A COMPARISON OF METHODS FOR THE TYPING OF FISH-PATHOGENIC VIBRIO SPP

The validity and distinctiveness of Vibrio anguillarum (= Listonella a nguillara), V. (= Photobacterium) damsela, V. ordalii and V. salmonici da was confirmed. However, strains received as V. cholerae and V. sple ndidus were heterogeneous. Ribotyping, phenotypic (BIOLOG-GN fingerpri nts and API 20E profiles), chemotaxonomic (lipopolysaccharide [LPS] an d outer membrane proteins [OMP]), serogrouping and plasmid profiling d ata were not always congruent. V. anguillarum isolates were recovered in a single ribotype cluster, but many serogroups. There was little va riation in OMP profiles, but not so for LPS profiles and plasmid compo sition. Heterogeneity was recorded in the phenotypic characters, parti cularly with the API 20E rapid identification system. V. damsela displ ayed heterogeneity by ribotyping, but homogeneity by BIOLOG-GN fingerp rints and API 20E profiles. Four serogroups were defined, but only one LPS profile was recognised. V. ordalii was homogeneous by ribotyping, serogrouping and plasmid profiling, was accommodated in two LPS group s, but was more heterogeneous by BIOLOG-GN and API 20E. Despite its mo re exacting cultural requirements, V. salmonicida autoagglutinated and could not be serogrouped, but was accommodated in a single LPS group showing a profile associated with rough strains, and contained plasmid s of 4.7 and 42 kb. Heterogeneity was recorded with the API 20E rapid identification system.