MICROBIOME AND UROLITHIASIS: THE ROLE OF GUT AND URINARY MICROBIOTA IN OXALATE METABOLISM AND STONE RECURRENCE: A SYSTEMATIC REVIEW

Abstract

Background: Kidney stone disease (nephrolithiasis) is a prevalent and recurrent urological condition, with calcium oxalate stones accounting for approximately 70–80% of all cases. Emerging evidence implicates both gut and urinary microbiota in the regulation of oxalate metabolism, stone crystallization, and recurrence risk. Objectives: To systematically evaluate the evidence regarding the role of gut and urinary microbiota in oxalate metabolism and urinary stone recurrence, and to assess the potential of microbiome-targeted interventions in stone disease prevention. Methods:A systematic literature search was conducted across PubMed/MEDLINE, Scopus, Embase, Web of Science, and the Cochrane Library for studies published between January 2000 and December 2024. Studies examining the associations between gut or urinary microbiota and urolithiasis, oxalate metabolism, or stone recurrence were included. Data were extracted and narratively synthesized. Results: Twelve studies met the inclusion criteria, encompassing observational studies, randomized controlled trials, and meta-analyses. Key findings identified consistent gut dysbiosis in stone formers characterized by depletion of Oxalobacter formigenes, Lactobacillus, Faecalibacterium, and Prevotella, alongside enrichment of Enterobacteriaceae and pro-inflammatory taxa. The urinary microbiome demonstrated distinct compositional differences between stone formers and healthy controls. Probiotic interventions targeting oxalate-degrading bacteria showed variable efficacy. Conclusions: The gut and urinary microbiota play pivotal roles in oxalate homeostasis and stone pathogenesis. Microbiome-targeted interventions are biologically plausible but require larger, well-designed clinical trials to establish clinical utility.