Clonality of Lactococcus garvieae isolated from rainbow trout cultured in Spain: A molecular, immunological, and proteomic approach

This study reports the characterization of a collection of 98 strains of L. garvieae using phenotypic, antigenic, genetic, proteomic, and chemotaxonomic methods, as well as the study of their virulence. Molecular (RAPD and REP-PCR) and proteomic (MALDI-TOF-MS) techniques allowed the separation of strains of L. garvieae isolated from human and bovine from those strains of L. garvieae isolated from the aquatic environment. On the other hand, PCR typing methods showed that the L. garvieae strains tested did not belong to serotype II and did not carry the capsule gene cluster described in the genome or plasmid of Japanese L. garvieae strains. The different clonal patterns observed in L. garvieae using RAPD and REP-PCR (7 profiles) and MALDI-TOF (six patterns) were closely related to the isolation source of L. garvieae strains but not with the virulence of the strains. In addition, two protein antigenic variants (W1 and W2), differing in reactivity in the range of 35 to 70 KDa, were detected using rabbit and rainbow trout antisera. Both antisera detected two highly immunogenic protein bands of 30 and 45 KDa. These results could contribute to a better understanding of the pathogenesis of lactococcosis and could help in the selection of targets for the development of effective vaccines.