六安地区结核分枝杆菌耐药基因katG 和rpoB 的突变特征

目的 分析临床分离的结核分枝杆菌katG 和rpoB 基因的突变情况与耐药之间的关系，了解六安地区耐药结核分枝杆菌的基因突变特征。方法 采用比例法对六安地区65 株结核分枝杆菌临床分离株进行药敏试验；通过特异性引物，对目的基因片段katG 和rpoB 进行扩增、测序后进行分析。结果 60 株结核分枝杆菌中分别有有9 株耐异烟肼和14 株耐利福平，其中同时耐异烟肼和利福平的6株。9 株耐异烟肼菌株中，4 株katG 在315（Ａ GC→ACC 或ACA）位点发生突变，占44.4％；14 株耐利福平菌株中，11 株rpoB 分别在516（GAC→GTC）、526(CAC→CGC 或TAC)和531(TCG→TTG)位点发生突变，占总耐药菌株的78.6％；6 株同时对利福平和异烟肼耐药，其中5 株katG 或rpoB 基因发生突变，占83.3％。结论 六安地区结核分枝杆菌耐异烟肼和耐利福平分别主要是由katG 和rpoB 基因突变引起，其中耐异烟肼主要在315（AGC→ACC 或ACA）位，而耐利福平在516（GAC→GTC）、526(CAC→CGC或TAC)和531(TCG→TTG)位，都发生了突变。

Characteristics of rpoB and katG gene mutation in drug-resistant Mycobacterium tuberculosis in Lu'an area

Objective To investigate the characteristics of mutations in the rpoB and katG genes(clinical isolates) leading to drug- resistance in Mycobacterium tuberculosis(M. tuberculosis) in Lu’an area. Methods Drug sensitive test was performed in 65 strains of M. tuberculosis clinically isolated from the sputum samples collected in Lu'an area, and the gene fragments of rpoB and katG were amplified with specific primers, sequenced and analyzed. Results Of the 60 strains of M. tuberculosis, 9 were mutations involved in resistance against isoniazid, 14 against rifampin, and 6 against both. The mutation for the 4 in 9 isoniazid-resistant strains(katG gene) occurred at codon 315(codon change from AGG to ACC or ACA, 44.4%), and 11 of 14 rifampin resistant strains(rpoB gene) occurred at codon 516(GAC→GTC), 526(CAC→CGC or TAC) and 531(TCG→TTG,78.6 %). Five in 6 strains resistant to both isoniazid and rifampin had mutations, which accounted for 83.3%.Conclusion Drug-resistance M. tuberculosis in Lu’an area is associated with katG and rpoB gene mutation,in which the katG gene primarily occurs at codon 315(AGC→ACC or ACA), and the rpoB at 516(GAC→GTC), 526(CAC→CGC or TAC) and 531(TCG→TTG).