Isolation, identification and molecular characterization of Vibrio parahaemolyticus from fish samples in Kolkata

Vibrio parahaemolyticus is a marine bacterium which is also responsible for acute diarrhoeal illness in human beings. Eating raw seafish or contaminated seafood is responsible for acute gastroenteritis. The aim of this study was to investigate the isolation, identification and molecular characterization of Vibrio parahaemolyticus from the fish samples in Kolkata, India.

In this study 90 fish samples were collected from 8 different market places in Kolkata, India. Fish samples collected were shrimp, prawn, bhetki, pamfret and hilsa. VP-toxR PCR was performed to confirm the presence of species specific toxR. tdh and trh genes PCR for detection of virulence genes were performed separately. GS-PCR was performed in tdh, trh gene positive strains to determine whether they belong to pandemic genotype. Serotyping was also done on the tdh, trh positive strains.

Out of the 90 fish samples collected from different local fish markets 60 were positive for Vibrio parahaemolyticus. 21 (35%) out of 60 Vibrio parahaemolyticus isolates from fish samples harboured the tdh gene. 1 (1.7%) out of 60 Vibrio parahaemolyticus isolates from fish samples carried trh gene. Out of 22 isolates only 2 were positive for GS-PCR. O10:KUT was the serovar maximum isolated.

Considerable percentage of Vibrio parahaemolyticus carrying the virulence genes and pandemic genotype among fish in Kolkata indicates that there is potential reservoir in Kolkata and consumption of sea fish or contaminated fish might cause Vibrio parahaemolyticus mediated diarrhea in this region.