The Prostate Microbiome Is Associated With Prostate Size and PSA Level, Independent of Age, in BPH Patients

The etiology of benign prostatic hyperplasia (BPH) is not well understood, though recent literature suggests that the urinary tract microbiome may play a role. We aimed to examine the prostatic microbiome in BPH and its associations with patient characteristics.

Men undergoing Holmium Laser Enucleation of the Prostate (HoLEP) were recruited if they were over 18 years old and had no history of prostate cancer, prostate surgery, or pelvic radiation. Exclusion criteria included positive preoperative urine culture, bladder stones, or catheter-dependence. Patient characteristics including age, prostate-specific antigen (PSA), American Urological Association symptom score (AUASS), and history of biopsy were recorded. Intraoperatively, prostate tissue was collected from each patient, as well as catheterized urine, urethral swabs, and swabs of the specimen container. Samples underwent DNA extraction, 16S sequencing, and analysis using R statistical software. Associations between bacterial taxonomic diversity and patient characteristics were quantified through Sparcc correlations.

Fifty patients were recruited. Mean age, PSA, prostate size, and AUASS were 67.8 years, 4.0 ng/mL, 108.6 g, and 19.4, respectively. After bioinformatic decontamination of prostate samples, alpha and beta diversity analyses indicated that microbiomes from the prostate, urethra, and urine were all distinct (p = 0.001); microbiota from the urine and urethra had higher similarity to each other than that of the prostate. Campylobacter, Caryophanaceae, Enterobacter, and Senegalimassilia positively correlated with prostate size or PSA.

The prostatic microbiome is unique and distinct from that of urine and urethra, with several known pathogens positively correlating with prostate size and PSA.