杭州地区结核分枝杆菌链霉素耐药相关基因rpsL和rrs突变分析

Analysis of rpsL and rrs gene mutations related to streptomycin-resistant clinical isolates of Mycobacterium tuberculosis in Hangzhou district

目的分析杭州地区结核分枝杆菌链霉素耐药相关基因核糖体蛋白S12编码基因(rpsL)和16SrRNA编码基因(rrs)的突变情况。方法采用比例法对杭州地区74株结核分支杆菌临床分离株进行药敏试验;设计特异性引物,对目的基因片段rpsL和rrs进行扩增、克隆后测序分析。结果 74株结核分枝杆菌中有31株耐链霉素表型阳性,耐药率41.9%。31株耐药株中,20株rpsL 43(AAG→AGG)位点发生突变,占总耐药菌株的64.5%;2株rpsL 88(AAG→AGG)位点发生突变,占总耐药菌株的6.5%;2株两个位点同时发生突变者占总耐药菌株的6.5%。43株链霉素敏感结核分支杆菌中未见rpsL和rrs基因发生突变、插入或缺失。结论杭州地区结核分支杆菌耐链霉素主要由rpsL基因突变引起。其中,rpsL 43(AAG→AGG)位点突变占绝大部分。

Objective To analyze the rpsL and rrs gene mutations related to streptomycin- resistant clinical isolates of Mycobacterium tuberculosis in Hangzhou district. Methods A total of 74 clinical isolates of Mycobacterium tuberculosis was detected by the proportion of susceptibility testing. The segments of rpsL and rrs genes were amplified by PCR and then sequenced after TA cloning. Results Of 74 clinical isolates, 31 streptomycin-resistant phenotypes were positive with a positive rate of 41.9%. RpsL 43（AAG→AGG） mutation was found in 20 of the total drug-resistant strains（64. 5%, 20/31） and rpsL 88（AAG→AGG） mutation was found in 2 of the total drug-resistant strains（6.5%,2/31）, while mutations in above two gene sites were found in 2 of the total drug- resistant strains （6.5 %, 2/31）. The mutation, insertion or deletion of rpsL and rrs genes was not found in the 43 streptomycin-sensitive Mycobacterium tuberculosis. Conclusion The mutation of rpsL gene, mainly the rpsL 43 （AAG--~ AGG） mutation, is responsible for streptomycin-resistance of Mycobacterium tuberculosis in Hangzhou district.