High-Risk CCL14 lineage drives severe Mycoplasma pneumoniae pneumonia in children: a study in central China.

BACKGROUND

The post-coronavirus disease 2019 (COVID-19) pandemic resurgence of Mycoplasma pneumoniae (MP) infections, particularly in China, underscores the need to understand the drivers of disease severity.

PURPOSE: This study aimed to evaluate the association between predominantly circulating MP strains and disease severity in Henan Province, central China.

METHODS

We integrated the clinical data of 3,060 pediatric patients and analyzed the epidemiological characteristics of MP pneumonia (MPP) in the Henan region in 2020-2024. Bronchoalveolar lavage fluid collected from 137 patients was analyzed using multilocus sequence typing and multilocus variable number tandem-repeat analysis to investigate the correlation between genotype and clinical outcome.

RESULTS

A significant post-COVID MPP outbreak was predicted in 2023. Genotyping revealed the cocirculation of 2 major genotypes: the prevalent ST3 (57.7%, severe ratio [31.6%]) and the less common but highly virulent ST14 (26.3%, severe ratio [72.2%]). Phylogenetic clustering confirmed ST14/3-5-6-2 as part of a broader hypervirulent lineage, common cluster label 14 (CCL14), which was significantly associated with disease severity (χ2=19.39; P<0.001). Patients infected with CCL14 strains exhibited a distinct hyperinflammatory profile marked by elevated D-dimer levels, complement C4 levels, and platelet count. The mutation ratio of macrolide resistance sites in the MP strains from Henan Province was approximately 75%.

CONCLUSION

Our findings identified the CCL14 lineage as a key driver of disease severity in macrolide-resistant pediatric MPP in Henan Province, China. This under scores the importance of integrating molecular surveillance with clinical monitoring to mitigate disease burden.