Immunomodulation of the Vaginal Ecosystem by Ligilactobacillus salivarius CECT 30632 Improves Pregnancy Rates among Women with Infertility of Unknown Origin or Habitual Abortions

In this study, the probiotic potential of Ligilactobacillus salivarius CECT 30632 was assessed, including properties specifically related with gynecological targets. This strain displayed co-aggregative and antimicrobial activity against a wide spectrum of vaginal pathogens while being respectful with the growth of vaginal lactobacilli. The strain produced a high concentration of lactic acid and displayed alpha-amylase activity when assayed in vitro. It showed a noticeable survival rate after exposition to conditions similar to those present in the human digestive tract and was adhesive to both vaginal and intestinal cells. Subsequently, their capacity to increase pregnancy rates among women with habitual abortion or infertility of unknown origin was studied. Administration of L. salivarius CECT 30632 (similar to 9 log(10) CFU) daily for a maximum of six months to these women was safe and led to a successful pregnancy rate of 67.5% (80% and 55% for women with repetitive abortion and infertile women, respectively). Significant differences in Nugent score, vaginal pH, and vaginal concentrations of lactobacilli, TGF-beta, and VEFG were observed when the samples collected before the intervention were compared with those collected after the treatment among those women who got pregnant. Therefore, this strain can modulate the vaginal ecosystem and lead to better fertility outcomes.

Automated summary

This study assessed the probiotic potential of Ligilactobacillus salivarius CECT 30632, specifically in relation to gynecological targets. The strain exhibited co-aggregative and antimicrobial activity against vaginal pathogens while promoting the growth of vaginal lactobacilli. It also showed survival after exposure to conditions similar to the human digestive tract and was adhesive to vaginal and intestinal cells. Furthermore, the administration of L. salivarius CECT 30632 to women with habitual abortion or infertility led to a successful pregnancy rate of 67.5%, indicating its ability to modulate the vaginal ecosystem and improve fertility outcomes.