Cefiderocol is a powerful, broad spectrum antibiotic approved to treat hospital-acquired or ventilator associated pneumonia and urinary tract infections. Although cefiderocol has labeled dosing recommendations, including augmented renal clearance, patients with burn injury remain an unstudied population at high risk for MDR pathogens. The primary objective of this study is to evaluate the pharmacokinetic principles of cefiderocol in patients after acute burn injury. Findings from this study will determine the dose and interval necessary to maintain therapeutic concentrations of cefiderocol in patients after burn injury for adequate bactericidal activity, prevention of resistance, and treatment outcomes.

Twelve patients with burn injuries will be enrolled after written consent is obtained. Six interval-specific samples will be drawn from each patient, depending on the dosing regimen chosen.

Inclusion Criteria: 1) age ≥ 18 and ≤ 80 years old, 2) estimated CLCR (eCLCR) ≥ 60 mL/min via Cockcroft-Gault equation Exclusion Criteria

1) KDIGO classification ≥ 1 at day of screening, 2) known HIV or HBV infection Non-compartmental modeling via WinNonlin and Monte Carlo simulation will be used to determine the probability of cefiderocol dosing regimens achieving the fT>MIC threshold for P.aeruginosa. Safety monitoring for adverse events will occur daily up to and through the sampling period.

Inclusion Criteria:

• age ≥ 18 and ≤ 80 years old
• estimated CLCR (eCLCR) ≥ 60 mL/min via Cockcroft-Gault equation

Exclusion Criteria:

• KDIGO classification ≥ 1 at day of screening
• known HIV or HBV infection