A Selective Culture Medium for Screening Ceftazidime-Avibactam Resistance in and Pseudomonas aeruginosa.

The SuperCAZ/AVI medium was developed for screening ceftazidime-avibactam (CZA) resistance among Gram-negative bacteria ( and ). It was evaluated using 50 CZA-susceptible and 42 CZA-resistant Gram-negative isolates. Its sensitivity and specificity of detection were 100%. Excellent performance of the medium was also observed by testing spiked stools, with the lower limit of detection ranging from 10 to 10 CFU/ml. This screening medium provides the opportunity to detect CZA-resistant isolates regardless of their resistance mechanisms.