Abstract
Objectives
We sought to determine the comparative efficacy of fosfomycin vs. ertapenem for outpatient treatment of complicated urinary tract infections (cUTI).
Methods
We conducted a multi-centered, retrospective cohort study involving patients with cUTI treated with outpatient oral fosfomycin vs. intravenous ertapenem at three public hospitals in Los Angeles County between January 2018 and September 2020. The primary outcome was resolution of clinical symptoms 30 days after diagnosis.
Results
We identified 322 patients with cUTI treated with fosfomycin (n = 110) or ertapenem (n = 212) meeting study criteria. Study arms had similar demographics, although patients treated with ertapenem more frequently had pyelonephritis or bacteremia while fosfomycin-treated patients had more retained catheters, nephrolithiasis, or urinary obstruction. Most infections were due to extended-spectrum β-lactamase-producing E. coli and Klebsiella pneumoniae; 80-90% of which were resistant to other oral options. Adjusted odds ratios for clinical success at 30 days, clinical success at last follow up, and relapse were 1.21 (0.68 to 2.16), 0.84 (0.46 to 1.52), and 0.94 (0.52 to 1.70), for fosfomycin vs. ertapenem, respectively. Patients treated with fosfomycin had significant reductions in length of hospital stay and length of antimicrobial therapy, and fewer adverse events (1 vs. 10). Fosfomycin outcomes were similar irrespective of duration of lead-in IV therapy or fosfomycin dosing interval (daily, every other day, every third day).
Conclusion
These results would support the conduct of a randomized controlled trial to verify efficacy. In the meantime, they suggest fosfomycin may be a reasonable stepdown from IV antibiotics for cUTI.
Impact of inappropriate empirical antibiotic treatment on clinical outcomes of urinary tract infections caused by Escherichia coli: a retrospective cohort study
