My last std screening was 3 weeks ago and all negative for everything. I had several new partners in the last month. Two were unprotected but also recently tested. However one of them said she developed a yeast infection and UTI after we had sex and another developed BV which leads me to believe I’m carrying something non std related but sex is causing it. I read that men cannot have BV but can transmit it. My confusion is around treatment . Is the BV caused by bacteria on the skin or in the urethra . Could these infections to partners just be caused by bad hygiene on their part or is it likely I’m the cause and need to be treated. Basically, if you were me what would you do next to make sure there’s no reinfection or I don’t cause future partners BV or UTIs? Thanks! 

I smiled when I read the title you chose for your question. Everybody is "confused about BV for males", including the world's top experts in bacterial vaginosis and other vaginal infections. The role of male partners in transmitting or otherwise increasing the risk of BV in women has been mysterious ever since BV was first described and understood as a distinct disorder of vaginal bacterial overgrowth, going back about 50 years. As you may know, recent research has provided the first evidence that some cases of BV indeed follow exposure to men who likely carry bacteria that can trigger it, and that treating male partners can reduce the frequency of repeat episodes of BV in their partners. But even this is only one study -- by highly competent and respected researchers, but still only one study. It's still a good bet that exposure to male "carriers" do not explain all cases of BV. In fact, the strongest evidence for sexual transmission of BV is in women with female partners:  nearly 100% of the lesbian partners of women with BV have it themselves, even if neither had recently had sex with men. 

From your experience, I think it is indeed possible you harbor one or more bacteria that can contribute to BV in women. However, it is very difficult to know for sure and no standard testing is available. It is true that "men cannot have BV" (the term means it occurs only in people with vaginas). Whether such bacteria are on the skin or urethra isn't clear; in uncircumcised men, under the foreskin might be the main location. "Bad hygiene" in women has absolutely nothing to do with BV, as far as known. And UTIs and yeast infection also are entirely separate health problems in women, having nothing to do with BV. That said, many women's health care providers can find it difficult to accurately differentiate these conditions, as well as other STIs, from BV.

In other words, this entire area of women's health and BV's status as an STI remains murky and uncertain. It is hoped ongoing research will clarify things in the not too distant future. The best advice I can give you is to use condoms, which not only are wise and smart to lower your own risk but likely would help prevent BV in your partners if you indeed happen to harbor some of the bacteria that might cause it. However, if you find that you continue to have new female partners who have BV and believe it started after sex with you, consider visiting your local public health sexual health clinic, or otherwise finding a provider who understands these complex issues -- such as some infectious disease specialists -- and discuss possible treatment with metronidazole orally and clindamycin cream for your penis, the regimen that the recent research found to help prevent BV in women.

This is probably more detail than you were expecting -- but sometimes I take the opportunity for a blog-like reply than might be useful to other readers and in reply to future questions. I hope it was a little bit helpful.

HHH, MD