肺炎支原体大环内酯类药物耐药机制研究

Molecular mechanisms of macrolide resistance of mycoplasma pneumonia

目的了解本地区儿童肺炎支原体(MP)的感染及大环内酯类耐药基因(23S rRNA)突变与耐药的相关性。方法收集614例肺炎患儿呼吸道样本,实时荧光定量PCR(RT-PCR)检测MP感染及23S rRNA基因2063和/或2064 A→G点突变情况,对MP阳性样本进行药敏试验,分析23S rRNA基因2063和/或2064 A→G点突变与大环内酯类药物耐药相关性。结果 614例样本,MP阳性77例,阳性率为12.5%,其中59例23S rRNA存在2063和/或2064A→G点突变,突变发生率为76.6%。所有突变株对对5种大环内酯类药物均不敏感,所有未突变株5种大环内酯类药物均敏感。结论肺炎支原体对大环内酯类药物耐药严重,耐药机制是23S rRNA基因2063和/或2064 A→G点突变,RT-PCR检测MP感染及23S rRNA基因点突变能为肺炎患儿临床MP感染的诊断和治疗提供一定的参考依据。

Objective To investigate the Mycoplasma pneumoniae（MP） infection in the local children and analyze the relationship between the mutations of macrolide resistance gene locus（23 S rRNA） and drug resistance. Methods A total of 614 respiratory tract samples were collected from children patients with pneumonia. MP infection and locus mutations（2063 A→G and/or 2064 A→G） in 23 S rRNA gene were detected by real-time PCR. Drug susceptibility test was performed on MP-positive samples; to analyze the association between locus mutations（2063 A → G and/or 2064 A → G） in 23 S rRNA gene and macrolide resistance. Results Among 614 respiratory tract samples,77 cases（12. 5%） were MP positive,and the mutations in 23 S rRNA gene were detected in 59 MP positive samples,with the positive detection rate of 76. 6%. All isolates presented mutation in 23 S rRNA gene were not sensitive to 5 macrolide drugs and all non-mutation isolates were sensitive to 5 macrolide drugs. Conclusion Mycoplasma pneumoniae has serious resistance to macrolides. The resistance mechanism is the mutations on 23 S rRNA gene 2063 and/or 2064 A→G loci. RT-PCR detection for MP infection and loci mutation of 23 S rRNA gene can provide a certain reference for the diagnosis and treatment of MP infection in children with pneumonia.