Purpose: Little is known about the role of gut microbiota in the pathogenesis of erectile dysfunction (ED). We performed a study to compare taxonomic profiles of gut microbiota of ED and healthy males.
Materials and methods: A total of 43 ED patients and 16 healthy controls were enrolled in the study. The 5-item version of the International Index of Erectile Function (IIEF-5) with a cutoff value of 21 was used to evaluate erectile function. All participants underwent nocturnal penile tumescence and rigidity test. Samples of stool were sequenced to determine the gut microbiota.
Results: We identified a distinct beta diversity of gut microbiome in ED patients by unweighted UniFrac analysis (R²=0.026, p=0.036). Linear discriminant analysis effect size (LEfse) analysis showed Actinomyces was significantly enriched, whereas Coprococcus_1, Lachnospiraceae_FCS020_group, Lactococcus, Ruminiclostridium_5, and Ruminococcaceae_UCG_002 were depleted in ED patients. Actinomyces showed a significant negative correlation with the duration of qualified erection, average maximum rigidity of tip, average maximum rigidity of base, tip tumescence activated unit (TAU), and base TAU. Coprococcus_1, Lachnospiraceae_FCS020_group, Ruminiclostridium_5, and Ruminococcaceae_UCG_002 were significantly correlated with the IIEF-5 score. Ruminiclostridium_5 and Ruminococcaceae_UCG_002 were positively related with average maximum rigidity of tip, average maximum rigidity of base, ΔTumescence of tip, and Tip TAU. Further, a random forest classifier based on the relative abundance of taxa showed good diagnostic efficacy with an area under curve of 0.72.
Conclusions: This pilot study identified evident alterations in the gut microbiome composition of ED patients and found Actinomyces was negatively correlated with erectile function, which may be a key pathogenic bacteria.
Keywords: Actinomyces; Erectile dysfunction; Microbiota; RNA, ribosomal, 16S.
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