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目的阐明结核分枝杆菌异烟肼(INH)耐药相关基因突变特征。方法对137株结核分枝杆菌临床分离株(耐异烟肼菌株87株,异烟肼敏感菌株50株)的9个结构基因furA、katG、inhA、kasA、Rv0340、iniB、iniA、iniC和efpA以及两个调控区oxyR-ahpC基因间隔区和mabA-inhA启动子进行DNA片段扩增及序列分析。结果82株(94．3％)INH耐药分离株的katG基因存在突变,其中katG Ser315Thr突变占优势(55．2％)。50株INH敏感的分离菌katG的463密码子没有突变。35株(40．2％)INH耐药的分离株katG的463有突变。87株INH耐药株中,20株(23．0％)的katG基因存在两重突变。13株(14．9％)分离菌inhA基因的启动子区存在突变,4．6％的分离菌有inhA结构基因突变,11．5％oxyR-ahpC基因间区存在突变。iniBAC区域和efpA中发现耐药性关联突变。结论研究证实多个基因突变与异烟肼耐药之间的关系,并且为阐明结核分枝杆菌耐药机制提供线索。
Objective To elucidate the characteristics of mutations associated with resistance to isoniazid (INH) in Mycobacterium tuberculosis. METHODS: Ninety-nine structural genes furA, katG, inhA, kasA, Rv0340, iniB, iniA, iniC and efpA in 137 M. tuberculosis clinical isolates (87 isoniazid resistant isolates and 50 isoniazid sensitive isolates) As well as the oxyR-ahpC intergenic region and the mabA-inhA promoter in two regulatory regions for DNA fragment amplification and sequence analysis. Results There were mutations in the katG gene of 82 (94.3%) isolates of INH resistance, of which katG Ser315Thr mutation predominated (55.2%). No mutations were found in 463 codons of 50 INH-sensitive isolates katG. 35 (40.2%) INH-resistant isolates of katG 463 mutations. Of the 87 INH resistant strains, 20 (23.0%) katG genes had a double mutation. There were mutations in the promoter region of 13 isolates (14.9%) inhA gene, 4.6% of isolates were inhA structural gene mutation, and 11.5% oxyR-ahpC gene mutation. IniBAC region and efpA found drug-resistant mutations. Conclusions The study confirmed the relationship between multiple gene mutations and isoniazid resistance and provided clues for elucidating the mechanism of drug resistance in M. tuberculosis.