Detection and differentiation of Vibrio spp. in seafood and fish samples with cultural and molecular methods

Abstract

Vibrio spp. as natural inhabitants of sea- and brackwater of both tropical and temperate regions of the world are commonly found in different kinds of seafood. Even among the three main human pathogenic species Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus most of the isolates from seafood do not carry the different virulence factors responsible for foodborne infections. Therefore, the risk assessment of Vibrio spp. in seafood is currently based mainly on the knowledge of the genetic setting of foodborne strains. For the detection and differentiation of Vibrio spp. (V. parahaemolyticus, V. cholerae and V. vulnificus) three probe-based multiplex real-time PCR systems were developed and validated. One real-time PCR system simultaneously detects V. parahaemolyticus, V. cholerae and V. vulnificus on genus level combined with an Internal Amplification Control. The detection limit for the system was between 1cfu/mL and 10cfu/mL in pure culture and in different artificially contaminated sample material, e. g. prawns or Alaska Pollock. The other two PCR systems were implemented for the detection of different virulence genes of V. parahaemolyticus and V. cholerae isolates. The molecular detection systems were applied for the investigation of 338 raw and cooked seafood and fish samples for the presence of the different Vibrio spp. The collected data indicate that the PCR systems can be useful for rapid detection and differentiation of Vibrio spp. in different food matrices as basis for a preventive consumer protection policy.