Investigation of contamination status of Vibrio parahaemolyticus in Guangzhou seafood and molecular subtyping on strains isolated

Objective:To learn about the contamination status of Vibrio parahaemolyticus in seafood of Guangzhou area and apply pulsed-field gel electrophoresis(PFGE) in the molecular subtyping of 28 strains of Vibrio parahaemolyticus isolated.Methods:MPN method was utilized to assay quantitatively Vibrio parahaemolyticus and isolated strains was identifed according to National Standards of Microbiological Examination for Vibrio parahaemolyticus(GB/T4789.7-2003) from 168 samples including shrimps,crabs,fish,shellfish and raw food sampled in restaurants,comprehensive markets for fish and meat and supermarkets as well.Twenty-eight strains of Vibrio parahaemolyticus were molecularly subtyped by PFGE with the application of restriction endonuclease Not Ⅰ and patterns obtained were subject to cluster analysis with BioNumerics Version 4.0 software(using Dice co-efficient and UPGMA).Results:57 of all 168 samples were Vibrio parahaemolyticus positive,with the detection rate being 33.93%.Among them,shellfish had the most highest carrier rate(55.56%),followed by shrimps,crabs and fish with no statistically significant difference between them(P0.05).Twenty-seven pulsotypes existed among twenty-eight stains,grouped into seven clusters(Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅴ,Ⅵ and Ⅶ),with the similar co-efficient no more than 77.4%.Conclusion:There is high degree of contamination by Vibrio parahaemolyticus in seafood of Guangzhou area and sanitary administrations are advised to take effective measures to prevent food-borne diseases caused by Vibrio parahaemolyticus from happening.Additionally,there was no correlation between PFGE results and the kinds of seafood,sampling time and spots,indicating that epidemiological trend did not exist in Vibrio parahaemolyticus in local seafood.