Duration of Antibiotic Therapy for Escherichia coli Bacteremia in Infants Without Cerebrospinal Fluid Evaluation.

OBJECTIVE

Escherichia coli is a leading cause of Gram-negative rod bacteremia in infants. Cerebrospinal fluid (CSF) evaluation is often deferred, and guidance on antibiotic duration is lacking in these circumstances. We evaluated whether treatment duration is associated with infection recurrence or mortality.

METHODS

This cohort study included infants discharged from Pediatrix Medical Group neonatal intensive care units (NICUs) from 1997 to 2022 with first instance of E coli bacteremia. Infants with CSF evaluation, delayed antimicrobial initiation (>2 days), or death/discharge during therapy were excluded. Antibiotic duration was categorized as <14, 14-21, or >21 days. Associations between treatment duration and 30-day and in-hospital mortality and the combined outcome of recurrence of infection or death within 30 days were evaluated by using 2-way tabulations and inverse probability weighted regression adjustment (IPWRA) models. Sensitivity analysis excluded courses <5 days.

RESULTS

We included 1125 infants with E coli bacteremia. After adjusting for gestational age, postnatal age, number of positive cultures, and severe disease, shorter courses were associated with higher 30-day and in-hospital mortality and the combined outcome. IPWRA modeling confirmed lower risks among infants treated for longer durations. The results were similar in the sensitivity analysis.

CONCLUSIONS

While the optimal duration of therapy for infants with E coli bacteremia without CSF evaluation requires further evaluation, our data suggest that infants should receive antibiotic therapy for at least 14 days and that longer durations (21 days) can be considered.