Genetic heterogeneity among Vibrio alginolyticus isolated from shrimp farms by PCR fingerprinting

Aims: To study the strain variability among Vibrio alginolyticus isolates from different sources by insertion sequence-targeted PCR fingerprinting and whole cell protein profile analysis. Methods and Results: Eleven strains of V. alginolyticus were isolated from seven different sources including healthy, infected, farm-reared and wild shrimps. Following biochemical characterization, the isolates were analysed by PCR fingerprinting and whole cell protein analysis by SDS-PAGE. The strains were genetically different irrespective of the sources of isolation. Conclusions: Strain variation exists in V. alginolyticus isolates obtained even from the same source, and PCR fingerprinting is a simple and efficient method in identifying strain-specific variations among the different isolates. Significance and Impact of the Study: Vibrio alginolyticus is implicated in severe vibriosis of marine aquaculture systems although many strains are avirulent and could be used as probiotic strains. As a wide variation exists among this species, differentiating the harmful and beneficial strains would help in finding ways of controlling the infections by eliminating harmful shrimp pathogenic vibrios.