433 - Antibiotic Stewardship in VLBW Newborns

Publication Number: 2421.433

Ishani Mehta, Georgetown University School of Medicine, washington, DC, United States; Ayah Arafat, MedStar Health Research Institute, Washington, DC, United States; Jayashree Ramasethu, MedStar Georgetown University Hospital, Washington, DC, United States

Background: Very Low Birth Weight (VLBW) infants have non-specific signs that mimic early onset sepsis (EOS), leading to empiric antibiotic use. Despite reliable blood culture systems, antibiotics are often continued beyond 48 hours in culture-negative infants, exposing them to increased risks of necrotizing enterocolitis and mortality.

Objective: To assess the compliance with AAP 2019 antibiotic stewardship guidelines for suspected EOS in VLBW newborn and identify barriers to timely antibiotic discontinuation.

Design/Methods: In this IRB approved retrospective cohort study, we reviewed the medical records of VLBW infants admitted within 24 hours of age to our Level IV NICU between Jan 2018 and Dec 2024 to study temporal changes in antibiotic use. Risk factors, Score for Neonatal Acute Physiology Perinatal Extension (SNAPPE II) and mortality rates were compared between 4 groups of infants: culture positive, culture-negative receiving antibiotics for >48 hours, culture-negative receiving antibiotics for ≤ 48 hours, infants who received no antibiotics in the first week. Chi squared test (Yate's correction), t-test and non-parametric tests were used to compare categorical and continuous variables. Multivariate logistic regression was used to assess which variables were associated with prolonged antibiotic use in culture negative patients.

Results: In 279 VLBW infants with blood cultures at birth, 214 (76%) received antibiotics (Tab. 1). Seven (2.5%) infants had positive cultures; 46 infants (16.5%) with negative culture received antibiotics for > 48 hours, and 161 (57.7%) infants with negative culture were treated for ≤48 hours. The number of VLBW newborns who received no antibiotics for EOS increased from 16 % in 2018 to 28 % in 2024. The use of prolonged antibiotics for culture negative VLBW newborns decreased from 41% % in 2018 to 9% by 2024 (Fig. 1).
Tab. 1 shows the gestational age, birth weight, risk factors and SNAPPE in infants in the 4 groups. Birth weight, gestational age, preterm labor, PPROM, and SNAPPE (0-12 hours and 24-48 hours) were not independently associated with prolonged antibiotic use despite showing significance in univariate analyses. Multivariate analysis showed chorioamnionitis as an independent predictor of prolonged antibiotic use (adjusted OR: 3.50; 95% CI: 1.23-10.00, p=0.018) after controlling for other factors.

Conclusion(s): Despite decrease in antibiotic use for culture negative infants, continued antibiotic use appeared to be driven by risk factors and severity of illness (SNAPPE). Evaluation of a larger cohort of VLBW infants may clarify this further.

Table 1: Comparison of risk factors and severity of illness in VLBW neonates with blood cultures at birth
GA Gestational age, PPROM Preterm premature rupture of membranes, PTL preterm labor, SNAPPE Score for Neonatal Acute Physiology Perinatal Extension, NEC necrotizing enterocolitis

*= p< 0.5 in comparisons of VLBW newborns who received antibiotics for > 48 hrs versus newborns who received antibiotics for ≤ 48 hrs. Other comparisons were not statistically significant.

Fig 1. Trends in prolonged antibiotic usage in VLBW newborns with negative blood cultures at birth %), with mean gestational age and median Score for Neonatal Acute Physiology with Perinatal Extension (SNAPPE II) scores from 2018 to 2024.