Effect of the oral consumption of capsules containing Lactobacillus paracasei LPC-S01on the vaginal microbiota of healthy adult women: a randomized, placebo-controlled, double-blind crossover study. LPC-S01on the vaginal microbiota

The oral consumption of probiotics is practical and can be an effective solution to preserve vaginal eubiosis. Here, we studied the impact of orally administered Lactobacillus paracasei LPC-S01 (DSM26760) on the composition of the vaginal microbiota in adult women and the ability to colonize the vagina. Forty volunteers took oral probiotic (24 billion CFU) or placebo capsules daily for four weeks, and after a four-week wash-out, they switched to placebo or probiotic capsules according to the crossover design. Twenty-three volunteers completed the study according to the protocol. Before and after capsule ingestion, vaginal swabs were collected for qPCR quantification to detect L. paracasei LPC-S01 and for 16S rRNA gene profiling. The bacterial community structure of most of the analyzed vaginal swabs was dominated by lactobacilli. L. paracasei LPC-S01 was detected in the vagina of two participants, suggesting that the colonization of orally ingested Lactobacillus spp. in the vagina was rare but possible. Statistical modeling (including mixed-effect linear model analysis) demonstrated that daily intake of probiotic capsules reduced the relative abundance of Gardnerella spp. Quantitative PCR with G. vaginalis primers confirmed this result. Considering the pathogenic nature of Gardnerellavaginalis, these results suggest a potential positive effect of the probiotic capsule on the vaginal microbial ecosystem.