Lactobacillus as a probiotic for preventing urogenital infections

The use of probiotics to control certain infections and to reestablish the human bacterial ecology is gaining acceptance as an alternative to conventional antibiotic therapy. This article discusses the role of Lactobacillus as a probiotic agent for the maintenance of vaginal microflora and the prevention of urogenital infections. Lactobacillus protects the vagina from colonization by pathogens by two main mechanisms: blocking their attachment to the vaginal epithelium and producing substances that inhibit their multiplication. Not all Lactobacillus strains express these properties with the same intensity; on the contrary, there are substantial differences among species and among strains from a single species. Some lactobacilli adhere avidly to vaginal epithelial cells, some block pathogen attachment to these cells, and others inhibit pathogen growth. Moreover, the same Lactobacillus strain can show different blocking and inhibiting activity against different pathogens. This demonstrates the importance of characterizing Lactobacillus strains prior to their use as probiotics in humans. To date only a small number of systematic clinical trials with well-characterized strains has been conducted and there are few conclusive results. Further large clinical studies are needed to define the role of Lactobacillus as a probiotic. The main indications for probiotic Lactobacillus use in urogenital tract infections would include recurrent urinary tract infection in healthy pre-menopausal and post-menopausal women, post-infection prophylaxis to re-establish the vaginal flora and prevent future episodes, bacterial vaginosis and recurrent vaginal candidiasis.