耐利福平结核分支杆菌耐药分子机制的研究

The studies on the molecular mechanism of rifampin-resistant Mycobacterium tuberculosis

目的研究中国五省、市部分耐利福平（ＲＦＰ）或含ＲＦＰ的耐多药结核分支杆菌临床分离株ｒｐｏＢ基因突变的情况及抽提鉴定是否含有质粒，为评价耐ＲＦＰ的分子机制，进而为结核病基础和临床研究提供分子遗传学依据。方法采用ＰＣＲ－ＳＳＣＰ技术，对来自河南省、河北省、安徽省、北京市、上海市２６２株结核分支杆菌临床分离株（其中敏感株７４株，耐ＲＦＰ或含ＲＦＰ耐多药株１８８株）ｒｐｏＢ基因突变的发生率进行研究；同时，对７６株结核分支杆菌临床分离株按碱性溶菌法抽提分离并鉴定是否含有质粒。结果中国五省、市的部分耐ＲＦＰ或含ＲＦＰ耐多药结核分支杆菌临床分离株ｒｐｏＢ基因突变的发生率平均为９２％，而各地分别为：河南省９０％，河北省９４％，安徽省９１％，北京市９１％，上海市９２％，经统计学处理，五省、市之间差异元显著性意义（Ｘ２＝０．４２，Ｐ＞０．０５），所有受试７４株对照敏感株ｒｐｏＢ基因均无突变；结核分支杆菌敏感株２９株、耐ＲＦＰ或含ＲＦＰ耐多药株３３株、耐ＩＮＨ、ＳＭ、ＥＭ １４株共７６株均未提取分离与鉴定含有质粒。结论结核分支杆菌耐ＲＦＰ与ｒｐｏＢ基因突变密切相关，ｒｐｏＢ基因突变是耐ＲＦＰ结核分支杆菌耐药性的主要分子机制；

Objective To evaluate the molecular mechanism of rifampin (RFP)-resistance of M.tuberculosis, and to provide evidence of molecular genetics for basic and clinical research of tuberculoois.Methods rpod gene mutation of M.tuberculosis was detected with PCR-SSCP from 262 clinical isolates, including 74 drug sensitive strains, and 188 RFP-resistant only or multiple drug-resistant strains of M.tuberculosis, collecting from Henan, Hebei and Anhui province, Beijing and Shanghai cities. Plasmids were extracted from 76 clinical isolates of M.tuberculosis with alkaline bacteriolytic methods. Results Mean mutation rate of rpoB gene was 92% in the RFP-resistant clinical isolates of M.tuberculosis. Respectively, the mutation rate was 90.0% in Henan province, 94% in Hebei province, 91% in Anhui province, 91% in Beijing city and 92% in Shanghai city. There was no significant difference between results from the provinces and the cities (X2 =0.42, P > 0.05). However, mutation of rpoB gene was not detected in 74 sensitive clinical isolates of M.tuberculosis. Moreover, in 76 clinical isolates of M.tuberculosis the plasmids were not found, including 29 sensitive strains, 33 RFP-resistant only or multiple drug-resistant strains and 14 RFP, isoniazid, steptomycin and ethambutol-resistant clinical isolates. Conclusions This study confirmed the strong correlation between the RFP-resistance and the mutation of the rpoB gene,which might be a major molecular mechanism of RFP-resistance in M.tuberculosis. No evidence shows that M.tuberculosis has the plasmid,which mediates RFP resistance to M.tuberculosis.