Oral beta-lactam step down in bacteremic E. coli urinary tract infections

BACKGROUND: Literature is scarce regarding oral step down to beta-lactams in bacteremic urinary tract infections. Oral fluoroquinolones are an accepted and common step down for bacteremic urinary tract infections; however, their use is associated with mounting safety concerns. We compared clinical cure in patients with E. coli bacteremic urinary tract infections who were stepped down to oral beta-lactams compared to oral fluoroquinolones. METHODS: This multicentre retrospective cohort study included patients with first positive concurrent urine and blood cultures from January 2016 to December 2016. Patients were included if they received empiric intravenous beta-lactam therapy with step down to either oral beta-lactam or fluoroquinolone for treatment completion. The primary outcome was clinical cure. Secondary outcomes were length of hospitalization, all-cause mortality and C. difficile infection. Multivariate analysis and propensity score were used to control for confounding. RESULTS: A total of 207 patients were identified with bacteremic E.coli urinary tract infections. Clinical cure was achieved in 72/77 (94%) in the oral beta-lactam group versus 127/130 (98%) in the oral fluoroquinolone group (absolute difference − 4.2, 95% confidence interval [CI] -10.3 to 1.9%, p = 0.13). The adjusted odds ratio (OR) for clinical cure with oral beta-lactams was 0.31 (95% CI 0.05–1.90, p = 0.21); propensity score adjusted analysis showed a similar result. There was no statistically significant difference in secondary outcomes. CONCLUSIONS: Oral beta-lactams appear to be a safe and effective step down option in bacteremic E. coli urinary tract infections compared to oral fluoroquinolones.