Pathogenic gene detection of Vibrio parahaemolyticus isolated from shrimp and genotyping by ERIC-PCR

Abstract:

In order to monitor the carrying status of pathogenic genes and the prevalence of potential pathogenic strains of Vibrio parahaemolyticus from shrimp in Shanghai, the polymerase chain reaction (PCR)and enterobacterial repetitive intergenic consensus sequence-polymerase chain reaction(ERIC-PCR)were applied to detect pathogenic genes and to make genotyping analysis of 1 standard V. parahaemolyticus strain and 19 V. parahaemolyticus strains isolated from shrimp in Shanghai. The results showed no tdh and ORF8 genes were detected in 19 isolated strains and only 1 strain carried trh gene, while the tox RS/new gene was detected in 14 positive strains and the carrying percentage was 73.7%.The AP1 and AP2 genes were detected in specificity V. parahaemolyticus which could cause acute hepatopancreas necrosis disease (AHPND) and the result showed there were 3 positive strains of both genes, and the gene carrying percentage was both 15.8%. The 20 V. parahaemolyticus strains were divided into 7 groups by ERIC-PCR, and the discrimination index(DI) was 0.811,which indicated ERIC-PCR have a good genotyping capability. According to the results of ERIC-PCR, the method could distinguish strains obtained from different periods of time effectively, while the distinction among different geographical strains was not obvious. These results suggested that the carrying percentage of pathogenic genes in V. parahaemolyticus from shrimp was relatively low, while there was a risk of prevalence of new pathogenic strains. These results will provide reference for the prevention and control of V. parahaemolyticus strains in shrimp farms.