【摘要】 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。更多还原

【Abstract】 Objective To study genotype of enterohemorrhagic Escherichia coli(EHEC) with three different subtyping methods,conduct molecular epidemiological analysis on EHEC detection in Heilongjiang and evaluate MLVA subtying effect on EHEC strains.Methods Seventy isolates of EHEC were analyzed by virulence gene identification,pulsed-field gel electrophoresis(PFGE) and multilocus variable-number tandem repeat analysis(MLVA).Results Twelve strains contained eaeA gene,seven strains contained hlyA gene,one strain contained stx1 and stx2 gene and 2 strains contained stx2 gene.Thirty five patterns in PFGE clusters were defined as strains that have same pattern by XbaⅠ digestion among 47 isolates,MLVA was performed by comparing the number of tandem repeats at seven loci,where seven loci showed 2 to 5 variations in the 10 isolates of EHEC O157,resulting in 8 MLVA types among the 10 isolates.Conclusion There was horizontal transmission of EHEC in household animal raising.Since null alleles existed in some strains were observed in 6 subtyping sites,more isolates are needed to conduct further study on subtyping effect of MLVA.更多还原