Salivary Microbiome in Patients with Benign Prostatic Hyperplasia: Altered Composition and Association with Prostate-Specific Antigen

Abstract Backgrounds Microbial dysbiosis in the gut and urine has been implicated in patients with benign prostatic hyperplasia (BPH) based on previous studies. Additionally, emerging evidence has shown that salivary dysbiosis is associated with various diseases and oral health conditions. Building upon these findings, we aimed to investigate whether BPH patients exhibit a distinct salivary microbiome. Methods and Materials We recruited a cohort of BPH patients (n=50) and age-BMI matched healthy controls (HC; n=50). Salivary samples were collected for 16S rRNA gene sequencing, and prostate-specific antigen (PSA) levels were examined. Results Comparison of the salivary microbial communities between BPH patients and HC revealed significant differences, characterized by increased bacterial richness and diversity (FDR<0.05) in the BPH group. Further analysis identified the enrichment of 13 bacterial genera, including Clostridia-UCG-014 , Oribacterium , and Filifactor , in BPH patients. Conversely, BPH patients exhibited a depletion of 4 bacterial genera, such as Actinomyces , Lachnoanaerobaculum , and Rothia (FDR<0.05). Several bacterial genera demonstrated potential as biomarkers for identifying BPH. Notably, we observed a negative correlation between the abundance of Oribacterium in BPH patients and the ratio of free PSA to total PSA (FPSA/TPSA) (r=-0.337, P=0.029). Conclusions Our findings indicate that the salivary microbiomes of BPH patients are dysbiotic. Moreover, we observed a significant association between this dysbiosis and dysregulation of PSA levels in BPH patients, suggesting the existence of a possible saliva-prostate axis. Modulating the salivary microbiome could potentially serve as an intervention strategy for BPH patients.