Vibrio anguillarum serovars associated with vibriosis in fish

A total of 517 Vibrio anguillarum strains isolated from diseased fish together with 14 V. anguillarum serogroup O2 and V. ordalii type strains were serotyped using the European serotyping system. Marked species differences were recorded. In isolates from salmonids serovar O1 (70.2%) and O2 (20.2%) were dominant, whilst a minor proportion belonged to other serogroups or were non-typeable. Figures for turbot were similar to those from salmonids. In 32 isolates from sea bass, sea bream and mullet, most strains belonged to serogroup O1, while one was O2a, one O7, and the rest non-typeable. In cod, serovar O2 was dominant while only a minor proportion belonged to other serogroups or were non-typeable. The eel isolates belonged equally to serovars O2 and O3. All O2 strains were subtyped with absorbed O2a and O2b antisera. O2a was dominant in all fish species, but in cod, the relative number of O2b isolates was considerably higher than in other fish species. The applicability of the European serotyping system is discussed and compared with other serotyping systems.