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

摘要:

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。

Abstract:

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.