CHARACTERIZATION OF PATHOGENIC YERSINIA-ENTEROCOLITICA SEROGROUPS BY PULSED-FIELD GEL-ELECTROPHORESIS OF GENOMIC NOTI RESTRICTION FRAGMENTS

Enteropathogenic Yersinia enterocolitica is an important cause of huma n and animal disease. Phenotypic and genotypic characteristics current ly used to identify Y. enterocolitica are not necessarily sufficient t o differentiate pathogenic from non-pathogenic strains or to analyse t he epidemiology of yersiniae at a molecular level. To improve the char acterisation of Yersinia isolates, NotI restriction fragment length po lymorphisms (RFLPs) of chromosomal DNA of more than 100 clinical, anim al and environmental isolates were analysed in pulsed-field gel electr ophoresis. Highly conserved RFLP patterns with fragments ranging from 15 to 400 kb were detected within each of 10 Y. enterocolitica serogro ups tested. Determination of RFLP types makes it possible to discrimin ate between isolates of different Y. enterocolitica serogroups and oth er Yersinia spp. Moreover, NotI restriction endonuclease analysis allo ws even subtyping of strains belonging to a unique serogroup-biotype. Identification of NotI fragments hybridising with inv- or ail-homologo us sequences was used as an additional discriminating marker. The resu lts indicate that NotI RFLP typing can provide a powerful new tool for the differentiation of clinical Y. enterocolitica isolates.