Background China is one of the high burden countries of Mycobacterium tuberculosis （TB） infection globally, with high incidence and mortality. We studied the molecular characteristics of rifampin （RIF） and isoniaz...Background China is one of the high burden countries of Mycobacterium tuberculosis （TB） infection globally, with high incidence and mortality. We studied the molecular characteristics of rifampin （RIF） and isoniazid （INH） resistant Mycobacterium tuberculosis strains from Beijing, China, in order to find out the genetic marker for rapid detection of specific drug resistance.Methods Forty pansusceptible and 81 resistant strains of Mycobacterium tuberculosis isolated from Beijing, China during 2002-2005 were analyzed. The modified rifampin oligonucleotide （RIFO） assay based on reverse line blot hybridization was used to detect mutations in the 81 bp hot-spot region of rpoB gene, which is associated with RIF resistance. The INH resistance associated genes, regulatory region mab-inhA （-15C/T） and structural gene katG S315T were detected by reverse line blot hybridization and PCR-restriction fragment length polymorphism （RFLP） method respectively. All the strains were typed by spoligotying and the Beijing genotype was further subdivided by NTF locus analysis. The distribution of drug resistance associated mutations in the above genes was compared in these groups. Results Sixty-five （91.5%） of 71 RIF resistant and 52 （92.9%） of 56 multidrug-resistant （MDR, i.e. resistant to at least RIF and INH） strains were found to harbor mutations in the rpoB hot-spot region. No mutation was detected in RIF sensitive strains. The specificity and sensitivity of the modified RIFO assay were 100% and 91.5%, respectively, katG315 AGC〉ACC and inhA-15C〉T mutations were found in 40 （60.6%） and 10 （15.2%） of 66 INH resistant strains, respectively; 7.6% of INH-resistant strains had mutations in both of these genes. Therefore, a combined use of both katG315 and inhA-15 identified 68.2% of INH-resistant strains. The Beijing genotype accounted for 91.7% of total strains and was further subdivided into ＂modern＂ （76.6%） and ＂ancestral＂ （23.4%） group. There is no significant difference展开更多
目的建立显色法芯片检测结核分枝杆菌耐药基因的方法。方法设计4对地高辛标记引物,扩增结核分枝杆菌rpoB、katG、inhA和ahpC 4个基因部分片段,根据结核分枝杆菌利福平(RFP)和异烟肼(INH)4条耐药相关基因上8个位点的25种单核苷酸多态性...目的建立显色法芯片检测结核分枝杆菌耐药基因的方法。方法设计4对地高辛标记引物,扩增结核分枝杆菌rpoB、katG、inhA和ahpC 4个基因部分片段,根据结核分枝杆菌利福平(RFP)和异烟肼(INH)4条耐药相关基因上8个位点的25种单核苷酸多态性设计探针制作芯片,扩增产物与芯片杂交,显色法判断结果;用该法检测46株结核分枝杆菌临床分离株。结果扩增产物琼脂糖电泳可见4条大小分别为165、181、245、315 bp DNA条带;结核分枝杆菌菌液浓度为1．6×103／ml时,该法仍可检测到各位点野生及突变信号;19种非结核分枝杆菌标准株和9种非分枝杆菌标准株扩增产物无DNA条带,与芯片杂交亦无信号,H37Rv结核分枝杆菌标准株芯片检测各位点均为野生型;5株结核分枝杆菌临床分离株重复检测5次,结果完全一致;6份PCR产物的测序结果与芯片检测结果完全一致;46株结核分枝杆菌临床分离株中,RFP耐药株28株,芯片检出突变株24株,突变率为85．7％,RFP敏感株18株,芯片检出突变株2株。INH耐药株31株,芯片检出突变株20株,突变率为64．5％,INH敏感株15株,芯片检出突变株4株。结论显色法芯片检测结核分枝杆菌耐药基因具有较高的敏感性和特异性,无需特殊仪器设备,有一定的推广应用价值。展开更多
基金This study was supported by a grant from the National Natural Science Foundation of China(No.30471841).
文摘Background China is one of the high burden countries of Mycobacterium tuberculosis （TB） infection globally, with high incidence and mortality. We studied the molecular characteristics of rifampin （RIF） and isoniazid （INH） resistant Mycobacterium tuberculosis strains from Beijing, China, in order to find out the genetic marker for rapid detection of specific drug resistance.Methods Forty pansusceptible and 81 resistant strains of Mycobacterium tuberculosis isolated from Beijing, China during 2002-2005 were analyzed. The modified rifampin oligonucleotide （RIFO） assay based on reverse line blot hybridization was used to detect mutations in the 81 bp hot-spot region of rpoB gene, which is associated with RIF resistance. The INH resistance associated genes, regulatory region mab-inhA （-15C/T） and structural gene katG S315T were detected by reverse line blot hybridization and PCR-restriction fragment length polymorphism （RFLP） method respectively. All the strains were typed by spoligotying and the Beijing genotype was further subdivided by NTF locus analysis. The distribution of drug resistance associated mutations in the above genes was compared in these groups. Results Sixty-five （91.5%） of 71 RIF resistant and 52 （92.9%） of 56 multidrug-resistant （MDR, i.e. resistant to at least RIF and INH） strains were found to harbor mutations in the rpoB hot-spot region. No mutation was detected in RIF sensitive strains. The specificity and sensitivity of the modified RIFO assay were 100% and 91.5%, respectively, katG315 AGC〉ACC and inhA-15C〉T mutations were found in 40 （60.6%） and 10 （15.2%） of 66 INH resistant strains, respectively; 7.6% of INH-resistant strains had mutations in both of these genes. Therefore, a combined use of both katG315 and inhA-15 identified 68.2% of INH-resistant strains. The Beijing genotype accounted for 91.7% of total strains and was further subdivided into ＂modern＂ （76.6%） and ＂ancestral＂ （23.4%） group. There is no significant difference
文摘目的建立显色法芯片检测结核分枝杆菌耐药基因的方法。方法设计4对地高辛标记引物,扩增结核分枝杆菌rpoB、katG、inhA和ahpC 4个基因部分片段,根据结核分枝杆菌利福平(RFP)和异烟肼(INH)4条耐药相关基因上8个位点的25种单核苷酸多态性设计探针制作芯片,扩增产物与芯片杂交,显色法判断结果;用该法检测46株结核分枝杆菌临床分离株。结果扩增产物琼脂糖电泳可见4条大小分别为165、181、245、315 bp DNA条带;结核分枝杆菌菌液浓度为1．6×103／ml时,该法仍可检测到各位点野生及突变信号;19种非结核分枝杆菌标准株和9种非分枝杆菌标准株扩增产物无DNA条带,与芯片杂交亦无信号,H37Rv结核分枝杆菌标准株芯片检测各位点均为野生型;5株结核分枝杆菌临床分离株重复检测5次,结果完全一致;6份PCR产物的测序结果与芯片检测结果完全一致;46株结核分枝杆菌临床分离株中,RFP耐药株28株,芯片检出突变株24株,突变率为85．7％,RFP敏感株18株,芯片检出突变株2株。INH耐药株31株,芯片检出突变株20株,突变率为64．5％,INH敏感株15株,芯片检出突变株4株。结论显色法芯片检测结核分枝杆菌耐药基因具有较高的敏感性和特异性,无需特殊仪器设备,有一定的推广应用价值。
