Real-world performance of susceptibility testing for cefiderocol: insights from a prospective multicentre study on Gram-negative bacteria.

Objectives: Cefiderocol is a novel siderophore-conjugated cephalosporin developed for the treatment of multidrug-resistant Gram-negative bacterial (GNB) infections. However, the current gold standard for cefiderocol susceptibility testing, broth microdilution (BMD) using iron-depleted cation-adjusted Mueller-Hinton broth, presents challenges for many microbiology laboratories. In this study, we evaluate the real-world performance of disc diffusion (DD) and a commercial BMD method (ComASP) to test cefiderocol susceptibility in a series of isolates collected prospectively from severely ill patients in a multicentre study.