Macrolide-resistant mycoplasma pneumoniae in respiratory tract infection and its clinical relevance

Abstract

Mycoplasma pneumoniae(MP) is a common etiological agent of pneumonia.Emergence of macrolide-resistant MP(MRMP)is now being reported.This study aims to assess the differences in clinical consequences between infected patients with MRMP and macrolide-susceptible strains(MSMP).One hundred and sixteen MP strains were isolated from 1100 patients with respiratory tract infections by real-time PCR assay from February,2012 to April,2015.Gene sequencing analysis to detect point mutations in 23S rRNA conferring resistant genotypes was performed.Clinical characteristics and outcome of patients with MRMP and MSMP group were compared.Of 116 clinical isolates, 31 (26.7%) were resistant to macrolide.Of 30 MRMP strains harbored an A-to-G transition mutation at position 2063 in 23S rRNA genes and only one was mutated at position 2064.Clinical data were completely available for 104 patients, 25 of whom had infected with MRMP.Demographic data, clinical symptoms, leukocyte counts and chest film findings were similar between both groups.Infected patients with MRMP had history of antibiotic exposure before 3 months more than MSMP group(80% versus 34.2%;P 0.001).Rate of changes from initially prescribed antibiotic therapy to levofloxacin were high in MRMP group(40% versus 0%;P 0.003) and duration of symptom resolution after initiation of antibiotic therapy were longer for the MRMP group than MSMP group (6 days versus 3 days;P 0.01).Infected patients with MRMP have a history of antibiotic exposure, time to resolution of symptoms are significantly longer for those patients.Macrolide-treated patients who are infected with MP and no clinical improvement,levofloxacin is the alternative treatment.