Katosova L K, Lazareva A V, Khokhlova T A, Ponomarenko O A, Alyabieva N M
Antibiot Khimioter. 2016 Aug;61:23-29.
The frequency and mechanisms of resistance to macrolides in Streptococcus.pyogenes isolated within 3 periods: 2011-2012 (246 strains), 2013-2014 (273 strains) and from January to November of 2015 (120 strains) were studied. The strains of S.pyogenes (639) were isolated from 17107 nasopharyngeal, vaginal and middle ear discharge smears of children on their visits to physiciants or hospitalization at somatic hospital departments. The susceptibility was tested by the disk diffusion method and E-test strips. Identification of the mechanisms of resistance to macrolides and lincosamides included phenotypic and molecular genetic methods. PCR was used to determine ermB and mef genes in 23 erythromycin resistant isolates. As compared to 2011-2012, resistance of S.pyogenes to macrolides increased from 5 to 16% in 2015 and that to clindamycin from 2 to 10%. Among 23 erythromycin resistant strains 6 (26.1%) belonged to the M phenotype, 3 (13.0%) belonged to the iMLS(b) phenotype and 14 (60.9%) belonged to the cMLS(b) pheno-type. The results of detecting the macrolide resistance genes in S.pyogenes showed that only 26.1% of the isolates expressed the mefA gene. The predominant share (65.2%) of the erythromycin resistant isolates possesed the ermB gene as a determinant and in 4.3% of the isolates the ermB gene was associatied with the mefgene. No resistance genes were detected 1 isolate. Therefore, the main mech- anism that determined resistance of S.pyogenes to macrolides was methylation of ribosomes mediated by the ermB gene.
对2011 - 2012年（246株）、2013 - 2014年（273株）以及2015年1月至11月（120株）这三个时间段分离出的化脓性链球菌对大环内酯类抗生素的耐药频率及机制进行了研究。639株化脓性链球菌菌株是从17107名儿童前往综合医院科室就诊或住院时的鼻咽、阴道及中耳分泌物涂片样本中分离得到的。采用纸片扩散法和E-test试纸条检测药敏性。对大环内酯类和林可酰胺类抗生素耐药机制的鉴定包括表型和分子遗传学方法。采用聚合酶链反应（PCR）检测23株红霉素耐药菌株中的ermB和mef基因。与2011 - 2012年相比，2015年化脓性链球菌对大环内酯类抗生素的耐药率从5%升至16%，对克林霉素的耐药率从2%升至10%。在23株红霉素耐药菌株中，6株（26.1%）属于M表型，3株（13.0%）属于iMLS(b)表型，14株（60.9%）属于cMLS(b)表型。化脓性链球菌大环内酯类耐药基因检测结果显示，仅26.1%的分离株表达mefA基因。红霉素耐药分离株中主要部分（65.2%）携带ermB基因作为决定因素，4.3%的分离株中ermB基因与mef基因相关。有1株未检测到耐药基因。因此，决定化脓性链球菌对大环内酯类抗生素耐药的主要机制是由ermB基因介导的核糖体甲基化。
