Twenty-nine healthy premenopausal women were randomly assigned to receive, immediately following menses, a vaginal gelatin capsule containing either 1) 109 Lactobacillus rhamnosus GR-1 and L. fermentum RC-14 or 2) 109 Lactobacillus rhamnosus GG. Women in group 1 had significantly higher intravaginal levels of one or both organisms at day 14 than did those in group 2 (p < 0.01). Both GR-1 and RC-14 inhibited the growth of Candida albicans. In a previous study, 50 women who received GR-1 and RC-14 by weekly vaginal application for up to one year experienced no cases of yeast vaginitis, compared with an expected 200 episodes in this number of women.

Comment: These findings suggest that administration of Lactobacillus rhamnosus GR-1 and L. fermentum RC-14 promotes healthy vaginal ecology and may prevent the development of yeast vaginitis. In contrast, Lactobacillus GG, which has been well documented as a beneficial organism for the human digestive tract, was less able to colonize the genitourinary tract. The results of this study suggest that the appropriate choice of probiotic may depend on the area of the body being treated. Note: Dr. Reid holds a patent on Lactobacillus rhamnosus GR-1 and L. fermentum RC-14. These lactobacillus strains are not yet commercially available.

Cadieux P, et al. Lactobacillus strains and vaginal ecology. JAMA 2002;287:1940-1941.