Occurrence and Abundance of Pathogenic Vibrio Species in Raw Oysters at Retail Seafood Markets in Northwestern Mexico

2019 ◽  
Vol 82 (12) ◽  
pp. 2094-2099 ◽  
Author(s):  
CLAUDIA VILLICAÑA ◽  
LUIS AMARILLAS ◽  
LILIANA SOTO-CASTRO ◽  
BRUNO GÓMEZ-GIL ◽  
MARCIAL LEONARDO LIZÁRRAGA-PARTIDA ◽  
...  

ABSTRACT Seafood has frequently been associated with foodborne illness because pathogens are easily introduced during seafood cultivation, handling, and processing. Vibrio parahaemolyticus and Vibrio cholerae are human pathogens that cause gastroenteritis and cholera, respectively, and Vibrio vulnificus can cause fatal wound infections and septicemia. However, information about the occurrence of these pathogens in oysters from the Pacific coast of Mexico is limited to V. parahaemolyticus. In the present study, we evaluated the presence and abundance of these three Vibrio species in 68 raw oysters (Crassostrea corteziensis) obtained from retail seafood markets in Sinaloa, Mexico. The most probable number (MPN)–PCR assay was used for amplification of the tlh (thermolabile hemolysin), ompW (outer membrane protein), and vvhA (hemolytic cytolysin) genes that are specific to V. parahaemolyticus, V. cholerae, and V. vulnificus, respectively. All oyster samples were positive for at least one Vibrio species. V. parahaemolyticus, V. cholerae, and V. vulnificus prevalences were 77.9, 8.8, and 32.3% overall, respectively, and most species were present in all sample periods with increased prevalence in period 3. The tdh (thermostable direct hemolysin) gene was detected in 30.1%, trh (TDH-related hemolysin) was detected in 3.7%, and tdh/trh was detected in 7.5% of the total tlh-positive samples (53 of 68), whereas the pandemic serotype O3:K6 (orf8 positive) was detected in only 1 sample (1.8%). The total prevalence of tdh and/or trh was 41.5%. In none of the samples positive for V. cholerae were the cholera toxin (ctxA) and cholix (chxA) toxigenic genes or the rfb gene encoding the O1 and O139 antigens amplified, suggesting the presence of non-O1 non-O139 V. cholerae strains. Our results clearly indicated a high prevalence of pathogenic Vibrio species in raw oysters from retail seafood markets in Mexico. Consumption of these raw oysters carries the potential risk of foodborne illness, which can be limited by cooking. HIGHLIGHTS

Author(s):  
Qingyao Wang ◽  
Songzhe Fu ◽  
Qian Yang ◽  
Jingwei Hao ◽  
Can Zhou ◽  
...  

The estuary is the ecological niche of pathogenic Vibrio spp. as it provides abundant organic and inorganic nutrients from seawater and rivers. However, little is known about the ecology of these Vibrio species in the inland brackish water area. In this study, their co-occurrence and relationships to key environmental constraints (salinity and temperature) in the Hun-Tai River of China were examined using the most probable number polymerase chain reaction (MPN-PCR) approach. We hereby report 2-year continuous surveillance based on six water indices of the Hun-Tai River. The results showed that seawater intrusion maximally reached inland as far as 26.5 km for the Hun-Tai River. Pathogenic Vibrio spp. were detected in 21.9% of the water samples. In particular, V. cholerae, V. parahaemolyticus, and V. vulnificus were isolated in 10 (10.4%), 20 (20.8.5%), and 2 (2.08%) samples, respectively. All V. parahaemolyticus strains were tdh gene negative, 10% were positive for the trh gene. Multi-locus sequence typing (MLST) divided V. parahaemolyticus strains into 12 sequence types (STs) for the Hun-Tai River. Five STs were respectively present in various locations along the Hun-Tai River. The PCR assay for detecting six virulence genes and Vibrio seventh pandemic island I and II revealed three genotypes in 12 V. cholerae isolates. The results of our study showed that seawater intrusion and salinity have profound effects on the distribution of pathogenic Vibrio spp. in the inland river, suggesting a potential health risk associated with the waters of the Hun-Tai River used for irrigation and drinking.


2010 ◽  
Vol 73 (4) ◽  
pp. 734-738 ◽  
Author(s):  
FRANCISKA M. SCHETS ◽  
HAROLD H. J. L. van den BERG ◽  
SASKIA A. RUTJES ◽  
ANA MARIA de RODA HUSMAN

Vibrio parahaemolyticus is a common cause of shellfish-related gastroenteritis all over the world. V. parahaemolyticus and Vibrio alginolyticus have previously been detected in water samples from the Oosterschelde, a large inlet on the North Sea, which is used for both recreational purposes and shellfish production. In 2006, oysters (Crassostrea gigas) from a noncommercial oyster bed in the Oosterschelde and oysters bought in Dutch fish shops were tested for the presence of pathogenic Vibrio species; in 2007 and 2008, oysters (C. gigas) and mussels (Mytilus edulis) from Oosterschelde production areas were examined. Total Vibrio numbers were related to water temperatures to study joint patterns. Vibrio was found in oysters and mussels from the production areas, and levels ranged from 6 to 622 most probable number (MPN) per g in oysters and 6 to 62 MPN/g in mussels. Vibrio levels in oysters from fish shops were 231 to >333 MPN/g, whereas levels in noncommercial oysters ranged from 231 to >2,398 MPN/g. About 80% of the isolated strains were V. alginolyticus, and approximately 10% were identified as V. parahaemolyticus. Vibrio counts in shellfish samples increased with increasing water temperature and declined when water temperatures dropped; Vibrio was not detected when water temperatures declined to <13.5°C. Based on the obtained results and the known high V. parahaemolyticus dose (<104 cells per serving of oysters) required for infection, it is concluded that the risk of gastrointestinal infections with V. parahaemolyticus through consumption of shellfish from the Oosterschelde production sites is presumably low.


2020 ◽  
Vol 86 (23) ◽  
Author(s):  
Salina Parveen ◽  
John Jacobs ◽  
Gulnihal Ozbay ◽  
Lathadevi K. Chintapenta ◽  
Esam Almuhaideb ◽  
...  

ABSTRACT 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.


2004 ◽  
Vol 70 (9) ◽  
pp. 5469-5476 ◽  
Author(s):  
Mark A. Randa ◽  
Martin F. Polz ◽  
Eelin Lim

ABSTRACT The abundance of Vibrio vulnificus in coastal environments has been linked to water temperature, while its relationship to salinity is less clear. We have developed a culture-independent, most-probable-number quantitative PCR approach to examine V. vulnificus population dynamics in Barnegat Bay, N.J. Based on the combined analysis of our results from Barnegat Bay and from the literature, the present data show that (i) V. vulnificus population dynamics are strongly correlated to water temperature and (ii) although the general trend is for V. vulnificus abundance to be inversely correlated with salinity, this relationship depends on salinity levels. Irrespective of temperature, high abundances of V. vulnificus are observed at 5 to 10 ppt, which thus appears to be the optimal salinity regime for their survival. At 20 to 25 ppt, V. vulnificus abundances show a positive correlation to salinity. Unsuccessful attempts to resuscitate V. vulnificus, combined with our inability to detect cells during the winter despite an assay adapted to detect viable but nonculturable (VBNC) cells, suggest that the decline and eventual disappearance of V. vulnificus from the water column during the winter months is due primarily to a significant reduction in population size and is not only the consequence of cells entering the VBNC state. These findings are in line with the hypothesis that the sediment serves as a refuge for a subpopulation of V. vulnificus over the winter and weather-driven mixing events during the spring initiate a summer bloom in the water column.


2005 ◽  
Vol 68 (7) ◽  
pp. 1454-1456 ◽  
Author(s):  
YI-CHENG SU ◽  
JINGYUN DUAN ◽  
WEN-HSIN WU

The thiosulfate–citrate–bile salts–sucrose agar (TCBS) used in the most-probable-number method for detecting Vibrio parahaemolyticus cannot differentiate growth of V. parahaemolyticus from Vibrio vulnificus or Vibrio mimicus. This study examined the selectivity and specificity of Bio-Chrome Vibrio medium (BCVM), a chromogenic medium that detects V. parahaemolyticus on the basis of the formation of distinct purple colonies on the medium. A panel consisting of 221 strains of bacteria, including 179 Vibrio spp. and 42 non-Vibrio spp., were examined for their ability to grow and produce colored colonies on BCVM. Growth of Salmonella, Shigella, Escherichia coli, Enterobacter cloacae, Yersinia enterocolitica, and Aeromonas was inhibited by both BCVM and TCBS. All 148 strains of V. parahaemolyticus grew on BCVM, and 145 of them produced purple colonies. The remaining 31 Vibrio spp., except one strain of Vibrio fluvialis, were either unable to grow or produced blue-green or white colonies on BCVM. Bio-Chrome Vibrio medium was capable of differentiating V. parahaemolyticus from other species, including V. vulnificus and V. mimicus. Further studies are needed to evaluate the sensitivity and specificity of BCVM for detecting V. parahaemolyticus in foods.


2009 ◽  
Vol 72 (1) ◽  
pp. 174-177 ◽  
Author(s):  
CHENGCHU LIU ◽  
JIANZHANG LU ◽  
YI-CHENG SU

This study investigated the effects of flash freezing, followed by frozen storage, on reducing Vibrio parahaemolyticus in Pacific raw oysters. Raw Pacific oysters were inoculated with a five-strain cocktail of V. parahaemolyticus at a total level of approximately 3.5 × 105 most probable number (MPN) per gram. Inoculated oysters were subjected to an ultralow flash-freezing process (−95.5°C for 12 min) and stored at −10, −20, and −30°C for 6 months. Populations of V. parahaemolyticus in the oysters declined slightly by 0.22 log MPN/g after the freezing process. Subsequent storage of frozen oysters at −10, −20, and −30°C resulted in considerable reductions of V. parahaemolyticus in the oysters. Storing oysters at −10°C was more effective in inactivating V. parahaemolyticus than was storage at −20 or −30°C. Populations of V. parahaemolyticus in the oysters declined by 2.45, 1.71, and 1.45 log MPN/g after 1 month of storage at −10, −20, and −30°C, respectively, and continued to decline during the storage. The levels of V. parahaemolyticus in oysters were reduced by 4.55, 4.13, and 2.53 log MPN/g after 6 months of storage at −10, −20, and −30°C, respectively. Three process validations, each separated by 1 week and conducted according to the National Shellfish Sanitation Program's postharvest processing validation–verification interim guidance for Vibrio vulnificus and Vibrio parahaemolyticus, confirmed that a process of flash freezing, followed by storage at −21 ± 2°C for 5 months, was capable of achieving greater than 3.52-log (MPN/g) reductions of V. parahaemolyticus in half-shell Pacific oysters.


2020 ◽  
Vol 8 (10) ◽  
pp. 804
Author(s):  
Candice A. Thorstenson ◽  
Matthias S. Ullrich

World-wide increases in Vibrio-associated diseases have been reported in aquaculture and humans in co-occurrence with increased sea surface temperatures. Twelve species of Vibrio are known to cause disease in humans, but three species dominate the number of human infections world-wide: Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus. Fluorescent protein (FP)-labelled bacteria have been used to make great progress through in situ studies of bacterial behavior in mixed cultures or within host tissues. Currently, FP-labelling methods specific for Vibrio species are still limited by time-consuming counterselection measures that require the use of modified media and temperatures below the optimal growth temperature of many Vibrio species. Within this study, we used a previously reported R6K-based suicide delivery vector and two newly constructed transposon variants to develop a tailored protocol for FP-labelling V. cholerae, V. parahaemolyticus, and V. vulnificus environmental isolates within two days of counterselection against the donor Escherichiacoli. This herein presented protocol worked universally across all tested strains (30) with a conjugation efficiency of at least two transconjugants per 10,000 recipients.


2009 ◽  
Vol 72 (10) ◽  
pp. 2110-2113 ◽  
Author(s):  
ANGELO DePAOLA ◽  
JESSICA L. JONES ◽  
KATHY E. NOE ◽  
ROBIN H. BYARS ◽  
JOHN C. BOWERS

From June through October 2004, the U.S. Food and Drug Administration collected oysters (61 samples) that had been subjected to postharvest processing (PHP) methods, including mild heat treatment, freezing, and high hydrostatic pressure, from processors and retail markets in various states to determine Vibrio vulnificus and V. parahaemolyticus levels. Presence in a 25-g sample and most probable number (MPN) using standard enrichment and selective isolation procedures were utilized. Suspect colonies were isolated and identified using DNA probe colony hybridization. Neither species of vibrio was detected in 25-g portions of most samples regardless of the PHP. The lowest frequency of isolation of either pathogen (<10%) was observed with the mild heat process. Few (12 to 13%) frozen samples collected at the processor but not at retail contained >30 MPN/g of either pathogen. The mean levels of either organism in PHP oysters observed in the present study were 5 to 6 log less than in unprocessed raw Gulf Coast oysters. Of the 70 V. vulnificus isolates examined, only 5 possessed the putative virulence marker, type B 16S rRNA. Neither the thermostable direct hemolysin (tdh) nor the tdh-related hemolysin (trh) virulence gene was detected in any of the 40 V. parahaemolyticus isolates examined in the present study. These data suggest that if there is any selective advantage to pathogenic strains of V. vulnificus and V. parahaemolyticus, these differences are minimal. These results indicate that all PHP treatments greatly reduce exposure of V. vulnificus and V. parahaemolyticus to raw-oyster consumers. Consequently, these PHP oysters pose a much lower risk of illness to consumers due to these pathogens.


2012 ◽  
Vol 75 (8) ◽  
pp. 1501-1506 ◽  
Author(s):  
ROBERTA JULIANO RAMOS ◽  
MARÍLIA MIOTTO ◽  
FRANCISCO JOSÉ LAGREZE SQUELLA ◽  
ANDRÉIA CIROLINI ◽  
JAIME FERNANDO FERREIRA ◽  
...  

The efficacy of depuration using UV light and chlorinated seawater for decontaminating Vibrio parahaemolyticus and Vibrio vulnificus from oysters was investigated. Oysters were contaminated with a five-strain cocktail of V. parahaemolyticus or V. vulnificus to levels of 104 to 105 CFU ml−1 for bioaccumulation. The depuration was conducted in a closed system in which 350 liters of seawater was recirculated at a rate of 7 liters/min for 48 h at room temperature. Counts of V. parahaemolyticus or V. vulnificus were determined at 0, 6, 18, 24, and 48 h. Three treatments were conducted: T1, control treatment; T2, UV treatment; and T3, UV plus chlorine treatment. After 48 h of depuration of V. parahaemolyticus, T3 reduced the count by 3.1 log most probable number (MPN) g−1 and T2 reduced the count by 2.4 log MPN g−1, while T1 reduced the count by only 2.0 log MPN g−1. After 48 h of depuration of V. vulnificus, T2 and T3 were efficient, reducing the counts by 2.5 and 2.4 log MPN g−1, respectively, while T1 reduced the count by only 1.4 log MPN g−1. The UV light plus chlorine treatment was more efficient for controlling V. parahaemolyticus in oysters. Both UV light and UV light plus chlorine were efficient for V. vulnificus. The present study is the first report showing the efficacy of depuration systems for decontaminating V. parahaemolyticus and V. vulnificus in oysters cultivated on the Brazilian coast. This study provides information on processes that can contribute to controlling and preventing such microorganisms in oysters and could be used for effective postharvest treatment by restaurants and small producers of oysters on the coast of Brazil.


2011 ◽  
Vol 74 (11) ◽  
pp. 1902-1907 ◽  
Author(s):  
CORINNE AUDEMARD ◽  
HOWARD I. KATOR ◽  
MARTHA W. RHODES ◽  
THOMAS GALLIVAN ◽  
A. J. ERSKINE ◽  
...  

In 2009 the U.S. Food and Drug Administration (FDA) announced its intention to implement postharvest processing (PHP) methods to eliminate Vibrio vulnificus from oysters intended for the raw, half-shell market that are harvested from the Gulf of Mexico during warmer months. FDA-approved PHP methods can be expensive and may be associated with unfavorable responses from some consumers. A relatively unexplored PHP method that uses relaying to high salinity waters could be an alternative strategy, considering that high salinities appear to negatively affect the survival of V. vulnificus. During relay, however, oysters may be exposed to rapid and large salinity increases that could cause increased mortality. In this study, the effectiveness of high salinity relay to reduce V. vulnificus to <30 most probable number (MPN) per g and the impact on oyster mortality were assessed in the lower Chesapeake Bay. Two relay experiments were performed during the summer and fall of 2010. Oysters collected from three grow-out sites, a low salinity site (14 to 15 practical salinity units [psu]) and two moderate salinity sites (22 to 25 psu), were relayed directly to a high salinity site (≥30 psu) on Virginia's Eastern Shore. Oysters were assayed for V. vulnificus and Vibrio parahaemolyticus (another Vibrio species of concern) densities at time 0 prior to relay and after 7 and 14 days of relay, using the FDA MPN enrichment method combined with detection by real-time PCR. After 14 days, both V. vulnificus and V. parahaemolyticus densities were ≤0.8 MPN/g, and decreases of 2 to 3 log in V. vulnificus densities were observed. Oyster mortalities were low (≤<4%) even for oysters from the low salinity harvest site, which experienced a salinity increase of approximately 15 psu. Results, although preliminary and requiring formal validation and economic analysis, suggest that high salinity relay could be an effective PHP method.


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