A week-by-week analysis of the low-risk criteria for serious bacterial infection in febrile neonates

Abstract

Objective: To examine the reliability of “low-risk” criteria (LRC) to exclude serious bacterial infection (SBI) in febrile neonates (≤28 days), according to age in weeks.

Design: Epidemiological and clinical data and final diagnosis of all febrile neonates presenting to the emergency room from June 1997 to May 2006 were reviewed. Neonates who fulfilled specific LRC for the presence of SBI were classified as LRC+. The prevalence of SBI and the percentage of LRC+ neonates who had SBI were calculated for each of the first 4 weeks of life.

Results: A total of 449 neonates were evaluated. Eighty-seven (19.4%) neonates had an SBI. The prevalence of SBI among infants 3–7, 8–14, 15–21 and 22–28 days of age was 21.6%, 26.1%, 17.9% and 12.1%, respectively (p = 0.007 for linear trend after second week of life). Of the 226 LRC+ neonates, 14 (6.2%) had an SBI, including one case of bacteraemia and meningitis and 13 cases of urinary tract infection (UTI). The negative predictive value (NPV) of the LRC for SBI was 93.8% (95% CI 90.1% to 96.4%). The prevalence of SBI among LRC+ infants 3–7, 8–14, 15–21 and 22–28 days of age was similar, with rates of 15%, 6.3%, 3.0% and 6.7%, respectively.

Conclusion: LRC are not sufficiently reliable to exclude the presence of SBI, including bacteraemia and meningitis in febrile neonates of all ages. All febrile neonates should therefore be hospitalised, undergo a full “sepsis evaluation” and receive empirical intravenous antibiotic therapy.