Clinical features and factors associated with severe illness in pediatric acute respiratory tract infections due to Escherichia coli: a retrospective tNGS-based study.

To investigate the detection rate, clinical characteristics, and factors associated with intensive care unit (ICU) admission in hospitalized children with acute respiratory tract infection (ARTI) involving Escherichia coli (E. coli). Bronchoalveolar lavage fluid samples from 4,199 hospitalized children were tested using targeted next-generation sequencing (tNGS). Clinical characteristics, laboratory parameters, imaging findings, and outcomes of E. coli-positive children were analyzed, with comparisons between ICU and non-ICU groups. E. coli was detected in 107 cases (2.5%). The median age was 7 months; males accounted for 70.1%, and 29.0% had underlying diseases. Mixed infections occurred in 95.3% of cases, with cytomegalovirus (47.7%), Pneumocystis jirovecii (38.3%), Mycoplasma pneumoniae (28.0%), and rhinovirus (27.1%) being the most common co-pathogens. Chest CT findings mainly showed increased bronchovascular markings (78.2%) and patchy opacities (72.3%). Respiratory support was required in 43.9% of cases, and 18.7% were admitted to the ICU. The median hospital stay was 9 days, and 95.3% were discharged after recovery. Compared with the non-ICU group, the ICU group had higher proportions of children aged ≤ 1 month (25.0% vs. 8.0%), underlying diseases (50.0% vs. 24.1%), fever, tachypnea, and dyspnea, as well as elevated procalcitonin and D-dimer levels (all P < 0.05). The detection rate of E. coli in hospitalized children with ARTI was 2.5%, predominantly affecting young infants and frequently involving underlying comorbidities (29.0%). Mixed infections are common, and 18.7% of patients require admission to the ICU. Young age, underlying diseases, fever, tachypnea, and elevated procalcitonin and D-dimer levels were clinical features significantly associated with ICU admission in affected children.