Evaluation of imipenem-relebactam susceptibility testing in carbapenem resistant Pseudomonas aeruginosa: comparison of sensititre microplates, disc diffusion, and MTS gradient strips with broth microdilution.

Four commercial tests EUMDROXF Sensititre microplates, MTS gradient strips, and disc diffusion were evaluated for imipenem-relebactam susceptibility in 148 ceftazidime and imipenem-resistant Pseudomonas aeruginosa strains, using broth microdilution (BMD) as the reference. EUMDROXF Sensititre microplates showed the highest accuracy (CA = 93.2%, EA = 93.

Performance of discs, sensititre EUMDROXF microplates and MTS gradient strips for the determination of the susceptibility of multidrug-resistant Pseudomonas aeruginosa to cefiderocol.

Objectives: To evaluate the performance of commercially available tests to determine the susceptibility of multidrug-resistant (MDR) clinical Pseudomonas aeruginosa strains to cefiderocol.

Methods: A collection of 150 clinical strains of P. aeruginosa resistant to ceftazidime, (MIC, Minimal Inhibitory Concentration, MIC > 8 mg/L) imipenem (MIC> 4 mg/L) and ceftolozane/tazobactam (MIC> 4/4 mg/L), isolated from 2015 to 2022 was selected.