DAO 59:49-56 (2004)  -  doi:10.3354/dao059049

Screening of Vibrio isolates to develop an experimental infection model in the Pacific oyster Crassostrea gigas

Mélanie Gay, Franck C. J. Berthe, Frédérique Le Roux*

Laboratoire de Génétique et Pathologie, Institut français de recherche pour l┬╣exploitation de la mer (IFREMER), 17390 La Tremblade, France
*Corresponding author. Email:

ABSTRACT: In an attempt to develop a reproducible experimental model of bacterial infection in Crassostrea gigas, oysters taken from very localised sub-populations suffering natural mortality outbreaks were used in cohabitation trials under laboratory conditions. From these trials, a collection of Vibrio strains was isolated from moribund and healthy oysters. In a second step, strains were experimentally tested for virulence by means of injection into healthy oysters. This screening revealed a span of virulence among isolated strains from none to medium. When pooling injected strains, results suggest increased virulence. Vibrio strains may have additive/synergistic action leading to higher C. gigas mortality rates in experimental challenges. Although the study initially aimed to develop a simple experimental model, a complex of interactions emerged between several bacterial strains during the pathogenic process in their molluscan host. Selected strains provide a suitable model of experimental disease for further studies and better understanding of bacterial interaction and pathogenesis in C. gigas.

KEY WORDS: Vibrio splendidus · Virulence · Agonism · Antagonism

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