致泻性大肠杆菌中发现小肠结肠炎耶尔森菌毒力岛

The high-pathogenicity island of Yersinia enterocolitica species existed in enteric Shiga-like-toxin producing and invasive Escherichia coli

目的 研究肠产志贺样毒素且具侵袭力的大肠杆菌 (ESIEC)菌株是否含有耶尔森菌的HPI(毒力岛 )基因。方法 采用PCR扩增和Southern杂交的方法。结果 从 35 %的ESIEC菌的染色体上同时扩出irp1、irp2和fyuA 3个片段 ,片段大小分别与小肠结肠炎耶尔森菌WA菌株的相应片段一致 ,鼠疫耶尔森菌HPI上的 6对引物均未扩出目的片段。 6 5 %的ESIEC使用以上 9对引物未扩出目的片段。ESIEC菌的染色体EcoRI酶切产物电泳后与小肠结肠炎耶尔森菌WA菌株的fyuA探针杂交出大小一致的条带 ,与irp1和irp2探针杂交出不同的带型。结论 ESIEC菌含有小肠结肠炎耶尔森菌的HPI,且有变异现象。

Objective To study whether the genes of HPI island of Yersinia is existed in enteric Shigelloid toxin producing and invasive Escherichia coli (ESIEC). Methods PCR amplification and Southern blots. Results The PCR results showed that 35% ESIEC strains ( n =43) yielded irp1, irp2 and fyuA fragments, of which the molecular size were identical to those of Yersinia enterocolitica WA. All of the E.coli strains tested were negative for other genes of HPI island which were existed in Y. pestis but not in Y.enterocolitica . The two E.coli strains with irp1, irp2 and fyuA gene were selected for further study. The chromosomal DNA was digested by EcoR Ⅰand hybridized with irp1, irp2 and fyuA DNA probes respectively, which were synthesized by PCR with chromosomal DNA of Y. enterocolitica as template. When fyuA probe was used, the Southern hybridization patterns of the two E. coli strains were identical to that of Y. enterocolitica WA. When irp1 and irp2 probe were used, the molecular size of hybridized fragments were different from that of Y. enterocolitica WA. Conclusion The HPI island of Y. enterocolitica was found to exist in 35% of ESIEC strains tested, and variation in restriction sites of various genes was observed.