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

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 r RNA 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(P0.05);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(P0.05)。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 r RNA 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。

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

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.