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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 -
Gut Microbes 2022is a halophilic Gram-negative bacterium regarded as an emerging unusual enteric pathogen of increasing public health concern. Our previous work has identified two type...
is a halophilic Gram-negative bacterium regarded as an emerging unusual enteric pathogen of increasing public health concern. Our previous work has identified two type VI secretion systems (T6SSs) in , VflT6SS1, and VflT6SS2, and the latter is functional in mediating interbacterial competitiveness. However, its antibacterial effectors remain to be clarified. In this work, we focused on a new potential effector/immunity pair TssI2/TsiI2. Bioinformatics analysis revealed that the C-terminal domain of TssI2 belongs to a widespread family of pesticin, and its antibacterial toxicity and corresponding protection by TsiI2 were proved via bacterial killing assays, and their action sites were localized to the periplasm of bacterial cells. The interaction of TssI2 and TsiI2 was demonstrated by the bacterial adenylate cyclase two-hybrid, protein pull-down and isothermal titration calorimetry assays. Site-directed mutagenesis demonstrated that, in addition to Glu-844, Thr-863, and Asp-869, which correspond to three reported residues in pesticin of , additional residues including Phe-837, Gly-845, Tyr-851, Gly-867, Gln-963, Trp-975, and Arg-1000 were also proved to be crucial to the bactericidal activity of TssI2. Muramidase/lysozyme-related peptidoglycan (PG) hydrolase activities of TssI2 and its variants were validated with permeabilized cells and purified PG substrate. Based on sequence homologies at C-terminals in various isolates, TssI2 was subdivided into five clusters (12-22% identity among them), and the antibacterial activities of representative effectors from other four Clusters were also confirmed through periplasmic over-expression in host. Two selected cognate immunities were proved to confer protection against the toxicities of their effectors. Additionally, TsiI2, which belongs to Cluster I, exhibited cross-protection to effector from Cluster V. Together, current findings expand our knowledge of the diversity and consistency of evolved VgrG effectors in and on how VflT6SS2 mediates a competitive advantage to gain a better survival.
Topics: Type VI Secretion Systems; Periplasm; Muramidase; Escherichia coli; Peptidoglycan; Adenylyl Cyclases; Gastrointestinal Microbiome; Bacterial Proteins; Anti-Bacterial Agents
PubMed: 36288406
DOI: 10.1080/19490976.2022.2136460 -
Iranian Journal of Microbiology Oct 2022is a Gram-negative, bacillus-shaped, curved bacterium known as an emerging pathogen. There are reports of outbreaks caused by this bacterium worldwide. Iran, especially...
BACKGROUND AND OBJECTIVES
is a Gram-negative, bacillus-shaped, curved bacterium known as an emerging pathogen. There are reports of outbreaks caused by this bacterium worldwide. Iran, especially Qom province, is an endemic region for gastrointestinal diseases caused by species. So, the aim was to isolate from clinical and environmental samples.
MATERIALS AND METHODS
During six months, 363 clinical and surface water samples were evaluated. The samples were cultured on specific media, and all incubated for 24 hours at 37°C. Suspicious colonies were evaluated by Gram staining and biochemical tests. The BD Phoenix automated microbiology system was used for the final confirmation of the isolated bacteria. Evaluation of antibiotic resistance of isolated strains was also performed according to CLSI standard.
RESULTS
Eight cases (2.2%) of , including seven from surface water samples (87.5%) and one from clinical samples (12.5%), were isolated. Based on antimicrobial susceptibility testing, all isolates were susceptible to amikacin, gentamicin, trimethoprim/sulfamethoxazole, ciprofloxacin, tetracycline, ceftazidime, and chloramphenicol. High-level resistance to ampicillin and amoxicillin/clavulanate was also observed. -infected patient had a mild fever, watery diarrhea, vomiting, nausea, and abdominal cramps that were manifested after drinking contaminated water or eating contaminated vegetables. The patient's symptoms recovered without antibiotic therapy after four days, resulting in self-limiting disease.
CONCLUSION
The current study is the first human case of infection isolated in Iran. Therefore, monitoring of water and food samples should be done routinely.
PubMed: 36531817
DOI: 10.18502/ijm.v14i5.10962 -
Revista Chilena de Infectologia :... Aug 2016
Topics: Humans; Polymerase Chain Reaction; Vibrio
PubMed: 27905630
DOI: 10.4067/S0716-10182016000400011 -
Biochemistry and Biophysics Reports Sep 2022V. fluvialis is an emerging foodborne pathogen and could cause cholera-like gastroenteritis syndrome and poses a potential threat to public health. VflT6SS2 is a...
V. fluvialis is an emerging foodborne pathogen and could cause cholera-like gastroenteritis syndrome and poses a potential threat to public health. VflT6SS2 is a functionally active type VI secretion system (T6SS) in which confers bactericidal activity. VflT6SS2 is composed of one major cluster and three - orphan clusters. Previously, we identified two quorum sensing (QS) systems CqsA/LuxS-HapR and VfqI-VfqR in and demonstrated that the former regulates VflT6SS2. However, whether VfqI-VfqR QS regulates VflT6SS2 is unknown. In this study, we showed that the mRNA abundances of VflT6SS2 2 (), 2 () and 2 () were all significantly decreased in VfqI or/and VfqR deletion mutant(s). Consistently, Hcp expression/secretion was reduced too in these mutants. Complementation assay with VfqR mutant further confirmed that the reduced Hcp expression/secretion and impaired antibacterial virulence are restored by introducing VfqR-expressing plasmid. Reporter fusion analyses revealed that VfqR modulates the promoter activities of VflT6SS2. Bioinformatical prediction and further reporter fusion assay in supported that VfqR acts as a transcriptional factor to bind and regulate the gene expression of the VflT6SS2 major cluster. However, VfqR seems to promote transcription of (2) in the orphan clusters through elevating the expression of which is encoded by the VflT6SS2 major cluster. Additionally, we found that the regulation intensity of VfqR on VflT6SS2 is weaker than that of HapR. In conclusion, our current study disclosed that in , VfqI-VfqR circuit upregulates the expression and function of VflT6SS2 by directly or indirectly activating its transcription. These findings will enhance our understanding of the complicated regulatory network between QS and T6SS in .
PubMed: 35669988
DOI: 10.1016/j.bbrep.2022.101282 -
Frontiers in Microbiology 2017is an emerging foodborne pathogen of increasing public health concern. The mechanism(s) that contribute to the bacterial survival and disease are still poorly...
is an emerging foodborne pathogen of increasing public health concern. The mechanism(s) that contribute to the bacterial survival and disease are still poorly understood. In other bacterial species, type VI secretion systems (T6SSs) are known to contribute to bacterial pathogenicity by exerting toxic effects on host cells or competing bacterial species. In this study, we characterized the genetic organization and prevalence of two T6SS gene clusters (VflT6SS1 and VflT6SS2) in . VflT6SS2 harbors three "orphan" modules and was more prevalent than VflT6SS1 in our isolates. We showed that VflT6SS2 is functionally active under low (25°C) and warm (30°C) temperatures by detecting the secretion of a T6SS substrate, Hcp. This finding suggests that VflT6SS2 may play an important role in the survival of the bacterium in the aquatic environment. The secretion of Hcp is growth phase-dependent and occurs in a narrow range of the growth phase (OD from 1.0 to 2.0). Osmolarity also regulates the function of VflT6SS2, as evidenced by our finding that increasing salinity (from 170 to 855 mM of NaCl) and exposure to high osmolarity KCl, sucrose, trehalose, or mannitol (equivalent to 340 mM of NaCl) induced significant secretion of Hcp under growth at 30°C. Furthermore, we found that although VflT6SS2 was inactive at a higher temperature (37°C), it became activated at this temperature if higher salinity conditions were present (from 513 to 855 mM of NaCl), indicating that it may be able to function under certain conditions in the infected host. Finally, we showed that the functional expression of VflT6SS2 is associated with anti-bacterial activity. This activity is Hcp-dependent and requires , a transcriptional regulator of T6SS. In sum, our study demonstrates that VflT6SS2 provides with an enhanced competitive fitness in the marine environment, and its activity is regulated by environmental signals, such as temperature and osmolarity.
PubMed: 28424671
DOI: 10.3389/fmicb.2017.00528 -
International Journal of Environmental... Oct 2010In developing countries, the fraction of treated wastewater effluents being discharged into watersheds have increased over the period of time, which have led to the... (Review)
Review
In developing countries, the fraction of treated wastewater effluents being discharged into watersheds have increased over the period of time, which have led to the deteriorations of the qualities of major rivers in developing nations. Consequently, high densities of disease causing bacteria in the watersheds are regularly reported including incidences of emerging Vibrio fluvialis. Vibrio fluvialis infection remains among those infectious diseases posing a potentially serious threat to public health. This paper addresses the epidemiology of this pathogen; pathogenesis of its disease; and its clinical manifestations in humans.
Topics: Public Health Practice; Vibrio; Vibrio Infections; Water Microbiology
PubMed: 21139853
DOI: 10.3390/ijerph7103628 -
Frontiers in Cellular and Infection... 2021The study investigated the occurrence of antimicrobial resistance genes and virulence determinants in species recovered from different freshwater sheds in rustic...
The study investigated the occurrence of antimicrobial resistance genes and virulence determinants in species recovered from different freshwater sheds in rustic milieu. A total of 118 isolates comprising (n=41), (n=40) and (n=37) was identified by amplification of , and genes. The amplification of virulence genes indicated that . (, , , , and ) genes were detected in 12.5%, 32.5%, 45%, 37.5% and 10% respectively. . genes (, and ) were harboured in 48.8%, 14.6% and 19.5% isolates congruently. The other virulence genes that include and were observed in 63.1% and 29% of isolates belonging to . . With the exceptions of imipenem, meropenem and ciprofloxacin, most isolates exhibited more than 50% resistance to antibiotics. The antimicrobial resistance was more prevalent for polymyxin B (100%), azithromycin (100%) and least in ciprofloxacin (16.1%). Multiple antibiotic resistance index range was 0.3 and 0.8 with most isolates showing MARI of 0.8. The TEM, AmpC, GES, IMP, OXA-48 and KPC genes were detected in 53.3%, 42%, 29.6%, 16.6%, 15%, 11.3% and 5.6% of the isolates. Non-beta lactamases such as streptomycin resistance ( and ), gentamicin resistance () and quinolone resistance gene () were found in 5.2%, 44.3%, 26% and 2.8%. Chloramphenicol resistance genes ( and ) were found in 5.2% and 44.3% among the isolates. Our findings reveal the presence of antimicrobial resistance genes and virulent species in aquatic environment which can have potential risk to human and animal's health.
Topics: Animals; Anti-Bacterial Agents; Drug Resistance, Microbial; Fresh Water; Humans; Microbial Sensitivity Tests; Vibrio; Virulence
PubMed: 34490150
DOI: 10.3389/fcimb.2021.732001 -
Scientific Reports Sep 2017Vibrio fluvialis is recognized as an emerging pathogen. However, not much is known about the mechanism of its pathogenesis, and its adaptation to a special niche such as...
Vibrio fluvialis is recognized as an emerging pathogen. However, not much is known about the mechanism of its pathogenesis, and its adaptation to a special niche such as the gall bladder. Here we describe two V. fluvialis strains that cause acute cholecystitis. It is noteworthy that both strains were susceptible to all antibiotics tested, which is in contrast to previous studies, suggesting substantial genetic diversity among V. fluvialis isolates. In agreement with their survival and growth in the gall bladder, the genomes of strains 12605 and 3663 contain a considerable number of genes that confer resistance to bile, including toxR, omp U, tolC, cmeABC, rlpB, yrbK, rpoS, damX and gltK. Furthermore, integrative and conjugative elements (ICEs), virulence factors and prophage regions were also detected in strains 12605 and 3663, reflecting their flexibility in recombination during the evolution of pathogenicity. Comparative analysis of nine available genomes of V. fluvialis revealed a core genome consisting of 3,147 genes. Our results highlight the association of V. fluvialis with a rare disease profile and shed light on the evolution of pathogenesis and niche adaptation of V. fluvialis.
Topics: Bacterial Proteins; Bile; Female; Genome, Bacterial; Humans; Male; Species Specificity; Vibrio; Virulence; Virulence Factors
PubMed: 28928424
DOI: 10.1038/s41598-017-12304-8 -
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