Risk factors for infections with extended- spectrum beta-lactamase-producing Escherichia coli in a county of Southern Sweden

Abstract

Johan Tham,1 Inga Odenholt,1 Mats Walder,2 Lina Andersson,1 Eva Melander2,3 1Infectious Diseases Unit, Department of Clinical Sciences, Lund University, Malmö, 2Medical Microbiology, Department of Laboratory Medicine, Lund University, Malmö, 3Department of Infection Control, Laboratory Medicine, Skåne County, Sweden Background: It is important to identify patients who are at risk for infections with extended-spectrum β-lactamase (ESBL)-producing bacteria in order to reduce mortality, to avoid spread of resistant bacteria in hospitals, and to minimize the number of patients receiving unnecessary treatment with broad-spectrum antibiotics. A case-control survey among Swedish patients was performed at Skåne University Hospital to identify risk factors for developing an infection with ESBL-producing Escherichia coli in a low endemic country. Methods: We used a computerized database to identify patients with growth of ESBL-producing E. coli (n = 109) in urine or blood cultures and an equal number of controls matched for age and gender with non ESBL-producing E. coli in urine and blood diagnosed between January and October 2008. We used unadjusted P-values. Results: Patients with ESBL-producing E. coli had a significantly (P < 0.05) higher likelihood of having traveled to Asia including Turkey and the Middle East including Egypt (14/58) than the non-ESBL-positive group (4/53). Hospital stay during the previous year (P < 0.04), especially for more than one month, was another significant (P = 0.01) risk factor for infection with ESBL-producing E. coli (8/58). A stay in the surgical department was a further risk factor (P < 0.01). Conclusion: In this study, we identified 22 of 58 (38%) patients with ESBL-producing E. coli by considered significant risk factors before starting antibiotics. Keywords: extended-spectrum β-lactamase, Enterobacteriaceae, resistant bacteria, risk factors, Escherichia coli