A transmission electron micrograph of a colony of Gardnerella vaginalis, a bacteria found in the vagina and urethra of men who have vaginal sex
Moreden Animal Health Ltd / Science Photo Library
The male urethra — the tube through which urine exits the body — is home to an array of bacteria, some of which are probably picked up during vaginal sex.
evelyn so and colleagues at the Indiana University School of Medicine swabbed the urethras of 110 men who had no sexually transmitted infections or problems related to the urethra. The men, average age 28, came from a variety of ethnic and racial backgrounds. Transgender people were not included in the study.
Of these men, 92 provided swabs containing sufficient levels of bacterial DNA for further analysis.
The bacteria discovered can be divided into two groups – those that can survive in the presence of oxygen and therefore probably live near the tip of the penis, and those that cannot survive when oxygen is present and therefore probably live in the urethra. Living up.
According to the researchers, the former group was found in most men’s swabs and are probably native to the penile urethra.
However, the latter group was dominated by bacteria that are often disrupted in the condition bacterial vaginosis (BV), a common cause of abnormal vaginal discharge that is thought to occur when the vaginal microbiome becomes out of sync.
Of the 110 men, 75 identified as heterosexual, 22 as gay and 13 as “bisexual or other”.
Only men who reported having vaginal sex had bacteria associated with BV, such as Gardnerella vaginalis, suggesting that he acquired them during vaginal sex. These bacteria were not associated with oral or anal sex.
“The most important conclusion of our study is that it establishes a baseline for healthy flora [penile] urethra,” say co-authors david nelsonAlso at Indiana University School of Medicine.
catriona bradshaw at Monash University in Melbourne, Australia, say this study details the bacterial composition of an infection-free penile urethra, which could serve as a baseline for measuring whether the penile microbiome is healthy or infected .
The results also support the hypothesis that men who have vaginal sex without a condom may transfer some bacteria from one woman to another, say Erica Plummer at Monash University.
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