Participants will receive 4-6 doses of cefiderocol 2 grams every 6-8 hours, in addition to standard intravenous antibiotic therapy selected by the site. Just prior and then after the final dose, a total of nine blood samples will be collected to measure cefiderocol concentrations. Data will be fit to a population pharmacokinetic model. The final model will be utilized in a Monte Carlo simulation to determine the probability of several different dosing regimens retaining concentrations above the minimum inhibitory concentration (MIC) for at least 75% of the dosing interval. These data will be utilized to determine an optimized dosing regimen for adults with CF.
