Contrary to what you might think, your pee is not totally germ-free. A recent study showed that in healthy men, the tube between their bladder and genitals is full of tiny germs and that engaging in vaginal sex can change its makeup. This research was published on March 24th in a medical journal called Cell Reports Medicine and it helps doctors and scientists figure out the difference between a urethra (entranceway of the bladder/reproductive organs) when it’s healthy or diseased.
Researchers at Indiana University are trying to figure out what kind of bugs live in our genital areas. David Nelson, a microbiologist, says these bugs usually come from the surroundings and spread through poop. So the question remains – where do they really come from?
A team of scientists collected penile urethra swabs from 110 adult men without any infection or ill-feeling, and they decoded the DNA contained in this sample. They found that two kinds of bacteria lived in the area – one was originally there while the other came from somewhere else.
Qunfeng Dong, a scientist at Loyola University Chicago, says it is really important to know what is healthy. Without that knowledge, we can’t figure out what diseases are.
Scientists have discovered that most healthy men have a small population of bacteria living close to the tip of their penis, where there is plenty of oxygen. These bacteria appear to be necessary for keeping the urethra (the tube leading from the bladder to the outside) in good health.
Some of the men had different types of bacteria in them which are usually found inside a vagina. The scientists think they survived deep down in the male urinary tube because it doesn’t have much oxygen. The only men who had these bacteria were the ones who reported having sex with a woman, suggesting that’s where they got them from.
Scientists looked at the sexual history of people and noticed that there was a strong connection between vaginal sex and certain bacteria living in the urinary-tract of males. Other activities, such as oral sex or anal sex, didn’t result in a similar effect. In addition, they found evidence which showed that the male urinary-tract microbiome changes after having sex with a female partner – these changes could still be detected two months after intercourse.
Nelson said that our study showed that vaginal sex affects 10% of all bacteria. He thought this was an important discovery because one behavior can have such a strong influence.
We recently found bacteria from vaginas can move and be found in penises. Next, we want to see if that works the other way too. We also hope our findings help us know more about why some people get illnesses related to their urethra (pee hole) or reproductive organs like Sexually Transmitted Infections (STIs).
Nelson says that sexually transmitted infections (STIs) usually affect people who don’t have much money, and they especially hurt women and minorities. Unfortunately, many people feel ashamed to talk about STIs, so it’s often not addressed properly. Nelson’s study might lead to a big change in how we handle STIs which could help everyone.
This work was funded by the National Institute of Allergy and Infectious Diseases. It was called the “Sexual behavior shapes male genitourinary microbiome composition” study, which studied how sexual activity changes the bacteria in men’s bodies. The study was published in Cell Reports Medicine online.
Reference: “Sexual behavior shapes male genitourinary microbiome composition” by Evelyn Toh, Yue Xing, Xiang Gao, Stephen J. Jordan, Teresa A. Batteiger, Byron E. Batteiger, Barbara Van Der Pol, Christina A. Muzny, Netsanet Gebregziabher, James A. Williams, Lora J. Fortenberry, J. Dennis Fortenberry, Qunfeng Dong and David E. Nelson, Cell Reports Medicine.
DOI: 10.1016/j.xcrm.2023.100981
