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, t-tests 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.