While overall gut microbial diversity did not differ significantly between groups, specific bacterial taxa—including Methanobrevibacter smithii, Collinsella, and Gastranaerophilales—were associated with prostate volume and residual bladder volume, supporting the concept of a gut-prostate axis.
Key Findings
Results
No significant differences in overall gut microbial alpha- or beta-diversity were observed between patient groups stratified by prostate volume or residual bladder volume.
Alpha-diversity was assessed using Chao1 and Shannon indices.
Beta-diversity was assessed using Jaccard distance.
Patients were stratified by prostate volume (≤40 mL vs. >40 mL) and residual bladder volume (≤100 mL vs. >100 mL).
The study included 28 patients undergoing transurethral surgery.
No statistically significant differences in diversity metrics were found between any of the stratified groups.
Results
Methanobrevibacter smithii was markedly less abundant in patients with prostate volume greater than 40 mL.
The difference in Methanobrevibacter smithii abundance between prostate volume groups was statistically significant (p < 0.01).
Patients were divided into groups with PV ≤40 mL and PV >40 mL.
LEfSe (linear discriminant analysis effect size) was used to identify differentially abundant taxa between groups.
Gut microbiota composition was analyzed using 16S rRNA gene sequencing.
Results
Patients with high residual bladder volume (≥100 mL) exhibited distinct gut microbial profiles characterized by reduced abundance of Collinsella and increased abundance of Gastranaerophilales compared to those with lower residual bladder volume.
Both differences in Collinsella and Gastranaerophilales abundance were statistically significant (p < 0.01).
Patients were stratified into groups with RBV ≤100 mL and RBV ≥100 mL.
LEfSe was used to identify these differentially abundant taxa.
These findings suggest that bladder dysfunction, as reflected by elevated residual bladder volume, may be associated with specific gut microbial signatures.
Methods
The study design was cross-sectional, analyzing stool samples from 28 patients undergoing transurethral surgery for benign prostatic hyperplasia.
Total sample size was 28 patients.
Gut microbiota composition was analyzed using 16S rRNA gene sequencing of stool samples.
Clinical parameters assessed included prostate volume and residual bladder volume.
The study is inherently limited by its cross-sectional design and small sample size, precluding causal inferences.
Discussion
The authors propose that future research should focus on longitudinal studies to investigate how gut and urinary microbiota evolve alongside BPH and lower urinary tract symptoms over time.
The authors suggest that microbial signatures could potentially serve as early indicators for symptomatic BPH.
The authors call for inclusion of urinary microbiota alongside gut microbiota in future longitudinal investigations.
The concept of a 'gut-prostate axis' is supported by the finding that specific taxa are associated with prostate and bladder phenotypes even when overall diversity is unchanged.
BPH is described as commonly linked to systemic inflammation and metabolic dysfunction, providing a plausible mechanistic context for gut microbiome involvement.
What This Means
This research suggests that the bacteria living in the gut may be connected to prostate health and bladder function in men with benign prostatic hyperplasia (BPH), a non-cancerous enlargement of the prostate that commonly affects older men. The study examined stool samples from 28 men undergoing prostate surgery and analyzed which types of gut bacteria were present. While the overall diversity and variety of gut bacteria did not differ between men with larger versus smaller prostates, or between men with higher versus lower amounts of urine left in the bladder after urinating, certain specific bacterial species were notably different between these groups. In particular, a bacterium called Methanobrevibacter smithii was much less common in men with larger prostates, and men with more residual urine in their bladder had lower levels of Collinsella and higher levels of Gastranaerophilales bacteria.
These findings support the idea of a 'gut-prostate axis'—the concept that the community of microorganisms in the digestive tract may influence prostate size and urinary function, possibly through effects on inflammation or metabolism. This research suggests that even when the general balance of gut bacteria appears normal, specific microbial differences may still reflect or contribute to prostate-related conditions.
Because this was a small, cross-sectional study (meaning it looked at a single point in time rather than tracking patients over time), it cannot establish whether the gut bacteria differences cause prostate changes or are simply associated with them. The authors call for larger, longer-term studies to better understand how gut bacteria change alongside prostate disease, and whether specific microbial patterns could one day serve as early warning signals for symptomatic BPH.
Surber J, Lork M, Morsy Y, Scharl M, Engeler D, Langenauer J, et al.. (2026). Exploring the Gut-Prostate Axis: Microbial Signatures Linked to Prostate Volume and Bladder Function.. The Prostate. https://doi.org/10.1002/pros.70160