Abstract: Objective To analyze the genotypes and genetic characteristics of Yersinia pestis isolated from Hebei plague foci. Methods The DNA of Y. pestis collected in Kangbao county from 1972 to 2017 was extracted by boiling method, the multiple locus variable number tandem repeat (MLVA) and the DFR primers according to a publication were synthesized by a biological company, then amplified by polymerase chain reaction, then genotypes were analyzed by agarose gel electrophoresis. Results All of the strains showed one MLVA genotype, and the main genotypes of Y. pestis from Hebei foci were G17 and G20. The absence of DFRs were 1, 6, 7, 13, 15, 16, 17, 18 in G17, the absence of DFRs were 1, 6, 7, 12, 13, 15, 16, 17, 18 in G20. Conclusion The genetic characteristics of enzootic plague in Hebei province remain stable. Further studies are warranted to confirm whether the epidemics among wildlife in 2017 was caused by spread of neighboring foci or by genetic shifting of the pathogen.

Key words: Yersinia pestis, Different regions, Variable number of tandem repeat, Genetic typing

摘要： 目的 分析河北省鼠疫疫源地分离的鼠疫耶尔森菌（鼠疫菌）基因型别和遗传变异特征。方法 采取水煮法对康保县1972-2017年分离的鼠疫菌提取DNA，利用已有文献报道的多位点可变数目串联重复序列（MLVA）和差异区段（DFR）两种分型方法，经过PCR扩增，琼脂糖凝胶电泳和序列分析后确定被测菌株的基因型别。结果 河北省分离的鼠疫菌MLVA基因分型一致，并确定了串联重复序列位点的重复数目；DFR基因型为G17和G20。G17型主要缺失DFR1、6、7、13、15、16、17、18，G20型主要缺失DFR1、6、7、12、13、15、16、17、18。结论 河北省鼠疫疫源地分离的鼠疫菌株遗传特征比较稳定，2017年动物间疫情是邻近地区的疫情蔓延还是当地菌株的遗传变异，需要进一步研究。

关键词: 鼠疫耶尔森菌, 差异区段, 多位点串联重复序列, 基因分型