Risk factors for community-acquired ciprofloxacin-resistant Escherichia coli urinary tract infection.

BACKGROUND: Fluoroquinolones are recommended for the empiric treatment of urinary tract infection (UTI) in communities in which uropathogen resistance to trimethoprim/sulfamethoxazole (TMP/SMX) is >or=10% to 20%. However, recent studies also have demonstrated an increase in the isolation of fluoroquinolone-resistant Escherichia coli. Identification of outpatients at increased risk for fluoroquinolone resistance would improve the selection of empiric treatment. OBJECTIVE: To identify risk factors for community-acquired UTIs due to ciprofloxacin-resistant E. coli (CREC). METHODS: All medical records from the University of California at San Francisco Medical Center from January to December 2001 were retrospectively reviewed to identify patients with community-acquired UTI due to CREC. Patients with community-acquired UTI due to ciprofloxacin-susceptible E. coli presenting during the same time period were randomly selected as the study group in a 1:2 ratio of case to controls. RESULTS: Independent risk factors for CREC included recurrent UTI (OR 8.13) and prior exposure to fluoroquinolones (OR 30.35). CONCLUSIONS: Fluoroquinolones continue to be appropriate empiric treatment in most patients with uncomplicated UTI. Nitrofurantoin or a cephalosporin may be better choices in patients with recurrent lower UTI and/or previous fluoroquinolone use.