In Vitro Antibacterial Properties of Cefiderocol, a Novel Siderophore Cephalosporin, against Gram-Negative Bacteria

Cefiderocol (CFDC; S-649266), a novel parenteral siderophore cephalosporin conjugated with a catechol moiety, has a characteristic antibacterial spectrum with a potent activity against a broad range of aerobic Gram-negative bacterial species, including carbapenem-resistant strains of and nonfermenting bacteria such as and Cefiderocol has affinity mainly for penicillin-binding protein 3 (PBP3) of and nonfermenting bacteria similar to that of ceftazidime. A deficiency of the iron transporter PiuA in or both CirA and Fiu in caused 16-fold increases in cefiderocol MICs, suggesting that these iron transporters contribute to the permeation of cefiderocol across the outer membrane. The deficiency of OmpK35/36 in and the overproduction of efflux pump MexA-MexB-OprM in showed no significant impact on the activity of cefiderocol.