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.