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目的 研究志贺毒素阴性的大肠埃希菌O15 7血清群菌株可能携带的毒力因子 ,以确定其致病群类型。方法 对 8株分离自杭州的志贺毒素阴性的大肠埃希菌O15 7血清群菌株及分离自美国和我国江苏的EHECO15 7菌株 ,应用PCR技术检测stx、hly、EPEC和EHEC共有的eaeA、EHEC特异的eaeA ,ELISA检测ETEC的耐热和不耐热肠毒素 ,HEP 2细胞粘附试验测定细菌与上皮细胞的粘附能力 ,并进行菌株质粒图谱分析。结果 8株志贺毒素阴性的大肠埃希菌O15 7菌株均未检出stx、hly、EHEC特异的eaeA以及ETEC的耐热和不耐热肠毒素 ,仅其中 2株菌株携有EPEC和EHEC共有的eaeA ,另 3株菌株对HEP 2细胞有集聚性粘附能力。结论 目前我国检获的大肠埃希菌O15 7菌株其致病类型表现为多样性 ,部分菌株尚不能明确其毒力因子。EHECO15 7的鉴定必须重视毒力因子的检测。
Objective To study the possible virulence factors of Shiga toxin-negative Escherichia coli O157 serogroups to determine their pathogenicity groups. Methods Eight isolates of Shiga toxin-negative Escherichia coli O157 isolates from Hangzhou and EHECO157 strains isolated from the United States and Jiangsu of China were detected by PCR. The eaeA, EHEC, EHEC, Specific eaeA, ELISA detection of heat-resistant and heat-labile enterotoxin ETEC, HEP 2 cell adhesion assay to determine the adhesion of bacteria and epithelial cells, and the plasmid map of the strain. Results None of the 8 isolates of Shiga toxin-negative Escherichia coli O157 were identified as stx, hly, EHEC-specific eaeA and ETEC-resistant heat-labile and heat-labile enterotoxins. Only two of the strains had the common EPEC and EHEC Of the eaeA, the other three strains of HEP 2 cells have a cohesive adhesion. Conclusions At present, the pathogenicity of Escherichia coli O15 7 seized in our country is diverse, and some strains are still not clear about their virulence factors. EHECO15 7 identification must pay attention to the detection of virulence factors.