Enumeration of Vibrio parahaemolyticus in oyster tissues following artificial contamination and depuration

Wang, D.; Yu, Songtao; Chen, W.; Zhang, D.; Shi, Xianming

doi:10.1111/j.1472-765x.2010.02865.x

Cited by 15 publications

(23 citation statements)

References 29 publications

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“…It is possible that different routes of inoculation might affect the distribution of V. parahaemolyticus in oyster tissues. For example, in natural oysters, V. parahaemolyticus and Vibrio vulnificus appear to accumulate at higher densities in the digestive glands than in other tissues (60,63). To account for this possibility, V. parahaemolyticus growth rates using injected oysters were compared with natural levels of the bacteria in model evaluation experiments.…”

Section: Discussionmentioning

confidence: 99%

Predictive Models for the Effect of Storage Temperature on Vibrio parahaemolyticus Viability and Counts of Total Viable Bacteria in Pacific Oysters (Crassostrea gigas)

Fernandez‐Piquer

Bowman

Ross

et al. 2011

Appl Environ Microbiol

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Vibrio parahaemolyticus is an indigenous bacterium of marine environments. It accumulates in oysters and may reach levels that cause human illness when postharvest temperatures are not properly controlled and oysters are consumed raw or undercooked. Predictive models were produced by injecting Pacific oysters (Crassostrea gigas) with a cocktail of V. parahaemolyticus strains, measuring viability rates at storage temperatures from 3.6 to 30.4°C, and fitting the data to a model to obtain parameter estimates. The models were evaluated with Pacific and Sydney Rock oysters (Saccostrea glomerata) containing natural populations of V. parahaemolyticus. V. parahaemolyticus viability was measured by direct plating samples on thiosulfate-citratebile salts-sucrose (TCBS) agar for injected oysters and by most probable number (MPN)-PCR for oysters containing natural populations. In parallel, total viable bacterial counts (TVC) were measured by direct plating on marine agar. Growth/inactivation rates for V. parahaemolyticus were ؊0.006, ؊0.004, ؊0.005, ؊0.003, 0.030, 0.075, 0.095, and 0.282 log 10 CFU/h at 3.6, 6.2, 9.6, 12.6, 18.4, 20.0, 25.7, and 30.4°C, respectively. The growth rates for TVC were 0.015, 0.023, 0.016, 0.048, 0.055, 0.071, 0.133, and 0.135 log 10 CFU/h at 3.6, 6.2, 9.3, 14.9, 18.4, 20.0, 25.7, and 30.4°C, respectively. Square root and Arrhenius-type secondary models were generated for V. parahaemolyticus growth and inactivation kinetic data, respectively. A square root model was produced for TVC growth. Evaluation studies showed that predictive growth for V. parahaemolyticus and TVC were "fail safe." The models can assist oyster companies and regulators in implementing management strategies to minimize V. parahaemolyticus risk and enhancing product quality in supply chains.Vibrio parahaemolyticus is a Gram-negative, halophilic, curved, rod-shaped bacterial species indigenous to marine environments (19). Oysters accumulate V. parahaemolyticus via filter feeding that may result in concentrations 100 times greater than those found in the surrounding seawater (16). Consequently, the consumption of raw or improperly cooked oysters can sometimes result in V. parahaemolyticus infection. Disease occurs worldwide (59), with a higher incidence reported in the United States (13, 64).Human disease usually displays as moderate to severe gastroenteritis, although septicemia may occur in individuals with impaired hepatic and renal capacity and the immunocompromised (66). Clinical illness is mostly associated with strains that produce the thermostable direct hemolysin (TDH) and/or TDH-related hemolysin (TRH) that are encoded by the tdh and trh genes, respectively (58).The reported frequency of tdh detection in oysters in studies at least 1 year in duration ranges from 3 to 70% (15,18,34,52) and 17 to 60% for trh (34), depending on the methodology and the region studied. In Australia, V. parahaemolyticus has been isolated from oysters (20,23,24,40,42), and two reported outbreaks have been linked to oyster consumption, with on...

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Section: Discussionmentioning

confidence: 99%

Predictive Models for the Effect of Storage Temperature on Vibrio parahaemolyticus Viability and Counts of Total Viable Bacteria in Pacific Oysters (Crassostrea gigas)

Fernandez‐Piquer

Bowman

Ross

et al. 2011

Appl Environ Microbiol

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“…Over 107 CFU of aerobic bacteria per gram were found in retail oysters after 1 week storage at 4°C [31]. Furthermore, it has been reported that the bacteria were mainly accumulated in digestive glands and gills [2,6,10,11]. Therefore, more bacteria should be accumulated in those tissues compared to other types of oyster tissues.…”

Section: Introductionmentioning

confidence: 99%

“…It is well known that oysters filter large volumes of water during feeding and are able to bio-accumulate bacteria including food-borne pathogens from the surrounding water [1,2], therefore, oysters may be an important vehicle for dissemination of food-borne pathogens [3][4][5][6]. In the coastal cities of China, more than 60% of seafood tested positive for bacterial pathogens [7,8].…”

Section: Introductionmentioning

confidence: 99%

http://www.omicsonline.org/open-access/overcoming-pseudomonas-aeruginosa-resistance-caused-by-glycocalyx-with-tobracef-1948-5948.1000145.php?aid=25925

Dai¹

2014

J Microb Biochem Technol

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Oysters are filter feeders that bioaccumulate bacteria in water while feeding. To evaluate the bacterial genomic DNA extracted from retail oyster tissues, including the gills and digestive glands, four isolation methods were used. Genomic DNA extraction was performed using the Allmag™ Blood Genomic DNA (Allrun, Shanghai, China), the MiniBEST Bacterial Genomic DNA Extraction kits (Takara, Dalian, China), and the phenol-chloroform and boiling lysis methods. The concentration of the genomic DNA was measured using a spectrophotometer. The purity of the genomic DNA was evaluated by PCR amplification of 16S rDNA followed by determining the cloning efficiency of the amplicon into the pMD19-T vector. Furthermore, the bacterial DNA quality was also evaluated by PCR assays using a pair of species-specific primers for Vibrio parahaemolyticus. Our results showed that the two commercial kits produced the highest purity of DNA, but with the lowest yields. The phenol-chloroform method produced the highest yield although it was time-consuming. The boiling lysis method was simple and cost effective; however, it was only suitable to isolate genomic DNA from bacteria present in retail samples following an enrichment step. The two commercial kits were good candidates for genomic DNA extraction from retail oyster tissues without enrichment.

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“…These methods have included the use of V. vulnificus strains with specific antibiotic resistance, natural bioluminescence, radiolabeling, alkaline phosphatase activity, fluorescence, or a specific molecular marker (8,13,(20)(21)(22) 31). These marked strains are critical for ensuring that the data collected on the uptake or depuration rates of the added cells are accurate and that factors such as outgrowth or a lingering population of similar bacteria are not confounding the results.…”

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confidence: 99%

“…The "core" method is described first, followed by examples of deviation from this formula. The core method, elegant in its simplicity, is to grow the bacterial strain of interest to the desired concentration and seed an aquarium with a specific concentration of those bacteria, while allowing oysters within that aquarium to bioaccumulate the cells (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). The use of this method often yields similar results in which the bacteria are rapidly and significantly taken up by the oysters but quickly depurated to minimal or nondetectable levels within a few days (11,12,19,(22)(23)(24).…”

mentioning

confidence: 99%

Factors Affecting the Uptake and Retention of Vibrio vulnificus in Oysters

Froelich

Noble

2014

Appl Environ Microbiol

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Vibrio vulnificus, a bacterium ubiquitous in oysters and coastal water, is capable of causing ailments ranging from gastroenteritis to grievous wound infections or septicemia. The uptake of these bacteria into oysters is often examined in vitro by placing oysters in seawater amended with V. vulnificus. Multiple teams have obtained similar results in studies where laboratory-grown bacteria were observed to be rapidly taken up by oysters but quickly eliminated. This technique, along with suggested modifications, is reviewed here. In contrast, the natural microflora within oysters is notoriously difficult to eliminate via depuration. The reason for the transiency of exogenous bacteria is that those bacteria are competitively excluded by the oyster's preexisting microflora. Evidence of this phenomenon is shown using in vitro oyster studies and a multiyear in situ case study. Depuration of the endogenous oyster bacteria occurs naturally and can also be artificially induced, but both of these events require extreme conditions, natural or otherwise, as explained here. Finally, the "viable but nonculturable" (VBNC) state of Vibrio is discussed. This bacterial torpor can easily be confused with a reduction in bacterial abundance, as bacteria in this state fail to grow on culture media. Thus, oysters collected from colder months may appear to be relatively free of Vibrio but in reality harbor VBNC cells that respond to exogenous bacteria and prevent colonization of oyster matrices. Bacterial-uptake experiments combined with studies involving cell-free spent media are detailed that demonstrate this occurrence, which could explain why the microbial community in oysters does not always mirror that of the surrounding water. Oysters are an important food source and can be prepared many ways but are often consumed live, raw, or undercooked. Unfortunately, undercooked and raw oysters are implicated as the predominant source of seafood-borne death in the United States, with an overwhelming (Ͼ95%) majority of these deaths caused by the bacterium Vibrio vulnificus (1-3). These bacteria are ubiquitous in estuarine and coastal environments, and one study of Louisiana restaurants found that the majority (67%) of raw and even some (25%) cooked oysters contained this pathogen (4). Infections caused by ingesting V. vulnificus can result in gastroenteritis with associated abdominal pain, diarrhea, and vomiting but have the potential to quickly progress to primary septicemia (2, 5). When this occurs, the infected patient can exhibit blistering skin lesions or organ failure, sometimes occurring as rapidly as within 24 h after exposure (2, 5). Even with aggressive medical treatment, death occurs more than 50% of the time, distinguishing V. vulnificus as having the highest case fatality rate of any food-borne pathogen (2, 6). For more-specific information on the pathogenesis of V. vulnificus and its interactions with oysters, please see the reviews by Jones and Oliver (3) and Froelich and Oliver (7), respectively.Because of the grievous natur...

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Enumeration of Vibrio parahaemolyticus in oyster tissues following artificial contamination and depuration

Cited by 15 publications

References 29 publications

Predictive Models for the Effect of Storage Temperature on Vibrio parahaemolyticus Viability and Counts of Total Viable Bacteria in Pacific Oysters (Crassostrea gigas)

Predictive Models for the Effect of Storage Temperature on Vibrio parahaemolyticus Viability and Counts of Total Viable Bacteria in Pacific Oysters (Crassostrea gigas)

http://www.omicsonline.org/open-access/overcoming-pseudomonas-aeruginosa-resistance-caused-by-glycocalyx-with-tobracef-1948-5948.1000145.php?aid=25925

Factors Affecting the Uptake and Retention of Vibrio vulnificus in Oysters

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