Vibrio vulnificus infection attributed to bee sting: a case report.

Vibrio vulnificus is a pathogenic marine bacteria associated with high mortality. Changes in climate and the global seafood trade have increased the prevalence of marine and freshwater systems affected by V. vulnificus. As a result, the incidence of land animals, plants, and insects contacting V. vulnificus and acting as disease vectors is on the rise. We report the case of a 53-year-old male who was infected with V. vulnificus as the result of a bee sting. The patient had no history of contact with the sea or fresh water or aquatic organisms or products. Due to bacterial pathogenicity and the patient's underlying diseases, his condition deteriorated rapidly and eventually resulted in death. Here, we review the pathogenic mechanisms and treatment of V. vulnificus. We determined that V. vulnificus has spread from seawater to freshwater and that individuals may become infected from insects, even in the absence of direct contact with infected water. This case report will inform clinicians about the possible sources of V. vulnificus infection and indicates the possibility that more insects may transmit V. vulnificus in the future.

Duplex On-Site Detection of Vibrio cholerae and Vibrio vulnificus by Recombinase Polymerase Amplification and Three-Segment Lateral Flow Strips.

Vibrio cholerae and Vibrio vulnificus are two most reported foodborne Vibrio pathogens related to seafood. Due to global ocean warming and an increase in seafood consumption worldwide, foodborne illnesses related to infection of these two bacteria are growing, leading to food safety issues and economic consequences. Molecular detection methods targeting species-specific genes are effective tools in the fight against bacterial infections for food safety. In this study, a duplex detection biosensor based on isothermal recombinase polymerase amplification (RPA) and a three-segment lateral flow strip (LFS) has been established. The biosensor used lolB gene of Vibrio cholerae and empV gene of Vibrio vulnificus as the detection markers based on previous reports. A duplex RPA reaction for both targets were constructed, and two chemical labels, FITC and DIG, of the amplification products were carefully tested for effective and accurate visualization on the strip. The biosensor demonstrated good specificity and achieved a sensitivity of 101 copies per reaction or one colony forming unit (CFU)/10 g of spiked food for both bacteria. Validation with clinical samples showed results consistent with that of real-time polymerase chain reaction. The detection process was simple and fast with a 30-min reaction at 37 °C and visualization on the strip within 5 min. With little dependence on laboratory settings, this biosensor was suitable for on-site detection, and the duplex system enabled simultaneous detection of the two important foodborne bacteria. Moreover, the principle can be extended to healthcare and food safety applications for other pathogens.

New Atypical Manifestations and Prognostic Factors of Vibrio vulnificus Infection: a 10-Year Retrospective Study.

Vibrio vulnificus (V. vulnificus) infection is rare but potentially fatal. This study explored new atypical manifestations and prognostic factors of V. vulnificus-infected patients during hospitalization. We retrospectively reviewed the medical records of 33 patients diagnosed with V. vulnificus infection in Guangdong Province, China between 2010 and 2020. Multiple logistic regression and receiver operating characteristic (ROC) curve analyses were performed. The new atypical manifestations included cholangitis, urinary tract infection, and suppurative otitis media. Eleven of the 33 (33.3%) V. vulnificus-infected patients eventually died. Univariate analysis showed that patients with cardio-cerebrovascular diseases, lower platelet counts, and higher levels of C-reactive protein and procalcitonin (PCT) had statistically higher mortality. However, multivariate analysis showed that only the PCT level (P = 0.036) was statistically significant. In addition, the area under the ROC value estimate for PCT was 0.8816 (95% confidence interval (CI), 0.759-1.000; P = 0.0009). More than half of the patients with V. vulnificus infection died when PCT was > 20 ng/mL, while no patient died when PCT was ≤ 20 ng/mL. This study found new atypical manifestations of V. vulnificus infection. In addition, PCT was an effective and independent predictor of mortality in patients with V. vulnificus infection, allowing clinicians to conduct early risk stratification and determine the best therapeutic strategies.

An isothermal recombinase polymerase amplification and lateral flow strip combined method for rapid on-site detection of Vibrio vulnificus in raw seafood.

Vibrio vulnificus is an important foodborne pathogenic bacterium that mainly contaminates seafood. Rapid and accurate technologies that suitable for on-site detection are critical for effective control of its spreading. Conventional detection methods and polymerase chain reaction (PCR)-based and qPCR-based approaches have application limitations in on-site scenarios. Application of loop-mediated isothermal amplification (LAMP) technology was a good step towards the on-site detection. In this study, a recombinase polymerase amplification (RPA)-based detection method for V. vulnificus was developed combining with lateral flow strip (LFS) for visualized signal. The method targeted the conservative empV gene encoding the extracellular metalloproteinase, and finished detection in 35 min at a conveniently low temperature of 37 °C. It showed good specificity and an excellent sensitivity of 2 copies of the genome or 10-1 colony forming unit (CFU) per reaction, or 1 CFU/10 g in spiked food samples with enrichment. The method tolerated unpurified templates directly from sample boiling, which added the convenience of the overall procedure. Application of the RPA-LFS method for clinical samples showed accurate and consistent detection results compared to bioassay and quantitative PCR. This RPA-LFS combined method is well suited for on-site detection of V. vulnificus.

Characteristics of Vibrio vulnificus isolates from clinical and environmental sources.

Researchers have developed multiple methods to characterize clinical and environmental strains of Vibrio vulnificus. The aim of our study was to use four assays to detect virulence factors in strains from infected patients and those from surface waters/sediments/oysters of South Carolina and the Gulf of Mexico. Vibrio vulnificus strains from clinical (n = 81) and environmental (n = 171) sources were tested using three real-time PCR methods designed to detect polymorphisms in the 16S rRNA, vcg and pilF genes and a phenotypic method, the ability to ferment D-mannitol. Although none of the tests correctly categorized all isolates, the differentiation between clinical and environmental isolates was similar for the pilF, vcgC/E and 16S rRNA assays, with sensitivities of 74.1-79.2% and specificities of 77.4-82.7%. The pilF and vcgC/E assays are comparable in efficacy to the widely used 16S rRNA method, while the D-mannitol fermentation test is less discriminatory (sensitivity = 77.8%, specificity = 61.4%). Overall percent agreement for the D-mannitol fermentation method was also lower (66.7%) than overall percent agreement for the 3 molecular assays (78.0%-80.2%). This study demonstrated, using a large, diverse group of Vibrio vulnificus isolates, that three assays could be used to distinguish most clinical vs environmental isolates; however, additional assays are needed to increase accuracy.

Protective Effects of Chicken Egg Yolk Immunoglobulins (IgYs) against Vibrio vulnificus Infections.

Vibrio (V.) vulnificus infection is a rare disease whose death rates exceed 50% despite aggressive antibiotic treatment and surgical debridement. The aim of this study was to assess the ability of specific anti-V. vulnificus immunoglobulins Y (IgYs) for preventing and treating V. vulnificus infections. IgYs were produced by immunizing egg laying hens with inactivated whole cell bacteria. Peritoneal cytokines, blood's bacterial load, and survival curves were obtained from both prophylactic and therapeutic mouse models. The results showed that the specific IgYs (i) inhibited the growth of V. vulnificus in vitro, (ii) dramatically reduced the inflammatory response and blood's bacterial load, and (iii) improved the survival rate of V. vulnificus-infected mice. These results prove that anti-V. vulnificus IgYs can be markedly effective means for the prophylaxis and the therapy of V. vulnificus infections.

Seasonal and Geographical Differences in Total and Pathogenic Vibrio parahaemolyticus and Vibrio vulnificus Levels in Seawater and Oysters from the Delaware and Chesapeake Bays Determined Using Several Methods.

Oyster and seawater samples were collected from five sites in the Chesapeake Bay, MD, and three sites in the Delaware Bay, DE, from May to October 2016 and 2017. Abundances and detection frequencies for total and pathogenic Vibrio parahaemolyticus and Vibrio vulnificus were compared using the standard most-probable-number-PCR (MPN-PCR) assay and a direct-plating (DP) method on CHROMagar Vibrio for total (tlh+ ) and pathogenic (tdh+ and trh+ ) V. parahaemolyticus genes and total (vvhA) and pathogenic (vcgC) V. vulnificus genes. The colony overlay procedure for peptidases (COPP) assay was evaluated for total Vibrionaceae DP had high false-negative rates (14 to 77%) for most PCR targets and was deemed unsatisfactory. Logistic regression models of the COPP assay showed high concordances with MPN-PCR for tdh+ and trh+V. parahaemolyticus and vvhA+V. vulnificus in oysters (85.7 to 90.9%) and seawater (81.1 to 92.7%) when seawater temperature and salinity were factored into the model, suggesting that the COPP assay could potentially serve as a more rapid method to detect vibrios in oysters and seawater. Differences in total Vibrionaceae and pathogenic Vibrio abundances between state sampling sites over different collection years were contrasted for oysters and seawater by MPN-PCR. Abundances of tdh+ and trh+V. parahaemolyticus were ∼8-fold higher in Delaware oysters than in Maryland oysters, whereas abundances of vcgC+V. vulnificus were nearly identical. For Delaware oysters, 93.5% were both tdh+ and trh+, compared to only 19.2% in Maryland. These results indicate that pathogenic V. parahaemolyticus was more prevalent in the Delaware Bay than in the Chesapeake Bay.IMPORTANCE While V. parahaemolyticus and V. vulnificus cause shellfish-associated morbidity and mortality among shellfish consumers, current regulatory assays for vibrios are complex, time-consuming, labor-intensive, and relatively expensive. In this study, the rapid, simple, and inexpensive COPP assay was identified as a possible alternative to MPN-PCR for shellfish monitoring. This paper shows differences in total Vibrionaceae and pathogenic vibrios found in seawater and oysters from the commercially important Delaware and Chesapeake Bays. Vibrio parahaemolyticus isolates from the Delaware Bay were more likely to contain commonly recognized pathogenicity genes than those from the Chesapeake Bay.

Phylogeography of the marine pathogen, Vibrio vulnificus, revealed the ancestral scenarios of its evolution.

Vibrio vulnificus is the leading cause of seafood-associated deaths worldwide. Despite the growing knowledge about the population structure of V. vulnificus, the evolutionary history and the ancestral relationships of strains isolated from various regions around the world have not been determined. Using the largest collection of sequence and isolate data of V. vulnificus to date, we applied ancestral character reconstruction to study the phylogeography of V. vulnificus. Multilocus sequence typing data from 10 housekeeping genes were used for the inference of ancestral states and reconstruction of the evolutionary history. The findings showed that the common ancestor of all V. vulnificus populations originated from East Asia, and later evolved into two main clusters that spread with time and eventually evolved into distinct populations in different parts of the world. While we found no meaningful insights concerning the evolution of V. vulnificus populations in the Middle East; however, we were able to reconstruct the ancestral scenarios of its evolution in East Asia, North America, and Western Europe.

Prevalence and virulence of Vibrio species isolated from raw shrimp from retail markets in Reynosa, Mexico.

In this study, the prevalence of Vibrio cholerae, Vibrio parahaemolyticus, Vibrio mimicus, Vibrio vulnificus and Vibrio spp. in shrimp from retail markets in Reynosa, Mexico was determined. A total of 765 isolates, identified as Vibrio spp. (59·1%), V. cholerae (17·8%), V. mimicus (6·7%) and V. parahaemolyticus (4·6%), were obtained; V. vulnificus was not detected. Most of the strains were isolated from supermarkets (48·1%), followed by street vendors (37·3%) and retail stores (14·6%). Moreover, several virulence genes were identified in V. cholerae: toxR (100%), OmpU (76·5%), hlyA (76·5%), VPI (19·9%) and tcpA (5·1%); in V. mimicus: vmh (100%), wzb (74·5%), pilF (54·9%), VPI (43·1%), OmpU (29·4%) and tdh (9·8%); and in V. parahaemolyticus: toxR (100%), tlh (100%), VP1680 (51·4%) and VPI (11·4%). These results show the low safety of this food and the potential risk to consumers' health, since this product in Mexican cuisine is sometimes served raw or semi-cooked. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows the prevalence of pathogenic Vibrio cholerae, Vibrio mimicus and Vibrio parahaemolyticus isolated from shrimp that is commercialized in Reynosa city. This could represent a risk to consumers' health, since outbreaks related to shrimp contaminated with Vibrio have been previously reported. Additionally, shrimp fishing has a major role in Mexico's economy.

Isolation and characterization of potentially pathogenic Vibrio species in a temperate, higher latitude hotspot.

The recent emergence of Vibrio infections at high latitudes represents a clear human health risk attributable to climate change. Here, we investigate the population dynamics of three Vibrio species: Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio cholerae within a British coastal estuarine site, with contrasting salinity and temperature regimes during an intense heatwave event. Water samples were collected weekly through the summer of 2018 and 2019 and filtered using membrane filtration and subsequently grown on selective media. Suspected vibrios were confirmed using a conventional species-specific PCR assay and further analysed for potential pathogenic markers. Results showed that Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio cholerae were present at high concentrations throughout both years, with their populations at substantially greater abundances corresponding to conditions of higher water temperatures during the heatwave of 2018 and at lower salinity sites, which is comparable to the results of previous studies. A subset of strains isolated during the extreme heatwave event in 2018 (46 Vibrio parahaemolyticus, 11 Vibrio cholerae and 4 Vibrio vulnificus) were genomically sequenced. Analysis of these 63 sequenced strains revealed a broad phenotypic and genomic diversity of strains circulating in the environment. An analysis of pathogenicity attributes identified a broad array of virulence genes across all three species, including a variety of genes associated with human disease. This study highlights the importance of the need for an increased Vibrio spp. surveillance system in temperate regions and the potential impact warming events such as heatwaves may have on the abundance of potentially pathogenic bacteria in the environment.

Influence of farming methods and seawater depth on Vibrio species in New Zealand Pacific oysters.

Studies conducted in seawaters around New Zealand have shown the numbers of human pathogenic Vibrio spp. are usually low, but high numbers sometimes occur during warmer summer/autumn months (January - April). In this study, Pacific oysters (Crassostrea gigas) were grown at Kaipara Harbour and Mahurangi Harbour in New Zealand at different heights from the seafloor in different ways: fixed positons intertidally and subtidally, and as floating long lines over the 2013 and 2014 summer periods. Two geographically distinct commercial harvest areas: Coromandel Harbour (North Island) and Croisilles Harbour (South Island) in New Zealand were also compared in 2015 where oysters are grown under different methods. Detection and enumeration of Vibrio spp. was performed according to the Bacteriological Analytical Manual using the Most Probable Number approach and real-time polymerase chain reaction technique. The only significant growing method effect was observed in Mahurangi Harbour, where intertidal oysters at 1.5 m from the seafloor had higher numbers of trh + Vibrio parahaemolyticus than other intertidal samples from Kaipara Harbour and Coromandel Harbour. All other samples showed a relationship with surface seawater temperature, but not with distance from seafloor or farming method. Overall, there is no clear evidence that different oyster farming methods (floating, subtidal or intertidal at different depths) affect Vibrio spp. population sizes, which were dominated by seasonal changes and environmental parameters.

Septicemia, necrotizing fasciitis, and peritonitis due to Vibrio vulnificus treated with early use of polymyxin B hemoperfusion in a patient undergoing CAPD: a case report.

BACKGROUND: Vibrio vulnificus infection is a rare but fatal foodborne illness. Here, we report a case of Vibrio vulnificus peritonitis followed by severe septicemia in a patient undergoing continuous ambulatory peritoneal dialysis (CAPD) who was treated with hemoperfusion using polymyxin B immobilized fiber. CASE PRESENTATION: A 63-year-old man undergoing CAPD was admitted to the emergency room due to general weakness, fever, and abdominal pain with hazy dialysate. Two days before admission, he had eaten raw fish. Initial laboratory tests including peritoneal fluid analysis suggested peritonitis. Despite empirical intraperitoneal antibiotic treatment, his fever did not subside, and multiple vesicles on the extremities newly appeared. The result of initial peritoneal fluid culture and blood cultures reported Vibrio vulnificus as the most likely causative pathogen. Hemoperfusion with polymyxin B immobilized fiber was performed to control gram-negative bacterial septicemia with antibiotics targeting the pathogenic organism. The patient recovered completely and was discharged without complications. DISCUSSION AND CONCLUSION: Suspicion of Vibrio vulnificus infection in susceptible immunocompromised patients is important for early diagnosis and prompt management. Peritonitis should be noted as a clinical manifestation of Vibrio vulnificus infection in CAPD patients, and polymyxin B hemoperfusion along with proper antibiotics could be considered as a treatment option.

A comparison between farmed oysters using floating cages and oysters grown on-bottom reveals more potentially human pathogenic Vibrio in the on-bottom oysters.

Eating raw oysters can come with serious health risks, as oysters can potentially contain bacteria of the Vibrio genus that cause food-borne infections. Vibrio bacteria are concentrated by oysters and, when consumed, infections can result with severe symptoms such as diarrhoea, lesions on the extremities, or even death. Vibrio spp. concentrations are strongly affected by season, location, and other factors such as temperature and salinity. Previous research in North Carolina oysters has been conducted on wild and farmed oysters but not at the same time. Farmed, or aquaculture raised, oysters are considerably different from wild oysters and could possibly pose different health risks. Farmed oysters are handled, raised from seed, and often grown using suspended grow-out systems called 'floating cages'. Therefore, farmed oysters can be grown at the surface of the estuary, while wild oysters typically grow at the bottom of the water column. This project compared the concentrations of Vibrio spp. in suspended, farm-grown oysters and wild oysters at three sites, using a paired approach with farmed and wild oysters sampled in proximity. An important part of this comparison was identifying pathogenicity of the bacteria isolated from the samples. Distinction was made between off- and on-bottom farming. Interestingly, on-bottom oysters had more pathogenic V. vulnificus than off-bottom oysters.

Faraday-Cage-Type Electrochemiluminescence Immunoassay: A Rise of Advanced Biosensing Strategy.

Electrochemiluminescence immunoassays are usually carried out through "on-electrode" strategy, i.e., sandwich-type immunoassay format, the sensitivity of which is restricted by two key bottlenecks: (1) the number of signal labels is limited and (2) only a part of signal labels could participate in the electrode reaction. In this Perspective, we discuss the development of an "in-electrode" Faraday-cage-type concept-based immunocomplex immobilization strategy. The biggest difference from the traditional sandwich-type one is that the designed "in-electrode" Faraday-cage-type immunoassay uses a conductive two-dimensional (2-D) nanomaterial simultaneously coated with signal labels and a recognition component as the detection unit, which could directly overlap on the electrode surface. In such a case, electrons could flow freely from the electrode to the detection unit, the outer Helmholtz plane (OHP) of the electrode is extended, and thousands of signal labels coated on the 2-D nanomaterial are all electrochemically "effective." Thus, then, the above-mentioned bottlenecks obstructing the improvement of the sensitivity in sandwich-type immunoassay are eliminated, and as a result a much higher sensitivity of the Faraday-cage-type immunoassay can be obtained. And, the applications of the proposed versatile "in-electrode" Faraday-cage-type immunoassay have been explored in the detection of target polypeptide, protein, pathogen, and microRNA, with the detection sensitivity improved tens to hundreds of times. Finally, the outlook and challenges in the field are summarized. The rise of Faraday-cage-type electrochemiluminescence immunoassay (FCT-ECLIA)-based biosensing strategies opens new horizons for a wide range of early clinical identification and diagnostic applications.

Application of gyrB targeted SYBR green based qPCR assay for the specific and rapid detection of Vibrio vulnificus in seafood.

A SYBR green based qPCR assay targeting a unique region of gyrB was developed for the detection of Vibrio vulnificus. The specificity of the assay was studied using V. vulnificus and other bacterial strains belonging to Vibrio and non-Vibrio species. The assay unambiguously distinguished V.vulnificus with a sensitivity of 101 CFU/mL in pure culture while 102CFU/g was detected in clam meat homogenate with an efficiency of ≥98%.The utility of the qPCR assay was validated with naturally incurred seafood samples, where 24 out of 59(40.67%) seafood samples tested positive for V. vulnificus after 6-8 h enrichment in APW-P broth. In contrast, conventional PCR could detect only 11 samples (18.64%). Our results showed that qPCR assay developed in this study could be used as a rapid method for screening seafood samples for the presence of V. vulnificus, as the assay can be completed within 9-12 h including the enrichment of seafood in APW-P broth. The gyrB targeted qPCR developed in this study can provide excellent results on the presence and load of V. vulnificus in naturally contaminated samples quickly and efficiently; thus it could find application as a routine test in the seafood industry for the analysis V. vulnificus.

First findings of potentially human pathogenic bacteria Vibrio in the south-eastern Baltic Sea coastal and transitional bathing waters.

Vibrio spp. are bacteria that inhabit fresh and marine waters throughout the world and can cause severe infections in humans. This study aimed to investigate the presence of potentially pathogenic Vibrio bacteria in the coastal waters of the Lithuanian Baltic Sea and the Curonian Lagoon. The results of cultivation on TCBS media showed that total abundance of Vibrio spp. varied from 1.2 × 102 to 6 × 104 CFU L-1. Real-time PCR revealed that the V. vulnificus vvhA gene varied from 2.8 × 103 to 3.7 × 104 copies L-1, with the highest amounts in sites with average water salinity of 7.1 PSU. Both green and blue-green algae and lower salinity play a role in the growth and spread of total Vibrio spp. Although potential infection risk was low at the time of this study, regular monitoring of Vibrio spp. and infection risk assessments are recommended.

Outcomes of Third-Generation Cephalosporin Plus Ciprofloxacin or Doxycycline Therapy in Patients with Vibrio vulnificus Septicemia: A Propensity Score-Matched Analysis.

BACKGROUND: Combination therapy with a third-generation cephalosporin (TGC) and a tetracycline analogue is recommended for Vibrio vulnificus infection. The combination of a TGC and ciprofloxacin has synergistic in vitro bactericidal activity against V. vulnificus. No clinical study has compared the standard regimen with TGC plus ciprofloxacin therapy for V. vulnificus infection. METHODS: Patients with a confirmed V. vulnificus infection at two medical centers in Korea from 1991 to 2016 were enrolled in this study. The patients were grouped according to the type of antibiotic administered. A retrospective propensity-score-matched case-control study of patients treated with TGC plus doxycycline or TGC plus ciprofloxacin was performed. The clinical characteristics and outcomes of the patients were analyzed. RESULTS: A total of 218 patients were confirmed to have V. vulnificus septicemia during the study, and the 30-day survival rate was 39% (85/218). The patients were classified into the following six treatment groups: TGC monotherapy (n = 82), TGC plus doxycycline therapy (n = 42), TGC plus ciprofloxacin therapy (n = 39), ciprofloxacin monotherapy (n = 14), other ß-lactam monotherapy (n = 10), and other (n = 31). The survival rates of these groups were as follows: TGC monotherapy (35%), TGC plus doxycycline (38%), TGC plus ciprofloxacin (54%), ciprofloxacin monotherapy (29%), other ß-lactam (20%), and other (39%). The 30-day survival rate showed no significant difference between the TGC plus doxycycline and TGC plus ciprofloxacin groups (log-rank test, P = 0.18). Among the 81 patients treated with TGC plus doxycycline or TGC plus ciprofloxacin, 12 per treatment group were selected by propensity-score matching. There was no significant difference in the baseline characteristics or the frequency of fasciotomy between the two groups. The 30-day survival rate showed no significant difference between the TGC plus doxycycline (50%) and TGC plus ciprofloxacin (67%) groups (log-rank test, P = 0.46). CONCLUSION: Our data suggest that the outcome of TGC plus ciprofloxacin therapy was comparable to that of TGC plus doxycycline therapy in patients with V. vulnificus septicemia.

Quantitative PCR enumeration of vcgC and 16S rRNA type A and B genes as virulence indicators for environmental and clinical strains of Vibrio vulnificus in Galveston Bay oysters.

Oysters from a reef in Galveston Bay, Texas, USA, were screened for more virulent clinical strains versus less virulent environmental strains of Vibrio vulnificus using a combination of quantitative PCR assays for the virulence correlating gene (clinical variant, vcgC) and 16S rRNA types A and B (type A = environmental, type B = clinical). The combination of vcgC and 16S rRNA type B loci to determine clinical type strains was suitable, as indicated by the strong correlation (R2 = 0.98; p < 0.001) between these gene counts over time and their relative proportion (up to 93.8% and 94.3%, respectively) to vvhA genes used to quantify all strains of V. vulnificus. A strong seasonal shift of V. vulnificus strain types was observed. Environmental strains (16S rRNA type A) predominated from April to mid-June as salinities increased from 22 to 27 PSU (practical salinity unit) and temperatures rose 20 to 28 °C, with peak gene quantities of 16 812 ± 56 CFU/g. As temperatures increased to ≥30 °C from mid-June to September and salinities rose above 27 PSU, clinical strains (16S rRNA type B; vcgC) predominated with peak quantities 31 868 ± 287 and 32 360 ± 178 CFU/g, respectively.

Dispersal of potentially pathogenic bacteria by plastic debris in Guanabara Bay, RJ, Brazil.

Analyses of thermotolerant coliform and heterotrophic bacteria as well as Escherichia coli and Vibrio species were carried out on plastic samples and in the surrounding waters of Guanabara Bay to evaluate plastic debris as vehicles of bacterial dispersal. Chemical characterizations of plastics were performed using Fourier transform infrared spectroscopy (FTIR). Plastic debris with high coliform contents were found, while their respective water samples had only low titers. No correlations were observed, however, between the amounts of bacteria and the chemical compositions of the plastic debris. Forty-four bacterial strains were PCR-confirmed as E. coli pathotypes, and 59 strains of Vibrio spp. (with 12 being identified as Vibrio cholerae [6], Vibrio vulnificus [5], and Vibrio mimicus [1]). These findings suggest these plastics can function as a substrate for bacterial biofilms (including pathogens). These debris, in turn, can be dispersed in aquatic environments not otherwise showing recent fecal bacterial contamination.

Evolutionary Model of Cluster Divergence of the Emergent Marine Pathogen Vibrio vulnificus: From Genotype to Ecotype.

Vibrio vulnificus, an opportunistic pathogen, is the causative agent of a life-threatening septicemia and a rising problem for aquaculture worldwide. The genetic factors that differentiate its clinical and environmental strains remain enigmatic. Furthermore, clinical strains have emerged from every clade of V. vulnificus In this work, we investigated the underlying genomic properties and population dynamics of the V. vulnificus species from an evolutionary and ecological point of view. Genome comparisons and bioinformatic analyses of 113 V. vulnificus isolates indicate that the population of V. vulnificus is made up of four different clusters. We found evidence that recombination and gene flow between the two largest clusters (cluster 1 [C1] and C2) have drastically decreased to the point where they are diverging independently. Pangenome and phenotypic analyses showed two markedly different lifestyles for these two clusters, indicating commensal (C2) and bloomer (C1) ecotypes, with differences in carbohydrate utilization, defense systems, and chemotaxis, among other characteristics. Nonetheless, we identified frequent intra- and interspecies exchange of mobile genetic elements (e.g., antibiotic resistance plasmids, novel "chromids," or two different and concurrent type VI secretion systems) that provide high levels of genetic diversity in the population. Surprisingly, we identified strains from both clusters in the mucosa of aquaculture species, indicating that manmade niches are bringing strains from the two clusters together. We propose an evolutionary model of V. vulnificus that could be broadly applicable to other pathogenic vibrios and facultative bacterial pathogens to pursue strategies to prevent their infections and emergence.IMPORTANCEVibrio vulnificus is an emergent marine pathogen and is the cause of a deadly septicemia. However, the genetic factors that differentiate its clinical and environmental strains and its several biotypes remain mostly enigmatic. In this work, we investigated the underlying genomic properties and population dynamics of the V. vulnificus species to elucidate the traits that make these strains emerge as a human pathogen. The acquisition of different ecological determinants could have allowed the development of highly divergent clusters with different lifestyles within the same environment. However, we identified strains from both clusters in the mucosa of aquaculture species, indicating that manmade niches are bringing strains from the two clusters together, posing a potential risk of recombination and of emergence of novel variants. We propose a new evolutionary model that provides a perspective that could be broadly applicable to other pathogenic vibrios and facultative bacterial pathogens to pursue strategies to prevent their infections.