Yersinia enterocolitica 16S rRNA gene types belong to the same genospeciesbut form three homology groups

The species Yersinia (Y.) enterocolitica consists of biochemically and sero logically heterogeneous strains. A vernacular nomenclature divides these st rains in 'European' and 'American' bioserotypes. We investigated six strain s of each group by DNA-DNA hybridization, determination of G + C mol% conte nt and sequence alignment studies. Based on different DNA-DNA hybridization values and the 16S rRNA gene sequences a division into two Yersinia entero colitica subspecies is justified. We propose the names Yersinia enterocolit ica subsp. enterocolitica for strains belonging to the 16S rRNA gene type r epresented by the Type strain ATCC 9610 and Yersinia enterocolitica subsp. palearctica for strains belonging to the 16S rRNA gene type of strain Y11 ( DSMZ13 030).