Duration of empiric antibiotics for suspected early-onset sepsis in extremely low birth weight infants.

Objectives: To study multicenter antibiotic practices for suspected early-onset sepsis (EOS) with negative blood cultures (NegBCs) and to identify opportunities for reduction of antimicrobial exposure.

Design: Retrospective study.

Setting: Thirty academic hospitals (University HealthSystem Consortium) located in 24 states.

Methods: Data were from a survey of 790 extremely low birth weight (ELBW) infants. Total antibiotic exposures (antibiotic-days per patient) were calculated.

Results: On admission to the NICU, 94% of 790 ELBW infants had BCs performed and empiric antibiotics initiated. When PosBC and NegBC infants were compared, 47 patients with PosBCs were similar to 695 with NegBCs in birth weight, gestational age (GA), and mortality. Patients with suspected EOS but NegBCs given ampicillin/aminoglycosides were grouped by length of administration and GA. For GA of 26 weeks or younger, 170 infants given a short (< or = 3 days) and 157 given a long (> or = 7 days) course were similar regarding birth weight, mortality, antepartum history, and CRIB scores, but were different (P < .01) in number receiving a third antimicrobial (3% and 17%) and antibiotic-days (23 and 38). For GA of 27 weeks or older, 113 infants given a short and 77 given a long course differed (P < .01) in number receiving a third antimicrobial (2% and 23%) and antibiotic-days (19 and 30).

Conclusions: Most suspected EOS infants with NegBCs are given antibiotics, but no antepartum historical risk factors or neonatal clinical signs explained prolonged administration. Discontinuing empiric antibiotics when BCs are negative in asymptomatic ELBW infants can reduce antimicrobial exposure without compromising clinical outcome.