Double-, single- and none-carbapenem-containing regimens for the treatment of carbapenem-resistant Enterobacterales (CRE) bloodstream infections: a retrospective cohort

Objectives To investigate the effect of double-, single- and none-carbapenem-containing antimicrobial regimens in the treatment of patients with carbapenem-resistant Enterobacterales (CRE) bloodstream infections (BSIs). Methods We conducted a retrospective cohort study from 2013 to 2020 in two Brazilian hospitals. Patients >= 18 years old with CRE BSI were included and excluded if death or treatment duration for <= 48 h after BSI or non-Class A-producing carbapenemase isolates. We evaluated the impact of different carbapenem-containing regimens on 30 day mortality through a propensity score adjusted model and a Cox proportional hazards model. Results Two-hundred and seventy-nine patients were included for analyses: 47 (16.9%), 149 (53.4%) and 83 (29.8%) were treated with double-, single- and none-carbapenem-containing regimens, respectively. One-hundred and seventeen (41.9%) patients died in 30 days. Treatment with a single-carbapenem regimen was associated with a lower risk of death in 30 days compared with therapies containing no carbapenem [adjusted HR (aHR) 0.66, 95% CI 0.44-0.99, P = 0.048], when adjusted for Charlson score and ICU admission at baseline, while double-carbapenem regimens were not associated with a lower risk of death (aHR 0.78, 95% CI 0.46-1.32, P = 0.35). Propensity score adjusted model results went in the same direction. Conclusions Double-carbapenem- was not superior to single-carbapenem-containing regimens in patients with CRE BSIs. Single-carbapenem-containing schemes were associated with a lower mortality risk.