Should antibiotics be discontinued at 48 hours for negative late-onset sepsis evaluations in the neonatal intensive care unit?

Objective: To establish the appropriate length of antibiotic therapy for negative late-onset sepsis evaluations in the neonatal intensive care unit (NICU), based on time to detection of positive bacterial cultures. Study Design: Culture results from late-onset sepsis evaluations between January 1, 1994 and June 30, 1998 from outborn neonates at the Arkansas Children's Hospital NICU were retrospectively reviewed. The time period from specimen collection to notification of NICU personnel was calculated for positive cultures. Results: There were 2783 blood, 724 urine, and 294 cerebrospinal fluid cultures obtained, of which 10.2%, 6.6%, and 5.4%, respectively, were positive for bacterial isolates. Of positive cultures, 98% had a time to detection ≤48 hours. Of cultures that became positive >48 hours, 7 of 8 grew coagulase-negative staphylococci; 4 were contaminants. Conclusion: Discontinuing antibiotic therapy for neonates with possible late-onset sepsis and negative cultures at 48 hours is appropriate and is now standard care in our NICU.