Penis microbes may trigger vaginal infection in female partners, could predict who may develop it: Study
It affects about 29% of American women aged between 14 and 49. If untreated, it can lead to complications during pregnancy and increase the risk of sexually transmitted diseases
Microorganisms colonizing the penis of their male partners seem to be behind bacterial vaginosis -- a condition that makes females susceptible to other sexually transmitted diseases, suggests a new study. These bacteria could help predict which women are likely to develop the condition.
Bacterial Vaginosis (BV) strikes when a group of bacteria take over, disrupting the natural balance of microbes in the vagina. It affects about 29% of American women aged between 14 and 49, according to the Centers for Disease Control and Prevention (CDC). If untreated, it can lead to complications during pregnancy and increase the risk of sexually transmitted diseases such as HIV, herpes simplex virus, chlamydia, or gonorrhea.
"Decades of observational data [collected by observing people] indicate men can carry some of the same bacteria on their penis and semen that are associated with BV in women," Dr Supriya D Mehta, an epidemiologist at the University of Illinois at Chicago and the first author of the study, told MEA WorldWide (MEAWW). So Mehta and her colleagues decided to examine this using advanced molecular methods to learn more. Besides, antibiotic treatment of BV has limited long-term success, with up to 50% of women having recurrence within 6 months. "So we need more effective approaches to treatment. Male sex partner treatment may be a new strategy," she adds. These results suggest that manipulating the penile microbiome.
"We did this study not to place directionality or blame on one partner or another, but to increase the options and opportunity for improved reproductive health, and hopefully reduce stigma from BV. The name of our study in Kiswahili is Afya Jozi, Afya Jamii, which translates to Healthy Pair, Healthy Community. This is a play on bacterial “community”, but also community-level reproductive health depends on the health of both members within sexual partnerships," Mehta explained.
She, however, adds that the strategy of focusing on male sex partners is not meant to target people. "I would like for clinicians, researchers, and the public to be inclusive of male sex partners in their efforts to improve women's reproductive health. Not to place directionality or blame on one partner or another, but to increase the options and opportunity for improved reproductive health, and hopefully reduce stigma from BV, Mehta explained.
To understand the role of penis microbiota in triggering BV in women, Mehta and her team enrolled 168 Kenyan heterosexual couples. None of the female participants had BV at the start of the study. The team examined if these women developed the condition for one year. At the end of the study, more than 31% of the women developed BV. Among them, 23 developed the condition after a month, 20 at 6 months, and the nine at 12 months. Only 16.7% of the participants reportedly used condoms during the last intercourse.
After analyzing the penis microbiota, they saw a link between a specific group of bacteria and the condition. Further, the researchers used machine learning algorithms to identify patterns. Ten penile bacteria -- found in some men -- could be used to accurately predict the onset of the condition in women, they note.
Mehta and her team think penile bacteria could be acting directly by triggering the condition after intercourse. Alternatively, it could indirectly disturb the natural balance of the vaginal microbiome, thereby inducing BV through long-term or repeated exposure. Both, however, are theories. Further studies will confirm if either of the two scenarios is playing out.
The team will also have to carry out randomized controlled trials --experiments that test the effectiveness of new treatments. For instance, if treating male sex partners help control BV in their female partners. "We will also have to determine which types, dose, and duration of antibiotics may be most beneficial. We are currently evaluating how the penile and vaginal microbiome interacts together over time," she explained.
Long-term studies "examining the role of the penile microbiome in vaginal microbiome outcomes in women, and randomized trials examining the potential effect of microbiome-altering treatments on the penile microbiome and in relation to preventing BV recurrence are warranted," say researchers. Talking about the limitations of the study, Mehta says: "Like many studies, we would prefer a larger sample size. This may have allowed us to estimated predictive capacity at each time point. We would also like replication – for other investigators to conduct similar studies."
The results are published in the open-access journal Frontiers in Cellular and Infection Microbiology.