Immunochemical analyses of Vibrio anguillarum strains isolated from cod, Gadus morhua L., suffering from vibriosis

Vibrio anguillarum isolates were sampled from cod fry showing clinical signs of vibriosis at different cod farms along the western coast of Norway. Except for one isolate, all were shown to cause mortality in laboratory challenge experiments. Using biochemical analysis and specific rabbit antisera (O1–O5), all the pathogenic isolates were classified as typical V. anguillarum serotype O2. SDS‐PAGE and Western blot analysis of both whole bacterial cells and purified lipopolysaccharides (LPS) showed that the LPS structures were heterogeneous. ELISA analyses using adsorbed antisera identified the presence of two different subgroups within serogroup O2, which correspond with O2a/O2α and O2b/O2β described previously.