Optimizing Antibiotic Treatment Duration for ESBL-Producing Enterobacteriaceae Bacteremia in ICU: A Multicentric Retrospective Cohort Study

Background: The optimal duration of antibiotic treatment for extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) bloodstream infections (BSI) in intensive care unit (ICU) is not established. We aim to evaluate the frequency and clinical outcomesof a short appropriate antibiotic treatment (≤7 days) (SAT) for ESBL-E BSI acquired in the ICU. We specifically assessed the rate of ESBL-E BSI relapse, and in-ICU mortality. Method: All patients who acquired ESBL-E BSI in three ICU in Northern France between January 2011 and June 2022 were included in a multicenter retrospective cohort study. The factors associated with prescribing short (SAT, ≤7 days) versus long (LAT, >7 days) antibiotic treatment were analyzed. To evaluate the impact of SAT on mortality in the ICU, an estimation was applied using a Cox model with a time-dependent co-variable adjusted by inverse weighting of the propensity score. Results: In total, 379 patients were included. The proportion of patients receiving a SAT was 40% in the entire cohort and 25% in survivors beyond 7 days. In bivariate analysis, the factors associated with prescribing a SAT in survivors were shorter pre-bacteremia ICU stay (<i>p</i> = 0.005), lower proportion of chronic renal failure history (<i>p</i> = 0.034), cancer (<i>p</i> = 0.042), or transplantation (<i>p</i> = 0.025), less frequent exposure to carbapenem within 3 months (<i>p</i> = 0.015). There was a higher proportion of septic shock (<i>p</i> = 0.017) or bacteremia secondary to pneumonia (<i>p</i> = 0.003) in the group of survivors receiving a LAT. After adjustment, no difference in survival was found between the two groups (HR: 1.65, 95%CI: 0.91–3.00, <i>p</i> = 0.10). Conclusion: In our cohort, one quarter of patients with ESBL-E bacteremia acquired in the ICU surviving beyond 7 days were treated with a SAT. SAT did not appear to affect survival. Patients who could benefit from a SAT need to be better identified.