The Safety and Efficacy of Oral Fosfomycin for the Treatment of Culture-Positive Lower Urinary Tract Infections in Kidney Transplant Recipients: A Systematic Review

OBJECTIVE: Urinary tract infections (UTIs) are the most common infection in kidney transplant recipients (KTRs), and the large increase in antibiotic-resistant pathogens is minimizing effective treatments. The objective of this study was to evaluate the safety and efficacy of fosfomycin for the treatment of culture-positive lower UTIs in KTRs. DATA RESOURCES: A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards was conducted through June 2025 on Embase, PubMed, Cochrane Central Register of Controlled Trials, Web of Science Core Collection, and the Global Index Medicus. STUDY SELECTION AND DATA EXTRACTION: The terminology used to create the search included UTIs and synonyms, fosfomycin and synonyms, and kidney transplant and synonyms. Patients with culture-positive lower UTIs, defined as either cystitis or asymptomatic bacteriuria and with documented clinical and microbiological cure data were included. Records with non-human, non-English, adolescents or children (<18), fosfomycin prophylaxis only, or upper UTI-only analyses were excluded. DATA SYNTHESIS: Six studies were included for data analysis. A total of 564 culture-positive lower UTI episodes in KTRs were treated with fosfomycin monotherapy. Treatment regimens were generally multi-dose with various frequencies and durations. All studies reported results in the form of clinical cure, microbiological outcomes, and treatment-emergent adverse effects. Many of the causative pathogenic bacteria in the treatment intervention were multi-drug resistant (MDR) in nature. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: The adequate treatment of UTIs in KTRs is imperative to long-term graft success, low mortality rates, and cost savings. Further randomized controlled trials (RCTs) are needed to assess fosfomycin use for MDR UTIs in this population. In aggregate, oral fosfomycin as monotherapy for UTIs in KTRs demonstrated positive outcomes regarding clinical cure, microbiological outcomes, and treatment-emergent adverse effects.