Salivary microbiome in patients with benign prostatic hyperplasia: altered composition and its association with prostate-specific antigen

Microbial dysbiosis in the gut and urine has been implicated in patients with benign prostatic hyperplasia (BPH) in previous studies. Additionally, emerging evidence suggests that salivary dysbiosis is associated with various diseases and oral health conditions. Building on these findings, this study aimed to investigate whether BPH patients exhibit a distinct salivary microbiome. We recruited a cohort of BPH patients (n = 50) and age- and BMI-matched healthy controls (HC; n = 50). Salivary samples were collected for 16S rRNA gene sequencing, and prostate-specific antigen (PSA) levels were measured. Comparing the salivary microbial communities between BPH patients and HC revealed significant differences, with BPH patients exhibiting increased bacterial richness and diversity (FDR < 0.05). Further analysis identified 13 bacterial genera, including Clostridia-UCG-014, Oribacterium, and Filifactor, that were enriched in BPH patients. In contrast, 4 bacterial genera, such as Actinomyces, Lachnoanaerobaculum, and Rothia, were depleted in BPH patients (FDR < 0.05). Several bacterial genera showed potential as biomarkers for identifying BPH. Importantly, no correlation was observed between the bacterial community and PSA levels in BPH patients (P > 0.05). Our findings indicate that the salivary microbiome in BPH patients is dysbiotic, with altered richness, diversity, and specific taxonomic changes compared to healthy controls. Importantly, although prostate-specific antigen (PSA) levels are known to increase with prostate volume, our analysis found no significant association between the salivary microbiome and PSA levels in BPH patients. This suggests that while salivary dysbiosis is a feature of BPH, it does not appear to contribute directly to PSA dysregulation. Further research is needed to clarify the potential role of the salivary microbiome in BPH pathogenesis and its possible clinical applications.