重庆地区扁桃体炎患儿GAS分离株emm分型、红霉素耐药基因与超抗原基因关系研究  

Emm type,macrolide-resistance genes and superantigen gene profile among GAS isolate from children with pharyngitis in Chongqing

作　　者：黎敏[1] 罗征秀[1] 何国琴[1] 符州[1] 

机构地区：[1]重庆医科大学附属儿童医院呼吸中心,重庆400014

出　　处：《重庆医科大学学报》2010年第3期408-412,共5页Journal of Chongqing Medical University

基　　金：国家科技部863项目(编号:2006AA02Z417)

摘　　要：目的:分析重庆地区扁桃体炎患儿A族链球菌(Group A streptococcus,GAS)分离株emm分型、红霉素耐药基因和超抗原基因相关性。方法:收集2007年重庆地区扁桃体炎患儿GAS分离株44株。对44株菌株进行emm分型,红霉素耐药基因ermB、ermTR和mefA以及8种超抗原基因(ssa、SMEZ、speA、speC、speG、speH、speI、speJ)检测。结果:儿童扁桃体炎GAS分离株emm分型以emm12最多见,共26株(占59.1%);其次为emm1,共7株(占15.9%);少见的emm型为emm22有2株,emm6有2株,emm3有2株,emm80、emm63、emm102、stG485和st1815分别各有1株。44株GAS菌株均检出耐药基因ermB(100%),33株检出耐药基因ermTR(75.0%),3株检出耐药基因mefA(6.8%)。44株菌株均检出ssa、SMEZ和speH超抗原基因,其余5种超抗原基因检出率依次为speG37株(84.1%),speC36株(81.8%),speI28株(63.6%),speA22株(50%),speJ7株(15.9%)。7株emm1菌株有6株检出speA基因(占85.7%),26株emm12菌株有7株检出speA基因(占26.9%),speA基因分布在emm1、emm12分布中的差异具有统计学意义(P=0.008,<0.05);耐药基因ermB、ermTR和mefA在不同的emm型中分布是随机的,emm分型和耐药基因之间未发现明显相关性。结论:重庆地区儿童扁桃体炎GAS分离株emm分型以emm12和emm1为主;对红霉素的耐药机制以ermB编码为主的23SrRNA甲基化酶致靶位改变为主;emm型与大环内酯类抗生素耐药基因分布无明显相关性;speA超抗原基因分布主要与emm1相关。Objective：To analyze emm type,macrolide-resistance genes and superantigen gene profile of GAS isolates from children with pharyngitis in Chongqing.Methods：A total of 44 clinical isolates of GAS were obtained from children with pharyngeal diseases in 2007,Chongqing.The macrolide-resistant genotype（ermB,ermTR and mefA） and superantigen gene of group A streptococcal isolates（ssa、SMEZ、speA、speC、speG、speH、speI and speJ）were detected by PCR.Emm types were applied by PCR and sequencing.Results：Emm12 was the most common emm type（26 isolates,59.1%）.Emm1 was the second（7 isolates,15.9%）.Emm22 had 2 isolates,emm6 had 2 isolates,emm3 had 2 isolates,and emm80,emm63,emm102,stG485 and st1815 had 1 isolate respectively.All 44 isolates were detected ermB gene（100%）,33 isolates were detected erm TR gene（75.0%）,and 3 isolates were detected mefA gene（6.8%）.All of the isolates were detected ssa,SMEZ and speH.The detection rates of other superantigen genes were speG（84.1%）,spec（81.2%）,speI（63.6%）,speA（50%）and speJ（15.9%）.Six in 7 isolates of emm1 type were detected speA gene（85.7%）,and 7 in 26 isolates of emm12 type were detected speA gene（26.9%）.The distribution of speA in emm1 and emm12 had a statistically significant difference（P=0.008,0.05）.The distribution of macrolide-resistant genotypes was at random,and had no correlation with emm types.Conclusion：The most prevalent emm types in pharyngeal isolates in Chongqing were emm12 and emm1.The macrolide-resistant mechanism was mostly determined by the change of target site in the 23SrRNA methylase encoded by erythromycin resistance methylase B（ermB） genes.Emm type was not apparantly related to macrolide-resistance genes,and the distribution of speA was mainly related to emml.

关 键 词：A族链球菌 红霉素 超抗原 emm分型 

分 类 号：R725.6[医药卫生—儿科]