Characteristics and Outcomes of Patients Treated with Carbapenem Versus Non-carbapenem Therapy for AmpC-Producing Enterobacterales Bacteremia: A Retrospective Study.

Introduction: Inducible AmpC β-lactamases in Gram-negative Enterobacterales pose therapeutic challenges. Although carbapenems are the preferred treatment, other antibiotics can serve as a viable alternative. Studies comparing treatment options report varied outcomes. This study evaluates 30-day mortality, treatment failure, and length of hospitalization in patients with AmpC-producing Enterobacterales bacteremia.

Methods: This retrospective cohort study included adult patients with bacteremia caused by AmpC-producing Enterobacterales. Exclusion criteria included: therapy duration < 72 h, coinfection, resistant isolates, and death within 72 h of diagnosis. Patients were divided into definitive carbapenem and noncarbapenem therapy. The primary outcome was 30-day mortality, while secondary outcomes evaluated treatment failure and length of hospitalization. Statistical analysis used descriptive statistics, group comparisons, and logistic regression.

Results: Of 214 screened patients, 80 met the inclusion criteria. Enterobacter cloacae (60%) was the predominant pathogen, primarily originating from line-related infections (55%). Carbapenems were the primary empirical (45%) and definitive (75%) therapies; 30-day mortality was higher in the non-carbapenem group (20% versus 3.3%, p = 0.08). Treatment failure was significantly higher in the non-carbapenem group (20% versus 1.6%, p < 0.01). The mean hospital stay was longer in the carbapenem group (26 ± 38.40 days) than the non-carbapenem group (11.15 ± 7.15 days, p = 0.87). Older age was significantly associated with higher mortality (odds ratio (OR) 1.07, 95% confidence intervals (CI): 0.98-12.20, p = 0.015).

Conclusions: Carbapenem use was significantly associated with improved survival, highlighting its importance in treatment strategies. Age significantly affects survival, stressing the need for personalized treatments. Further research and strategies are needed to address clinical failures and enhance antimicrobial stewardship.