肺炎支原体肺炎患儿肺炎支原体耐药性与DNA载量和基因型的关系研究

Association of drug resistance of Mycoplasma pneumoniae with DNA load and genotypes in children with Mycoplasma pneumoniae pneumonia

摘要:

目的 探讨肺炎支原体（MP）肺炎患儿MP耐药情况及其与DNA载量和基因型的关系。方法 选取2012年1月至2016年12月诊断为MP肺炎的230例住院患儿为研究对象，采集所有患儿咽拭子标本，采用快速培养基培养药敏法测定9种常用抗菌药物对MP临床分离株的药物敏感性；荧光实时定量PCR检测患儿咽拭子MP-DNA载量；PCR测序检测MP 23S rRNA V区2063位基因型。结果 230例MP患儿中，86例2063位基因型为A（37.4%），134例为G（58.3%），8例为C（3.5%），2例为T（0.9%）。突变基因型（G+C+T）MP-DNA载量高于野生基因型（A）菌株（P < 0.05）；红霉素、阿奇霉素、克拉霉素、克林霉素耐药组MP-DNA载量高于非耐药组（P < 0.05）。MP对大环内酯类抗生素耐药率较高，60%以上产生大环内酯类耐药的病例均检测出A2063G突变，喹诺酮类药物少见MP耐药（低于2%）。结论 23S rRNA V区2063位点发生基因突变可能导致MP对大环内酯类药物耐药和DNA载量的变化，可作为MP治疗用药的选择依据。

Abstract:

Objective To investigate the association of drug resistance of Mycoplasma pneumoniae (MP) with DNA load and genotypes in children with MP pneumonia. Methods A total of 230 children who were hospitalized and diagnosed with MP pneumonia between January 2012 and December 2016 were enrolled. Throat swabs were collected from the 230 children, and a rapid drug sensitivity assay was used to determine the sensitivity of clinical isolates of MP to nine commonly used antibacterial agents. Quantitative real-time PCR was used to measure MP-DNA load in throat swabs. PCR sequencing was used to determine the genotype of 2063 locus of the MP 23S rRNA V domain. Results Of the 230 children, 86 (37.4%) had genotype A in 2063 locus, 134 (58.3%) had genotype G, 8 (3.5%) had genotype C, and 2 (0.9%) had genotype T. Mutant strains (genotype G+C+T) had a significantly higher MP-DNA load than wild-type strains (genotype A) (P < 0.05). The strains resistant to erythromycin, azithromycin, clarithromycin, and clindamycin had a significantly higher MP-DNA load than non-resistant strains (P < 0.05). MP had a high drug resistance rate to macrolide antibiotics. More than 60% of the cases with resistance to macrolides were found to have A2063G mutations. MP was rarely resistant to quinolones (less than 2%). Conclusions Mutations in 2063 locus of the MP 23S rRNA V domain may result in the resistance of MP to macrolides and the change in DNA load and can be used as a basis for selecting drugs for MP.