Antibiotic exposure in culture-negative preterm infants: a 10-year single-centre study

Antibiotic exposure in neonatal intensive care units (NICU) is high. This study describes antibiotic use in very preterm infants and examines the association between duration of exposure and outcomes in blood culture negative (CN) infants.

Infants <32 weeks' gestation admitted between January 2012 and June 2022 were included in this retrospective cohort study. Data were extracted from electronic databases. Antibiotic exposure was calculated as duration of treatment (DOT) and antibiotic utilisation rate (AUR) and compared with neonatal outcomes including mortality, late onset sepsis (LOS), necrotising enterocolitis (NEC), chronic lung disease (CLD), severe retinopathy of prematurity (ROP) and/or severe brain injury.

There were 3235 CN infants included in the study; 1601 (49.5%) received antibiotics for ≤ 2 days of which 266 (8.2%) received no antibiotics; 841 (26.0%) received antibiotics for ≥ 5 days. DOT decreased from 78.0 to 61.9 per 1000 and AUR from 0.07 (IQR 0.04-0.11) to 0.05 (IQR 0.03-0.10) from 2012 to 2022. Higher AUR and/or prolonged antibiotic exposure was associated with increased mortality, brain injury, NEC, ROP, LOS, and CLD.

Antibiotics are critical for infants with sepsis but can cause harm in those without. Strategies to reduce antibiotic exposure are needed to improve preterm infant outcomes.

Prolonged antibiotic exposure is common in culture-negative, very preterm infants. Although antibiotics are critical for infants with culture-positive sepsis, they can cause harm in those who are culture-negative. This study adds to the small pool of evidence examining antibiotic use and its association with increased morbidity and mortality in very preterm infants. The study findings will impact antibiotic prescribing practices significantly and result in strategies to reduce antibiotic exposure in these at-risk infants.