结核分支杆菌耐异烟肼分子机制的研究

Studies on the Molecular Mechanism of Isoniazid Resistance in Mycobacterium Tuberculosis Clinical Isolates

目的 探讨耐异烟肼结核分支杆菌KatG基因突变在结核分支杆菌耐异烟肼耐药性测定中的应用价值。方法 采用PCR和PCR -SSCP方法对 72株结核分支杆菌临床分离株和 30例耐INH肺结核病人痰标本KatG基因突变进行检测。结果 以结核分支杆菌H37RV为对照 ,30株药物敏感株的KatG基因PCR扩增产物2 82bp片段 2 8例SSCP图谱正常 ;2例异常。 4 2例耐INH分离株中 ,38株KatG基因扩增阳性 ,其中 2 4株SSCP图谱异常 ,其敏感性为 6 3 1%。 30例耐INH肺结核病人痰标本有 18例PCR扩增阳性 ,10例SSCP图谱与H37RV株有差异 ,KatG突变率为 5 5 6 %。结论 结核分支杆菌INH耐药的产生可能是由于其KatG基因完全缺失或KatG基因突变所致 ,PCR

Objective To study the applied value of mutation in isoniazid-resistant Mycobacterium tubeculosis isoniazid-resistant KatG gene mutation in detecting resistance of Mycobacterium tubeculosis polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP).Methods of 30 drug-susceptible isolates,28 KatG PCR products had no differences in the SSCP profiles with control.72 clinical isolates of Mycobacterium tuberculosis(30 drug susceptible,42 inoniazid-resistance or multidrug resistance including inoniazid),and 30 sputum specimens from pulmonary tuberculosis were detected using PCR-SSCP.Results SSCP pattern of Mycobacterium tuberculosis H37RV as control,SSCP patterns of 24 inoniazid resistant clinical isolates were different from the control.The specificity was 63 1%.30 sputum specimens from pulmonary tuberculosis were detected using PCR-SSCP,18 sputum specimens had postive PCR products,10 PCR products of sputum specimens had different SSCP patterns from the control.The KatG mutation rate of sputum specimens was 55 6% using PCR-SSCP.Conclusions Inoniazid resistance in some M.tuberculosis strains is associated with the complete deletion of KatG gene or the mutations of KatG gene.PCR-SSCP technigue could directly be applied to detect the drug susceptibility of Mycobacterium tuberculosis in sputum specimens.