Disappearance of the 'uncomplicated' urinary tract infection: The impact of emerging resistance

Objective: The increasing frequency of clinical failure and recurrence of uncomplicated urinary tract infections (UTIs) may be due to emerging resistance to commonly prescribed antimicrobials. This study evaluated resistance patterns of urinary pathogens and how they influence clinical outcome. Design: Prospective, observational study. Setting: General internal medicine clinic of a tertiary care university hospital. Patients: 156 women with symptoms of acute cystitis submitted urine for routine culture and susceptibility testing. A medical record review, including medical history, physical examination and prescribed antimicrobial treatment at the time of presentation, was performed. Results: Of the 156 patients, 114 met the case definition of a UTI and represent the evaluable patients. Escherichia coli was identified as the infecting organism in 89 (78%) isolates, of which 47 (53%) were susceptible to all antimicrobials tested. Forty-two (47%) E. coli isolates were resistant to one or more antimicrobials, including 22% ampicillin-resistant and 22% cotrimoxazole (trimethoprim/sulfamethoxazole)-resistant (6.7% were resistant only to cotrimoxazole and 15.7% were both ampicillin- and cotrimoxazole-resistant). Only two of the E. coli isolates were fluoroquinolone-resistant. Clinical cure was achieved in 89% of the patients with a susceptible E. coli compared with 61% of patients with an antimicrobial-resistant E. coli infection (p = 0.008). The cost for 4 patients (all in the drug-resistant group) requiring hospitalisation exceeded $US35 000. Conclusions: Resistance to commonly prescribed antimicrobials for patients with cystitis is common. Women with antibiotic-resistant E. coli were significantly more likely to fail empirical therapy than those with susceptible organisms. A re-evaluation of empirical antimicrobial therapy for outpatients with uncomplicated UTIs may be warranted.