Prevalence of Vibrio cholerae and Other Vibrios from Environmental and Seafood Sources, Tamil Nadu, India

Abstract

Aims: The aim of this study was to investigate the prevalence of diarrhoea causing human pathogen V. cholerae and other vibrios from different environmental and seafood samples in Tamil Nadu, India. Place and Duration of Study: Laboratory of Clinical Microbiology, Department of Bio-Medical Science, School of Basic Medical Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India between 2012 and 2013. Methodology: Seafood, water and plankton samples were collected at different locations of Tamil Nadu, India. All the samples were primarily enriched with alkaline peptone water (APW). 2-3 loopful of overnight cultures were streaked onto Thiosulphate Citrate Bile salt Sucrose (TCBS) agar plates. Suspected Vibrio cholerae, V. parahaemolyticus and other vibrios were picked up and identified by using standard biochemical and serological characterization and also by molecular methods. Results: Among the various samples that includes freshwater, coastal water, plankton and various seafoods, only plankton and seafood samples were found to be harbored with V. cholerae, V. parahaemolyticus and V. fluvialis. The remaining samples were negative for vibrios. All V. cholerae, V. parahaemolyticus and V. fluvialis strains possessed outer membrane protein W (ompW), thermostable direct haemolysin (tdh) and toxin regulatory protein (toxR) gene respectively. Hemolytic activity of V. cholerae exihibited different reaction isolated from seafood and plankton. The median lethal dose (LD50) of some V. cholerae strains was generally high. Conclusion: The result of the study suggested that the seafoods may act as an important reservoir of pathogenic vibrios and pose threat to human health.