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

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.

To identify risk factors for community-acquired UTIs due to ciprofloxacin-resistant E. coli (CREC).

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.

Independent risk factors for CREC included recurrent UTI (OR 8.13) and prior exposure to fluoroquinolones (OR 30.35).

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.