Clinical severity and co-infection of respiratory pathogens among children and adolescents with Mycoplasma pneumoniae infection in Guangzhou, China: a single-center retrospective cohort study

Abstract Background Mycoplasma pneumoniae (MP) is a major cause of respiratory infections in children and adolescents. COVID-19 pandemic control measures may have disrupted the respiratory microenvironment and increased the risk of co-infection associated with severe community-acquired pneumonia (CAP). Previous studies on MP co-infections were limited by small samples and lacked generalizability, with little evidence on MP-bacterial co-infection. This retrospective cohort study investigated co-infections and clinical severity in pediatric MP patients in Guangzhou. Methods In this single-center retrospective cohort study, patients aged ≤ 18 years with confirmed MP infection were recruited from July 2023 to January 2024 in Guangzhou, China. Blood and/or respiratory specimens were collected for respiratory pathogen testing. Participants who completed testing for all 8 viral and 5 bacterial pathogens were included in the multivariable analyses. Multivariate logistic regression and negative binomial regression models were applied to investigate the co-infection patterns and clinical severity of MP infection. Findings A total of 1499 patients (mean [SD] age: 6.39 [3.49], 50.7% males) with confirmed MP infection were enrolled during the study period. The majority of patients (68%, 1020/1499) were hospitalized, among whom 62% (630/1020) had severe infection. HPIV (7.5%) was the most common co-pathogen with MP, followed by IFV (7.2%). MP-HPIV co-infection predominated from early July to late September 2023 and then decreased, while MP-IFV co-infection remained common throughout the study period. Hospitalized patients had a higher overall rate of MP-viral co-infection and MP-bacterial co-infection than outpatients. Multivariate analysis of the respiratory co-infection patterns revealed that co-infection of MP with adenovirus, human metapneumovirus, human parainfluenza virus, human rhinovirus, influenza A and B viruses, Klebsiella pneumoniae , or Streptococcus pneumoniae was associated with a significantly higher risk of severe clinical outcomes, longer hospital stay, and longer fever duration. Conclusions Children with MP infection were associated with the occurrence of severe disease, particularly those aged 0–5 years. These findings suggest that age-adapted clinical management strategies for MP cases should be developed, with special attention to specific co-infection patterns to improve the prognosis of MP infection.