Association Of Drug Resistance Of Mycoplasma Pneumoniae With DNA Load And Genotypes In Xiamen’s Children

Objective To investigate the association of drug resistance of Mycoplasma pneumoniae(MP)with DNA load and genotypes in Xiamen’s children.Methods(1)A total of 230 children who were hospitalized and diagnosed with MP pneumonia between January 2012 to December 2016 were enrolled in Xiamen Maternal and Children’s Hospital,male 122,female 108,age from 1 year 3 month to 8 year 3month,average age 4.8±1.9,collected their oropharyngeal swabs.(2)A rapid drug sensitivity assay was used to determine the sensitivity of clinical isolates of MP to nine commonly used antibacterial agents(erythromycin,azithromycin,roxithromycin,clarithromycin,acetylspiramycin,clindamycin,Levofloxacin,gatifloxacin,sparfloxacin).The MP-DNA load were detected by real-time quantitative PCR,and the genotype of loci 2063 of 23 S rRNA gene were detected by PCR.(3)Statisticsed MP drug resistance in Xiamen,divided all cases into resistant strains and non-resistant strains according to drug sensitivity test,compared their MPLI,knew about the association of MP 9 kind antibiotic resistance and MP-DNA load,compared the resistant strains MP 23 S rRNA V Genotypes,analysised the association of MP-DNA load and MP 23 S rRNA V Genotypes,sequencing probability test was used in all analysis and P<0.05 was considered as significance.Results(1)In Xiamen,70.4% and 73.0% MP were resistant to erythromycin,roxithromycin;52.2% and 55.6% MP were resistant to acetylspiramycin,clindamycin;24.4% and 34.8% MP were resistant to azithromycin,clarithromycin;less than 2% to quinolones(levofloxacin,gatifloxacin,sparfloxacin),all MP were sensitive to sparfloxacin.(2)The resistant strains MP-DNA load were higher than non-resistant strains,the difference was statistically significant(P<0.05)between erythromycin,azithromycin,clarithromycin and clindamycin,but not significant between roxithromycin,acetylspiramycin,levofloxacin and gatifloxacin.(3)During the 230 cases,the genotypes of 86 cases were A(37.4%),134 cases were G(58.3%),8 cases were C(3.5%),2 case were T(0.9%).The MP-DNA load of the mutant strains were higher than that of the wild type strains,and the difference was statistically significant(P<0.05).(4)2063 locus of 23 S rRNA V region may lead to MP drug resistance to macrolides and thechange of MP-DNA load,can be used to MP drugs selection.(5)MP-DNA load objective response the balance of MP and host’s immune clearance,was worth spreading on clinic.But MPLI level can be used for predicting MP drug resistance still need multicenter and large sample to confirm.Conclusion Nowadays in Xiamen,MP drug resistance to macrolides is less than other region reported,less than 35% are resistant to azithromycin and clarithromycin,but is sensitive to quinolones.Mutations in the 2063 locus of 23 S rRNA V region may affect the generation of drug resistance and the change of DNA load for MP.And the genotyping may be used as the basis for the selection of antibiotic drug use during the MP treatment.