结核分枝杆菌耐利福平和异烟肼相关基因快速检测的应用研究

目的 利用DNA芯片检测技术直接检测痰标本中结核分枝杆菌耐利福平(RFP)、异烟肼(INH)相关的耐药基因(rpoB、katG/inhA),评价DNA芯片检测技术临床应用的可行性.方法 对586份涂阳痰标本使用L-J培养并用终点法确定其耐药性,同时利用DNA芯片检测技术检测痰标觋本中结核分枝杆菌的rpoB、katG/inhA常见基因突变位点的突变情况,比对两种方法的检测结果,对不符合的菌株测定其相应DNA序列,评估上述试验的准确性.结果 (1)586份涂阳痰标本,其中3(+)163份、2(+)204份、1(+)217份,培养阳性584份.耐药结果显示,对INH、RFP敏感的菌株分别为361株和327株,耐药菌株分别为223株和247株,其中低浓度耐药、高浓度敏感菌株分别为93株和59株,低浓度、高浓度均耐药菌株分别为130株和188株.(2)耐药基因特异性片段扩增阳性标本367份(62.8%)、阴性217份(37.2%).对INH耐药相关基因(katG/inhA)突变检出率是28.4%,突发发生位点集中在katG315位密码子(89.8%);对RFP耐药相关基因(rpoB)突变检出率是55.9%(137/247),突变发生位点主要在rpoB 531和rpoB 526位密码子,发生率分别是68.6%和16.1%.(3)对L-J药敏结果与DNA芯片检测结果不符的菌株进行DNA序列分析,发现有漏检现象.结论 DNA芯片技术直接检测样本中结核分枝杆菌的相关耐药基因存在可行性,如直接应用于临床样本检测,关键要解决样本中DNA的提取效率、PCR的扩增效率和试验的质量控制.

The exploratory development of the related genes with rifampin and isoniazid in Mycobacterium tuberculosis

Objective To detect the related genes with rifampin and isoniazid in Mycobacterium tuberculosis in sputums using the DNA chip technique and evaluate the fensibility of the clinical application of the DNA chip technique.Methods 586 sputum smear specimen was detected using the L-J cultivation to determine their drug resistance.Simultaneously.DNA chip was employed to detect the mutation of the frequent mutable points rpoB,katG/inhA in mycobaeterium tuberculosis isolates.These two assays were compared and samples showing discrepancy were chosen for additional sequencing to evaluate the accuracy of the detection.Results(1)There were 584 culture positive sputum smear specimens including 3(+)163 specimens,2(+)204 specimens,and 1(+)217 specimens.The drug fast results displayed that 361 strains were sensitive to INH,223 strains tolerated INH in which 93 strains tolerated it in low concentration while sensitive to it in high concentration.and 130 strains tolerated it in both low and high concentration.While 327 strains were sensitive to RFP.247 strains tolerated RFP in which 59 strains tolemted it in low concentration while sensitive to it in high concentration,and 188 strains tolerated it in both low and high concentration.(2)There were 367 positive strains(62.8%)and 217 negative strains(37.2%)identified by PCR amplification of the specific resistance gene fragments.The detection rate of the katG/inhA was 28.4%,and the mutation sites were mainly focused on the katG315(89.8%).The detection rate of the rpoB was 55.9%(137/247),and the mutation sites were mainly focused on rpoB531(68.6%)and rpoB 526(16.1%).(3)The sequencing of sample,which showed discrepancy with L-J cultivation and the DNA chip confirm a certain omission ratio.Conclusions It is feasible to detect the related resistant genes in Mycobacterium tuberculosis isolates using the DNA chip technique.The key factor is to raise the efficiency of the DNA extraction,the effciency of the PCR and the quality control of the experiment to facilitate its clinical application.