【摘要 】 目的 探讨过氧化氢酶活性、KatG基因及其突变与结核分支杆菌异烟肼(INH)耐药性的相关关系。方法 对58株结核分支杆菌临床分离株进行过氧化氢酶活性测定，并采用聚合酶链反应-单链构象多态性(PCR-SSCP)方法进一步分析结核分支杆菌中KatG基因及其突变的情况。结果所有26株敏感菌均有KatG基因及过氧化氢酶的表达；32株耐药菌中，8株(25%)缺乏过氧化氢酶活性，3株(10%)KatG基因完全缺失，且主要发生于高度耐药菌中。进一步对8株耐药菌进行PCR-SSCP分析，发现均存在KatG基因突变。结论 过氧化氢酶活性缺乏及KatG基因的完全缺失主要与INH高度耐药性有关，而KatG基因突变可能是INH耐药性更为重要的原因。

Wang Xiaochuan, Han Qingshao,Liang Biao. Shenzheng Municipal Longgang Central Hospital, Shenzhen 518116

【Abstract 】 Objective To investigate the relationship between catalase activity, KatGgene, gene mutation and INH-resistance in M.tuberculosis.Method Catalase activities in 58 M.tuberculosis isolates weretested, and KatG gene mutations were detected futher by PCR-SSCP. Result None of INH-sensitive isolates lacked KatG sequences andall expressed catalase. 8(25%) INH-resistant isolates did not express catalase and 3(10%)lacked KatG gene, most of which were strains of high levels of resistance (MIC>50 μg/ml). 8 INH-resistant isolates were analyzed futher byPCR-SSCP and all were found to have KatG gene mutation. Conclusion These findings indicated that lacking of catalase activity and KatGgene deletion occured mainly in those highly INH-resistant strains, gene mutation otherthan complete deletion of KatG gene may be the major mechanism of INH-resistance.

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