The role of the urobiome in kidney transplantation: A systematic review

Abstract

Background. The urinary microbiome, also known as the urobiome, was traditionally considered sterile. However, emerging evidence suggests its presence in the urinary tract. Urobiome dysbiosis has been associated with various urologic conditions, making it a topic of interest also in kidney transplantation. This systematic review examines the evidence of urobiome changes in kidney transplant recipients (KTRs). Methods. Systematic literature searches in the PubMed and SCOPUS databases. Results. Of the 770 articles identified, 8 met the inclusion criteria. The urobiome showed reduced diversity in KTRs compared with healthy controls and patients on dialysis. Proteobacteria enrichment was associated with graft stability or spontaneous tolerance in KTRs without immunological events. Kidney interstitial fibrosis and tubular atrophy were associated with changes in resident urinary microbes and increased pathogenic bacteria. Additionally, KTRs with chronic allograft dysfunction had a higher prevalence of Corynebacterium. Conclusions. The review highlights the importance of studying the urobiome in KTRs and its potential impact on transplant outcomes. The field remains largely unexplored, and further research is needed to establish consistent study designs and objectives. Future studies could lead to biomarker discovery, personalized therapies, and improved outcomes and graft survival in KTRs.