耐异烟肼结核分枝杆菌及其katG、inhA基因的突变

目的探讨耐异烟肼结核分枝杆菌及其katG与inhA基因突变的特征,为临床选择抗结核药物治疗提供实验室参考。方法回顾性分析2015年1月1日-2017年1月1日在上海交通大学附属同仁医院海南分院的260例患者标本,对213例进行结核分枝杆菌分离培养,对47例进行博奥芯片法检测,再对213例培养所得菌株进行博奥芯片检测,对博奥芯片检测的47例痰标本进行结核分枝杆菌分离培养;对101株结核分杆菌进行katG与inhA基因检测。结果培养法和博奥芯片结核分枝杆菌检出率分别为36.6%(78/213)和48.9%(23/47);培养法和博奥芯片耐多药结核分枝杆菌检出率分别为41.0%(32/78)和47.8%(11/23);博奥芯片法和比例法耐异烟肼符合率98.7%(77/78);男性结核分枝杆菌阳性率45.9%高于女性阳性率29.2%;检测katG基因和inhA基因,3个基因区域都发生突变,突变发生率大小依次为katG315(AGC→ACC)密码子(32株,54.2%)、katG315(AGC→AAC)密码子(16株,27.1%)、inhA-15(C→T)(10株,16.9%)。24株(23.8%,24/101)对异烟肼无突变但对利福平发生突变;43株也同时耐利福平(42.6%,43/101)。突变频率较高的突变位点是315,突变频率为81.4%(48/59),1株(1.7%,1/59)为双位点联合突变且突变频率最低。结论结核分枝杆菌katG和inhA基因突变与耐INH相关,这为临床及时准确诊断、及早使用抗结核药物联合治疗提供了帮助。

Isoniazid resistant Mycobacterium tuberculosis and its katG and inhA gene mutations

Objective To investigate the characteristics of isoniazid resistant Mycobacterium tuberculosis and its katG and inhA gene mutations, for clinical selection of anti-tuberculosis drug treatment to provide laboratory reference. Methods A retrospective analysis of 260 specimens in Shanghai Jiaotong University Tongren Hospital Hainan Branch from 1 January 2015 to 1 January 2017 was carried out. According to the purpose of the examination, 213 cases were isolated and cultured by Mycobacterium tuberculosis, 47 cases were tested by Boao chip method, then, 213 cases were tested by Boao chip, and 47 cases of sputum specimens detected by Boao chip were also isolated and cultured by Mycobacterium tuberculosis. And 101 strains of Mycobacterium tuberculosis were detected for katG and inhA genes. Results The detection rates of Mycobacterium tuberculosis by culture and biochip were 36.6% (78/213) and 48.9% (23/47); The detection rate of MDR Mycobacterium tuberculosis by culture method and biochip were 41.0% (32/78) and 47.8% (11/23) respectively. The coincidence rate of isoniazid-resistant Mycobacterium tuberculosis by biochip and proportion method was 98.7% (77/78). The positive rate of Mycobacterium tuberculosis in male was 45.9%, higher than that in female 29.2%. katG gene and inhA gene were detected, and there were mutations in all three gene domains. The mutation rates were katG315 (AGC → ACC) codon (32 strains, 54.2%), katG315 (AGC → AAC) codon (16 strains, 27.1%), inhA-15 (C → T) (10 strains, 16.9%). And 24 strains (23.8%, 24/101) without isoniazid mutation but rifampin mutation, 43 strains were also resistant to rifampicin (42.6%, 43/101). The mutation site with higher mutation frequency was 315, the mutation frequency was 81.4% (48/59), and 1 strain (1.7%, 1/59) had two-site combination mutation, with the lowest mutation frequency. Conclusions Mutations in the katG and inhA genes of Mycobacterium tuberculosis are associated with INH resistance, which provides help for timely and accurate clinical diagnosis and early use of anti-TB drug combination therapy.