TITLE: Antibiotic Therapy in Moderate to Late Preterm Infants with Presumed Early Onset Sepsis is Associated with Aberrations to Feeding Tolerance and Hyperbilirubinemia

Presumed early onset sepsis (PEOS) requiring antibiotics is concerning for our cohort of moderate to late preterm infants. Studies on very premature neonates have shown disruption to feeding tolerance achievement. We aimed to assess whether this concern is valid in our cohort and whether a link existed to prolonged jaundice. A single site retrospective study was performed on infants born between 32 + 3 and 36 + 6 weeks (2016 to 2019). PEOS infants on antibiotics (ABX) were strictly matched by gestational age (± 1 day) and birthweight (± 5%) against a reference group of non-PEOS infants (REF). Key outcomes included: enteral feeding commencement and achievement; feeding intolerance (FI); phototherapy commencement and duration; antibiotic therapy duration; maximum bilirubin (MaxBili); length of stay (LEN); net post-birth weight gain. ABX(n = 185):REF(n = 185) univariate and multivariable analysis revealed (respectively): delayed enteral feed commencement (p < 0.001, p < 0.001); no difference in FI; delayed onset of peak jaundice (p = 0.002, p = 0.001); increased duration of phototherapy (p = 0.016, p = 0.001); increased LEN (p < 0.002, p < 0.035). Univariate analysis also showed (ABX:REF): no significant difference in MaxBili; delayed full enteral feed achievement (p = 0.010). Univariant or multivariable analysis found no difference in irradiance level. However, for REF infants having 0 or 1 lights, there was a bias towards increased irradiance for ABX infants (< 0.001, 0.037 respectively). In moderate to late preterm infants, PEOS antibiotic therapy is associated with negative impacts on feeding and jaundice, adding to an infant’s burden of suffering.