Comprehensive study of community acquired Mycoplasma pneumoniae pneumonia in children in Baoding, China, 2023

Mycoplasma pneumoniae (M. pneumoniae) is considered to be one of the causative agents of community acquired pneumonia in children with general or severe course of disease. Severe M. pneumoniae pneumonia (SMPP) has emerged as a crucial global health concern due to high mortality rate in children under 5 years, potentially life-threatening complications, and growing challenges in pediatric treatment associated with rising macrolide resistance. Additionally, MPP can be complicated by other bacterial and/or viral pathogens, which may exacerbate disease severity. After the lifting of strict non-pharmaceutical interventions (NPIs) worldwide, the dramatic rise of incidence of MPP in Asia and Europe was observed.

To perform the comprehensive study of community acquired MPP cases registered in 2023 in Baoding Hospital, China.

A total of 1160 children from 1 month to 15 years old with confirmed MPP diagnosis were enrolled in the study. The blood and respiratory samples were collected within the 24 hours after admission. The hematological parameters, biochemical markers, cytokine profiles were assessed. The respiratory samples were tested for the presence of M. pneumoniae and other 23 bacterial/viral pathogens by multiplex polymerase chain reaction (PCR). The macrolide resistance mutations (A2063G, A2064G in the 23S rRNA gene of M. pneumoniae) were determined by PCR.

Number of MPP cases has dramatically increased starting August with peak in November. SMPP and general MPP (GMPP) were identified in 264 and 896 of 1160 hospitalized children. The binary logistic regression analysis identified six [C-reactive protein (CRP), lactate dehydrogenase, procalcitonin, erythrocyte sedimentation rate, fibrin and fibrinogen degradation products (FDPs), D-dimer] and four (neutrophils, CRP, FDPs, prothrombin time) predictors of SMPP in age groups 2-5 years and 6-15 years, respectively. Children with SMPP showed significantly higher levels of cytokine interleukin (IL)-17F (2-5 years), and cytokines interferon-gamma, tumor necrosis factor-alpha, IL-10 (6-13 years). Concomitant viral/bacterial pathogens were determined in 24.3% and 28.0% cases of SMPP and GMPP. Among them, Streptococcus pneumoniae (S. pneumoniae) and Haemophilus influenzae (H. influenzae) were predominant. 93.2% cases of MPP were associated with macrolide resistant M. pneumoniae.

Specific MPP epidemiological pattern associated with lifting NPIs was revealed: Increase of hospitalized cases, prevalence of S. pneumoniae and H. influenzae among concomitant pathogens, 93.2% of macrolide resistant M. pneumonia.