cefiderocol + sulbactam

Cefiderocol + sulbactam is a combination of two antibacterial agents used primarily for the treatment of infections caused by multidrug-resistant Gram-negative bacteria, especially carbapenem-resistant Acinetobacter baumannii (CRAB). Cefiderocol is a novel siderophore cephalosporin that utilizes both passive diffusion and active transport via bacterial iron channels to enter the periplasmic space, where it binds to penicillin-binding proteins (primarily PBP3), inhibiting cell wall synthesis and leading to bacterial cell death. It is structurally stable against all classes of β-lactamases, including serine- and metallo-β-lactamases. Sulbactam is a β-lactamase inhibitor with intrinsic activity against Acinetobacter species; it inhibits class A β-lactamases and weakly inhibits Acinetobacter-derived cephalosporinases (ADCs), thereby restoring or enhancing the activity of partner antibiotics like cefiderocol. The combination has been investigated for synergistic effects in vitro and in vivo against CRAB isolates, though some studies have reported potential antagonism depending on strain-specific factors. This regimen may be considered as salvage therapy for severe infections due to extensively drug-resistant A. baumannii when other options are limited[1][2][4][5].