Key Findings

Cefiderocol showed high in vitro activity against carbapenem-resistant gram-negative bacteria, with resistance mechanisms involving beta-lactamase genes (bla OXA-66, bla OXA-23, bla SHV-12), mutations in envZ, cirA, nuoC, and ampC, and loss or altered expression of iron transporter genes (piuA, pirA, fepA).