Bone and Skin / Subcutaneous Tissue Concentrations of Cefiderocol During Treatment of Extensively Drug Resistant Pseudomonas aeruginosa.

Pyoderma gangrenosum is a rare dermatologic disorder that disrupts the skin barrier, requiring immunosuppressive therapy. We successfully used cefiderocol for the treatment of an extensively drug-resistant Pseudomonas aeruginosa bacteremia, and presumed osteomyelitis in a patient with severe pyoderma gangrenosum and associated immunosuppressive therapy while being medically optimized for skin grafting. We obtained bone and skin / subcutaneous tissue while the patient was on cefiderocol under an institutional review board approved biologic waste recovery protocol. Cefiderocol concentrations in bone and skin / subcutaneous tissue were 13.9 and 35.9 mcg/g, respectively. The patient recovered from bacteremia and underwent autografting without further complications. Cefiderocol at approved dosing of 2 grams IV (3-hour infusion) every 8 hours resulted in bone and skin / subcutaneous tissue concentrations adequate to treat extensively drug resistant Gram-negative bacteria that remain susceptible to cefiderocol.