Extended-Spectrum β-Lactamase–Producing<i>Escherichia coli</i>and<i>Klebsiella</i>Species: Risk Factors for Colonization and Impact of Antimicrobial Formulary Interventions on Colonization Prevalence

Abstract

ESbetaL-EK colonization was associated only with duration of hospitalization and there was no significant reduction following antimicrobial formulary interventions. The evidence for nosocomial spread and the high percentage of patients with ESbetaL-EK admitted from other sites suggest that greater emphasis must be placed on controlling the spread of such organisms within and between institutions.