Prospective cohort study of risk factors for extended-spectrum ß-lactamase-producing Escherichia coli urinary tract infections in elderly patients admitted to hospital.

BACKGROUND: Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli are currently common in community-onset infections, limiting therapeutic options. In this work we aim to identify the prevalence of and risk factors for ESBL-producing E. coli in elderly patients with urinary tract infections (UTI) admitted to hospital. METHODS: Prospective cohort study on elderly patients with E. coli UTI admitted to a university hospital in Spain, from January 2013 to December 2015. Clinical features, microbiology and outcomes were recorded from the electronic medical records and reviewed by two researchers. Cases were segregated according to ESBL-producing E. coli. Risk factors for ESBL-producing E. coli were analysed by multivariate analysis. RESULTS: The prevalence of ESBL-producing E. coli was 27.4% (85/310). Healthcare-associated UTI was the only risk factor for ESBL-producing E. coli (OR 6.79; 95% CI 3.22-14.31, P < .001) by multivariate analysis. ESBL-producing E. coli was 43.9% in the healthcare-associated UTI group and 8.9% in the community-acquired UTI group (P < .001). Inadequate empirical antibiotic therapy and length of stay in hospital were higher in the ESBL-producing E. coli group than in the non-ESBL-producing E. coli group (62.3% vs 5.3% and 6.60 ± 3.69 days vs 5.61 ± 3.16 days, respectively). Mortality was not significantly different between groups (13% in ESBL-producing E. coli group vs 7.5% in non-ESBL-producing E. coli group, P = .140). SUMMARY: Healthcare-associated UTI was a risk factor for ESBL-producing E. coli in elderly patients with UTI admitted to hospital. Our results might help clinicians in choosing empirical antibiotics in an overall high rate setting of ESBL-producing E. coli.