Prevalence of serious bacterial infections in return visits to the emergency department among infants aged 90 days or younger.

OBJECTIVE: The main objective of this study was to describe the epidemiology of return visits (RVs) in well-appearing infants to an urban emergency department (ED) who were evaluated for serious bacterial infection (SBI) at their index ED visit. METHODS: We conducted a retrospective chart review on infants aged 90 days and younger who were evaluated for SBI at their initial ED visit from 2003 through 2009. A parent database of all febrile infants evaluated for SBI was queried to identify patients who had an RV within 7 days of the index visit. We collected demographic variables including age, sex, and past medical history as well as laboratory test results including white blood cell count, blood, urine, and cerebrospinal fluid cultures and viral studies. RESULTS: Of eligible febrile infants, 10.8% (350/3220) had an RV to the ED within 7 days. The prevalence of SBI in the RV cohort was 6.0% (21/350), which included 1.7% (6/350) bacteremia, 3.7% (13/350) urinary tract infection, and 0.6% (2/350) combined urinary tract infection and bacteremia. The blood culture contamination rate was 88%. CONCLUSIONS: Infants aged 90 days or younger who are evaluated for SBI have high RV rates. A substantial number of RVs are due to contaminated blood cultures. Future studies should be conducted to identify predictors for false-positive blood cultures.