Bacterial viability under combined exposure to cefiderocol and polymyxin B

Bacterial viability under combined exposure to cefiderocol and polymyxin B refers to the physiological state and survival rate of bacteria subjected to the synergistic action of these two antibiotics. Cefiderocol is a siderophore cephalosporin that targets penicillin-binding proteins (PBPs), primarily PBP3, to inhibit cell wall synthesis (PubChem, 2024). It enters the bacterial periplasm by mimicking iron-siderophore complexes, bypassing many porin-related resistance mechanisms. Polymyxin B is a lipopeptide antibiotic that targets the lipopolysaccharide (LPS) in the outer membrane of Gram-negative bacteria, acting as a surfactant to disrupt membrane integrity (StatPearls, 2023). The combination is specifically utilized to combat multidrug-resistant (MDR) pathogens like Carbapenem-resistant Acinetobacter baumannii (CRAB), where polymyxin B may enhance cefiderocol's access to its targets. This therapeutic strategy is evaluated through viability assays and time-kill studies to determine its efficacy in clinical settings where monotherapy is insufficient. Monitoring bacterial viability in this context is essential for optimizing dosing regimens and minimizing the emergence of further resistance.

Other names

Cefiderocol-Polymyxin B synergyBacterial survival under antibiotic combination therapyCefiderocol and polymyxin B combination

Cefiderocol inhibits cell wall synthesis by binding to penicillin-binding proteins (PBPs) after siderophore-mediated entry; Polymyxin B disrupts the outer membrane by binding to lipopolysaccharides (LPS) (FDA, 2019; StatPearls, 2023).