MOLECULAR CHARACTERIZATION OF DRUG RESISTANCE IN MYCOBACTERIUM TUBERCULOSIS

由于多重耐药分枝杆菌的出现， 结核菌株的临床分离，我们的实验室已经开始了一个 M.耐药性的分子特征。结核 对异烟肼（INH）的耐药性，INH是治疗 结核病通常与过氧化氢酶-过氧化物酶的丧失有关 活动最近，我们已经证明，通过使用过氧化物酶测定和 一种亲和纯化的多克隆抗体， 过氧化氢酶-过氧化物酶阳性M.结核病H37 Rv株不具有 可检测的过氧化氢酶蛋白 此外，Southern印迹杂交 过氧化氢酶-过氧化物酶基因探针的研究表明， 从INH抗性菌株中删除编码该蛋白的基因。我们 目前正在研究其他INH耐药菌株，以阐明 过氧化氢酶在INH抗性中的作用。 在原核生物和真核生物中，对链霉素（SM）的抗性，另一种 主要结核药物，通常是由核糖体突变引起的。 S12蛋白基因。我们最近用PCR和核苷酸 序列分析表明，2种不同SM抗性的M.株结核 在S12蛋白基因上有相同的突变。这些地点 突变的M。结核病S12基因与 先前在其他SM耐药细胞中描述的S12突变。

Because of the emergence of multiply drug resistant Mycobacterium tuberculosis strains in clinical isolates, our laboratory has begun a molecular characterization of drug resistance in M. tuberculosis. Resistance to isoniazid (INH), the primary drug for treatment of tuberculosis, is frequently correlated with a loss of catalase-peroxidase activity. Recently, we have demonstrated by using peroxidase assays and an affinity purified polyclonal antibody that an INH resistant mutant of the catalase-peroxidase positive M. tuberculosis H37Rv strain has no detectable catalase protein. Furthermore, Southern blot hybridizations with a catalase-peroxidase gene probe have demonstrated that the gene encoding this protein is deleted from the INH resistant strain. We are currently examining other INH resistant strains to elucidate the role of catalase in INH resistance. In prokayotes and eukaryotes, resistance to streptomyocin (SM), another primary tuberculosis drug, often results from mutations in the ribosomal S12 protein gene. We have recently demonstrated with PCR and nucleotide sequence analyses that 2 different SM resistant M. tuberculosis strains have identical mutations in the S12 protein gene. The location of these mutations within the M. tuberculosis S12 gene is identical to the site of S12 mutations previously described in other SM resistant cells.