Characterisation of pathogenic Yersinia enterocolitica serogroups by pulsed-field gel electrophoresis of genomic NotI restriction fragments.

Enteropathogenic Yersinia enterocolitica is an important cause of human and animal disease. Phenotypic and genotypic characteristics currently used to identify Y. enterocolitica are not necessarily sufficient to differentiate pathogenic from non-pathogenic strains or to analyse the epidemiology of yersiniae at a molecular level. To improve the characterisation of Yersinia isolates, NotI restriction fragment length polymorphisms (RFLPs) of chromosomal DNA of more than 100 clinical, animal and environmental isolates were analysed in pulsed-field gel electrophoresis. Highly conserved RFLP patterns with fragments ranging from 15 to 400 kb were detected within each of 10 Y. enterocolitica serogroups tested. Determination of RFLP types makes it possible to discriminate between isolates of different Y. enterocolitica serogroups and other Yersinia spp. Moreover, NotI restriction endonuclease analysis allows even subtyping of strains belonging to a unique serogroup-biotype. Identification of NotI fragments hybridising with inv- or ail-homologous sequences was used as an additional discriminating marker. The results indicate that NotI RFLP typing can provide a powerful new tool for the differentiation of clinical Y. enterocolitica isolates.