A study from the Kwon Lab at the Ragon Institute, published on Mar. 27 in Cell Host & Microbe, examines how a new bacterial therapy helps prevent recurrent bacterial vaginosis (BV) and why its effectiveness varies among women.
BV is a common vaginal condition affecting over 25% of reproductive-age women worldwide. It is linked to discomfort and increased risk of preterm birth, cervical cancer, and sexually transmitted infections such as HIV. Standard antibiotic treatments often fail to provide lasting relief, with more than half of treated women experiencing recurrence within a year.
The research focused on LACTIN-V, a live biotherapeutic product containing Lactobacillus crispatus. In previous clinical trials, LACTIN-V reduced BV recurrence after antibiotic treatment but did not work for all patients. The new study analyzed samples from 213 trial participants using microbiome sequencing and immune profiling to determine why some women benefited more than others.
Findings showed that twelve weeks after starting LACTIN-V treatment, 30% of recipients developed a healthy vaginal microbiome dominated by L. crispatus compared to just 9% in the placebo group. The colonization was mainly due to the strain found in LACTIN-V; however, in some cases naturally occurring L. crispatus took over instead. Women whose vaginal microbiomes were initially dominated by Prevotella or Gardnerella species responded best to treatment while those with Candidatus Lachnocurva vaginae saw little improvement.
"This study's results offer key insights for vaginal health," says Seth Bloom, co-first author who began this research as a postdoctoral trainee at the Kwon Lab and now leads his own lab. "Our results offer a roadmap to guide development and use of LACTIN-V and similar live biotherapeutic products to improve the health of the millions of women worldwide who experience BV." Doug Kwon, senior author of the study said: "This study provides the most detailed view to date of how a live biotherapeutic can reshape the vaginal microbiome to promote long-term vaginal health. By identifying the microbial and host factors that determine whether Lactobacillus crispatus successfully colonizes, we can begin to design more precise and effective treatments to improve women's health."
