The objective of this study is to evaluate the effects of oral administration of Lactobacillus BSL_PS71 on the presence of S. agalactiae in vaginal microbiota of healthy women.

Group B streptococci (Streptococcus agalactiae) are found in the vaginal microbiota in 10-30% of women without showing signs of infection. However, during delivery, it can be transmitted to the baby and, although in most cases it does not lead to disease, in a percentage of 5% of babies it causes serious infections that can trigger the death of the baby. In order to avoid this risk, a protocol of intra-partum preventive administration of antibiotics was implanted decades ago in women with a positive vaginal culture for this species in the weeks before birth. Taking into account the high percentage of women who show positive culture, this represents a high percentage of women who receive preventive antibiotic treatment with the consequences that this has for the mother's and baby's microbiota, as well as contributing to the generation of antibiotic resistance, a serious problem for today's society.

The fecal microbiota is considered a source of bacteria for the vaginal microbiota. In fact, women who present S. agalactiae in the vaginal microbiota also have it in stool. Given the demonstrated ability of Lactobacillus to control certain bacterial populations, the ability of a battery of Lactobacillus strains to inhibit the growth of S. agalactiae in the context of the fecal microbiota was analyzed. From these tests the strain Lactobacillus BSL_PS71 was selected for its antibacterial capacity against S. agalactiae.

Inclusion Criteria:

• Test positive for S. agalactiae in vaginal exudate
• Accept freely to participate in the study and sign the informed consent document

Exclusion Criteria:

• Consumption of probiotic supplements
• Antibiotic use in the period of 2 weeks before the start of the study
• Being pregnant or intending to get pregnant in the next 8 weeks
• Being allergic to any group of antibiotics