PSHP 2026 Residency Conference

Purpose: 
The aim of this study was to evaluate the impact of albumin status on clinical and microbiological outcomes of patients treated with ertapenem or meropenem for ESBL-E bacteremia, and to identify factors associated with treatment failure.
 
Methods:
We conducted a dual-center, retrospective cohort study of adult patients admitted between October 1, 2022, and October 1, 2025, who received ertapenem or meropenem for the treatment of ESBL-E bacteremia (ceftriaxone-resistant Escherichia coli, Klebsiella spp. (non-aerogenes), or Proteus spp.). Patients were stratified by albumin status (L-Alb: serum albumin < 2.5 mg/dL or N-Alb: serum albumin ≥ 2.5 mg/dL) and carbapenem selection. The primary outcome was a composite of treatment failure: death, readmission for related infectious causes, recurrent infection, or absence of clinical improvement by day 14. Secondary outcomes included 30-day all-cause mortality and evaluation of clinical characteristics hypothesized to be associated with treatment failure. Categorical variables were compared using chi-square or Fisher’s exact tests. A multivariable logistic regression was performed to identify factors independently associated with outcomes.
 
Results: 
Among 203 patients with a median age of 63 years, 23.6% had L-Alb, and 49.8% were immunocompromised. Bacteremia was primarily caused by E. coli (57.6%) from urinary or intra-abdominal sources, and the 30-day all-cause mortality rate was 14.3%. The primary outcome occurred in 24.6% of the cohort. Treatment failure was higher in patients with L-Alb versus N-Alb (47.9% vs 17.4%, P < 0.01) and with ertapenem in relation to albumin status (42.3% vs 12.9%, P < 0.01), but not with meropenem (54.5% vs 35.5%, P = 0.17). On multivariable analysis, L‑Alb (OR 2.76, 95% CI [1.26-6.04]) and lack of source control (OR 4.45, 95% CI [1.77-11.22]) independently predicted treatment failure, while ertapenem did not appear to (OR 0.42, 95% CI [0.19–0.93]).
 
Conclusion: 
Our study presents medically complex patients with ESBL-E bacteremia not limited by infectious source. While prior literature cautions against ertapenem in patients who are critically ill and/or with L-Alb, our data suggests that poor ertapenem efficacy is multifactorial. Although failure rates were higher in patients with L-Alb receiving ertapenem, ertapenem did not appear to be associated with increased failure after adjusting for confounders.