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目的用直接测序法研究临床分离的多耐药结核杆菌的katG和inhA的基因变异机理。方法用未见报还katG和inhA基因中的片须为引物，PCR法扩增产物，克隆后大量制备质粒，经全自动测序系统测定其DNA序列。结果15株耐INH≥1ug/ml的细菌均有katG突变，主要为点突变。其中14株有463位和315位AA密码子改变。13个变异位点中，9个未见文献报告。关于inhA变异，在18个耐INH≥1ug/ml的菌株中，全部出现inhA基因变异，主要为点突变和缺失，其中又以单个位点变异为主。各菌株之间变异不同。耐式菌株中，katG和inhA同时出现变异的比例较大。结论结核杆菌耐药基因变异机理复杂，我国分离的多耐药结核菌株与国外的菌株上述二基因变异特点不同。
Objective To study the gene mutation mechanism of katG and inhA in clinical isolates of multidrug-resistant M. tuberculosis by direct sequencing. Methods The fragments of katG and inhA genes, which have not been reported, were used as primers to amplify the products by PCR. After cloning, a large number of plasmids were prepared and their DNA sequences were determined by automatic sequencing system. Results 15 strains of INH ≥ 1ug / ml bacteria have katG mutations, mainly for point mutations. Of these 14 strains, there were 463 and 315 AA codon changes. Of the 13 variants, 9 reported no literature. About inhA mutation, inhE1 ≥ 18 ug / ml strains, all inhA gene mutations, mainly point mutations and deletions, which in turn a single site-based mutation. Variation among strains varies. Endurance-resistant strains, katG and inhA mutation at the same time a larger proportion. Conclusion The mutational mechanism of Mycobacterium tuberculosis resistance gene is complex. The multi-drug resistant tuberculosis strains isolated in China and foreign strains have different characteristics of the above two genes.