西安市耐异烟肼的结核杆菌耐药性及分子特征分析

Drug resistance analysis and molecular characterization of Isoniazid resistant mycobacterium tuberculosis in Xi'an

目的了解西安市临床分离的结核分枝杆菌异烟肼耐药菌株katG315、inhA-15突变情况及其分子特征。方法利用BACTAC MGIT960分枝杆菌快速培养系统对临床分离结核分枝杆菌进行药敏试验,采用定向缺失多重PCR(DTM-PCR)对异烟肼耐药菌株进行基因分型研究,分别利用多重等位基因特异PCR(MAS-PCR)和PCR-DNA测序法对其katG315和inhA-15突变热点进行检测。结果 117株异烟肼耐药菌株有73株为多重耐药结核分枝杆菌(62.39%),104株为北京型菌株(88.89%),81株存在katG315位点突变(69.23%),10株存在inhA-15位点突变(8.55%)。结论西安市异烟肼耐药分枝杆菌以北京型菌株为主,耐药表型主要表现为多重耐药,主要突变为katG315突变。

Objective To investigate the drug resistance of Isoniazid(INH)-resistant mycobacterium tuberculosis(MTB)in Xi’an and molecular characteristics.Methods Totally 117 INH-resistant MTB were isolated and subjected to molecular characterization of hotspot mutations within katG315 and inhA-15 by MAS-PCR(Multiplex allele-specific PCR)and direct sequencing.The isolates were genotyped by DTM-PCR(Deletion-targeted multiplex PCR).Results Among 117 isolated colonies,73 were MDR-MTB(62.39%).Hotspot mutations analysis demonstrated that 81(69.23%)isolates had mutation in the katG315 and 10(8.55%)isolates had mutation in inhA-15 promotor region.DTM-PCR indicated that 104 isolates(88.9%)were Beijing genotype.Conclusion Beijing genotype accounts for the majority of INH-resistant isolates in Xi’an.Multidrug resistance of MTB in Xi’an is prevailing,and more than 70%INH-resistant isolates harbor mutation in katG315.