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