-
Journal of Thoracic Disease May 2014This study was performed to evaluate the analytical and practical performance of the matrix-assisted laser desorption ionization-time of flight mass spectrometry...
OBJECTIVE
This study was performed to evaluate the analytical and practical performance of the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) compared to the sequencing method and the Vitek 2 system for identification of enteropathogens in the clinical microbiology laboratory.
METHODS
Ten type strains and 73 clinical isolates of enteropathogens representing eight genera were analyzed by MALDI-TOF MS. All isolates were also characterized by gene sequencing allowing interpretation of the results from MALDI-TOF MS. In addition, MALDI-TOF MS was compared with the Vitek 2 system for the identification of ten isolates of Aeromonas and six of Salmonella.
RESULTS
As previously known, identification between Shigella and Escherichia coli is not possible to distinguish. MALDI-TOF MS produced the correct identifications for all other type strains and clinical isolates to the genus level. Fifteen Campylobacter jejuni, six Campylobacter coli, three Plesiomonas shigelloides, three Yersinia enterocolitica, two Clostridium difficile, one Vibrio parahaemolyticus, one Vibrio fluvialis, and one Vibrio cholera were all correctly identified to the species level. Genus and species identifications of ten Aeromonas and six Salmonella isolates by MALDI-TOF MS were consistent with those by the Vitek 2, but with much less cost and about ten times faster.
CONCLUSIONS
This study demonstrates that MALDI-TOF MS is a powerful tool for fast, accurate and low-cost identification of enteropathogens in the clinical microbiology laboratory.
PubMed: 24822116
DOI: 10.3978/j.issn.2072-1439.2014.02.20 -
Frontiers in Microbiology 2014Vibrio fluvialis is a pathogen commonly found in coastal environs. Considering recent increase in numbers of diarrheal outbreaks and sporadic extraintestinal cases, V.... (Review)
Review
Vibrio fluvialis is a pathogen commonly found in coastal environs. Considering recent increase in numbers of diarrheal outbreaks and sporadic extraintestinal cases, V. fluvialis has been considered as an emerging pathogen. Though this pathogen can be easily isolated by existing culture methods, its identification is still a challenging problem due to close phenotypic resemblance either with Vibrio cholerae or Aeromonas spp. However, using molecular tools, it is easy to identify V. fluvialis from clinical and different environmental samples. Many putative virulence factors have been reported, but its mechanisms of pathogenesis and survival fitness in the environment are yet to be explored. This chapter covers some of the major discoveries that have been made to understand the importance of V. fluvialis.
PubMed: 24653717
DOI: 10.3389/fmicb.2014.00091 -
Applied and Environmental Microbiology Mar 2014Vibrio fluvialis is an important food-borne pathogen that causes diarrheal illness and sometimes extraintestinal infections in humans. In this study, we sequenced the... (Comparative Study)
Comparative Study
Vibrio fluvialis is an important food-borne pathogen that causes diarrheal illness and sometimes extraintestinal infections in humans. In this study, we sequenced the genome of a clinical V. fluvialis strain and determined its phylogenetic relationships with other Vibrio species by comparative genomic analysis. We found that the closest relationship was between V. fluvialis and V. furnissii, followed by those with V. cholerae and V. mimicus. Moreover, based on genome comparisons and gene complementation experiments, we revealed genetic mechanisms of the biochemical tests that differentiate V. fluvialis from closely related species. Importantly, we identified a variety of genes encoding potential virulence factors, including multiple hemolysins, transcriptional regulators, and environmental survival and adaptation apparatuses, and the type VI secretion system, which is indicative of complex regulatory pathways modulating pathogenesis in this organism. The availability of V. fluvialis genome sequences may promote our understanding of pathogenic mechanisms for this emerging pathogen.
Topics: DNA, Bacterial; Genetic Complementation Test; Genome, Bacterial; Genomics; Humans; Metabolic Networks and Pathways; Molecular Sequence Data; Sequence Analysis, DNA; Vibrio; Virulence Factors
PubMed: 24441165
DOI: 10.1128/AEM.03588-13 -
Gut Pathogens Jul 2013Vibrio 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...
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 growth analysis.
CONCLUSIONS
Combined in silico and growth analysis establish a new metabolic capacity of V. fluvialis to harvest energy from ethanolamine.
PubMed: 23895343
DOI: 10.1186/1757-4749-5-20 -
Foodborne Pathogens and Disease Oct 2013Salmonella enterica serovar Weltevreden and Vibrio fluvialis were identified as etiological agents of a foodborne gastroenteritis outbreak after an Iftar feast in North...
Salmonella enterica serovar Weltevreden and Vibrio fluvialis were identified as etiological agents of a foodborne gastroenteritis outbreak after an Iftar feast in North Dumdum. Of the 278 cases admitted to the Infectious Diseases Hospital, Kolkata, 44 stool samples were tested for the enteric pathogens. Six were positive for Salmonella Weltevreden, 5 for Vibrio fluvialis, and 8 contained both of the pathogens. Consumption of mutton-ghogni might have been the likely vehicle of this outbreak. In the pulsed-field gel electrophoresis, Salmonella Weltevreden was identified as a single clone but the V. fluvialis strains were heterogeneous.
Topics: Adolescent; Adult; Child; Cluster Analysis; Disease Outbreaks; Electrophoresis, Gel, Pulsed-Field; Epidemiological Monitoring; Feces; Female; Foodborne Diseases; Gastroenteritis; Humans; India; Male; Middle Aged; Salmonella enterica; Serotyping; Vibrio; Young Adult
PubMed: 23789767
DOI: 10.1089/fpd.2013.1491 -
ACS Chemical Biology Sep 2013The human protein siderocalin (Scn) inhibits bacterial iron acquisition by binding catechol siderophores. Several pathogenic bacteria respond by making stealth...
The human protein siderocalin (Scn) inhibits bacterial iron acquisition by binding catechol siderophores. Several pathogenic bacteria respond by making stealth siderophores that are not recognized by Scn. Fluvibactin and vibriobactin, respectively of Vibrio fluvialis and Vibrio cholerae , include an oxazoline adjacent to a catechol. This chelating unit binds iron either in a catecholate or a phenolate-oxazoline coordination mode. The latter has been suggested to make vibriobactin a stealth siderophore without directly identifying the coordination mode in relation to Scn binding. We use Scn binding assays with the two siderophores and two oxazoline-substituted analogs and the crystal structure of Fe-fluvibactin:Scn to show that the oxazoline does not prevent Scn binding; hence, vibriobactin is not a stealth siderophore. We show that the phenolate-oxazoline coordination mode is present at physiological pH and is not bound by Scn. However, Scn binding shifts the coordination to the catecholate mode and thereby inactivates this siderophore.
Topics: Carrier Proteins; Catechols; Humans; Iron; Lipocalin-2; Models, Molecular; Oxazoles; Siderophores; Vibrio cholerae
PubMed: 23755875
DOI: 10.1021/cb4002552 -
Journal of Bacteriology Aug 2013Quorum sensing (QS) is a process by which individual bacteria are able to communicate with one another, thereby enabling the population as a whole to coordinate gene...
Quorum sensing (QS) is a process by which individual bacteria are able to communicate with one another, thereby enabling the population as a whole to coordinate gene regulation and subsequent phenotypic outcomes. Communication is accomplished through production and detection of small molecules in the extracellular milieu. In many bacteria, particularly Vibrio species, multiple QS systems result in multiple signals, as well as cross talk between systems. In this study, we identify two QS systems in the halophilic enteric pathogen Vibrio fluvialis: one acyl-homoserine lactone (AHL) based and one CAI-1/AI-2 based. We show that a LuxI homolog, VfqI, primarily produces 3-oxo-C10-HSL, which is sensed by a LuxR homolog, VfqR. VfqR-AHL is required to activate vfqI expression and autorepress vfqR expression. In addition, we have shown that similar to that in V. cholerae and V. harveyi, V. fluvialis produces CAI-1 and AI-2 signal molecules to activate the expression of a V. cholerae HapR homolog through LuxO. Although VfqR-AHL does not regulate hapR expression, HapR can repress vfqR transcription. Furthermore, we found that QS in V. fluvialis positively regulates production of two potential virulence factors, an extracellular protease and hemolysin. QS also affects cytotoxic activity against epithelial tissue cultures. These data suggest that V. fluvialis integrates QS regulatory pathways to play important physiological roles in pathogenesis.
Topics: Bacterial Proteins; Gene Expression Regulation, Bacterial; Quorum Sensing; Vibrio; Virulence Factors
PubMed: 23749976
DOI: 10.1128/JB.00508-13 -
PloS One 2013Clip domain serine proteinase homologs are involved in many biological processes including immune response. To identify the immune function of a serine proteinase...
Clip domain serine proteinase homologs are involved in many biological processes including immune response. To identify the immune function of a serine proteinase homolog (Sp-SPH), originally isolated from hemocytes of the mud crab, Scylla paramamosain, the Sp-SPH was expressed recombinantly and purified for further studies. It was found that the Sp-SPH protein could bind to a number of bacteria (including Aeromonas hydrophila, Escherichia coli, Staphylococcus aureus, Vibrio fluvialis, Vibrio harveyi and Vibrio parahemolyticus), bacterial cell wall components such as lipopolysaccharide or peptidoglycan (PGN), and β-1, 3-glucan of fungus. But no direct antibacterial activity of Sp-SPH protein was shown by using minimum inhibitory concentration or minimum bactericidal concentration assays. Nevertheless, the Sp-SPH protein was found to significantly enhance the crab hemocyte adhesion activity (paired t-test, P<0.05), and increase phenoloxidase activity if triggered by PGN in vitro (paired t-test, P<0.05). Importantly, the Sp-SPH protein was demonstrated to promote the survival rate of the animals after challenge with A. hydrophila or V. parahemolyticus which were both recognized by Sp-SPH protein, if pre-incubated with Sp-SPH protein, respectively. Whereas, the crabs died much faster when challenged with Vibrio alginolyiicus, a pathogenic bacterium not recognized by Sp-SPH protein, compared to those of crabs challenged with A. hydrophila or V. parahemolyticus when pre-coated with Sp-SPH protein. Taken together, these data suggested that Sp-SPH molecule might play an important role in immune defense against bacterial infection in the mud crab S. paramamosain.
Topics: Animals; Bacteria; Brachyura; Cell Adhesion; Cell Extracts; Electrophoresis, Polyacrylamide Gel; Fungi; Hemocytes; Immunity; Monophenol Monooxygenase; Protein Binding; Recombinant Proteins; Sequence Homology, Amino Acid; Serine Proteases
PubMed: 23724001
DOI: 10.1371/journal.pone.0063787 -
Marine Drugs May 2013Interesting biological activities have been found for numerous marine compounds. In fact, screening of phylogenetically diverse marine microorganisms from extreme...
Interesting biological activities have been found for numerous marine compounds. In fact, screening of phylogenetically diverse marine microorganisms from extreme environments revealed to be a rational approach for the discovery of novel molecules with relevant bioactivities for industries such as pharmaceutical and cosmeceutical. Nevertheless, marine sources deliverables are still far from the expectations and new extreme sources of microbes should be explored. In this work, a marine prokaryotic collection from four Mid-Atlantic Ridge (MAR) deep sea hydrothermal vents near the Azores Islands, Portugal, was created, characterized and tested for its photoprotective capacity. Within 246 isolates, a polyphasic approach, using chemotaxonomic and molecular typing methods, identified 23-related clusters of phenetically similar isolates with high indexes of diversity. Interestingly, 16S rRNA gene sequencing suggested the presence of 43% new prokaryotic species. A sub-set of 139 isolates of the prokaryotic collection was selected for biotechnological exploitation with 484 bacterial extracts prepared in a sustainable upscalling manner. 22% of the extracts showed an industrially relevant photoprotective activity, with two extracts, belonging to new strains of the species Shewanella algae and Vibrio fluvialis, uniquely showing UV-A, UV-B and UV-C protective capacity. This clearly demonstrates the high potential of the bacteria MAR vents collection in natural product synthesis with market applications.
Topics: Aquatic Organisms; Bacteria; Bacterial Typing Techniques; Biotechnology; Hydrothermal Vents; Portugal; RNA, Ribosomal, 16S; Ultraviolet Rays
PubMed: 23665957
DOI: 10.3390/md11051506 -
The virulence phenotypes and molecular epidemiological characteristics of Vibrio fluvialis in China.Gut Pathogens Mar 2013Vibrio fluvialis is considered to be an emerging foodborne pathogen and has been becoming a high human public health hazard all over the world, especially in coastal...
BACKGROUND
Vibrio fluvialis is considered to be an emerging foodborne pathogen and has been becoming a high human public health hazard all over the world, especially in coastal areas of developing countries and regions with poor sanitation. The distribution of virulence factors, microbiological and molecular epidemiological features of V. fluvialis isolates in China remains to be examined.
METHODS AND RESULTS
PCR targeted at the virulence determinants and phenotype tests including metabolism, virulence and antibiotic susceptibility were performed. Pulsed-field gel electrophoresis (PFGE) analysis was used to access the relatedness of isolates. A strain with deletion of the arginine dihydrolase system was first reported and proved in molecular level by PCR. Virulence genes vfh, hupO and vfpA were detected in all strains, the ability to produce hemolysin, cytotxin, protease and biofilm formation varied with strains. High resistance rate to β-lactams, azithromycin and sulfamethoxazole were observed. Twenty-seven percent of test strains showed resistant to two and three antibiotics. PFGE analysis demonstrated great genetic heterogeneity of test V. fluvialis strains.
CONCLUSION
This study evaluated firstly the biological characteristics and molecular epidemiological features of V. fluvialis in China. Some uncommon biochemical characteristics were found. Virulence genes were widely distributed in the isolates from patient and seafood sources, and the occurrence of virulence phenotypes varied with strains. Continued and enhanced laboratory based-surveillance is needed in the future together with systematically collection of the epidemiological information of the cases or the outbreaks.
PubMed: 23522652
DOI: 10.1186/1757-4749-5-6