Resurgent Pediatric Mycoplasma pneumoniae in Taiwan Linked to Emerging Resistant Subclades

Researchers examined laboratory surveillance and clinical records from four Chang Gung Memorial Hospital branches in Taiwan during 2017–2024 to assess pediatric Mycoplasma pneumoniae infections, intensive care unit (ICU) admissions, and central nervous system (CNS) complications. The study also included a prospective 2023–2024 cohort of 226 children with laboratory-confirmed infection and phylogenetic analysis of 698 genomes.

Compared with the 2019 peak, infection incidence doubled in 2024 to 546 per 100,000 population. ICU admission incidence increased 2.2-fold to 10.9 per 100,000, while CNS complications increased 13.7-fold to 6.1 per 100,000. In the prospective cohort, factors associated with ICU admission included neutrophils above 7,000/μL (adjusted odds ratio [aOR] 6.2), platelets above 400,000/μL (aOR 12.5), pleural effusion (aOR 9.7), and CNS involvement (aOR 27.9). Confidence intervals were wide; for CNS involvement, the 95% interval was 4.1–188.3.

Genomic analysis identified four emerging subclades that replaced pre-pandemic lineages by mid-2024; one was associated with severe outcomes. These findings support enhanced surveillance and attention to neurologic manifestations, but do not establish that bacterial genetic changes caused greater severity. Clinician-directed testing and estimated hospital catchment populations may affect incidence estimates. The prospective cohort excluded several chronic conditions, limiting generalizability. The journal article is an early-release version subject to revision.