Duration of Antibiotic Therapy for Gram-Negative Bloodstream Infections in the Neonatal Intensive Care Unit

OBJECTIVE: To evaluate the effectiveness and safety of short (≤8 days) vs long (≥9 days) duration of antibiotic therapy for uncomplicated gram-negative (GN) bloodstream infections (BSI) among infants in the neonatal intensive care unit (NICU). STUDY DESIGN: Retrospective analysis of infants treated for GN BSI at 7 NICUs within 2 health care systems. Infants were identified by review of positive blood cultures from the microbiology laboratory and electronic health records. Patients were excluded if they had polymicrobial BSI, meningitis/osteomyelitis/endocarditis, or died before completion of therapy as ordered. The primary outcome was recurrence of BSI with the same organism within 14 days of discontinuation of effective antimicrobial therapy ("treatment failure.") Secondary outcomes were emergence of GN multidrug-resistant organisms (MDRO) and mortality. RESULTS: In all, 76 infants (39 short duration; 37 long duration) were included; 15 (38%) and 25 (69%) infants had a central venous catheter in place at onset of BSI in the short and long duration groups, respectively. Escherichia coli was the most common pathogen in both groups (27 [69%], short duration; 18 [49%], long duration). There were 2 recurrences of BSI, both in the long duration group. Among study infants, 5 had a subsequent GN MDRO infection; all were in the long duration group. CONCLUSIONS: Treatment failure and GN MDROs occurred among infants who received ≥9 days of antibiotic therapy. Shorter antibiotic duration (≤8 days) appeared to be an effective intervention that could reduce antibiotic exposure and its adverse consequences among NICU infants.