 A single dose pharmacokinetic study of ceftolozane and tazobactam will be conducted in patients with burns at the Burn Center at Parkland Memorial Hospital. The Burn Center was established in 1962 and was expanded last year to include 12 intensive care unit beds and 18 acute care beds. The Burn Center meets the criteria of the American Burn Associations Burn Center VerificationConsultation Program has Burn Center Verification status. A total of 12 adults aged 18 to 80 years with 20 percent total body surface area burned will be required to complete the study. A single intravenous dose of ceftolozane and tazobactam of 2 grams1 gram will be administered over 60 minutes and whole blood will be obtained predose and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, and 24 hours following the start of infusion. Urine samples 5 ml will be collected from a urine collection bag if the patient has urinated at the following timepoints: 0-0.5, 0.5-1, 1-2, 2-4, 4-8, 8-12, and 12-24 hours for analysis of ceftolozane and tazobactam content. Urine for collected during each time period will be measured to determine urine volume for urine clearance calculations. The volume of urine in the urine over the entire 24 hour period and an aliquot sent for analysis of urine creatinine content to determine the patients 24 hour creatinine clearance. 