High co-infection burden and ICU-specific pathogen profiles in pediatric Candida albicans respiratory infections: a large-scale tNGS analysis.

Background: Candida albicans is a significant opportunistic pathogen in pediatric respiratory infections, yet systematic analyses of its role in hospitalized children remain scarce. This study evaluates the prevalence, clinical profiles, and outcomes of C. albicans-associated respiratory infections in this population.

Methods: From April 2021 to December 2024, 10,310 pediatric inpatients with respiratory infections at Guangxi Zhuang Autonomous Region Maternal and Child Health Hospital underwent pathogen screening via targeted next-generation sequencing (tNGS).

Results: C. albicans was detected in 5.0% (511/10,310), with detection rates varying by specimen: highest in sputum (10.3%), followed by bronchoalveolar lavage fluid (8.8%), and minimal in throat swabs (0.3%). Co-infections occurred in 99.0% (506/511), predominantly involving Mycoplasma pneumoniae (189), Haemophilus influenzae (174), and Rhinovirus (169). ICU patients (6.3%) demonstrated elevated inflammatory markers (PCT: 0.31 vs. 0.08 ng/mL; D-dimer: 795 vs. 360 ng/mL FEU; P < 0.001), prolonged hospitalization (median 17 vs. 7 days, P < 0.001), and distinct pathogens (Acinetobacter baumannii vs. M. pneumoniae in non-ICU). 51.7% and 35.4% of the children experienced respiratory and other systemic complications, respectively. Among the 511 children diagnosed with C. albicans infection, 32 (6.3%) required ICU admission for monitoring. The median duration of hospitalization for these 511 children was 7 days. Of these, 482 (94.3%) recovered and were discharged following treatment, while 26 (5.0%) had family members who requested voluntary discharge due to unsatisfactory outcomes or other reasons. Unfortunately, 3 children (0.6%) died despite receiving intensive medical treatment.

Conclusion: This large-scale tNGS-based study addresses critical knowledge gaps, revealing ICU-specific pathogen profiles (A. baumannii), high co-infection burdens (99.0%), and complications linked to prematurity/immunodeficiency. The predominance of lower respiratory tract involvement (sputum/BALF positivity) underscores the need for specimen-selective diagnostics. Findings advocate for optimized tNGS protocols, ICU-tailored antimicrobial strategies, and early interventions in high-risk subgroups to reduce morbidity (e.g., sepsis risk) and socioeconomic burdens.