Sexual behavior shapes male genitourinary microbiome composition

Insertive vaginal sex is associated with altered penile immunology and enrichment of Gardnerella vaginalis in uncircumcised Ugandan men

“…Our study was not appropriately powered to perform a detailed analysis of the microbiome associations of prior vaginal sex, and instead focused on the presence/abundance of Gardnerella vaginalis , the prototypic bacterial species associated with the development of bacterial vaginosis (BV) 29 . However, the recent study from Toh and colleagues analyzed the penile urethra microbiome in relation to the time from vaginal intercourse, and found that several bacterial species associated with BV were only present only in the urethra of men reporting recent vaginal intercourse 19 . Likewise, earlier work from Zozoya et al.…”

“…are key BASIC species and are also important contributors to bacterial vaginosis (BV), a condition which causes vaginal inflammation and enhances HIV transmission risk 13–16 . Other BV‐associated bacteria such as Gardnerella vaginalis are less frequent on the penis, although they are found in a minority of men and have been linked to the vaginal microbiome of a man's sexual partner, 17–20 but to our knowledge they have not been linked with penile immune changes or increased penile HIV susceptibility 21,22 . Not all genital microbes enhance HIV susceptibility, and some may play a protective role.…”

“…density in the penile coronal sulcus 23 . Several prior studies have demonstrated that there may be sharing of genital bacteria between female and male partners after penile‐vaginal sex, 17–20,24,25 but the impact of these shared bacteria on penile immunology and HIV susceptibility is unclear. Here we explore associations between insertive penile‐vaginal sex and the immune milieu and microbiome of the coronal sulcus and distal urethra in a cohort of uncircumcised Ugandan men.…”

The Relationship Between Insertive Oral and Anal Sex and Select Measures of the Composition of the Urethral Microbiota Among Men Who Have Sex With Men

“…Among adolescent men, certain bacterial genera were only detected in urine from sexually active men, suggesting colonization via urethral sexual exposures. 7 Some cross-sectional studies have detected associations between vaginal sex and specific bacteria/taxa or community type 8,9 ; others have not detected associations with sexual exposures. [10][11][12] One cross-sectional study suggested that vaginal sex impacts the urethral microbiota but identified little to no evidence of an association between insertive oral sex (IOS) or insertive anal intercourse (IAI) and the urethral microbiota.…”

“…[10][11][12] One cross-sectional study suggested that vaginal sex impacts the urethral microbiota but identified little to no evidence of an association between insertive oral sex (IOS) or insertive anal intercourse (IAI) and the urethral microbiota. 9 One cohort study found that heterosexual men reporting recent condom use and a longer time since last sexual episode had less diverse penile microbiota. 13 However, most prior studies evaluating the relationship between sex and the male urethral microbiota considered broad measures of sexual activity (e.g., exposures in the last few months), potentially obscuring short-term influences of specific exposures, and were relatively small, cross-sectional, or predominantly among heterosexual men.…”