimicus species.
Topics: Bacterial Proteins; Caco-2 Cells; Cell Line; Gene Expression Regulation, Bacterial; Humans; Molecular Sequence Data; Phylogeny; Vibrio; Vibrio Infections; Vibrio mimicus; Virulence Factors
PubMed: 21110901
DOI: 10.1186/1471-2180-10-302 -
Proceedings of the National Academy of... Dec 2010Whether Vibrio mimicus is a variant of Vibrio cholerae or a separate species has been the subject of taxonomic controversy. A genomic analysis was undertaken to resolve... (Comparative Study)
Comparative Study
Whether Vibrio mimicus is a variant of Vibrio cholerae or a separate species has been the subject of taxonomic controversy. A genomic analysis was undertaken to resolve the issue. The genomes of V. mimicus MB451, a clinical isolate, and VM223, an environmental isolate, comprise ca. 4,347,971 and 4,313,453 bp and encode 3,802 and 3,290 ORFs, respectively. As in other vibrios, chromosome I (C-I) predominantly contains genes necessary for growth and viability, whereas chromosome II (C-II) bears genes for adaptation to environmental change. C-I harbors many virulence genes, including some not previously reported in V. mimicus, such as mannose-sensitive hemagglutinin (MSHA), and enterotoxigenic hemolysin (HlyA); C-II encodes a variant of Vibrio pathogenicity island 2 (VPI-2), and Vibrio seventh pandemic island II (VSP-II) cluster of genes. Extensive genomic rearrangement in C-II indicates it is a hot spot for evolution and genesis of speciation for the genus Vibrio. The number of virulence regions discovered in this study (VSP-II, MSHA, HlyA, type IV pilin, PilE, and integron integrase, IntI4) with no notable difference in potential virulence genes between clinical and environmental strains suggests these genes also may play a role in the environment and that pathogenic strains may arise in the environment. Significant genome synteny with prototypic pre-seventh pandemic strains of V. cholerae was observed, and the results of phylogenetic analysis support the hypothesis that, in the course of evolution, V. mimicus and V. cholerae diverged from a common ancestor with a prototypic sixth pandemic genomic backbone.
Topics: Chromosomes, Bacterial; Genes, Bacterial; Genetic Speciation; Genome, Bacterial; Genomics; Synteny; Vibrio cholerae; Vibrio mimicus
PubMed: 21078967
DOI: 10.1073/pnas.1013825107