Risk factors for the acquisition of carbapenem-resistant Escherichia coli in a tertiary care hospital in South Korea : a matched case-control study

Abstract

Background: Carbapenem resistance among Gram-negative bacilli has become an emerging threat worldwide. The objective of this study was to identify risk factors for the acquisition of carbapenem-resistant Escherichia coli (CRE).Methods: We conducted a matched case-control study involving 57 cases with acquisition of CRE and 114 controls (1:2 matched) selected among patients with carbapenem-susceptible E. coli between January 2006 and December 2010 in a 2,000-bed tertiary care hospital in South Korea. The two groups were matched for the site and date of E. coli isolation.Results: In univariate analysis, previous use of carbapenem (p<0.001), fluoroquinolone (p=0.001), and glycopeptide (p<0.001), total number of previous antibiotic treatments (p=0.004), and length of hospital stay (p=0.047) were significantly associated with CRE acquisition. However, the year of isolation, attending healthcare workers, department or ward at the time of isolation, and the existence of CRE during the hospital stay were not associated with CRE acquisition. In multivariate analysis, previous use of carbapenem [odds ratio (OR) 4.56, 95% confidence interval (CI) 1.44-14.457, p=0.009] and previous use of fluoroquinolone (OR 2.81, 95% CI 1.137-6.991, p=0.0253) were independent risk factors for CRE acquisition.Conclusions: In this institute, antibiotic selective pressure seems to be more important for CRE acquisition than nosocomial transmission