The study will enroll healthy pre-menopausal female volunteers in the community. These subjects will act as their own controls. The subjects will collect voided urine and peri-urethral swab specimens daily for several months. They will also be asked to collect vaginal and peri-rectal swab specimens at various time points. Subjects will document various lifestyle variables daily. During the middle of the study, subjects will be randomized to probiotic vs placebo. Using bacterial culture and 16S rRNA gene sequencing, the study will measure the bacterial populations of several anatomic sites longitudinally: voided urine, peri-urethra, vagina, and peri-rectal. The study hypothesizes that oral probiotic usage will alter the bacterial populations and ratio of Lactobacillus to E. coli within each of these sites. Additionally, the study hypothesizes that the changes within each site will occur first in the rectum (i.e. GI tract), followed by the vagina, and then the urethra and bladder.

Using the prospective design of daily sampling and lifestyle variable documentation, the study may be able to identify possible influences on microbiome stability within the sampled sites. The lifestyle variables recorded include: diet, medication usage, menstruation, sexual activity, and alcohol consumption.

This pilot study will establish the variance of the outcome variables among healthy women and confirm the emergence of the probiotic with the recommended dose. With this information, future researchers will be able to calculate the power needed for a larger randomized trial. This trial would also randomize patients who may be at risk for a UTI to receive a probiotic vs placebo. The primary outcome measurement will be the change in the ratio of Lactobacillus to E. coli. As a secondary aim, the study will evaluate the incidence of UTI in the patients.