Objective: To describe the distribution of high-pathogenicity island (HPI) of Yersinia enterocolitica in enterotoxingenic E.coli (ETEC) and enteropathogenic E.coli (EPEC), and to understand the structure and function of HPI.
Methods: PCR was used to detect irp2, fyua and asn-intB genes with subsequent sequence analysis of these genes. Nucleic acid in situ hybridization was employed to identify the specificity of irp2 and fyua.
Results: Thirty irp2-positive strains were isolated from 93 ETEC strains and 3 from 10 EPEC strains, making a positivity rate of 32.25% and 30% respectively, and the positivity rates of fyua gene in ETEC and EPEC were 21.51% and 30% respectively. In most of these positive isolates, HPI was bordered by an asn tRNA locus, as in Yersinia sp.
Conclusions: This study demonstrates that the high positivity rate of HPI of Yersinia enterocolitica in ETEC and EPEC strains may be crucial to the virulence changes, virulence evolution and virulence regulation in E.coli.