Post-pandemic resurgence of Mycoplasma pneumoniae and its emerging link with Rhinovirus in children

BACKGROUND: Mycoplasma pneumoniae (MPP) infections occur regularly every 1 to 3 years. A wave of infections was anticipated around late 2022 to early 2023. However, our data revealed a delayed onset, with a notable increase in cases in 2023/24. This study describes pediatric MPP detections during this resurgence and explores clinical differences between MPP mono-detection and MPP with rhinovirus/enterovirus (RV/EV) co-detection. METHODS: We retrospectively analyzed PCR-confirmed MPP detections in children aged 0-17 years presenting to a tertiary pediatric hospital between 2017 and 2024. Cases from 2017 to 2022 were used as descriptive historical background data (G1, n = 10), while the main analysis focused on the 2023/24 cohort (G2, n = 87). Within this cohort, children with MPP mono-detection were compared with those with MPP plus RV/EV co-detection. Group comparisons were performed using chi-square or Fisher's exact test and t-test or Mann-Whitney U test, as appropriate. RESULTS: Ten sporadic MPP detections occurred between 2017 and 2022, compared with 87 detections in 2023/24, indicating a marked increase in hospital presentations. Because of the small historical group, comparisons with 2023/24 were interpreted descriptively. In the 2023/24 cohort, RV/EV was the most frequent viral co-detection. Compared with children with MPP mono-detection, children with MPP plus RV/EV co-detection were more often male, were less frequently febrile, and showed lower inflammatory parameters, including lower rates of elevated CRP and higher rates of leukopenia and neutropenia. CONCLUSION: In 2023/24, Mycoplasma pneumoniae infections surged dramatically, accompanied by an unprecedented rise in Rhino/Enterovirus coinfections especially in young, male patients. While these findings highlight a potentially important phenotypic pattern, further prospective studies are needed to clarify causality, temporal sequence, and distinct underlying mechanisms.