Clinical Efficacy of Ertapenem for Recurrent Cystitis Caused by Multidrug-Resistant Extended-Spectrum β-Lactamase-Producing Escherichia coli in Female Outpatients

PURPOSE: To evaluate the clinical outcomes of ertapenem administered as an outpatient parenteral antibiotic therapy for intractable cystitis caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. MATERIALS AND METHODS: We retrospectively reviewed a case series of 3 years of therapeutic experience with ertapenem for intractable recurrent cystitis caused by ESBL-producing E. coli. Ertapenem 1 g/d was parenterally administered to the patients on an outpatient basis until the acquisition of symptomatic improvement and negative conversion of urine culture. Demographic and clinical characteristics of patients, antimicrobial resistance, and clinical response data were analyzed from the patients' medical records. RESULTS: During the course of this study, a total of 383 patients were diagnosed with cystitis, and 24 of them showed ESBL-producing E. coli (6.26%). The mean treatment duration of all patients was 8.5 days. The early clinical and microbiological cure rates 0 to 7 days after the end of treatment were 91.7% (22/24) and 90.9% (20/22), respectively. The late clinical and microbiological cure rates 4 to 6 weeks after the end of treatment were 72.2% (13/18) at both time points. CONCLUSIONS: Parenteral ertapenem treatment can be an effective and well-tolerated treatment option for intractable recurrent cystitis by multidrug-resistant ESBL-producing E. coli.