结核分枝杆菌链霉素耐药临床分离株rpsL基因突变特征分析

Analysis on the characteristics of rpsL gene mutations in Streptomycin resistance isolates of Mycobacterium tuberculosis

目的了解我国结核分枝杆菌(Mycobacterium tuberculosis,MTB)rpsL基因突变特征及其与链霉素耐药的相关性,并评价其应用价值。方法对302株结核分枝杆菌临床分离株的rpsL基因采用聚合酶链反应-直接测序(PCR-DS)进行检测。结果 59株对INH、RFP、SM、EMB和PAS全部敏感,rpsL基因没有突变,61株对SM敏感的耐药株有6株突变,SM敏感菌株突变率为5.00%(6/120)。182株SM耐药MTB,rpsL基因突变率为70.33%,其中43位密码子赖氨酸转变为精氨酸(Lys43Arg)突变率为52.20%;88位密码子有4种突变类型,突变率为17.58%;86位密码子精氨酸转变为谷氨酰胺(Arg86Gln)突变率为0.55%。SM耐药株的rpsL基因突变率明显高于SM敏感株的基因突变率,两者之间的差异有统计学意义,χ2=125.05,P<0.05。结论 rpsL基因突变与结核分枝杆菌链霉素耐药高度相关,其中Lys43Arg突变是主要突变类型,PCR-DS检测rpsL基因突变可以用于临床结核菌链霉素耐药的快速检测。

The objective was to understand the characteristics of rpsL gene mutation in Streptomycin resistant clinical isolates of Mycobacterium tuberculosis（M.tuberculosis） in China,and evaluate the application of rapid detection of rpsL gene mutation by PCR.The 302 M.tuberculosis clinical isolates were detected by drug sensitivity test（DST）,and the rpsL was detected by PCR-directly sequence（PCR-DS）.Of 59 strains were pan-susceptible to 5 drugs including INH,RFP,SM,EMB and PAS,and 61 strains were sensitive to streptomycin（SM） but resistant to the other drugs.The mutation rate of SM susceptible isolates was 5.00%（6/120）.In the 182 SM resistant isolates,the rpsL mutation rate was 70.33%,and the mutation rate of codon43 Lys→Arg was 52.20%;there were 4 mutation types in codon 88,and the mutation rate was 20.33%;the mutation rate of codon 86 Arg→Gln was 0.55%.The rpsL gene mutation rate of SM resistant strains was significantly higher than that of SM-sensitive strains χ2=125.04,P0.05.In conclusion,the rpsL mutation in M.tuberculosis is highly associated with Streptomycin resistance,and codon 43 Lys→Arg mutation is the main and important type.Meanwhile,the PCR-DS could be applied to rapid detection of rpsL mutation in clinical M.tuberculosis isolates for identifying SM susceptibility.