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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Produce Safety and Microbiology Research » Research » Publications at this Location » Publication #337491

Research Project: Ecology and Detection of Human Pathogens in the Produce Production Continuum

Location: Produce Safety and Microbiology Research

Title: Prevalence and Molecular Typing of Vibrio parahaemolyticus (tdh+) isolated from seafood using PCR-based methods

Author
item Zhang, Yujie - Shanghai Ocean University
item Sun, Xiaohong - Shanghai Ocean University
item Pan, Yingjie - Shanghai Ocean University
item Wu, Vivian

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/18/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Vibrio parahaemolyticus is a pathogen most frequently implicated in foodborne outbreaks linked to the consumption of seafood in the coastal cities of China. The pathogenicity of environmental V. parahaemolyticus is mostly correlated with the production of thermostable direct hemolysin (TDH). In order to develop intervention strategies to reduce the incidence of the illness, it is necessary to investigate the genetic diversity and contamination pathway of pathogenic V. parahaemolyticus (tdh+) in seafood. The aim of this study was to use two PCR-based techniques to analyze the genetic variability of V. parahaemolyticus (tdh+) in seafood isolated from retail stores in Shanghai to provide insights into the distribution and population of V. parahaemolyticus (tdh+) across seafood in Shanghai and the differentiation of V. parahaemolyticus (tdh+) strains in different seafood. All strains isolated from seafood in Shanghai from 2012 to 2013 were analyzed for the presence of tdh gene by PCR. Genomic DNA was extracted from 48 tdh+ V. parahaemolyticus isolates using DNA extraction kits. Molecular typing was performed using the repetitive extragenic palindromic PCR (REP-PCR) and enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR). Results indicated that 48 strains of V. parahaemolyticus represented a wide range of patterns. Among the variety of shrimps, Penaeus vannamei had the highest diversity of V. parahaemolyticus (tdh+). The 48 isolates were classified into 5 clusters by REP-PCR at a relative similarity coefficient of 0.66, whereas the strains were grouped into 3 clusters by ERIC-PCR. Further analysis showed that 48 strains of V. parahaemolyticus could be grouped into 20 and 13 types with discrimination index of 0.9 by REP-PCR and ERIC-PCR, respectively. Although both methods could be used for the subtyping of V. paraheamolyticus, REP-PCR is preferable to ERIC-PCR because of the greater discriminative abilities of its fingerprints. Moreover, REP-PCR is more repeatable and stable than ERIC-PCR. In conclusion, shrimps are of a particular concern of V. parahaemolyticus (tdh+) contamination among seafood. The genetic diversity of V. parahaemolyticus (tdh+) suggested the dissemination and contamination pathways of virulence strains. This finding enhances the microbiological risk assessment in seafood from the retail stores and is useful for further epidemiological studies.