2231. Assessing Clinical Cure of Empiric Piperacillin-Tazobactam for ESBL Urinary Tract Infections (ACCEPT-UTI)

Abstract Background While literature supports use of carbapenems over piperacillin-tazobactam (TZP) for extended spectrum beta-lactamase (ESBL) bacteremia, data is limited regarding the use of TZP for ESBL urinary tract infections (UTIs). The objective of this study is to determine if patients have similar clinical outcomes when empirically treated with TZP versus carbapenems for ESBL UTIs. Methods This IRB-approved, retrospective, non-inferiority study evaluated adult patients admitted to a 5-facility healthcare system from January 1, 2016 to June 30, 2021. Patients who received a carbapenem or TZP empirically for at least 48 hours with a urine culture positive for an ESBL, urinary symptoms or leukocytosis, and isolate susceptibility to the empiric antibiotic of choice were included. The primary outcome was clinical success within 48 hours defined as resolution of temperature (36-38 °C), resolution of symptoms or leukocytosis (WBC < 12 x103/μL) in the absence of symptoms, and the absence of readmission for an ESBL UTI within 6 months. Secondary outcomes included time to clinical success, hospital length of stay (LOS), and 30-day all-cause mortality. Results A total of 223 patients were included with 123 (55%) patients receiving TZP and 100 (45%) patients receiving a carbapenem. Patients were predominantly female (65%) and Caucasian (52%) with a median (IQR) age of 70 (58, 81) years. Baseline characteristics were similar between the groups with no difference in complicated cystitis (60%), pyelonephritis (27%), or concomitant bacteremia (25%) (Table 1). There was no difference in the primary outcome of clinical success between the carbapenem and TZP group (60% vs 59%, respectively; p=0.92). Additionally, there was no difference in median (IQR) time to clinical success [39 (21, 52) vs 40 (25, 57) hrs, p=0.53], median hospital LOS [7.0 (5.1, 10.6) vs 6.8 (4.7, 9.2) days, p=0.12], or 30-day all-cause mortality (4% vs 2%, p=0.72) between the carbapenem and TZP groups, respectively (Table 2). Conclusion In this large, multi-center study, we found no difference in clinical outcomes in patients with UTIs caused by ESBL-producing organisms treated empirically with TZP versus carbapenems. Clinicians could consider using TZP in patients with ESBL UTIs susceptible to TZP. Disclosures Michael S. Gelfand, MD, AbbVie: Expert Testimony|La Jolla: Expert Testimony Kerry O. Cleveland, MD, AbbVie: Honoraria|Cumberland: Honoraria|Merck: Honoraria|Pfizer: Honoraria.