Risk factors for community- and health facility–acquired extended-spectrum β-lactamase–producing bacterial infections in patients at the University of Minnesota Medical Center, Fairview

BackgroundThis study examined risk factors for extended-spectrum β-lactamase (ESBL) infection in patients at the University of Minnesota Medical Center, Fairview.MethodsLaboratory-confirmed cases of ESBL infection between January 2005 and June 2008 were evaluated in a case-control study. Risk factors were assessed based on source of infection, either health facility–acquired (HFA) or community-acquired (CA). Cases were identified through hospital infection control department ESBL surveillance records. Controls were selected from the patient population present within the same facility as the cases.ResultsOur evaluation revealed that 60.6% of the health facility–acquired ESBL infections were due to Escherichia coli. Risk factors included previous antibiotic use (odds ratio [OR], 23.7; P < .0001), recurrent urinary tract infection (OR, 7.0; P < .022), venous or arterial catheter use (OR, 12.5; P < .0001), and long-term care facility residence (OR, 7.7; P = .043). For each day of antibiotic use, the risk of infection increased by 2%. Similarly, 76.5% of the community-acquired ESBL infections were due to E coli. Risk factors included previous antibiotic use (OR, 5.1; P = .0005) and recurrent urinary tract infection (OR, 9.1; P = .0098). For each day of antibiotic use, the risk of infection increased by 1%.ConclusionsDeveloping policies and methods to promote good antibiotic stewardship and reduce the incidence of urinary tract infections will decrease the risk of ESBL infection.