PREVALENCE OF THE HIGH-PATHOGENICITY ISLAND OF YERSINIA SPECIES AMONGESCHERICHIA-COLI STRAINS THAT ARE PATHOGENIC TO HUMANS

The fyuA-irp gene cluster contributes to the virulence of highly patho genic Yersinia (Yersinia pestis, Yersinia pseudotuberculosis, and Yers inia enterocolitica 1B). The cluster encodes an iron uptake system med iated by the siderophore yersiniabactin and reveals features of a path ogenicity island, Two evolutionary lineages of this ''high pathogenici ty island'' (HPI) can be distinguished on the basis of DNA sequence co mparison: a Y. pestis group and a Y. enterocolitica group, In this stu dy we demonstrate that the HPI of the Y. pestis evolutionary group is disseminated among species of the family Enterobacteriaceae which are pathogenic to humans. It prevails in enteroaggregative Escherichia col i and in E. coli blood culture isolates (93 and 80%, respectively), bu t is rarely found in enteropathogenic E. coil, enteroinvasive E. coli, and enterotoxigenic E. coil isolates, In contrast, the HPI was absent from enterohemorrhagic E. coli, Shigella, and Salmonella enterica str ains investigated, Polypeptides encoded by the fyuA, irp1, and irp2 ge nes located on the HPI could be detected in E. coli strains pathogenic to humans, However, these E. coil strains showed a reduced sensitivit y to the bacteriocin pesticin, whose uptake is mediated by the FyuA re ceptor, Escherichia strains do not possess the hms gene locus thought to be a part of the HPI of Y. pestis, Deletions of the fyuA-irp gene c luster affecting solely the fyuA part of the HPI were identified in 3% of the E. coli strains tested, These results suggest horizontal trans fer of the HPI between Y. pestis and some pathogenic E. coli strains.