耐多药结核病耐药分子机制的研究

目的 研究耐多药结核分支杆菌耐药的分子机理，建立快速检测耐药基因的分子药敏试验方法。方法 通过ＰＣＲ和ＰＣＲ－ＳＳＣＰ分析结构分支杆菌耐多药临床分离株的ｒｐｏＢ、ｒｐｓＬ、ｋａｔＧ基因和ｉｎｈＡ调节序列。结果 ＰＣＲ分析耐药基因的敏感性为１－０ｐｇＤＮＡ；除ｒｐｏＢ基因引物ＰＣＲ扩增为属特异性外，余耐药基因引物ＰＣＲ扩增都具有较高的的特异性。２０株耐多药分离株中，９０％有２种以上耐药遗传标志改变，

Study on the molecular mechanism of multi-drug resistance in clinical isolates of Mycobacterium tuberculosis

OBJECTIVE: To study the molecular mechanism of multi-drug resistance in M. Tuberculosis, and to develop a new method for detecting genes related with multi-drug resistance. METHOD: The ropB, rpsL, katG genes and inhA regulatory sequence in clinical isolates of M. tuberculosis were analyzed with PCR and PCR-SSCP techniques. RESULT: The sensitivity of amplifing the drug-resistant genes with PCR was 1-10 pg DNA. Of the 20 multiple resistant strains with reduced sensitivity to streptomycin, rifampin and isoniazid, 90% showed mutations in more than two genetic markers associated with resistance to each of these three drugs, 10% revealed only mutations in rpoB gene. CONCLUSION: Multi-drug resistance in M. tuberculosis could be caused by an accumulation of mutations in chromosomal genes encoding drug targets or an alteration at a single multiple resistance locus. PCR and PCR-SSCP techniques might become simple, rapid and reliable diagnostic tests for multi-drug resistance.