Background: The lack of lactobacilli in the vagina of postmenopausal women due to estrogen deficiency plays an important role in the development of bacteriuria. In the last few years, the use of lactobacilli for the prevention of genitourinary infections has been explored using different probiotic strains.

Objectives: To evaluate the vaginal colonization by Lactobacillus rhamnosus GG in postmenopausal healthy women following oral administration of the bacteria in a yogurt base for 1 month, as a first step in evaluating the potential probiotic role of LGG[1] in the prevention of recurrent urinary tract infections.

Methods: One or two doses per day of yogurt containing 10⁹ colony forming units of LGG were administered orally to 42 postmenopausal healthy women for 1 month. Vaginal and rectal swabs were cultured at the beginning and end of the study.

Results: At the end of the study, the vaginas of only four women (9.5%) were colonized with LGG, at a very low number of bacteria, despite the fact that the gastrointestinal tracts of 33 women (78.6%) were colonized. There were no significant differences between one or two doses daily.

Conclusions: LGG should not be considered as a probiotic agent in urinary infections since it does not attach well to the vaginal epithelium.