Avoid continuing antibiotic treatment in newborns after 36–48 hours if blood cultures show no growth and the clinical condition is normal

Rationale:

Antibiotics disrupt the normal bacterial colonization of newborns. Prolonged antibiotic use in the neonatal period is associated with an increased risk of later infections, necrotizing enterocolitis, mortality, and potential long-term effects. 

References:

• Kuppala VS et al. Prolonged Initial Empirical Antibiotic Treatment is Associated with Adverse Outcome in Premature Infants. J Pediatr 2011; 159: 720-725. 
• Cotten CM et al. Prolonged Duration of Initial Empirical Antibiotic Treatment Is Associated With Increased Rates of  Necrotizing Enterocolitis and Death for Extremely Low Birth Weight Infants. Pediatrics 2009; 123:58-66.
• Cotten CM. Adverse Consequences of Neonatal Antibiotic Exposure. urr Opin Pediatr 2016; 28: 141-149.
• Arboleya S et al. Intestinal Microbiota Development in Preterm Neonates and Effect on Perinatal Antibiotics. J Pediatr 2015; 166: 538-44.
• Esaiassen E et al. Antibiotic exposure in neonates and early adverse outcomes: a systematic review and meta-analysis. J Antimicrob Chemother 2017; 72: 1858-70.