Urobiome composition after renal transplantation: an exploratory study

Area of Science:

• Microbiology
• Transplant Immunology
• Urology

Background:

• The urinary microbiome (urobiome) in renal transplant recipients remains largely undefined.
• Understanding urobiome dynamics is crucial for post-transplant allograft health.
• Investigating urobiome changes in relation to rejection and graft function is critical.

Purpose of the Study:

• To characterize urobiome alterations in renal transplant recipients.
• To compare pre- to post-transplant urobiome states.
• To assess urobiome differences between acute T-cell mediated rejection (TCMR) and non-rejector cohorts, and across varying allograft function levels.

Main Methods:

• Urine samples from 41 renal transplant recipients (10 rejectors, 16 women, 15 men) were analyzed.
• Samples were collected pre-transplant, at TCMR diagnosis, and at 1 and 3 months post-transplant.
• 16S rRNA sequencing was performed, followed by diversity and differential abundance analyses.

Main Results:

• The urobiome composition significantly changed post-transplant, differing from pre-transplant states by ~75%.
• Rejectors showed an increase in Corynebacterium and Pseudomonas, while non-rejectors gained Lactobacillus.
• Urobiome composition varied by sex, and a loss of Lactobacillus correlated with decreased eGFR (estimated glomerular filtration rate) at 3 months post-transplant.

Conclusions:

• Renal transplantation profoundly impacts individual urobiome composition, but not necessarily diversity.
• Microbial imbalances in the urobiome may be associated with acute rejection and impaired post-transplant renal function.
• The urobiome holds potential as a biomarker for, or contributor to, post-transplant allograft health, warranting further investigation.