Increased incidence and antimicrobial resistance among Vibrio parahaemolyticus in shellfishes from major fish markets in Cochin, South India: Seafood risk assessment

India remains as a top supplier of value-added seafoods to the global markets. Cochin is one of the leading fishing ports in India contributing to country’s major seafood export. As part of risk assessment, we analyzed the prevalence of multi-drug resistant Vibrio parahaemolyticus; seafood borne gastroenteritis-causing pathogen, in shellfishes collected from major fish markets in Cochin. This bacterial species was initially isolated on thiosulfate-citrate-bile salts-sucrose agar and HiCrome™ Vibrio agar, further confirmed by detection of V. parahaemolyticus species-specific toxR gene and by 16S r RNA sequencing. A total of 113 confirmed V. parahaemolyticus were recovered. Almost all the strains exhibited resistance towards three or more antibiotics (multiple-drug resistant) and harbored virulence related exoenzymes especially hemolysin (Kanagawa phenomenon); which is indeed a matter of concern. The multiple antibiotic resistance (MAR) index of the isolates ranged from 0.21 to 0.57. Furthermore, our results also indicate a substantial increase in the incidence of the pathogen in seafood from the area compared to previous years. This may pose a risk to the local and international consumers of the seafood. Practicing complete hygiene and adequate cooking is strongly recommended. Regular monitoring of aquaculture areas and fish markets is urged to reduce dissemination of pathogenic V. parahaemolyticus in seafood and to prevent fatal cases of human infection induced by this species in the country.