Multicenter Evaluation of the New Etest Gradient Diffusion Method for Piperacillin-Tazobactam Susceptibility Testing of Enterobacterales , Pseudomonas aeruginosa , and Acinetobacter baumannii Complex

Piperacillin-tazobactam (P/T) is a β-lactam–β-lactamase inhibitor combination frequently used in the hospital setting. Etest is a gradient diffusion method that represents an alternative to broth microdilution (BMD) for performing antimicrobial susceptibility testing. We conducted a multicenter evaluation of the performance of the new P/T Etest compared to that of BMD following...