产志贺毒素大肠埃希菌分离株多位点可变数目串联重复序列分析

目的 探讨多位点可变数目串联重复序列分析multiple-locus VNTR (variable-number tandem repeats) analysis,MLVA]分型方法对产志贺毒素大肠埃希菌分离株的分型效果,初步了解菌株分子流行病学特征。 方法 采用7个VNTR位点对70株产志贺毒素大肠埃希菌分离株进行分析,并根据多态性位点的重复数目利用BioNumerics软件进行聚类分析。 结果 70株菌株被分为46种MLVA型别,O157与非O157菌株可分为A、B两个明显不同的群。除少部分菌株外,不同宿主来源、志贺毒素型别及血清型的非O157菌株与MLVA型别存在较好的相关性。 结论 7个VNTR位点的MLVA分型方案对于产志贺毒素大肠埃希菌的菌株分型、暴发溯源等具有一定的参考价值,但仍需进一步完善。

Multiple-locus variable-number tandem repeats analysis typing of Shiga toxin-producing Escherichia coli isolates

Objective To evaluate the performance of multiple-locus variable number tandem repeats analysis (MLVA) in typing of Shiga toxin producing Escherichia coli (STEC) isolates, and understand the molecular epidemiological characteristics of the stains. Methods Totally 70 STEC isolates were typed by MLVA using 7 VNTR loci. A dendrogram was constructed using BioNumerics based on allele numbers. Results Using the MLVA protocol, 46 MLVA types were obtained from 70 STEC isolates. O157 and non-O157 isolates were divided into A and B groups. Isolates of different sources, serotypes or Shiga toxin gene types are well divided with some exceptions. Conclusion Though it needs to be improved, the MLVA protocol based on 7 VNTR loci is useful to differentiate STEC isolates, to trace the source of outbreak and so on.