Background: Community-acquired pneumonia (CAP) represents a substantial global health burden; however, the characteristics of its etiological spectrum remain incompletely defined. Targeted next-generation sequencing (tNGS) has significantly advanced the understanding of the etiological spectrum. This study aimed to investigate the pathogen characteristics in CAP patients across different age groups and severity levels based on tNGS results. Methods: We retrospectively analyzed the etiological test results of 272 hospitalized CAP patients at the First Hospital of Shanxi Medical University (Taiyuan, China) from 2021 to 2024. Patients were stratified by age and Pneumonia Severity Index (PSI) score, and their clinical characteristics, etiological spectrum, and infection patterns were systematically evaluated. Results: Among the 145 patients included in the final analysis, 34.48% had simple infections, while 65.52% had multiple infections. Elderly patients (≥ 80 years) exhibited the highest proportion of mixed infections (81.82%), with the detection rates of viruses and fungi—such as Epstein-Barr virus, Human herpesvirus 5, Candida glabrata , and Candida albicans —increasing significantly with advancing age. Younger patients (18– 39 years) were more susceptible to atypical pathogen infections (eg, Mycoplasma pneumoniae ). The proportion of mixed infections in severe cases was significantly higher than that in mild cases (76.92% vs 59.14%), and triple co-infections (involving bacteria, viruses, and fungi) were significantly concentrated in the severe group. Significant specific differences in the composition of the etiological spectrum were also observed among different age and severity groups; for instance, the detection rates of Klebsiella spp . and Acinetobacter baumannii were higher in the elderly and severe groups, whereas atypical pathogens were mainly concentrated in the young group. Conclusion: The etiological spectrum of CAP exhibits significant differences across different age groups and disease severity levels. Therefore, stratified diagnosis and therapeutic strategies should be developed based on age and disease severity to optimize prognosis and reduce the misuse of antibiotics. Keywords: community-acquired pneumonia, age stratification, disease severity, pathogen, tNGS
Cui et al. (Sun,) studied this question.