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Applied and Environmental Microbiology Jan 2014A novel Vibrio vulnificus-infecting bacteriophage, SSP002, belonging to the Siphoviridae family, was isolated from the coastal area of the Yellow Sea of South Korea....
A novel Vibrio vulnificus-infecting bacteriophage, SSP002, belonging to the Siphoviridae family, was isolated from the coastal area of the Yellow Sea of South Korea. Host range analysis revealed that the growth inhibition of phage SSP002 is relatively specific to V. vulnificus strains from both clinical and environmental samples. In addition, a one-step growth curve analysis and a bacteriophage stability test revealed a latent period of 65 min, a burst size of 23 ± 2 PFU, as well as broad temperature (20°C to 60°C) and pH stability (pH 3 to 12) ranges. A Tn5 random transposon mutation of V. vulnificus and partial DNA sequencing of the inserted Tn5 regions revealed that the flhA, flhB, fliF, and fleQ mutants are resistant to SSP002 phage infection, suggesting that the flagellum may be the host receptor for infection. The subsequent construction of specific gene-inactivated mutants (flhA, flhB, fliF, and fleQ) and complementation experiments substantiated this. Previously, the genome of phage SSP002 was completely sequenced and analyzed. Comparative genomic analysis of phage SSP002 and Vibrio parahaemolyticus phage vB_VpaS_MAR10 showed differences among their tail-related genes, supporting different host ranges at the species level, even though their genome sequences are highly similar. An additional mouse survival test showed that the administration of phage SSP002 at a multiplicity of infection of 1,000 significantly protects mice from infection by V. vulnificus for up to 2 months, suggesting that this phage may be a good candidate for the development of biocontrol agents against V. vulnificus infection.
Topics: Animals; Bacterial Proteins; Bacteriophages; Biological Control Agents; DNA Transposable Elements; Genetic Complementation Test; Genome, Viral; Host Specificity; Membrane Proteins; Mice; Mutation; Republic of Korea; Vibrio Infections; Vibrio vulnificus
PubMed: 24212569
DOI: 10.1128/AEM.02675-13 -
Journal of Clinical Microbiology Jan 2011We determined the association between DNA load and mortality in patients with Vibrio vulnificus infection. Real-time PCR performed on sera of 27 culture-positive...
We determined the association between DNA load and mortality in patients with Vibrio vulnificus infection. Real-time PCR performed on sera of 27 culture-positive patients showed a significantly higher median DNA load in nonsurvivors than in survivors. Hence, real-time PCR can be used as an early prognostic factor in V. vulnificus septicemia.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Bacterial Load; DNA, Bacterial; Female; Humans; Male; Middle Aged; Polymerase Chain Reaction; Prognosis; Sepsis; Vibrio Infections; Vibrio vulnificus; Young Adult
PubMed: 21068289
DOI: 10.1128/JCM.01913-09 -
Journal of Biomedical Science Aug 2017Vibrio vulnificus is a marine bacterial species that causes opportunistic infections manifested by serious skin lesions and fulminant septicemia in humans. We have...
BACKGROUND
Vibrio vulnificus is a marine bacterial species that causes opportunistic infections manifested by serious skin lesions and fulminant septicemia in humans. We have previously shown that the multifunctional autoprocessing repeats in toxin (MARTX) of a biotype 1 V. vulnificus strain promotes survival of this organism in the host by preventing it from engulfment by the phagocytes. The purpose of this study was to further explore how MARTX inhibits phagocytosis of this microorganism by the macrophage.
METHODS
We compared between a wild-type V. vulnificus strain and its MARTX-deficient mutant for a variety of phagocytosis-related responses, including morphological change and activation of signaling molecules, they induced in the macrophage. We also characterized a set of MARTX domain-deletion mutants to define the regions associated with antiphagocytosis activity.
RESULTS
The RAW 264.7 cells and mouse peritoneal exudate macrophages underwent cell rounding accompanied by F-actin disorganization in the presence of MARTX. In addition, phosphorylation of some F-actin rearrangement-associated signaling molecules, including Lyn, Fgr and Hck of the Src family kinases (SFKs), focal adhesion kinase (FAK), proline-rich tyrosine kinase 2 (Pyk2), phosphoinositide 3-kinase (PI3K) and Akt, but not p38, was decreased. By using specific inhibitors, we found that these kinases were all involved in the phagocytosis of MARTX-deficient mutant in an order of SFKs-FAK/Pyk2-PI3K-Akt. Deletion of the effector domains in the central region of MARTX could lead to reduced cytotoxicity, depending on the region and size of deletion, but did not affect the antiphagocytosis activity and ability to cause rounding of macrophage. Reduced phosphorylation of Akt was closely associated with inhibition of phagocytosis by the wild-type strain and MARTX domain-deletion mutants, and expression of the constitutively active Akt, myr-Akt, enhanced the engulfment of these strains by macrophage.
CONCLUSIONS
MARTX could inactivate the SFKs-FAK/Pyk2-PI3K-Akt signaling pathway in the macrophages. This might lead to impaired phagocytosis of the V. vulnificus-infected macrophage. The majority of the central region of MARTX is not associated with the antiphagocytosis activity.
Topics: Animals; Bacterial Toxins; Cytotoxins; Macrophages; Male; Mice, Inbred BALB C; Phagocytosis; Vibrio Infections; Vibrio vulnificus
PubMed: 28822352
DOI: 10.1186/s12929-017-0368-2 -
Journal of Bacteriology Nov 2020Pathogenic species use many different approaches to subvert, attack, and undermine the host response. The toxins they produce are often responsible for the devastating... (Review)
Review
Pathogenic species use many different approaches to subvert, attack, and undermine the host response. The toxins they produce are often responsible for the devastating effects associated with their diseases. These toxins target a variety of host proteins, which leads to deleterious effects, including dissolution of cell organelle integrity and inhibition of protein secretion. Becoming increasingly prevalent as cofactors for toxins are proteins of the small GTPase families. ADP-ribosylation factor small GTPases (ARFs) in particular are emerging as a common host cofactor necessary for full activation of toxins. While ARFs are not the direct target of cholera toxin (CT), ARF binding is required for its optimal activity as an ADP-ribosyltransferase. The makes caterpillars floppy (MCF)-like and the domain X (DmX) effectors of the multifunctional autoprocessing repeats-in-toxin (MARTX) toxin also both require ARFs to initiate autoprocessing and activation as independent effectors. ARFs are ubiquitously expressed in eukaryotes and are key regulators of many cellular processes, and as such they are ideal cofactors for pathogens that infect many host species. In this review, we cover in detail the known toxins that use ARFs as cross-kingdom activators to both stimulate and optimize their activity. We further discuss how these contrast to toxins and effectors from other bacterial species that coactivate, stimulate, or directly modify host ARFs as their mechanisms of action.
Topics: ADP-Ribosylation Factors; Animals; Bacterial Toxins; Host-Pathogen Interactions; Humans; Multigene Family; Vibrio Infections; Vibrio vulnificus
PubMed: 32900828
DOI: 10.1128/JB.00278-20 -
International Journal of Molecular... Dec 2022is an opportunistic human pathogen causing self-limiting gastroenteritis, life-threatening necrotizing soft tissue infection, and fulminating septicaemia. An increasing...
is an opportunistic human pathogen causing self-limiting gastroenteritis, life-threatening necrotizing soft tissue infection, and fulminating septicaemia. An increasing rate of infections has been reported worldwide, characterized by sudden onset of sepsis and/or rapid progression to irreversible tissue damage or death. Timely intervention is essential to control the infection, and it is based on antibiotic therapy, which does not always result in the effective and rapid blocking of virulence. Inhibitors of essential virulence regulators have been reported in the last years, but none of them has been further developed, so far. We aimed to investigate whether exposure to some carbon compounds, mostly easily metabolizable, could result in transcriptional down-regulation of virulence genes. We screened various carbon sources already available for human use (thus potentially easy to be repurposed), finding some of them (including mannitol and glycerol) highly effective in down-regulating, in vitro and ex-vivo, the mRNA levels of several relevant -even essential- virulence factors (, , , , , , among others). This paves the way for further investigations aiming at their development as virulence inhibitors and to unveil mechanisms explaining such observed effects. Moreover, data suggesting the existence of additional regulatory networks of some virulence genes are reported.
Topics: Humans; Vibrio vulnificus; Carbon; Bacterial Proteins; Virulence; Virulence Factors; Vibrio Infections
PubMed: 36499602
DOI: 10.3390/ijms232315278 -
Southern Medical Journal Feb 2004
Topics: Animals; Humans; Incidence; Shellfish; Vibrio Infections; Vibrio vulnificus
PubMed: 14982256
DOI: 10.1097/01.SMJ.0000092520.47509.C2 -
Applied and Environmental Microbiology Mar 2022To better understand the controls on the opportunistic human pathogen Vibrio vulnificus in warm tropical waters, we conducted a year-long investigation in the Ala Wai...
To better understand the controls on the opportunistic human pathogen Vibrio vulnificus in warm tropical waters, we conducted a year-long investigation in the Ala Wai Canal, a channelized estuary in Honolulu, HI. The abundance of V. vulnificus, as determined by quantitative PCR (qPCR) of the hemolysin gene (), varied spatially and temporally by nearly 4 orders of magnitude (≤3 to 14,000 mL). Unlike in temperate and subtropical systems, temperatures were persistently warm (19 to 31°C) and explained little of the variability in V. vulnificus abundance. Salinity (1 to 36 ppt) had a significant, but nonlinear, relationship with V. vulnificus abundance with the highest concentrations (>2,500 mL) observed only at salinities from 7 to 22 ppt. V. vulnificus abundances were lower on average during the summer dry season, when waters were warmer but more saline. The highest canal-wide average abundances were observed during a time of modest rainfall, when moderate salinities and elevated concentrations of reduced nitrogen species and silica suggested a groundwater influence. Parallel quantification of the gene suggested that C-type strains, which are responsible for most human infections, comprised 25% of the total V. vulnificus on average, but their relative contribution was greater at higher salinities, suggesting a broader salinity tolerance. Generalized regression models suggested that up to 67% of sample-to-sample variation ( = 202) in log-transformed V. vulnificus abundance was explained using the measured environmental variables, and up to 97% of the monthly variation in canal-wide average concentrations ( = 13) was explained with the best subset of four variables. Our data illustrate that, in the absence of strong seasonal variation in water temperature in the tropics, variation in salinity driven by rainfall becomes a primary controlling variable on V. vulnificus abundance. There is thus a tendency for a rainfall-driven seasonal cycle in V. vulnificus abundance which is inverted from the temperature-driven seasonal cycle at higher latitudes. However, stochasticity in rainfall and its nonlinear, indirect effects on V. vulnificus concentration means that high abundances can occur at any location in the canal at any time of year, making it challenging to predict concentrations of this pathogen at a high temporal or spatial resolution. Much of the variability in canal-wide average concentrations, on the other hand, was explained by a few variables that reflect the magnitude of freshwater input to the system, suggesting that relative risk of exposure to this pathogen could be predicted as an average for the system.
Topics: Estuaries; Fresh Water; Humans; Salinity; Temperature; Vibrio vulnificus
PubMed: 35196141
DOI: 10.1128/AEM.01884-21 -
MicrobiologyOpen Dec 2012HlyU is a master regulator that plays an essential role in the virulence of the human pathogen Vibrio vulnificus. One of the most noteworthy characteristics of HlyU... (Review)
Review
HlyU is a master regulator that plays an essential role in the virulence of the human pathogen Vibrio vulnificus. One of the most noteworthy characteristics of HlyU regulation in this organism is its positive control of the expression of the repeat-in-toxin (RtxA1) gene, one of the most important virulence factors accounting for the fulminating and damaging nature of V. vulnificus infections. In this work, we reviewed the latest studies of RtxA1 in this bacterium and highlight the mechanism of gene regulation of rtxA1 expression by HlyU under a broader gene regulatory network.
Topics: Gene Expression Regulation, Bacterial; Hemolysin Factors; Vibrio Infections; Vibrio vulnificus; Virulence; Virulence Factors
PubMed: 23233275
DOI: 10.1002/mbo3.48 -
Journal of Microbiology (Seoul, Korea) Dec 2021RraA, a protein regulator of RNase E activity, plays a unique role in modulating the mRNA abundance in Escherichia coli. The marine pathogenic bacterium Vibrio...
RraA, a protein regulator of RNase E activity, plays a unique role in modulating the mRNA abundance in Escherichia coli. The marine pathogenic bacterium Vibrio vulnificus also possesses homologs of RNase E (VvRNase E) and RraA (VvRraA1 and VvRraA2). However, their physiological roles have not yet been investigated. In this study, we demonstrated that VvRraA1 expression levels affect the pathogenicity of V. vulnificus. Compared to the wild-type strain, the VvrraA1-deleted strain (ΔVvrraA1) showed decreased motility, invasiveness, biofilm formation ability as well as virulence in mice; these phenotypic changes of ΔVvrraA1 were restored by the exogenous expression of VvrraA1. Transcriptomic analysis indicated that VvRraA1 expression levels affect the abundance of a large number of mRNA species. Among them, the half-lives of mRNA species encoding virulence factors (e.g., smcR and htpG) that have been previously shown to affect VvrraA1 expression-dependent phenotypes were positively correlated with VvrraA1 expression levels. These findings suggest that VvRraA1 modulates the pathogenicity of V. vulnificus by regulating the abundance of a subset of mRNA species.
Topics: Animals; Bacterial Proteins; Biofilms; Endoribonucleases; Flagella; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Genes, Bacterial; Mice; Movement; RNA, Bacterial; RNA, Messenger; Vibrio Infections; Vibrio vulnificus; Virulence; Virulence Factors
PubMed: 34751908
DOI: 10.1007/s12275-021-1518-5 -
Applied and Environmental Microbiology Jun 2024Antibiotics are often used to treat severe infections, with third-generation cephalosporins and tetracyclines combined or fluoroquinolones alone being recommended by...
Antibiotics are often used to treat severe infections, with third-generation cephalosporins and tetracyclines combined or fluoroquinolones alone being recommended by the US Centers for Disease Control and Prevention. Increases in antibiotic resistance of both environmental and clinical vibrios are of concern; however, limited longitudinal data have been generated among environmental isolates to inform how resistance patterns may be changing over time. Hence, we evaluated long-term trends in antibiotic resistance of vibrios isolated from Chesapeake Bay waters (Maryland) across two 3-year sampling periods (2009-2012 and 2019-2022). ( = 134) and ( = 94) tR-confirmed isolates were randomly selected from both sampling periods and tested for antimicrobial susceptibility against eight antibiotics using the Kirby-Bauer disk diffusion method. A high percentage (94%-96%) of isolates from both sampling periods were resistant to ampicillin and only 2%-6% of these isolates expressed intermediate resistance or resistance to third-generation cephalosporins, amikacin, tetracycline, and trimethoprim-sulfamethoxazole. Even lower percentages of resistant isolates were observed and those were mostly recovered from 2009 to 2012, however, the presence of multiple virulence factors was observed. The frequency of multi-drug resistance was relatively low (6%-8%) but included resistance against antibiotics used to treat severe vibriosis in adults and children. All isolates were susceptible to ciprofloxacin, a fluoroquinolone, indicating its sustained efficacy as a first-line agent in the treatment of severe vibriosis. Overall, our data indicate that antibiotic resistance patterns among and recovered from the lower Chesapeake Bay have remained relatively stable since 2009.IMPORTANCE spp. have historically been susceptible to most clinically relevant antibiotics; however, resistance and intermediate-resistance have been increasingly recorded in both environmental and clinical isolates. Our data showed that while the percentage of multi-drug resistance and resistance to antibiotics was relatively low and stable across time, some isolates displayed resistance and intermediate resistance to antibiotics typically used to treat severe vibriosis (e.g., third-generation cephalosporins, tetracyclines, sulfamethoxazole-trimethoprim, and aminoglycosides). Also, given the high case fatality rates observed with infections, the presence of multiple virulence factors in the tested isolates is concerning. Nevertheless, the continued susceptibility of all tested isolates against ciprofloxacin, a fluoroquinolone, is indicative of its use as an effective first-line treatment of severe spp. infections stemming from exposure to Chesapeake Bay waters or contaminated seafood ingestion.
Topics: Vibrio parahaemolyticus; Vibrio vulnificus; Bays; Anti-Bacterial Agents; Longitudinal Studies; Maryland; Microbial Sensitivity Tests; Drug Resistance, Bacterial; Vibrio Infections; Humans
PubMed: 38809043
DOI: 10.1128/aem.00539-24