Risk Factors for Serious Bacterial Infection in Febrile Young Infants in a Community Referral Hospital

Differentiation of serious bacterial infection (SBI) from self-limiting viral illness in febrile infants younger than three months is a significant challenge for clinicians. We aimed to assess the risk factors for SBI in febrile infants. Data were obtained from 221 infants younger than three months who visited a single community referral hospital for fever and underwent a complete sepsis workup between August 2003 and July 2006. The causes of fever were febrile illness without a documented cause (FISDC, 65%), urinary tract infection (UTI, 12%), aseptic meningitis (12%), bacteremia (4%), bacterial meningitis (2%). Cerebrospinal fluid enterovirus polymerase chain reaction was positive in 28% of FISDC and 48% of aseptic meningitis cases. When UTI was excluded, the risk factors for SBI were 1) C-reactive protein (CRP) level of ≥1.87 mg/dL and 2) fevers of ≥38.9℃. The specificity and negative predictive values of risk factors 1) and 2) for the diagnosis of SBI were 94% and 95%, respectively. We concluded that enteroviral infection may be a major cause of febrile episodes in infants younger than three months. If UTI could be excluded, the presence of CRP levels ≥1.87 mg/dL and fevers of ≥38.9℃ can be used as criteria to rule out SBI in these infants.