Clinical Infectious Diseases (CID)Fosfomycin as Oral Transition Therapy Versus Continued Intravenous β-Lactams for Complicated Urinary Tract Infections Caused by Extended-Spectrum β-Lactamase–Producing Enterobacterales: A Multicenter, Open-Label, Randomized Controlled Trial

✅ Clinical Decision Support / Validated Tool

A randomized trial found that oral fosfomycin was noninferior to continued intravenous β‑lactams for ESBL complicated UTIs after initial IV stabilization. The findings support an oral step-down strategy to reduce carbapenem use and healthcare burden in appropriately selected patients.

Clinical Considerations

• Clinical cure rates were 92.8% with oral fosfomycin vs 95.2% with IV therapy, meeting noninferiority criteria.
• Microbiologic cure exceeded 96% in both groups across urine and blood cultures.
• The trial included 299 hospitalized adults with ESBL complicated UTIs randomized after 3–7 days of IV therapy.
• Safety outcomes and 30-day recurrence rates were comparable, supporting similar short-term durability.

Practice Applications

• Consider oral fosfomycin as a step-down option after initial IV response in ESBL complicated UTIs
• Recognize potential to reduce carbapenem exposure and preserve last-line agents
• Evaluate patient stability, source control, and adherence before transition to oral therapy
• Monitor recurrence and resistance patterns as oral strategies expand