Comparing ceftolozane/tazobactam versus piperacillin/tazobactam for the initial empiric therapy of urinary tract infections: A retrospective comparative study

Introduction: This study compares the clinical and microbiological efficacy of ceftolozane/tazobactam (CTLZ/TAZ) and piperacillin/tazobactam (PIPC/TAZ) for treating complicated cystitis or acute pyelonephritis.Methods: Patients who had been treated with empiric antibiotics, CTLZ/TAZ (52 cases) or PIPC/TAZ (47 cases), due to urinary tract infections (UTIs) were eligible for this study. Patients' demographic backgrounds, types of UTIs, and causative microorganisms isolated from urine or blood bacterial cultures were collected. Short-term clinical efficacy at the end of the initial empiric therapy, long-term clinical efficacy including sequential antibiotic treatments (nonrecurrence rate within 1 month after the initial empiric therapy), and microbiological efficacy were retrospectively compared in both CTLZ/TAZ and PIPC/TAZ groups.Results: Complicated UTIs were present in most eligible patients, and no significant difference in the patients' background was observed between the two groups. Escherichia coli and Enterococcus faecalis were the most common microorganisms isolated from urine culture in both groups. The short-term clinical effective rate of CTLZ/TAZ and PIPC/TAZ was 80.8% and 87.2%, respectively. For long-term clinical efficacy, the nonrecurrence rate of UTIs was present in 95.1% and 89.7% of patients with CTLZ/TAZ and PIPC/TAZ, respectively. No significant difference was observed in the short- and long-term effects between the two groups. The microbiological efficacy of the CTLZ/TAZ and PIPC/TAZ groups was 72.7% and 86.0%, respectively. No significant difference in microbiological effects was also observed between the two groups.Conclusions: This study demonstrated the noninferiority of CTLZ/TAZ to PIPC/TAZ, suggesting that CTLZ/TAZ is an alternative antibiotic used as empiric therapy for UTIs.