Clinical Factors Associated with Inappropriate Antibiotic Use in Children with Acute Bronchiolitis

Background/Objectives: Although serious bacterial infections are rare in children with acute bronchiolitis, which is predominantly caused by respiratory viruses, antibiotics are often prescribed. This study aimed to identify clinical factors associated with inappropriate antibiotic use in children with acute bronchiolitis. Methods: We retrospectively reviewed the medical records of 612 children aged 3 to 23 months who were hospitalized with their first episode of acute bronchiolitis. Based on antibiotic prescription at admission, children were categorized into two groups: the antibiotic group and the non-antibiotic group. Clinical variables were compared between groups to identify factors associated with inappropriate antibiotic use. Results: Of the 612 children included, 514 (84.0%) received antibiotic therapy on admission. Bacteremia was diagnosed in 0.5% of the cohort. In multivariate analysis, fever (p = 0.002) and C-reactive protein ≥0.50 mg/dL (p < 0.001) were independently associated with inappropriate antibiotic use. The duration of fever after admission was significantly longer in the antibiotic group than in the non-antibiotic group (p = 0.005). Conclusions: Despite the very low prevalence of serious bacterial infections and lack of clinical benefit, most children hospitalized with acute bronchiolitis received antibiotic therapy. Inappropriate antibiotic use was primarily driven by fever and elevated C-reactive protein levels, which lacked sufficient diagnostic justification.