中文摘要：

目的探讨淮南矿区尘肺并发结核患者感染耐多药结核分枝杆菌（multiple drugs resistant Mycobacterium tuberculosis,MDR-MTB）L型异烟肼耐药基因katG突变特点。方法收集114株MTB菌L型临床分离株,用药敏试验鉴定MDR-MTB菌L型;抽提MDR-MTB L型和H37Rv标准菌株DNA,PCR法扩增katG基因,并对katG基因的突变集中区域进行测序分析。结果从114株临床分离株中检出MDR-MTB菌L型31株（27.2%）,其katG基因突变率为61.3%（19/31）;主要集中在315位点碱基置换突变,以Ser315Thr为主（AGC→ACC）（48.4%,15/31）,其次是315位点Ser315Asn（AGC→AAC）突变（9.7%,3/31）以及431位点Ala431Val（GCG→GTG）突变（3.2%,1/31）,未发现多位点联合突变,12株（38.7%,12/31）未发现katG基因突变;随机检测的10株异烟肼敏感株未见katG基因单链构象异常。结论淮南矿区尘肺并发结核患者感染的MDR-MTB菌L型异烟肼耐药情况较为严重,高度保守的katG基因突变是导致异烟肼耐药的分子基础,其突变位点呈多样性。

英文摘要：

Objective To investigate the mutational characteristics of isoniazid-resistant gene katG in multiple drugs resistant Mycobacterium tuberculosis （MDR-MTB） L-form from the patients with pneumoconiosis and tuberculosis in Huainan mining district. Methods A total of 114 clinical isolates of MTB L-form were collected, and MDR-MTB were identified by the conventional antimicrobial susceptibility test （AST）. The genome DNA from MDR-MTB L-form and standard strain H37Rv was extracted, and the katG gene was amplified by PCR. Then, the hot mutation regions in katG gene were analyzed by direct sequencing. Results Thirty-one （27.2%） MDR-MTB L-form strains were detected from 114 clinical isolates, and the mutation rate of katG gene was 61.3% （ 19/31 ）. The mutation sites were mainly located on codon 315, including Ser315Thr （AGC→ACC, 15/31,48.4% ） and Ser315Asn （AGC→AAC, 3/ 31, 9.7% ） , and codon 431 （Ala431Val, GCG→GTG, 1/31, 3.2% ）. No multisite mutation was found. Moreover, no single strand conformation abnormity of katG gene was found in randomly collected 10 isoniazid-sensitive strains. Conclusion There was serious isoniazid-resistance of MDR-MTB L-form in the patients with pneumoconiosis and tuberculosis in Huainan mining district. The mutation of highly conserved katG gene was responsible for isoniazid-resistance of MDR-MTB L-form, and there were diversiform mutation sites.