Occurrence and expression of virulence-related properties by environmental halophilic Vibrio spp. in in vitro and in vivo systems

The virulence characteristics of 87 strains of halophilic Vibrio spp. from seawater collected near aquaculture areas and seafood products were evaluated by in vitro and in vivo methods.Adhesive properties were revealed in 69% of the analysed strains in Caco-2 cells and in 82.7% when using Hep-2 cells. A weak type of adherence seems to be more common. 19.3% of the strains, prevalently represented by V. alginolyticus, appears to produce cytotoxic effects on HeLa cell line while 8.6% exhibits enterotoxic activity. Five of the six V. parahaemolyticus strains results able to produce a thermostable direct haemolysin (TDH), confirmed as the major virulence factor in the pathogenic mechanism of action of this Vibrio species. Because of the strain-specific pathogenicity of most halophilic Vibrio spp., their detection in seafood, giving particular attention to their pathogenicity, is necessary to improve the control of these products