Mtb耐异烟肼基因变异株的体外最小抑菌浓度研究

目的 研究Mtb耐INH临床分离株katG基因、inhA基因、ahpC基因突变对其体外最小抑菌浓度（MIC）的影响。方法 对临床分离的耐INH的160株Mtb及对INH敏感的40株Mtb进行耐药基因芯片检测；并对所有标本进行INH MIC测定，比较不同变异株的MIC结果，其数据采用t检验进行比较，以P＜0.05为差异有统计学意义。结果 Mtb耐INH株katG 315基因变异占68.8%（110/160），katG 315基因变异株的MIC为（20.20±19.46 μg/ml），高于inhA变异株（0.73±0.82 μg/ml）（t′=10.9171，t′_α=1.9807，P＜0.05）；低于katG 315+inhA变异株（69.33±32.45 μg/ml）,（t′= 7.164，t′_α= 2.0627，P＜0.05）。结论 Mtb耐INH基因有不同的突变模式，各模式存在不同的耐药程度，此可以给临床用药进一步提供参考。

In vitro minimum inhibitory concentration of Mycobacterium tuberculosis isoniazid-resistant gene mutants

Objective To study katG,inhA and ahpC mutations of Mycobacterium tuberculosis isoniazid-resistant clinical isolates,and their effect on minimum inhibitory concentration(MIC) in vitro.Methods Isoniazid-resistant genes of 160 Mycobacterium tuberculosis isoniazid-resistant strains and 40 isoniazid-sensitive strains were detected by gene chip.All samples with different gene mutations were determined and compared MICs of iso-niazid.Results Of isoniazid-resistant strains,68.8%(110/160) had katG315 mutations,the MICs of katG315 gene mutants(20.20±19.46 μg/ml)was significantly higher than inhA gene mutants(0.73±0.82 μg/ml,t′=10.9171,t′ α=1.9807,P<0.05),and significantly lower than katG315 plus inhA gene mutants(69.33±32.45 μg/ml,t′= 7.164,t′ α= 2.0627,P<0.05).Conclusion Isoniazid-resistant strains had different gene mutation patterns,different genotypes had different levels of isoniazid resistance,which can provide a reference to the clinical.