结核分枝杆菌散在分布重复单位基因型分型法的应用研究

Evaluation of the mycobacterial interspersed repetitive units typing as a practical approach in molecular epidemiology of Mycobacterium tuberculosis

目的建立结核分枝杆菌散在分布重复单位(mycobacterialinterspersedrepetitiveunits,MIRU)基因型分型法,评估该方法在我国应用的可行性。方法采用简单数字表法随机抽取上海地区2000年至2002年保存的菌株,对其进行MIRU分型,并与间隔区寡核苷酸分型法(Spoligotyping)的结果进行比较。结果用Spoligotyping方法对随机抽样的91株临床菌株进行基因型分型,得到20种基因型,其中81株(89%)属于北京基因型菌株,而用MIRU分型方法可将这些菌株分为46种基因型。81株北京基因型菌株可以分为39种不同的MIRU基因型。12个MIRU位点的多态性分析表明各位点有较大的区别,其中位点26显示了较高的多态性,位点16、31、40显示了中等程度的多态性。结论MIRU分型方法简单快速,其数字化结果清晰可靠,是一种有效的结核分枝杆菌基因型分型方法。

Objective To introduce a new genotyping method, mycobacterial interspersed repetitive units(MIRU) typing, for Mycobacterium tuberculosis and to evaluate its feasibility. Methods Mycobacterium tuberculosis strains stored at Shanghai Municipal Center for Disease Control and Prevention during 2000 to 2002,were randomly selected by simple digital table and genotyped by MIRU and Spoligotyping. Results By Spoligotyping method, 91 strains were typed to 20 genotypes, of which 89% (81/91) strains belonged to Beijing genotype, while by MIRU method, these strains were divided into 46 genotypes. The MIRU typing showed high discriminatory power, especially for the Beijing genotype strains. The 81 Beijing genotype strains could be subdivided into 39 different MIRU genotypes. In this sample collection, 12 MIRU loci showed different discriminative according to their allelic diversity. Locus 26 showed highly discriminative, while locus 16, 31, and 40 showed moderately discriminative. Conclusions MIRU genotyping is a simple and fast method. Its numerical result facilitates the comparison among strains of Mycobacterium tuberculosis from different labs.