应用VNTR技术对绵阳地区结核分枝杆菌进行基因分型

Genotyping of mycobacterium tuberculosis with VNTR technique in Mianyang,Sichuan

目的应用数目可变串联重复序列(variable number of tandem repeats,VNTRs)分析技术探讨绵阳地区结核分枝杆菌的基因分型,为结核病的防治提供科学依据。方法选取绵阳地区结核分枝杆菌临床分离菌株,采用聚合酶链反应(PCR)分别对VNTR位点进行检测分析,应用BioNumerics 5.0软件进行聚类分析。结果共对79株结核分枝杆菌的15个VNTR位点进行了检测,结果显示明显的基因多态性。各个位点的分辨能力不同,QUB-11b位点的分辨指数(Hunter-Gaston index,HGI)最高,为0.880;ETR C的HGI最低,为0.234;总HGI达到1。经聚类分析,79株菌可分为7个基因群、79个基因型,以Ⅲ群和Ⅴ群所占比例较大,Ⅲ群含37株菌,占46.8%;Ⅴ群含33株菌,占41.8%,其他菌株呈散在分布。结论绵阳地区结核分枝杆菌VNTRs基因存在明显的多态性,主要流行菌群为Ⅲ群和Ⅴ群,应加强此两群菌株的监控。

Objective To discuss the genotyping of mycobacterium tuberculosis clinical isolates in Mianyang area by variable number tandem repeats （VNTRs） technique and provide scientific basis for the prevention and control of tu- berculosis. Methods Mycobacterium tuberculosis clinical isolates were selected from Miaxlyang area, the polymorphism of VNTR locus was tested with PCR. The clustering of genotype was analyzed with BioNumerics 5.0. Results 15 VNTR loci of 79 mycobacterium tuberculosis clinical isolates were analyzed respectively. The results showed that there were obvi- ous polymorphisms of VNTRs. The discrimination power of these loci appeared different from each other, with the biggest Hunter-Gaston index （0. 880） loci was QUB-11b, the smallest one （0. 234） loci was ETR C, HGI of 15-locus reached 1. The clustering of genotype showed that these strains could be categorized into 7 gene clusters and 79 genotypes, the proprtions of cluster Ⅲ and cluster V were the biggest, 46.8 % were cluster Ⅲ which including 37 strains and 41. 8 % were cluster V which including 33 strains, other strains were of scattered distribution. Conelusions The results showed that there were obvious polymorphisms of VNTRs of mycobacterium tuberculosis clinical strains in Mi-anyang, most of the epidemic strains belonged to cluster Ⅲ and cluster V. It is suggested that surveillance of these epi- demic genotvpe should be strengthened.