VNTR技术用于宁波地区结核分枝杆菌基因分型的初步研究

Genotyping of Mycobacterium tuberculosis strains isolated from the patients in Ningbo with variable number tandem repeat method

目的:应用数目可变串联重复序列(VNTR)分子分型技术,对宁波地区90株肺结核临床分离株进行分型研究,探讨宁波地区菌株DNA多态性及基因型特征。方法:采用PCR和琼脂糖凝胶电泳技术对结核分枝杆菌15个VNTR位点进行检测,并应用BioNumerics软件进行基因分型的聚类分析。结果:90株结核分枝杆菌可分为4个基因群(Ⅰ群、Ⅱ群、Ⅲ群、Ⅳ群),84个基因型。Ⅰ群占11.1%,含有10个基因型,Ⅱ群占17.8%,含15个基因型,Ⅲ群占65.6%,含54个基因型,Ⅳ群占5.6%,含5个基因型。结论:宁波地区的结核分枝杆菌存在基因多态性,其主要流行群为Ⅲ群。

Objective：To investigate the genotyping and distribution pattern of Mycobacterium tuberculosis clinical isolates in Ningbo with variable number tandem repeats（VNTR） analysis.Methods： M.tuberculosis clinical isolates selected from Ningbo randomly were cultured with Lowenstein-Jensen medium.The bacteria from which the genome DNA was extracted were collected.The polymorphism of VNTR locus was tested in the DNA sample with PCR respectively.The clustering of genotype was analyzed with BioNumerics.Results： 15 VNTR loci of 90 M.tuberculosis clinical isolates were analyzed respectively.The results showed that there were obvious polymorphisms of VNTRs.The clustering of genotype showed that these strains could be categorized into 4 gene clusters（Ⅰ,Ⅱ,Ⅲ,Ⅳ） and 84 genotypes.11.1% were clusterⅠincluding 10 genotypes,17.8% were clusterⅡincluding 15 genotypes,65.6% were cluster Ⅲ including 54 genotypes,5.6% were cluster Ⅳ including 5 genotypes.Conclusion： The results showed that there were obvious polymorphisms of VNTRs of M.tuberculosis clinical strains preliminarily.There were at least 4 clusters of VNTR genotype and cluster Ⅲ was the predominant prevalent strain in Ningbo.