论文部分内容阅读
目的对2006年-2014年在上海地区分离的大肠埃希菌O157进行分子分型研究。方法通过脉冲场凝胶电泳(PFGE)和多位点序列分型(MLST)技术的联合应用,对来自中国上海地区的16株大肠埃希菌O157分离株和4株标准株进行分子分型研究。结果 PFGE方法可将20株菌株分为12种型别,分辨力为0.921 1。其中14株O157:H7菌株处于同一聚类,其与6株O157:H?菌株为不相关菌株。MLST方法可将20株菌株分为6种ST型,分辨力为0.726 3。7个管家基因的核苷酸多态性范围为0.000 784~0.009 449。其中14株O157:H7菌株分为ST2966型和ST11型,属于同一克隆群。6株O157:H?分离株分为4种ST型,包括3种新的ST型,且与本研究中的O157:H7菌株间的管家基因型别相差至少6个。结论上海地区从动物和患者粪便中分离的大肠埃希菌O157:H7分离株间的遗传谱系接近,与本实验研究中的大肠埃希菌O157:H?菌株间亲缘关系较远。需加强对上海地区大肠埃希菌O157的病原学监测,并进一步比较2种分型技术对大肠埃希菌O157的分型效果。
Objective To investigate the molecular typing of Escherichia coli O157 isolated in Shanghai from 2006 to 2014. Methods 16 strains of Escherichia coli O157 and 4 strains from Shanghai area of China were genotyped by the combination of pulse field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) . Results PFGE method could divide 20 strains into 12 types with a resolution of 0.921 1. Fourteen strains of O157: H7 were in the same cluster, which was not related to six strains of O157: H ?. The MLST method can classify 20 strains into 6 ST types with a resolution of 0.726. The nucleotide polymorphism of 3.7 housekeeping genes ranged from 0.000 784 to 0.009 449. Fourteen strains of O157: H7 were divided into ST2966 and ST11 and belonged to the same clonal group. Six O157: H? Isolates were divided into four ST types, including three new ST types, at least 6 different from the housekeeping genotypes of the O157: H7 strains in this study. Conclusion The genetic lineage of Escherichia coli O157: H7 isolates isolated from animal and patient feces in Shanghai was close and far from the Escherichia coli O157: H? Strains in this study. It is necessary to strengthen the etiological surveillance of Escherichia coli O157 in Shanghai and further compare the typing effects of the two typing technologies on Escherichia coli O157.