Invasive and urinary tract infections in febrile neonates in the emergency department: a retrospective analysis.

This study aimed to describe the epidemiology, microbiology, and antibiotic resistance of invasive bacterial infections and urinary tract infections in febrile neonates evaluated in the emergency department, and to assess the value of clinical features and CRP in their identification. Retrospective review of medical records from neonates ≤ 28 days admitted for fever to the emergency department of a Belgian tertiary hospital between January 2020 and December 2022. Among 189 febrile neonates, 8% had a urinary tract infection, predominantly caused by Escherichia coli, and 1.6% had an invasive bacterial infection. Ampicillin resistance was frequent. Urinary tract infections were more common in males and associated with fever ≥ 38.5 °C, fever documented in the emergency department, and absence of rhinorrhea. A CRP level below 5 mg/L excluded urinary tract infection with a 100% negative predictive value and no invasive bacterial infection was observed below this threshold, while levels of 15 mg/L or higher were strongly associated with urinary tract infection-though sensitivity was limited, as one invasive bacterial infection occurred with CRP levels below 10 mg/L.

conclusionUrinary tract infections were frequent in this neonatal population and associated with specific clinical features. Invasive bacterial infections were rare, and CRP should be interpreted with caution, as low values do not reliably exclude them. WHAT IS KNOWN: • Febrile neonates are at risk of invasive bacterial infections; clinical signs and biomarkers are often unreliable. • Empirical management exposes many to unnecessary lumbar puncture and antibiotics. WHAT IS NEW: • In this Belgian cohort, invasive bacterial infections were uncommon (1.6%), while urinary tract infections accounted for 8%, mostly due to Escherichia coli. • Urinary tract infections were more frequent in males and linked to specific features. CRP <5 mg/L excluded urinary tract infection. Low CRP could not reliably exclude invasive bacterial infection.