青海省结核分枝杆菌临床分离株可变数目串联重复序列基因多态性研究

Study on VNTR diversity of clinical Mycobacterium tuberculosis isolates from Qinghai

目的 初步了解青海省结核分枝杆菌临床分离株基因多态性和基因分型特征.方法 2009-2012年收集青海省疾病预防控制中心分离的结核分枝杆菌临床分离株,提取DNA,对15个可变数目串联重复序列（VNTR）位点进行PCR扩增和产物电泳分析,使用BioNumerics软件对菌株进行聚类分析.结果 共检测251株结核分枝杆菌临床分离株的15个VNTR位点,显示这些菌株有明显的基因多态性,15个VNTR位点中Hunter-Gaston指数＞0.6的VNTR位点有6个,位点分辨能力最高的是MIRU26,经聚类分析,可分为4个基因群,238个基因型.4个基因群分别占4.9％、91.9％、1.6％和1.6％.结论 青海省流行的结核分枝杆菌菌株存在明显的VNTR基因多态性.

Objective To investigate the variable number tandem repeats （VNTR） genetic polymorphisms,genotyping and distribution pattern of clinical Mycobacterium （M.） tuberculosis isolates from Qinghai province.Methods The clinical M.tuberculosis strains isolated from the patients with tuberculosis and related background data were collected from Qinghai Provincial Center for Disease Control and Prevention from 2009 to 2012.Genotyping was conducted by using multiple locus VNTR analysis （MLVA）.Genomic DNA was extracted and 15 VNTR loci were amplified with PCR and the PCR products were detected with gel electrophoresis.The VNTR diversity and clusters of genotyping were analyzed with BioNumerics （Version 5.0）.Results A total of 251 clinical M.tuberculosis isolates were analyzed with 15 VNTR loci showing that there were great genetic diversity in these isolates.Six of the 15 VNTR loci,showed that the Hunter-Gaston index （HGI） were higher than 0.6,in which the highest resolution was MIRU26.The clusters of genotyping showed that these isolates could be categorized into four gene clusters and 238 genotypes.The four gene clusters accounted for 4.9%,91.9%,1.6% and 1.6% of the clinical isolates,respectively.Conclusion The results showed that there is great variety of VNTR genetic polymorphisms in clinical M.tuberculosis isolates in Qinghai province.