产毒性和致病性大肠杆菌中小肠结肠炎耶尔森菌强毒力岛的检测

目的 了解小肠结肠炎耶尔森菌强毒力岛在产毒性和致病性大肠杆菌中的分布，探讨毒力岛在大肠杆菌中的结构和功能。方法 对毒力岛的关键基因irp2,fyua和asn-intB进行PCR扩增和DNA测序，并对irp2和fyua进行原位杂交。结果 在检测的93株肠产毒性大肠杆菌的10株肠致病性大肠杆菌基因irp2的检出率分别为32.25%(30/93)和30%（3/10),fyua的阳性率为21.51%(20/93)和30%（3/10）。而且这些阳性菌株中的毒力岛大部分连接到天门冬氨酸tRNA(asntRNA）位点。结论 小肠结肠炎耶尔森菌强毒力岛在产毒性和致病性大肠肝菌中较高的阳性率，对于大肠杆菌毒力的变化和毒力的调控以及细菌毒力的进化可能具有重要意义。

Detection of the high-pathogenicity island of Yersinia enterocolitica in enterotoxigenic and enteropathogenic E.coli strains.

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.