Macrolide-resistant Mycoplasma pneumoniae resurgence in Chinese children in 2023: a longitudinal, cross-sectional, genomic epidemiology study.

Summary

Genomic epidemiology showed that two established macrolide-resistant lineages (harboring 23S rRNA A2063G) drove China’s 2023 M. pneumoniae resurgence, with no resurgence-specific mutations. Time-calibrated phylogenies suggest emergence circa 1997 and 2014 with rapid mixing across regions, aligning with historical azithromycin use and underscoring stewardship and surveillance.

Key Findings

• Two macrolide-resistant clusters (T1-2-EC1, T2-2-EC2) with 23S rRNA A2063G drove the 2023 resurgence; no resurgence-specific mutations were detected.
• Lineages likely emerged circa 1997 and 2014 and outcompeted predecessors, coinciding with widespread pediatric azithromycin use.
• Phylogeography showed rapid inter-regional mixing across China, emphasizing surveillance needs.

Clinical Implications

Expect high macrolide resistance in pediatric atypical pneumonia; reinforce diagnostic stewardship, consider alternative therapies, and strengthen genomic surveillance to guide empirical choices.

Limitations

• Clinical phenotype and treatment outcome data were limited; sampling may not uniformly represent all regions/timepoints
• Causality between antibiotic use patterns and lineage expansion is inferred, not proven

Future Directions

Link genomic data with clinical outcomes and antimicrobial exposures; expand international surveillance; assess fitness costs and transmissibility of resistant lineages.