间隔区寡核苷酸分型运用于西藏自治区藏族结核分枝杆菌临床分离株的基因多态性分析

Analysis on genetic diversity of Mycobacterium tuberculosis isolates from Tibetan patients in Tibet by spacer oligonucleotide typing

目的了解西藏自治区藏族结核分枝杆菌的基因多态性，优势流行菌株及相关影响因素。方法采用间隔区寡核苷酸分型对577株西藏自治区藏族结核分枝杆菌进行分型，应用BioNumerics5．0软件对分型结果进行聚类分析，并与SITVIT2数据库作比对分析。结果577例西藏自治区藏族结核病患者中，男329例，女248例。577株结核分枝杆菌可分为23种基因型，基因多态性为3．99％。其中563株（97．57％）表现出12种已知的基因型，分属为北京家族、T家族、cAs家族和MANU2家族，另有14株表现出11种新的基因型。对577株菌株的基因家族进行分析发现，北京家族菌株最多，共522株（90．47％），表现出7种基因型，基因多态性为1．34％。北京家族菌株之间的相似性较高，可聚为一个大的基因群，而在非北京家族菌株中，T家族与MANU2家族的相似性较高，可构成一个基因群，而与CAS家族的相似性较低。北京家族菌株比例最高的地区为昌都（97．83％）。北京家族菌株的发生与性别、年龄、卡介苗接种情况和治疗史均不相关（P值分别为1．00、0．36、0．83和1．00）。结论西藏自治区藏族结核分枝杆菌的基因多态性低，其中北京家族菌株为主要的流行菌株。

Objective To detect the genetic diversity and prevalent strains of Mycobacterium tuberculosis isolates from Tibetan patients in Tibet and to analyze factors associated with prevalent strains. Methods A total of 577 Mycobacterium tuberculosis isolates were genotyped by spacen oligonucleotide typing （spoligotyping） and the results were analyzed with BioNumeries software （Version 5. 0） and compared with the international spoligotype database of SITVIT2. Results Among the 577 cases of Tibet patients, 329 were male and 248 were female. Based on spoligotyping, 23 different spoligotypes were identified among 577 Mycobacterium tuberculosis isolates, with a genetic diversity of 3.99 %. The majority （97.57%, 563/577） of the isolates belonged to four known families, such as Beijing family, T family, CAS family and MANU2 family. The remaining 14 isolates had 11 novel spoligotypes. 522 （90.47%） isolates belonging to Beijing family presented with 7 spoligotypes, resulting in the genetic diversity of Beijing family of 1.34 %. With high similarity, Beijing family strains could he clustered into one genotype; among non-Beijing family strains, strains belonging to T family and MANU2 family were similar and could be clustered into one genotype. Changdu had the highest prevalence （97.83 %） of Beijng family strains. In this study, the occurrence of Beijing family strains was not associated with age, sex, bacillus Calmette- Guerin vaccination or treatment history （P= 1.00, 0.36, 0.83 and 1.00, respectively）. Conclusions In this study, the genetic diversity of Tibetan Mycobacterium tuberculosis is low and Beijing family strains are highly prevent in Tibet, by classical spoligotyping.