28 April 2026 : Review article
Urinary Microbiome Characteristics in Kidney Transplant Recipients and Their Clinical Implications: A Narrative Review
Shuzhan Sun ABCDEF 1,2, Yuhui He ABDEF 1, Yisen Deng ABDEF 1, Jianfeng Wang ACDEFG 1*DOI: 10.12659/AOT.952286
Ann Transplant 2026; 31:e952286
Table 2 Complication-specific urinary microbiome patterns, proposed mechanisms, major confounders, and evidence strength.
| Outcome | Reported microbiome pattern/biomarker | Direction | Proposed link (hypothesis) | Predominant evidence | Major confounders | Strength* | Key references |
|---|---|---|---|---|---|---|---|
| UTI | Lower α-diversity before/at UTI | ↓ | Loss of colonization resistance → pathogen overgrowth | Observational; some longitudinal | Antibiotics, catheter, sampling method | Moderate | [,,]11 |
| UTI | Enterococcus expansion (esp. under prophylaxis) | ↑ | Antibiotic selection + resistance potential | Observational | TMP–SMX prophylaxis, hospitalization | Moderate | []11 |
| UTI | Lactobacillus depletion (female cohorts) | ↓ | Reduced barrier functions (lactic acid/bacteriocins) | Cross-sectional; mixed cohorts | Menopause/hormones, antibiotics | Low–Moderate | [,]15 |
| Acute rejection (AR) | Urinary CXCL10 elevated with acute graft lesions related to T cell-/antibody-mediated damage | ↑ | Immune activation marker; may complement microbiome signals | Observational biomarker study | Sampling time, immunosuppression, infection | Moderate | []110 |
| IF/TA/CAD | Early post-transplant microbiome changes correlate with IF/TA | ↓ | Potential early marker of injury | Longitudinal surveillance biopsy cohort | Antibiotics, baseline sex/age, DGF | Moderate | []22 |
| IF/TA/CAD | Corynebacterium enrichment in CAD cohorts | ↑ | Unknown; correlative with chronic injury milieu | Cross-sectional | Sex, batch/bioinformatics effects | Low–Moderate | []40 |
| UTI – urinary tract infection; AR – acute rejection; IF/TA – interstitial fibrosis and tubular atrophy; CAD – chronic allograft dysfunction; TMP–SMX – trimethoprim–sulfamethoxazole; DGF – delayed graft function. “Direction” indicates associations reported in cited studies (increase ↑/decrease ↓). Proposed mechanisms are hypothesis-generating unless supported by experimental validation. Strength* (qualitative for a narrative review): High=replicated longitudinal/multicenter with adjudicated endpoints; Moderate=longitudinal single-center or consistent across multiple cohorts; Low=cross-sectional/small N/high confounding risk. | |||||||