A Multi-Strain Oral Probiotic Improves the Balance of the Vaginal Microbiota in Women with Asymptomatic Bacterial Vaginosis: Preliminary Evidence

Background/Objectives: the vaginal microbiota is known to confer protection in the genital ecosystem, due to the predominance of different Lactobacillus species, playing a crucial role in women’s health; alterations in the composition of the microbial communities in the vagina can be associated with the development of bacterial vaginosis (BV). Current therapy for BV involves oral or intravaginal administration of metronidazole or clindamycin, albeit the high recurrence rates suggest a need for alternative therapeutic tools, such as probiotics. Herein, the diversity and composition of vaginal microbiota in women with asymptomatic BV was investigated before and after the oral administration of a multi-strain probiotic formulation. Methods: a prospective observational pilot study with pre–post design was carried out from 1 June 2022, to 31 December 2022, on reproductive- age women with asymptomatic BV, as diagnosed via Nugent score, and matched healthy controls. The probiotic was administered to all study participants as acid-resistant oral capsules (twice daily), and a vaginal swab was collected at baseline and after 2 months of treatment, for the metagenomic analysis of 16s rDNA. Results: the diversity and richness of the vaginal microbiota in women with BV were significantly reduced after 2 months of supplementation with the oral probiotic, as evidenced by measures of α-diversity. Interestingly, some bacterial genera typically associated with dysbiosis, such as Megasphaera spp., were significantly decreased; whereas, at the same time, Lactobacillus spp. Doubled. Conclusions: our preliminary results suggest that the multi-strain oral probiotic is a beneficial treatment specifically targeting the dysbiotic vaginal microenvironment.