Macrolide-resistant Mycoplasma pneumoniae prevalence at 94% in pediatric CAP cohort

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Frontiers in Medicine Published April 23, 2026 Medically reviewed May 25, 2026 DOI ↗ By Dr. Sofia Müller, MD · Lifespan & Whole-Person Care

Key Takeaway

Consider that macrolide-resistant M. pneumoniae is highly prevalent and linked to worse clinical outcomes in this pediatric cohort.

This retrospective cohort study included 71 pediatric patients with confirmed Mycoplasma pneumoniae community-acquired pneumonia in Anhui, China. The study compared macrolide-resistant M. pneumoniae (MRMP) infection to macrolide-susceptible M. pneumoniae (MSMP) infection.

The prevalence of macrolide resistance was 67 of 71 isolates (94.4%). The predominant molecular mechanism was the A2063G mutation, found in 81.7% of resistant isolates. MIC50/MIC90 for erythromycin was 126/512 μg/mL, and for azithromycin was 16/126 μg/mL.

Clinical outcomes were worse with MRMP. Median fever duration was 6.5 days for MRMP vs 4.0 days for MSMP. Median hospitalization duration was 7.0 days for MRMP vs 5.0 days for MSMP. Median hs-CRP was 11.2 mg/L for MRMP vs 4.8 mg/L for MSMP. Median LDH was 258.5 U/L for MRMP vs 210.3 U/L for MSMP. Treatment failure or antibiotic switch rates were 20.9% for MRMP vs 0% for MSMP. MRMP was associated with more persistent cough and delayed radiographic resolution.

Safety and tolerability were not reported. Key limitations include an extremely small comparator group (n=4 MSMP), the descriptive nature of the analysis, and the retrospective design. The practice relevance is that MRMP prevalence exceeded 94% in this cohort, and MRMP infections were associated with a prolonged clinical course and elevated inflammatory markers. Associations are reported, not causal, due to the observational design.

Study Details

Study typeCohort

EvidenceLevel 3

PublishedApr 2026

View Original Abstract ↓

IntroductionMacrolide-resistant Mycoplasma pneumoniae (MRMP) has reached extremely high prevalence among children in Asia. However, genotype -phenotype correlations and their impact on clinical outcomes in pediatric community-acquired pneumonia (CAP) remain insufficiently characterized in many regions of China. This study aimed to determine the prevalence, molecular mechanisms, antimicrobial susceptibility, and clinical characteristics of macrolide resistance in children with M. pneumoniae CAP in Anhui, China.MethodsA retrospective cohort study was conducted among 71 pediatric patients with confirmed M. pneumoniae CAP between October 2023 and September 2024. Macrolide resistance was assessed using 23S rRNA domain V sequencing and broth microdilution minimum inhibitory concentration (MIC) testing. Clinical features, laboratory markers, treatment response, and outcomes were descriptively compared between macrolide-resistant M. pneumoniae (MRMP) and macrolide-susceptible M. pneumoniae (MSMP) cases.ResultsOf the 71 isolates, 67 (94.4%) were macrolide-resistant, predominantly harboring the A2063G mutation (81.7%). The MIC₅₀/MIC₉₀ values for erythromycin and azithromycin were 126/512 μg/mL and 16/126 μg/mL, respectively. Compared with the small MSMP group (n = 4), children with MRMP appeared to have longer median fever duration (6.5 vs. 4.0 days), longer hospitalization (7.0 vs. 5.0 days), higher hs-CRP (11.2 vs. 4.8 mg/L), higher LDH (258.5 vs. 210.3 U/L), more persistent cough, delayed radiographic resolution, and higher treatment-failure or antibiotic-switch rates (20.9% vs. 0%).DiscussionMacrolide resistance exceeded 94% and was mainly driven by the A2063G mutation, accompanied by high MIC values. MRMP infections were associated with prolonged clinical course and elevated inflammatory markers; however, these findings should be interpreted cautiously due to the extremely small comparator group and the descriptive nature of the analysis.