Characterisation of atypical biotype 3, serotype O∶3Yersinia and development of a simple identification scheme

Five clinical strains ofYersinia isolated in Japan and identified as atypical biotype 3 or biotype 3B, serotype O∶:3, phage type II (3*/O∶3/II)Yersinia enterocolitica were characterised since the biochemical reactions of these strains indicate they might also belong to the speciesYersinia bercovieri. Biochemical tests, characterisation of the β-lactamases and DNA-DNA hybridization studies provided strong evidence indicating that these strains should be classified asYersinia enterocolitica. A simple scheme combining a disc diffusion test and four biochemical tests was devised for identification of these atypical strains.