Improved isolation and detection of pathogenic Vibrio parahaemolyticus from seafood using a new enrichment broth

The efficiency of a new enrichment broth containing bile salt, sodium taurocholate (ST broth) in detecting pathogenic Vibrio parahaemolyticus from seafood was compared with the traditional alkaline peptone water (APW). Both the enrichment broths were compared using 58 seafood samples harvested along the southwest coast of India using conventional isolation, colony hybridization following enrichment (CFE) and PCR. V. parahaemolyticus carrying tdh gene were isolated from 6.9% (4/58) and 3.4% (2/58) of the samples after enrichment in ST broth and APW, respectively. Pathogenic V. parahaemolyticus carrying trh gene were isolated from 20.7% (12/58) and 13.8% (8/58) of the samples after enrichment in ST broth and APW respectively. PCR using enrichment lysate as template could detect V. parahaemolyticus carrying tdh gene in 8 (13.8%) and 12 (20.7%) samples after enrichment in APW and ST broth, respectively. Positivity for trh gene based PCR was 24 (41.4%) for ST broth and 19 (32.8%) for APW. Total V. parahaemolyticus were detected and isolated from almost same number of samples using two enrichment broths by three methods used in this study. The results suggest that the ST broth is superior to APW for detection and isolation of pathogenic V. parahaemolyticus from seafood.