Targeted next-generation sequencing reveals pathogen spectrum distribution and hematological correlations in children...

To analyze the pathogen spectrum, age and seasonal distribution, and multi-infection patterns in children hospitalized with acute lower respiratory infections (ALRIs). To explore correlations between major pathogens and hematological and immune indicators.

This retrospective study involved 893 hospitalized children who underwent targeted next-generation sequencing (tNGS). Sputum or bronchoalveolar lavage fluid samples were collected. Baseline characteristics, infection types, seasonal distribution, and hematological indicators were recorded. The χ² test or Fisher's exact test was employed to compare subgroup differences. Co-infection networks were constructed. Spearman's correlation analyzed pathogen-hematological associations.

A total of 88 pathogens were detected, with Mycoplasma pneumoniae being the most prevalent (61.70%). Major bacteria included Haemophilus influenzae (25.87%), Streptococcus pneumoniae (22.84%), and Staphylococcus aureus (20.16%). Multi-infections accounted for 71.00%, mainly "Mycoplasma + bacteria". Viral and fungal infections predominated in infancy, while Mycoplasma detection peaked in school-age children. A high incidence was in the spring. Fungal infections were prominent in summer. Mycoplasma pneumoniae infection was positively associated with IgG, IgA, and IgM levels. Streptococcus pneumoniae and Haemophilus influenzae showed pronounced positive correlations with CRP and NEU%, while conditional pathogens like Klebsiella pneumoniae correlated negatively with immunoglobulins.

tNGS comprehensively elucidates the pathogen spectrum and multi-infection characteristics in pediatric ALRIs. Distinct pathogens exhibit specific hematological and immune correlation patterns, facilitating early identification of infection types and optimization of empirical therapy, thereby supporting precise clinical management.