Epidemiological characteristics of severe community-acquired pneumonia in children admitted to two tertiary hospitals in Shihezi, Xinjiang Region, China in 2023: a cross-sectional analysis. Journal of thoracic disease Background:Severe community-acquired pneumonia (SCAP) in children is associated with high morbidity and mortality, and the data of epidemiological characteristics of SCAP in Shihezi area were inadequate. The main pathogens responsible for SCAP may vary dramatically according to the geographical area. We identified two tertiary hospitals with better medical level and the largest number of hospitalized children in Shihezi as sentinel hospitals. The primary purpose of the study is to cross-sectionally summarize the epidemiological characteristics of SCAP in children admitted to hospitals in Shihezi, Xinjiang, China in 2023. Methods:SCAP was defined as involving the respiratory and other systems, accompanied by significant systemic toxic symptoms. We prospectively included all patients <15 years old who diagnosed with SCAP according to the SCAP diagnostic criteria. We enrolled all patients <15 years who were diagnosed with SCAP during the study period (January to December 2023), a total of 309 cases were included from two sentinel hospitals in Shihezi, Xinjiang, from January to December 2023. Basic information and clinical data were collected on a standardized questionnaire, and respiratory samples were obtained for the detection of 27 respiratory pathogens using a panel, targeted next-generation sequencing (t-NGS), and metagenomic next-generation sequencing (mNGS). Results:We enrolled 309 patients aged 1-14 years: 157 males (50.8%) and 152 females (49.2%). There were 45 infants (1 month to 1 year, 14.6%), 33 toddlers (>1-3 years, 10.7%), 121 preschool children (>3-7 years, 39.2%), and 110 school-age children (>7-14 years, 35.6%). Overall, the number of SCAP cases in spring was 39 (12.6%), in summer was 44 (14.2%), in autumn was 137 (44.3%), and in winter was 89 (28.8%). A total of 572 pathogens were detected in this study, primarily (MP) (n=120, 21.0%), respiratory syncytial virus (RSV) (n=82 strains, 14.3%), and (SP) (n=67, 11.7%). MP was prevalent mainly during the cold season of autumn, with its detection starting from July and reaching a peak detection rate in November. By studying the interaction among 22 common respiratory pathogens, we found a strong negative correlation between MP and SP, yet the highest number of co-infected cases involved MP and SP. Seventy-six (63.3% of all MP) SCAP were identified as macrolide-resistant (all with mutations at the A2063G site). MP SCAP was associated with prolonged illness duration and fever spikes. We observed incidence of pediatric SCAP showed an inverse trend with PM2.5 level changes. Conclusions:The most common pathogens responsible for SCAP in the Shihezi region in 2023 were MP, RSV, and SP. MP was the primary cause of SCAP in children, and increased risk of co-infections, and high prevalence of macrolides resistance-all related to mutations at the A2063G site. Early identification of SCAP pathogen epidemiological characteristics can reduce severe case occurrence. 10.21037/jtd-24-1417