Unveiling the virulence, genetic links, and enzyme profiles of bivalve-associated Vibrio parahaemolyticus from the southwest coast of India.

The article focuses on the investigation of virulence factors, enzymatic activity, and genetic diversity of Vibrio parahaemolyticus isolates obtained from bivalves along the southwest coast of India. The study found a low prevalence of the virulence genes tdh (thermostable direct hemolysin) and trh (thermostable-related hemolysin), with none of the isolates carrying both genes or the T3SS2α and T3SS2β secretion system genes, while all isolates possessed T3SS1 genes and 64% expressed T6SS1 genes. Enzymatic profiling revealed widespread production of extracellular enzymes such as gelatinase, lipase, and caseinase, which are implicated in pathogenicity. Genetic subtyping using ERIC-PCR and pulsed field gel electrophoresis (PFGE) demonstrated considerable heterogeneity and clustering of environmental isolates with clinical strains, suggesting potential health risks from consumption of raw or undercooked bivalves. The findings underscore the importance of ongoing surveillance and seafood safety measures to monitor the distribution of potentially pathogenic V. parahaemolyticus in marine environments.