AbstractBackgroundData are limited regarding use of piperacillin/tazobactam for ESBL urinary tract infections (UTIs). The objective of this study was to compare clinical outcomes of patients treated empirically with piperacillin/tazobactam versus carbapenems for ESBL UTIs.MethodsThis retrospective, observational, propensity score-matched study evaluated adults with an ESBL on urine culture. Patients who had UTI symptoms or leukocytosis, and who received a carbapenem or piperacillin/tazobactam empirically for at least 48 h were included. The primary outcome was clinical success within 48 h, defined as resolution of temperature (36–38°C), resolution of symptoms or leukocytosis (WBC <12 × 103/μL) in the absence of documented symptoms, and the absence of readmission for an ESBL UTI within 6 months. Secondary outcomes included time to clinical resolution, hospital length of stay, and in-hospital and 30 day all-cause mortality.ResultsOverall, 223 patients were included in the full cohort and 200 patients in the matched cohort (piperacillin/tazobactam = 100, carbapenem = 100). Baseline characteristics were similar between the groups. There was no difference in the primary outcome of clinical success between the carbapenem and piperacillin/tazobactam groups (58% versus 56%, respectively;P= 0.76). Additionally, there was no difference in median (IQR) time to clinical resolution [38.9 h (21.5, 50.9 h) versus 40.3 h (27.4, 57.5 h);P= 0.37], in-hospital all-cause mortality (3% versus 3%;P= 1.00), or 30 day all-cause mortality (4% versus 2%;P= 0.68) between the carbapenem and piperacillin/tazobactam groups, respectively.ConclusionsThere was no significant difference in clinical success for patients treated empirically with piperacillin/tazobactam compared with carbapenems for ESBL UTIs.