a. Pyelonephritis and normal urinary tract anatomy (no more than 30% of the total population), OR b. cUTI with at least one of the following conditions associated with a risk for developing cUTI: i. Indwelling urinary catheter ii. Urinary retention (approximately 100 mL of residual urine after voiding) iii. Neurogenic bladder iv. Partial obstructive uropathy (eg, nephrolithiasis, bladder stones, and ureteral strictures) v. Azotemia of renal origin (not CHF or volume related) such that the serum BUN is elevated (> 20 mg/dL) AND the serum BUN:creatinine ratio is < 15 vi. Surgically modified or abnormal urinary tract anatomy (eg, bladder diverticula, redundant urine collection system, etc.) EXCEPT surgery within the last month