肠产志贺样毒素的大肠杆菌菌株中小肠结肠炎耶尔森菌毒力岛基因irp-2的检测

The pathogenicity island gene irp-2 of Yersinia enterocolitica was detected in enteric Shiga-like-toxin producing and invasive E. coli isolated in China

目的 了解肠产志贺样毒素且具侵袭力的大肠杆菌 (ESIEC)菌株中的小肠结肠炎耶尔森菌HPI毒力岛基因irp 2的存在情况。方法 使用菌落原位杂交、DNA打点杂交和PCR扩增方法。结果 用菌落原位杂交的方法发现在检测从各地收集的 371株ESIEC菌株中 ,6 7株和irp 2基因探针杂交 ,占 18 0 6 %。在这 6 7株菌种中 ,6 4株菌可使用PCR方法扩增出irp 2基因 ,占 95 5 %。鉴于在一部分肠侵袭性大肠杆菌 (EIEC)中可检测到irp 2基因 ,因而检测了EIEC的侵袭性基因ipaB基因。在 6 7株与irp 2探针杂交呈阳性反应的菌株中只有 1株为ipaB探针杂交阳性。为了比较菌落原位杂交和DNA打点杂交方法的特异性 ,随机挑选了 2 0株irp 2基因菌落原位杂交和PCR试验阳性的ES IEC菌株、2 0株菌落原位杂交和PCR试验阴性的ESIEC菌株 ,进行irp 2、ipaB的全菌DNA打点杂交试验。其中有 38株菌的试验结果和菌落原位杂交结果一致 ,符合率为 95 %。结论 从我国不同地区分离的ESIEC菌株中可检出小肠结肠炎耶尔森菌毒力岛基因irp 2 ,比例达 18 0 6 %。irp 2 + ipaB-可以作为鉴定部分ESIEC菌株的指标之一。PCR方法和菌落原位杂交方法均可采用。

Objective Detection of the pathogenicity island gene irp 2 of Yersinia enterocolitica species from enteric Shiga like toxin producing and invasive Escherichia coli (ESIEC) strains isolated in various provinces of China. Methods Colony hybridization, DNA dot hybridization and polymerase chain reaction (PCR). Results By colony blots, 67 of the 371 (18.06%) strains of ESIEC were hybridized with the irp 2 gene probe. The replicon of irp 2 gene was identified by PCR method in 64 of 67 strains (95.5%) hybridized with irp 2 probe. And, one of the 67 strains hybridized with ipaB gene probe of entero invasive E. coli (EIEC). A few strains of EIEC have been proved to be irp 2 gene positive. 20 irp 2 positive and 20 irp 2 negative strains of ESIEC, demonstrated by colony hybridization and PCR methods were selected to test irp 2 and ipaB genes by DNA dot blots. 38 of 40 strains were shown to be identical. Conclusion The irp 2 of Yersinia species is widely existed among the ESIEC strains isolated in China, and the irp 2 + ipaB - could be used as one of the diagnostic marker for some strain that were named ESIEC before.