Mortality and clinical outcomes of ceftazidime/avibactam vs best available therapy in treating carbapenem-resistant enterobacterales infections: A retrospective cohort study

Objective: The epidemiology of infectious diseases shows that antimicrobial resistance (AMR) is a global health issue.This study aimed to compare 14-day mortality in patients with confirmed Carbapenem-resistant Enterobacterales (CRE) infections treated with Ceftazidime/Avibactam (CAZ-AVI) to the best available therapies (BAT) in the Kingdom of Saudi Arabia where there is a predominance of the OXA-48 gene.Methods: This retrospective cohort study included adult patients with confirmed CRE infections treated with CAZ-AVI or BAT between 2018 and 2021.The Cox proportional hazards model was applied to derive both unadjusted and adjusted hazard ratios for 14-days and 30-day mortality.Bivariate analyses included chi-squared tests for categorical data, ttests and Mann-Whitney tests for continuous data. Results:The study included 157 patients; of those, 88 (56 %) were males, 63 (40.1%) had malignancy, and the mean age was 54.85 years.Seventy (44.59%) received CAZ-AVI.Bacteraemia (28%) and urinary tract infections (27.3%) were the most common sources.Klebsiella pneumonia (126, 80.25%) was the predominant pathogen, with OXA-48 gene identified in 35.67% of cases.The risk of 14-day mortality for patients treated with Ceftazidime/Avibactam was significantly lower compared to patients treated with the best available therapies (adjusted HR = 0.45, 95% CI = 0.22-0.92). Conclusion:CRE represents a global threat and is associated with high mortality and morbidity.Ceftazidime/Avibactam was associated with a lower risk of 14-day mortality in patients treated for CRE infections.Larger-scale prospective trials to confirm the outcomes of this study are needed.