宁波地区耐多药结核分枝杆菌链霉素耐药相关基因rpsL和rrs突变研究

Mutation of streptomycin-resistant genes rpsL and rrsin multidrug-resistant Mycobacterium tuberculosis isolates in Ningbo

目的阐明宁波地区耐多药结核分枝杆菌链霉素耐药相关基因rpsL和rrs的分子突变特征,为宁波地区耐多药结核病的有效防控提供科学依据。方法从宁波市疾病预防控制中心收集67例耐多药结核分枝杆菌临床分离株,包括耐链霉素菌株40株和链霉素敏感菌株27株。采用PCR直接测序法分析rpsL和rrs基因的分子突变特征。对链霉素耐药与基因突变率关系之间的差异采用χ2检验,P<0.05为差异有统计学意义。结果 40株耐链霉素菌株中,31株(77.50%)检测到rpsL发生突变。突变位点集中在第43位和第88位密码子;6株耐链霉素菌株(15.00%)检测到2种不同类型的rrs基因突变,分别为A1401G(7.50%,3/40);A514C(7.50%,3/40)。27株链霉素敏感菌株中有4株(14.81%)发生rpsL突变,突变位点集中在第104位和第119位密码子,1株链霉素敏感菌株的rrs基因检测到A1401G突变。耐多药结核分枝杆菌中链霉素耐药株rpsL基因突变率高于链霉素敏感株,两者之间差异有统计学意义(χ2=25.387,P<0.05)。结论宁波地区耐多药结核分枝杆菌对链霉素的耐药与rpsL突变高度相关,耐药基因突变类型存在地域差异。

Objective To discuss the mutation of streptomycin-resistant genes rpsLand rrsin multidrug-resistant Mycobacterium tuberculosis isolates in Ningbo. Methods 67multidrug-resistant Mycobacterium tuberculosis isolates were collected from Ningbo Municipal Center for Disease Control and Prevention,including 40streptomycin（SM）-resistant isolates and 27 non streptomycin-resistant isolates.The mutation of rpsLand rrs genes were analyzed by PCR and sequencing. Results rpsL mutations were found in 31SM-resistant clinical isolates（77.50%）,and rpsL Lys43 Arg and Lys88 Arg were the most common mutation sites.Two types of mutations of rrs gene including A1401G（7.50%,3/40）,A514C（7.50%,3/40）were identified in 6SM-resistant isolates（15.00%）.rpsL mutations were found in 4SM-susceptible clinical isolates（14.81%）,and rpsL Ala119 Gly was the most common mutation site.Only one type of rrs mutation A1401 G was identified in one SM-susceptible isolate.The rpsLgene mutation rate in SM resistant strains was significantly higher than that in SM-susceptible strains（χ^2=25.387,P〈0.05）. Conclusions The rpsLgene mutation in multidrug-resistant Mycobacterium tuberculosis isolates is highly associated with streptomycin resistance,and the mutation type varies due to geographical difference.