Bacterial vaginosis (BV) is a bothersome bacterial infection of the vagina that affects close to 30% of women of reproductive age in the US. Even though BV can be treated with an antibiotic, it comes back within 12 weeks in up to three-quarters of women.

In addition to causing vaginal discharge and other troubling symptoms (see below), the infection has been linked to increased risk for preterm birth in pregnant women and low-birth weight babies. Having BV, which upsets the healthy balance of “good” and “harmful” bacteria (known as the microbiome) in the vagina, also can increase a woman’s chances on contracting a sexually transmitted disease, such as chlamydia or gonorrhea. In Africa, BV is associated with the spread of HIV, where the disease affects more women than men.

Risk for BV, which typically causes pain, itching or burning of the vagina and a strong, fish-like odor, especially after sex, is increased in women who douche and/or have a new sex partner or multiple sex partners—all of which can upset the balance of bacteria in the vagina. Using a latex condom during sex may help reduce the risk of developing BV.

Because this infection is so common and carries such serious potential harms, researchers from the University of California, San Francisco (UCSF) and other universities joined forces to investigate a so-called “live biotherapeutic”—a therapy that involves inserting healthy vaginal bacteria directly into the vagina.

Research findings: In the study, reported in The New England Journal of Medicine, 228 women with BV were treated with an antibiotic vaginal gel called metronidazole. After treatment some women were treated with a microbiome therapy called Lactin-V, a powder formulation derived from the healthy vaginal bacterium species Lactobacillus crispatus. Lactin-V is self-administered into the vagina with an applicator. The other women served as a control group and were not given the Lactin-V.

The women in the treatment group applied the powder every day for five days and then twice per week for 10 weeks. The other group used a placebo. After 12 weeks, the researchers found a significant reduction in BV recurrence— 30% of the women treated with Lactin-V after the antibiotic treatment experienced a recurrence compared with 45% of those who received a placebo after the antibiotic. No safety risks were found from the bacteria used in the Lactin-V formulation.

“The initial indication for Lactin-V is for the prevention of BV, which millions of women in the US have each year,” explained Craig R. Cohen, MD, first author of the study and professor of obstetrics, gynecology and reproductive sciences at UCSF. “But this product also has the potential to be an effective intervention to prevent HIV infection and preterm birth.”

Before granting FDA approval for Lactin-V, which is produced by Osel, Inc. of Mountain View, California, the FDA will likely require a larger (phase III) trial.  Funding for the study was provided by the National Institute of Allergy and Infectious Diseases (NIAID).

For more strategies to help prevent BV, read here.

Source: The study “Randomization Trial of Lactin-V to Prevent Recurrence of Bacterial Vaginosis” led by researchers at the University of California, San Francisco and published in The New England Journal of Medicine.