Reassessing Cefiderocol for NDM-Producing AMR Infections

"Reassessing Cefiderocol for NDM-Producing AMR Infections" considers whether emerging data justify treating cefiderocol as a co-preferred agent for NDM. Cefiderocol sits alongside aztreonam-avibactam as a preferred option for NDM-producing Enterobacterales in the guidance, but a growing body of laboratory and clinical evidence has led the panel to question that parity. Dr. Haidar explains the drug's siderophore mechanism, in which it exploits bacterial iron transport systems to enter the cell, while cautioning that mutations in those transporters can blunt its activity.

He shares that his own practice has shifted away from cefiderocol for NDM producers, and he voices concern about baseline and treatment-emergent resistance to both preferred agents as global travel and transplant tourism introduce more resistant strains. Dr. Pogue reinforces this view, noting that cefiderocol minimum inhibitory concentrations (MICs) for NDM producers tend to cluster near the susceptibility breakpoint.

Dr. Pogue also points to a recent bloodstream infection trial in which a small subgroup with metallo-beta-lactamase producers showed an unfavorable mortality signal with cefiderocol. Taken together with less favorable pharmacokinetic-pharmacodynamic profiles, he believes the emerging evidence supports preferential use of aztreonam-avibactam. Dr. Shields adds mechanistic nuance, explaining that cefiderocol is stable against some metallo-beta-lactamases but is hydrolyzed by NDM, depending on the variant.

Dr. Shields also raises drug access, reminding viewers that clinicians outside the United States may lack these agents and must optimize what they have. Dr. Tamma questions whether the US breakpoint is set higher than clinical effectiveness supports, noting that the European breakpoint is lower and that certain NDM variants show reduced susceptibility. She mentions an investigational inhibitor that could eventually restore activity. For now, the panel advises clinicians to weigh cefiderocol cautiously in NDM infections and to expect future guidance to revisit its standing.

Dosing these agents in critically ill patients is the focus of "Dosing Novel AMR Agents During Renal Replacement Therapy," where the pharmacists on the panel offer practical guidance.