In Vitro Efficacy of Ceftazidime-Avibactam on Carbapenem-Resistant Pseudomonas aeruginosa Isolates

Pseudomonas aeruginosa is the main Pseudomonas species causing hospital infections. Ceftazidime-avibactam (CZA) is a new beta-lactam/beta-lactamase inhibitor combination effective against carbapenem-resistant P. aeruginosa isolates. The aim of this study was to evaluate the in vitro activity of CZA against carbapenem-resistant P. aeruginosa isolates. In hospitalized patient culture samples, 190 isolates that were evaluated as significant growth and identified as P. aeruginosa with the Vitek 2 Compact automated system (BioMérieux, France) and determined as imipenem resistant (≥ 8 mg/L) and meropenem resistant (≥ 16 mg/L)with the same system were included in the study. 88% (167/190) of P. aeruginosa strains were isolated from patients in intensive care units and 78% (148/190) from respiratory tract samples. CZA activity was studied with disk diffusion test (10-4 µg disk) and zone diameters