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

Background: This study examined risk factors for extended-spectrum β-lactamase (ESBL) infection in patients at the University of Minnesota Medical Center, Fairview. Methods: Laboratory-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. Results: Our 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%. Conclusions: Developing policies and methods to promote good antibiotic stewardship and reduce the incidence of urinary tract infections will decrease the risk of ESBL infection.