Ertapenem Versus Meropenem for the Treatment of Extended Spectrum Beta-Lactamase-Producing Enterobacterales Bacteremia in Critically Ill Patients

Background: The preferred carbapenem for treatment of infections caused by extended spectrum beta-lactamase-producing Enterobacterales (ESBL-E) in critically ill patients is debated. Objective: The purpose of this study was to evaluate the difference in clinical failure between ertapenem and meropenem for treatment of ESBL-E bacteremia in critically ill patients. Of concern is ertapenem use in hypoalbuminemia given the potential for higher drug clearance. Methods: This retrospective, matched cohort study compared critically ill patients treated with ertapenem or meropenem for ESBL-E bacteremia between October 2016 and August 2022. Patients were matched on age, sex, lowest albumin, and in a 1:2 ratio of ertapenem to meropenem. The primary outcome, clinical failure, was a composite of 30-day mortality, antibiotic escalation, and microbiological failure. Secondary outcomes included all-cause readmission and development of superinfection. Results: Of 54 patients, 18 received ertapenem and 36 meropenem. Most had a urinary infection source (55.6% vs 41.7%, P = 0.393). There was no difference in clinical failure (50.0% vs 38.9%, P = 0.436). Ertapenem patients had antibiotic escalation more often (33.3% vs 2.8%, P = 0.002). There was no difference in 30-day mortality (11.1% vs 27.8%, P = 0.298), microbiological failure (27.8% vs 11.1%, P = 0.142), all-cause readmission (22.2% vs 13.9%, P = 0.461), or development of superinfection (11.1% vs 13.9%, P = 1.000). Conclusion and relevance: There was no difference in clinical failure in a small, retrospective cohort of critically ill patients receiving ertapenem or meropenem for ESBL-E bacteremia. Ertapenem may be appropriate in some critically ill and hypoalbuminemic patients, though additional data are needed.