Retail meat consumption and the acquisition of antimicrobial resistant Escherichia coli causing urinary tract infections: a case-control study.

BACKGROUND The increasing incidence of community-acquired urinary tract infections (UTIs) caused by antimicrobial resistant Escherichia coli, and observations of potential outbreaks of UTI-causing E. coli, suggest that food may be an important source of E. coli in women who develop UTI. We sought to determine if acquisition of and infection with a UTI-causing, antimicrobial resistant E. coli isolate is associated with a woman's dietary habits, specifically her preparation and consumption of retail meat products. METHODS Between April 2003 and June 2004, a case-control study was conducted. The dietary habits of women with UTI caused by an antimicrobial resistant E. coli (cases) and women with UTI caused by fully susceptible E. coli (controls) were compared. Broth microdilution was used to perform antimicrobial resistance testing. All E. coli isolates were genotyped by the pulsed-field gel electrophoresis (PFGE) method. RESULTS Ninety-nine women met study criteria. Women who were infected with multidrug-resistant E. coli reported more frequent chicken consumption (adjusted OR = 3.7, 95% CI 1.1, 12.4). Women with UTI caused by an ampicillin- or cephalosporin-resistant E. coli isolate reported more frequent consumption of pork (adjusted OR = 3.2, 95% CI 1.0, 10.3 and adjusted OR = 4.0, 95% CI 1.0, 15.5, respectively). Frequent alcohol consumption was associated with antimicrobial resistant UTI. CONCLUSIONS This study provides epidemiologic evidence that antimicrobial resistant, UTI-causing E. coli could have a food reservoir, possibly in poultry or pork.