Evaluation of clinical and microbiological factors related to mortality in patients with Gram-negative bacterial infections treated with ceftazidime-avibactam: A prospective multicentric cohort study

Objectives: This study aimed to evaluate the clinical and microbiological risk factors associated with mortality in patients treated with ceftazidime-avibactam for carbapenem-resistant Gram-negative bacterial infections. Methods: This multicentric prospective cohort study included hospitalized adult patients with a microbiologically confirmed infection treated with ceftazidime-avibactam for >= 48 hours. The clinical and microbiological risk factors for 30-day mortality were evaluated using a Cox regression model. Results: Of the 193 patients evaluated from the five tertiary hospitals, 127 were included in the study. Thirty-five patients (27.6%) died within 30 days. Infections with AmpC beta-lactamase-carrying bacteria were independently related to 30-day mortality (adjusted hazard ratio [aHR] 2.49, 95% confidence interval [CI] 1.28-4.84, P < 0.01) after adjusting for time from infection to antimicrobial prescription ( P = 0.04). Further, these bacterial infections were also related to higher in-hospital mortality (aHR 2.17, 95% CI 1.24- 3.78, P < 0.01). Only one patient developed resistance to ceftazidime-avibactam during treatment. Conclusions: Treatment with ceftazidime-avibactam had worse clinical outcomes in patients with infections with bacteria with chromosomally encoded AmpC beta-lactamase. However, these findings should be confirmed in future studies. (c) 2024 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )