结核分支杆菌inhA基因突变的测序研究

Sequencing of inhA in drug resistant Mycobacterium tuberculosis isolates

目的 对耐药结核分支杆菌的inhA基因进行测序分析以研究其变异的分子机制。方法 以inhA片段为引物 ,聚合酶链反应扩增H37Rv、耐药株和敏感株的inhA基因 ,产物克隆后制备质粒 ,ABI 377全自动核酸测序系统测定DNA序列。结果 在 17个耐异烟肼菌株中 ,11株出现inhA基因变异 ,突变率为 6 5 % ,其中 10株至少每株有 1个错义突变。变异主要为点突变 ,包括碱基置换和缺失。各菌株变异不同。katG和inhA同时变异的达 6 2 %。首次发现了 18个与结核分支杆菌耐INH和EMB特性有关的inhA基因位点。

Objective To determine and characterize inhA mutations of drug resistant isolates of Mycobacterium tuberculosis Methods PCR products of inhA of drug resistant and susceptible isolates and H 37 R v were purified,cloned and analyzed by ABI 377 auto DNA sequencing system Results 11 out of 17 drug resistant M Tuberculosis isolates were detected having inhA variations 10 out of the 11 strains with variations had at least one missense mutation The variations consisted of point mutation (transition,transversion and deletion) Molecular mechanisms were different from strain to strain 8 of 13 (62%) strains had both katG and inhA mutations. 18 variation positions and mechanisms different from previous report have been described Conclusion These results suggested that binding sites decrease caused by inhA point mutations be associated with M. tuberculosis′ resistance to INH and EMB