The increase of sea water temperature up-regulate the expression of Vibrio parahaemolyticus virulence factors implicated in adhesion and biofilm formation on plastics

Climate change driven seawater temperature (SWT) increase results in greater abundance and geographical expansion of marine pathogens, among which Vibrio parahaemolyticus (Vp) causes serious economical and health issues. In addition, plastic pollution in ocean constitutes a vector for harmful pathogens dissemination. We investigate the effect of elevated SWT on the expression of genes implicated in adhesion and biofilm formation on abiotic surfaces in the clinical Vp strain RIMD2210633, that express hemolysins. Among the gene studied, the multivalent adhesion molecule-7 (MAM-7) and the GlcNAc binding protein A (GpbA) were implicated in the adhesion of Vp to abiotic and biotic surface while the type IV pili, the mannose sensitive haemagglutinin (MSHA) and chitin-regulated pilus (PilA) facilitate attachment and biofilm formation.  Data presented here show that at 21°C Vp are still viable but didn’t proliferate nor express the virulence factors. Interestingly, at 27°C all the factors are transiently expressed only in free-living bacteria as early as 1 hour of incubation and they are significantly up-regulated at 31°C. These data clearly show that SWT have an impact on the adhesion properties of free-living Vp to plastic support and thus emphasize the importance of climate change on the spread of this pathogenic bacteria.