Prevention of urogenital infections by oral administration of probiotic lactobacilli

In general, lactobacilli are nonpathogenic part of the normal urogenital microflora and have been recognized as a barrier against colonization of unwanted (pathogen) microflora. The results of many in vitro studies suggest following mechanisms of probiotic lactobacilli action in urogenital tract: adhesion to urogenital cells, competition with pathogens for adhesive sites, production of biosurfactants, co-aggregation with pathogens, production of antimicrobial substances (organic acids, hydrogen peroxide and bacteriocins) and stimulation of immune system. From 80 different lactobacilli species isolated from human or animal intestinal and urogenital tract, only few lactobacilli strains possess optimal properties to be effective as probiotic therapeutics against infections in the urogenital tract. Combination of Lactobacillus rhamnosus GR-1 and Lactobacillus fermentum RC-14 was proposed as the best one for epithelial vaginal cells colonization and inhibition of uropathogens adhesion. The results of a number of clinical studies confirmed beneficial role of oral lactobacilli. However, the most of commercially available Lactobacillus strains, which are ordinary used in fermented dairy products,are seriously limited in protection of urogenital tract when they are ingested orally.