Abstract:
OBJECTIVE To investigate the age stratification and mixed infection characteristics of the pathogen spectrum in bronchoalveolar lavage fluid (BALF) based on targeted next-generation sequencing (tNGS), thereby providing references for clinical interpretation of tNGS reports and formulating precise age-tailored anti-infection strategies.
METHODS A retrospective analysis was performed on the tNGS results of 799 screened BALF samples collected from multiple hospitals in Henan Province between Sep. 2024 and Dec. 2024. The patients' data were stratified into five age groups: ≤18 years (n=49), >18–40 years (n=77), >40–65 years (n=315), >65–80 years (n=288) and >80 years (n=70). The overall pathogen spectrum and mixed infection characteristics were analyzed, and differences in pathogen distribution across age groups were compared.
RESULTS Among the 799 samples, 739 (92.49%) were positive, including 494 (66.85%) cases of mixed infection and 245 (33.15%) cases of single infection. A total of 107 pathogens and 1 856 strains were detected, with the top three being Klebsiella pneumoniae (8.51%), Candida albicans (6.52%) and Pseudomonas aeruginosa (5.33%). Additionally, gram-negative bacteria predominated (32.92%), followed by viruses (23.55%) and fungi (20.58%). In mixed infection samples, C. albicans, Acinetobacter baumannii and K. pneumoniae exhibited the highest mixed infection rates (96.69%, 96.15% and 87.97%, respectively). Age-stratified analysis revealed statistically significant differences among groups in the number of pathogen types, single infection rates and mixed infection rates (all P<0.001). The ≤18 years group was characterized by Mycoplasma pneumoniae, Haemophilus influenzae and Staphylococcus aureus (RR=9.39, 2.19 and 3.67, respectively), while the >80 years group was dominated by K. pneumoniae and Corynebacterium striatum (RR=1.68 and 4.58, respectively).
CONCLUSIONS The tNGS facilitates systematic analysis of complex pathogen spectra and mixed infection patterns in BALF. The distribution of pathogens and mixed infection profiles exhibit significant age-specificity, providing significant insights for clinical interpretation of tNGS reports and the development of age-tailored precision anti-infection strategies.