摘要目的 了解2012年北京市儿童来源A组链球菌(GAS)的耐药性和大环内酯类抗生素耐药基因携带情况.方法 于2012年5-7月,从北京市36家医院收集GAS 199株.全部菌株均来自咽拭子标本.采用VITEK-2全自动微生物分析系统及GPS-67药敏测定卡检测菌株对10种抗生素(青霉素、氨苄西林、红霉素、克林霉素、四环素、左氧氟沙星、替加环素、万古霉素、利奈唑胺和链阳霉素)的最小抑菌浓度(MIC值)；PCR方法检测大环内酯类抗生素耐药基因(ermA、ermB、mefA)；双纸片法(D实验)检测大环内酯类抗生素耐药表型.结果 199株GAS中,包括郊区101株(50.8％),城区98株(49.2％);111株(55.8％)分离自猩红热患者,88株(44.2％)分离自咽部感染患者.菌株对青霉素和氨苄西林敏感率均为100.0％ (199/199)；对红霉素、克林霉素和四环素耐药率较高,分别为96.5％ (192/199)、95.5％ (190/199)和92.0％ (183/199),对左氧氟沙星、替加环素、万古霉素、利奈唑胺和链阳霉素全部敏感.菌株对红霉素、克林霉素和四环素耐药率在不同地区、年龄和临床诊断间的分布差异无统计学意义(P＞0.05).全部菌株中,耐药基因ermB检出率为98.5％ (196/199),仅检测到5株携带ermA基因,未检测到mefA基因.全部菌株表现为固有型耐药,未检测到诱导型耐药.结论 2012年北京市儿童来源A组链球菌对克林霉素耐药率较高,对大环内酯类抗菌药物的耐药水平较高,以ermB基因介导的固有型耐药为主.

abstractsObjective To investigate the genetic features of drug resistance to group A streptococcus(GAS) and macrolides antibiotics among pediatric patients in Beijing 2012.Methods A total of 199 strains of GAS were collected from 36 hospitals in Beijing between May and July,2012.All strains were isolated from oropharyngeal swabs.The minimum inhibitory concentrations (MICs) of ten antibiotics (penicillin,ampicillin,erythromycin,clindamycin,tetracycline,levofloxacin,tigecycline,vancomycin,linezolid and streptogramin) were detected by VITEK-2 compact with GPS-67 test kit.The genes encoding macrolides resistance (ermA,ermB and mefA) were amplified and tested by PCR.The macrolides resistant phenotype of group A streptococcus was detected by double disc test (D-test).Results Among 199 strains of GAS collected in this study,101 (50.8％) were from suburbs and the other 98(49.2％) were from urban areas.111 (55.8％) strains were collected from scarlet fever patients while the other 88(44.2％) were from oropharyngeal infection cases.All the strains were sensitive to penicillin and ampicillin,and the percentage of resistance to erythromycin,clindamycin and tetracycline were 96.5％ (192/199),95.5％ (190/199) and 92.0％ (183/199),respectively.All strains were susceptible to levofloxacin,tigecycline,vancomycin,linezolid and streptogramin.The ratesof resistance to erythromycin,clindamycin and tetracycline were different in different districts,however,the difference in it between ages and clinical diagnosis did not show statistical significance(P ＞0.05).The detected rate of drug resistance gene ermB was 98.5％ (196/199).The gene ermA was only detected out in 5 strains and the gene mefA was not detected out.199 strains showed A macrolides resistant phenotype cMLS,while the phenotype iMLS was not found in this study.Conclusion This study demonstrates the high level of clindamycin resistance in group A streptococcus collected from children in Beijing,2012.The macrolides resistance of group A streptococcus was highly prevalent in Beijing,and the dominant phenotype was cMLS mediated by gene ermB.