Genome sequencing of seafood-borne Vibrio parahaemolyticus VP49 reveals the presence of novel virulence attributes

Abstract

Vibrio parahaemolyticus is a Gram-negative, halophilic bacterium autochthonous to the marine environments and responsible for seafood-borne gastroenteritis. Though the hemolysins TDH and/or TRH are classical virulence factors, several other potential virulence factors may contribute to their pathogenicity. In this study, V. parahaemolyticus was isolated from the seafood harvested along southwest coast of India and confirmed by standard biochemical and molecular methods. Genome sequencing of V. parahaemolyticus revealed the presence of T3SS2 operon in an approximately 44 kb region in close proximity to the hemolysin gene trh. The annotation of T3SS2 operon revealed the presence of genes encoding apparatus proteins VscC2/R2/S2/T2/U2/N2, VcrD2, an ATPase VscN2, transloconsVopB2/D2, and effectors VopA/C/L. To the best of knowledge, this is the first report on sequencing and characterization of a T3SS gene cluster in seafood isolate of V. parahaemolyticus and this information will be of assistance in future studies to determine the different virulence attributes as well as mechanisms that enhance environmental or host fitness of V. parahaemolyticus. The presence of such virulence attributes in V. parahaemolyticus isolated from seafood suggests the potential of these isolates to cause infection in humans upon ingestion of contaminated seafood and questions the safety of seafood to consumers.