Molecular epidemiology of Mycoplasma pneumoniae pneumonia in children, Wuhan, 2020-2022

Abstract Background Mycoplasma pneumoniae ( M. pneumoniae ) is an important pathogen of community-acquired pneumonia in children. However, prior to this study, there was a lack of research on the genotypes and macrolide resistance monitoring of M. pneumoniae in Wuhan. The factors contributing to the severity of illness caused by M. pneumoniae infection are still under investigation. We aimed to evaluate the clinical manifestations, genotypes, macrolide resistance, respiratory microenvironment, and their relationship with the severity of illness in children with M. pneumoniae pneumonia in Wuhan. Results Among 1,259 clinical samples, 461 samples were positive for M. pneumoniae via qPCR. We successfully identified the P1 genotypes of 127 samples based on metagenomic and Sanger sequencing, with P1-type 1 (113/127, 88.98%) being the dominant genotype. In addition, we identified the MLST genotypes of 67 samples, with ST-3 being the most common (60/67, 89.6%), followed by ST-14 (5/67, 7.4%) and ST-7 (2/67, 3%). No significant difference in pathogenicity was observed among different genotypes. The macrolide resistance rate of M. pneumoniae isolates was 96% (48/50) and all mutations were A2063G in domain V of 23S rRNA gene. There was no significant difference between the upper respiratory microbiome of patients with mild and severe symptoms. The pan-genome analysis revealed that the genome of M. pneumoniae is highly conserved, with the core genome comprising 79% of the total genome length. In addition, the initial serological test cannot accurately diagnose M. pneumoniae infection. qPCR is suitable for detecting M. pneumoniae infection, while IgM titers greater than 1:160 can be used as a predictor of severity. Conclusions This study is the first to characterize the epidemic and genomic features of M. pneumoniae in Wuhan after the COVID-19 outbreak in 2020, which provides a scientific data basis for monitoring and infection prevention and control of M. pneumoniae in the post-pandemic era.