Comparative evaluation of three agar media-based methods for presumptive identification of seafood-originated Vibrio parahaemolyticus strains

Vibrio parahaemolyticus has been one of the major bacterial species responsible for summer food poisoning. However, the limitations of current medium-based strategies for its detection necessitates a more effective selective or discriminatory agar media-based method. In this study, we first developed ChromoVP agar for more specific differentiation of V. parahaemolyticus from other bacterial species. Secondly, we compared this new medium with the commercially-available CHROMagar (TM) Vibrio medium and thiosulfate-citrate-bile salts-sucrose (TCBS) agar medium for the identification of V. parahaemolyticus strains isolated from seafood. The sensitivity, specificity, accuracy, and positive and negative predictive values of each of these agar media-based methods in the identification of V. parahaemolyticus were determined and compared using 38 V. parahaemolyticus strains and 102 other Vibrio and non-Vibrio strains. As a benchmark, a species-specific polymerase chain reaction assay was performed to detect V. parahaemolyticus and four other Vibrio species in seafood samples based on their genetic differences. Our results showed that ChromoVP agar was more sensitive (89.5%), specific (89.2%), and accurate (89.3%) than CHROMagar (TM) Vibrio and TCBS agar media in differentiating V. parahaemolyticus strains from other organisms. Therefore, ChromoVP agar is an effective medium for the isolation and enumeration of V. parahaemolyticus from seafood samples.