Piperacillin/tazobactam versus carbapenems in the treatment of urinary tract infections caused by extended-spectrum beta-lactamases-producing Escherichia coli

Background: Infections caused by extended-spectrum beta-lactamase (ESBL) producing gram-negative bacteriaincreasing widespread and it raises major concerns because of growing limitation of therapeutic alternatives.Aim: To examine the clinical and microbiologic outcomes of piperacillin/tazobactam versus carbapenems in thetreatment of urinary tract infections (UTI) caused by ESBL-producing E.coli. Methods: This was a retrospectivestudy, comparing the clinical and microbiologic outcomes of patients receiving intravenouspiperacillin/tazobactam (4,5g q8h) or carbapenems (imipenem 500mg q6h, meropenem 1 g q8h or ertapenem 1gq24h) in the treatment of urinary tract infections caused by ESBL-producing E.coli at Erciyes University,School of Medicine, Kayseri in Turkey, during 2006-2010. Results: A total of 110 patients with urinary tractinfection caused by ESBL-E.coli have been identified. UTIs were classified as nosocomial in 22 (20 %) ofpatients, health care associated in 65 (59 %) and community acquired in 23 (21 %) of them. Twenty- eight(25.5%) of the UTIs were non-complicated and 82 (74.5%) of them were complicated. Fifty-five (50%) ofpatients received carbapenems, 55 (50 %) of them received piperacillin/tazobactam according to the results ofantibiotic susceptibility testing. No statistically significant difference between patients receivingpiperacillin/tazobactam and carbapenems in terms of demographic characteristics, comorbidities, presence ofurinary catheter, bacteremia, therapeutic failure and relapse. Median duration of treatment and hospitalizationwas shorter with patients treated with piperacillin/tazobactam than carbapenems (10, 12 days and 11, 13 daysrespectively). Conclusion: Effectiveness of these two groups of antibiotics in the treatment of UTIs caused byESBL-producing E.coli was similar. Patients treated piperacillin/tazobactam has shorter duration of treatmentand hospitalization (p<0,05).