Efficacy and Safety of Oral Fosfomycin for Asymptomatic Bacteriuria in Kidney Transplant Recipients: Results from a Spanish Multicenter Cohort

Current guidelines recommend against systematic screening for or treating asymptomatic bacteriuria (AB) among kidney transplant (KT) recipients, although the evidence regarding episodes occurring early after transplantation or in the presence of anatomical abnormalities is inconclusive. Oral fosfomycin may constitute a good option for the treatment of posttransplant AB, particularly due to the emergence of multidrug-resistant (MDR) uropathogens. Available clinical evidence supporting its use in this specific setting, however, remains scarce. We performed a retrospective study in 14 Spanish institutions from January 2005 to December 2017. Overall, 137 episodes of AB diagnosed in 133 KT recipients treated with oral fosfomycin (calcium and trometamol salts) with a test-of-cure urine culture within the first 30 days were included. Median time from transplantation to diagnosis was 3.1 months (interquartile range [IQR], 1.1 to 10.5). Most episodes (96.4% [132/137]) were caused by Gram-negative bacteria (GNB), and 56.9% (78/137) were categorized as MDR (extended‐spectrum β‐lactamase‐producing Enterobacterales [20.4%] and carbapenem‐resistant GNB [2.9%]). Rate of microbiological failure at month 1 was 40.1% (95% confidence interval [CI], 31.9% to 48.9%) for the whole cohort and 42.3% (95% CI, 31.2% to 54.0%) for episodes due to MDR pathogens. Previous urinary tract infection (odds ratio [OR], 2.42; 95% CI, 1.11 to 5.29; P value = 0.027) and use of fosfomycin as salvage therapy (OR, 8.31; 95% CI, 1.67 to 41.35; P value = 0.010) were predictors of microbiological failure. No severe treatment-related adverse events were detected. Oral fosfomycin appears to be a suitable and safe alternative for the treatment (if indicated) of AB after KT, including those episodes due to MDR uropathogens.This study was supported by Plan Nacional de I+D+i 2013‐2016 and Instituto de Salud Carlos III (ISCIII), Subdirección General de Redes y Centros de Investigación Cooperativa, Ministry of Science and Innovation, Spanish Network for Research in Infectious Diseases (REIPI RD16/0016), and Spanish Network for Research in Renal Diseases (REDInREN RD16/0009) and cofinanced by the European Development Regional Fund entitled A way to achieve Europe. M.F.-R. holds a research contract (Miguel Servet, CP18/00073), from the Spanish Ministry of Science and Innovation, ISCIII.Peer reviewe