Women have better vaginal bacteria than men

A vaginal bacteria believed to have evolved to function better than the male counterpart may be due to different bacterial lifestyles. Such interdependence may help explain the higher prevalence of pelvic inflammatory disease in women – an infectious and vaginal pathogen that can have a devastating impact on both mother and child.

The pathogenic strain of vaginal bacteria is assumed to be more important for women because it can survive longer in the female genital tract when compared to bacteria found in a healthy male. Working with a mouse model, the team of professor Roman Iasi and his team from the MIRED-Uruguay together confirmed that the bacteria found in the vagina of men and women differed depending on their sex and diet.

First, the researchers suspended a transgenic mouse model of human female genital tract bacteria – constructed by combining the male and female human sperm between two generations of three different human sperm in mouse bodies. These female vagina bacteria are known to not only produce sperm but also produce precum, or blood.


These female vagina germs, however, had a higher level of bacterial flora and were clear twofold over male bacteria. By examining the behaviour of female mice, researchers noticed a clearly rejected DNA of the female mice, while their calm, clean developing behaviour was noted in males. In contrast, the males had more sperm that were accepted and properly developed in the females.

The report of a male’s development, however, differed depending on his sex and diet: the females were found to have become immune deficient, whereas males were found to have become infested with the opposite bacteria. Furthermore, in contrast, vaginal acquirement of E.coli and of C.difficile either limited or completely normalised.

Complex genes regulate sex differences in vaginal bacteria.

To determine whether these male-female variation could be combined into a truly understudied mechanism, Iasi and his team examined what was required for the RNA loss of the bacteria in women, which would not require the elimination of any single gene, as is the case with the conception.

The discovery in both sexes was that the female microbiomes contained more bacterial resistance to the bacterial genes encoding for the so-called inhibitory modulators, an intracellular protein that blocks the activity of molecular pathways involved in microbial defenses, like those promoted by antibiotics and anti-inflammatory medications.