中国部分地区159株结核分枝杆菌临床分离株MLVA-19分型分析

Analysis on genotyping of 159 strains of Mycobacterium tuberculosis isolated clinically in some areas of China with MLVA-19-Loci

目的初步了解中国部分地区结核分枝杆菌临床分离菌株数目可变串联重复序列(variable number of tandem repeats,VNTRs)基因多态性特征。方法采用多位点VNTRs分析(multiple loci VNTRS analysis,MLVA)技术,随机选取159株中国部分地区结核分枝杆菌临床分离菌株,PCR和琼脂糖凝胶电泳技术,对结核分枝杆菌的19个VNTRs位点进行检测,用BioNumerics(Version 5.0)软件进行结果分析,数据结果与国际MLVA数据库(http://minisatellites.u-psud.fr)比对,初步分析结核分枝杆菌DNA多态性特征。结果159株菌株大致被分成4个主要的簇,其中73.8%的菌株为北京家族菌株,其次为H37Rv相似菌株及在数据库中没有比对结果的一簇,这一簇的MLVA特点是ETRD>3,MIRU10、MIRU27、MIRU39、MIRU40及Mtub21位点结果为22221,与其他簇的菌株结果有比较明显的区别。可能是中国特有的菌株。另外发现与BCG相似的一簇。结论本次研究中的中国结核分枝杆菌具有明显的VNTR基因多态性,主要流行菌株为北京家族菌株,可能存在中国特异的VNTR基因型。BCG临床分离株的发现,提示BCG疫苗相关病例可能成为值得关注的卫生问题。

Objective To investigate the polymorphic genetic characteristics of Mycobacterium tuberculosis （M. tuberculosis） strains isolated in China based on variable number of tandem repeats （VNTRs）. Methods Nineteen tandem repeat loci were used for typing 159 randomly selected strains of M. tuberculosis isolated in some areas in China. The loci were analyzed by PCR and agarose gel electrophoresis respectively. The polymorphic genetic characteristics of DNA fingerprinting of these strains were detected with the BioNumerics 5.0 software. The results of genotyping were compared with the Intel-database of MLVA （http：//minisatellites. u-psud, fr）. Results 159 strains of M. tuberculosis were divided into 4 main clusters, the majority belonged to Beijing family cluster （73.8%）, followed by H37Rv-like strains, BCG-like strains, and a no-matched cluster compared with the Intel-database. The tandem repeats characteristics of no-matched strains was that the repeat number of ETRD 〉3, MIRU10, MIRU27, M1RU39, MIRU40, and Mtub21 was 2, 2, 2, 2, 1 respectively, witch had significant difference with the strains of other cluster and might be a peculiar strain in China. A BCG like cluster was found too. Condusion Obvious genetic polymorphism for the strains of M. tuberculosis isolated in China was observed in this study, The major strains belonged to Beijing family. There might be peculiar strains in the strains of M. tuberculosis isolated in China. The detection of BCG-like strains indicated that the BCG vaccine related cases might be a public health problem which should be pay attention to.