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目的对肠出血性大肠埃希菌(EHEC)的遗传基因型别进行不同分子分型方法的对比研究,从分子流行病学角度分析黑龙江省EHEC的检出情况,并对多位点串联重复序列分析(MLVA)分型方法用于EHEC的分型效果进行评价。方法采用毒力基因鉴定、核酸脉冲场凝胶电泳(PFGE)与MLVA 3种方法对70株EHEC进行遗传基因型别分析。结果 70株菌中有12株含有eaeA基因,7株含有hlyA基因,1株含stx1与stx2,2株含有stx2基因。在PFGE的研究中,依据经XbaⅠ酶切后,具有相同电泳图谱的菌株被定义为PFGE同一群落的菌株,将47株菌株分成35个型别。MLVA通过对7个位点的串联重复序列的比较研究,发现10株O157菌株在7个位点上等位基因的数目为2~5种,10株细菌被分为8个MLVA的型别。结论在农户养殖中存在EHEC的水平传播,MLVA的6个分型位点对EHEC O157菌株都有部分菌株不存在等位基因,还需增加菌株数量以对其分型位点做进一步研究。
Objective To compare the genotypes of EHEC among different molecular typing methods and analyze the detection of EHEC in Heilongjiang Province from the perspective of molecular epidemiology. Analysis (MLVA) typing method was used to evaluate the typing effect of EHEC. Methods 70 EHECs were genotyped by virulence gene identification, nucleic acid pulsed-field gel electrophoresis (PFGE) and MLVA. Results Of 70 strains, 12 contained eaeA gene, 7 contained hlyA gene, 1 contained stx1 and stx2, 2 contained stx2 gene. In the PFGE study, 47 isolates were divided into 35 isolates based on the XbaI digestion of strains with the same electropherogram and defined as the same strain of PFGE. MLVA compared the tandem repeats of seven loci and found that there were 2 to 5 alleles at 7 loci in 10 O157 strains and 10 strains were divided into 8 MLVA types. Conclusion There is level transmission of EHEC in farmer households. There are 6 alleles of MLVA in some isolates of EHEC O157 which do not exist alleles, and the number of isolates should be increased to further study their typing sites.