Treating Males For Bacterial Vaginosis May Reduce Recurrence In Females

Bacterial vaginosis (BV) is not classified as a sexually transmitted infection, but the results of a new study could change that. ljubaphoto/Getty Images

• New research suggests a common vaginal infection may actually be a sexually transmitted infection.
• Researchers say bacterial vaginosis (BV) also occurs in males despite being often viewed as a condition affecting only females.
• Treatments for BV, which has a high recurrence rate, should include treating the other sexual partner.
• The study found that treating both partners for the infection significantly lowered the recurrence rate.

Bacterial vaginosis (BV) is a common vaginal infection affecting nearly 1 in 3 females globally with strong recurrence rates.

While the emphasis on treatment has focused on females, a new study suggests that sexual partners should also be treated for the condition that researchers say fits the profile of a sexually transmitted infection (STI).

BV infection may develop following exposure to a new sexual partner without a condom or other barrier method. Reinfection or recurrence following treatment is associated with exposure to a regular sexual partner.

During sexual intercourse, bacterial vaginosis-associated organisms are exchanged between partners, the researchers found.

When female and male sexual partners were treated for BV, recurrence rates were lower. Females received first-line antimicrobial agents, and males were administered combined oral and topical antimicrobial therapy. Researchers say this combination therapy contributed to the lower BV recurrence rates in females within 12 weeks.

These findings suggest that including male partners in treatment for BV could improve treatment success and potentially lead to a cure. The study was published on March 5 in The New England Journal of Medicine.

“Clinicians and researchers with similar views have undertaken partner treatment trials in the past, but none failed to reduce recurrence or improve BV cure for women,” said study co-author Catriona Bradshaw, PhD, of the Melbourne School of Population and Global Health at the University of Melbourne, Australia.

“This was in part due to trial limitations, but we also believe this may be because they all used oral antibiotics for men only,” Bradshaw told Healthline.

Treating male partners reduced BV recurrence

Although BV is both treatable and curable, around 50% of females experience recurrence within six months after antibiotic treatment, which may raise the risk of obstetric complications down the road.

When there is a regular sexual partner, the risk of BV recurrence increases three-fold.

Experts haven’t considered BV an STI because the bacteria typically originates from within versus sexual transmission. However, as the new study points out, this isn’t always true.

Prior research has shown that men carry bacterial species linked to BV in the urethra and penis.

To show that BV fits the profile of an STI, researchers collected a body of evidence that Bradshaw described as a journey 20 years in the making.

The randomized controlled trial involved 164 heterosexual monogamous couples in which the female had bacterial vaginosis. 

The partner-treatment group involved 81 couples. Female partners received first-line antimicrobial treatment, and male partners received combined oral and topical antimicrobial therapy (metronidazole 400-milligram tablets and 2% clindamycin cream applied to penile skin) twice daily for 7 days. 

“We believed it was important to try and target the bacteria on the penile skin with a topical antibiotic cream as well as inside the urethra with an oral antibiotic,” Bradshaw explained. “This had never been done before.”

The control group had 83 couples, in which females received the same standard of care and males received no treatment. The primary outcome was BV recurrence within 12 weeks. 

The trial was stopped at the 12-week follow-up mark because the female-only treatment was inferior to treating both partners.

In the both-partner treatment group, BV recurrence occurred in 35% of females compared to a 63% recurrence rate among females in the control group. 

Adverse events in male partners receiving treatment were mild and included: 

• nausea
• headache
• metallic taste

“We are relieved that this treatment strategy has been so effective,” Bradshaw said. 

“It enables us to understand that reinfection of women with BV bacteria from men is responsible for a large proportion of BV recurrence in women. The treatment is easy and well tolerated and only needs to be taken for a week.”

Improving bacterial vaginosis testing and treatment

Bradshaw noted that more studies in diverse populations and settings are needed to confirm the findings.

For instance, Bradshaw would like to further investigate what may be causing BV treatment failures and driving high recurrence rates. 

She’s also curious why BV persisted among a smaller group of females who still had the infection after finishing their antibiotics even though they had not resumed sex, she explained.

Still, these findings could eventually pave the way for improved BV treatments involving both partners.

“Our program of research is focused on analyzing the samples from couples to understand if there are specific BV bacteria in men that are causing BV recurrence in women, which would help us develop better tests for BV, including something that has not been done before — a test for men,” Bradshaw said.

“We do hope that this trial helps clinicians individualize BV treatment for their patients. This trial is relevant to women in a current monogamous relationship with a male, but for women without a current partner, messaging needs to be more around treating them and understanding that condoms provide some protection against catching BV as they do for many STIs.”

To help increase awareness about treating BV as an STI, the researchers produced a website with resources for healthcare professionals, patients, and their male partners.

What to know about bacterial vaginosis

​​Bacterial vaginosis (BV) develops when there is a disruption to the balance of bacteria in the vagina, which leads to an overgrowth of certain bacteria. 

BV causes uncomfortable symptoms such as:

• Unusual vaginal discharge that may appear thin, gray, white, or green
• Fishy odor that may intensify after sexual intercourse
• Vaginal itching or irritation
• Burning sensation while urinating

Some individuals with BV may not experience any symptoms, which means regular gynecological visits are important for detection.

How is BV treated?

First-line treatments for bacterial vaginosis usually include antibiotics that can be taken orally, or that may come in the form of a vaginal gel or suppository. These include:

• Antibiotics (oral or vaginal) 
• Vaginal pessaries (inserts)
• Medicated vaginal gels

Managing recurrent BV

When BV persists after first-line treatments, other approaches may include:

• Longer course of antibiotics
• Preventive habits (i.e., avoiding scented menstrual products, changing out of tight or sweaty clothes, and wearing breathable cotton underwear)
• Changes to sexual habits (i.e., limiting sexual partners and using latex condoms or other barrier methods during sexual intercourse)

When to seek medical care

Contact a healthcare professional if you experience:

• Unusual vaginal discharge with odor
• Persistent vaginal irritation or discomfort
• Symptoms that return after first-line treatment
• Concerns about infection

Takeaway

Bacterial vaginosis (BV) is not classified as a sexually transmitted infection, but the results of a new study could change that.

Evidence shows that BV occurs in males, and researchers at the University of Melbourne say that treating both partners could help lower high infection recurrence rates in females.

More studies in larger, diverse groups are needed to confirm these findings and better understand why some people with BV continue to resist treatment.