Infection expérimentale chez Crassostrea gigas : étude de deux souches pathogènes apparentées à Vibrio splendidus

Infectious diseases are a limiting factor to the development and sustainability of aquaculture. For mollusc cultures, only prophylactic measures may be applied, their development usually facilitated by the reproduction of the disease under experimental conditions. To develop an experimental infection in Crassostrea gigas, Vibrio strains were isolated and their virulence was experimentally evaluated. Collaboration phenomena between some strains were observed in infection trial, leading to higher mortality rate when two strains are concomitantly inoculated. Two pathogenic strains, belonging to the polyphyletic group of Vibrio splendidus and named 31 and 32 illustrate this phenomenon. They induce extensive alterations of the adductor muscle in C. gigas. The issue of infection trials with these strains is influenced by intrinsic C. gigas factors. Eventually, strain 32 was used as target strain to select inhibitory strain, potentially usable as a probiotic.