Ceftazidime-Avibactam Compared With Doripenem Followed by Oral Therapy for Hospitalized Adults With Complicated UTIs (Urinary Tract Infections)

Inclusion Criteria: * 18 to 90 years of age inclusive * Female patients can participate if they are surgically sterile or completed menopause or females capable of having children and agree not to attempt pregnancy while receiving IV study therapy and for a period of 7 days after * Has pyuria with \>/= 10 WBCs (white blood cell) and has a positive urine culture within 48 hours of enrollment containing \>/=10 to the fifth CFU (colony forming unit ) /ml of a recognized uropathogen known to be susceptible to IV study therapy (CAZ-AVI and doripenem) * Demonstrates either acute pyelonephritis or complicated lower UTI without pyelonephritis. Exclusion Criteria: * Urine pathogen is a Gram-positive pathogen or a uropathogen resistant to CAZ-AVI or doripenem * Patient's urine culture at study entry isolates more than 2 microorganisms regardless of colony count or patient has a confirmed fungal UTI * Patient is receiving hemodialysis or peritoneal dialysis or had a renal transplant * Patient is immunocompromised * Patient is considered unlikely to survive the 6- to 8-week study period or has a rapidly progressive or terminal illness including septic shock which is associated with a high risk of mortality