Survey of a food poisoning event caused by Vibrio parahaemolyticus

In July 2008, a food poisoning event caused by Vibrio parahaemolyticus (VP) occurred in an employee canteen in Xiacheng district of Hangzhou. Twenty five samples were collected, which included patients stool samples, cooks rectal swabs and processing smear samples. By routine detection, eleven strains of VP were identified (10 from patients stool samples and 1 from smear sample). The serotying and drug susceptibility test indicated that 11 strains of VP belonged to O3:K6 serotype and were positive to kanagawa phenomenon (KP). The biological characters and the results of drug susceptibility test were consistent among 11strains of VP. The polymerase chain reaction (PCR) was used genus-specific gene ( R72H) and virulence genes ( tdh and trh). The subtyping and cluster analysis were conducted by using pulsed field gel electrophoresis (PFGE). R72H was detected in all 11 strains. Multiplex PCR indicated that the strains were positive for tdh (434bp) and negative for trh (250bp). The 11 strains had 3 PFEG patterns. The cluster analysis indicated that the similarity was 93%.