Drug Resistance of MP and Its Mechanism: A Study of Children in Beijing District in 2011

Backgrounds Macrolides( MLs) are considered as the first choice for the treatment of Mycoplasma pneumoniae( MP)-associated respiratory diseases in children and adolescents,but Macrolide-resistance to MP has increased gradually in recent years. Objective To investigate prevalent condition of the Macrolide-resistant MP in Beijing Distrect in 2011 and its molecular mechanism. Methods The throat swab specimens of 205 MP children admitted to Pediatric Departments of Beijing Friendship Hospital and Chaoyang Hospital in the year of 2011 were collected and cultured,and drug sensitivity test performed. Nested PCR amplification method( nPCR) was used to identify MP resistance loci. Results In collected 205 MP strains,there were 59 strains of MP culture positive( 28. 8%); 122 strains of 23S rRNA nPCR positive( 59. 5%),including 19 sensitive strains,103 drug-resistance strains,with a rate of 84. 4%,which were all A2063G point mutations in 23S rRNA V domain. Totally 26 positive MP strains were established,including 2 sensitive strains 〔erythromycin minimum inhibitory concentration( MIC) ≤0. 01 mg / L〕,24 drug-resistance strains( MIC = 32. 00-256. 00 mg / L),with a drug-resistance rate of 92. 3%. And 26 isolates had no gene changes in 23S rRNA Ⅱ domain and had A2063G point mutations in 23S rRNA V domain. One sensitive strain and MP standard strain FH had point mutations at 162 loci C-A and 430 loci A-G of ribosomal protein L4,1 sensitive strain had point mutation of 209 loci A-T; 26 isolates all had 508 loci T-C point mutation of ribosomal protein L22. Conclusion MP is widely prevalent in children and its resistance to MLs is serious. Point mutation in domain Ⅴ of 23S rRNA is the main molecular mechanism. But point mutation in ribosomal protein and the change of amino acid remains unclear,which requires further investigation.