 This study will help provide information about how patients with burn handle two antibiotics ceftolozane and tazobactam and use that information to guide dosing recommendations for these patients. The 12 patients who complete the study will receive a single dose of 3 grams ceftolozanetazobactam intravenously. We will collect blood and urine samples to determine how much of each antibiotic is in the body and urine at various times over a 24 hour period. This information will be used with previously published information from microbiology laboratories to perform simulations that will provide recommendations on optimal dosing recommendations of these antibiotics in patients with burns. 