Background: P. aeruginosa is a worrisome multidrug (MDR) or even extensively drug-resistant (XDR) nosocomial pathogen. Ceftolozane/tazobactam(C/T) and ceftazidime/avibactam (CAZ/AVI), novel combinations, were recently approved for the treatment of MDR Gram-negative pathogens. Objective: To assess the in vitro activity of C/T & CAZ/AVI and against MDR/XDR P. aeruginosa isolates , detect the synergi...