Oral probiotic containing microbial lysates modulates rectal and vaginal microbial environments but does not change the vaginal community state type – a pilot study

The main aim of this study was to characterize the changes in the rectal and vaginal microbiota, as well as local inflammatory responses following the use of multi-strain oral probiotic containing microbial lysates. Eleven healthy premenopausal women received a one-month regimen of a multi-strain oral probiotic preparation containing Lactobacillus crispatus , Lactobacillus rhamnosus , and Bifidobacterium animalis , microbial lysates and fructooligosaccharides. Rectal and vaginal swab samples were collected at baseline, after one month of probiotic use, and after a one-month washout period. Microbiota composition was assessed using 16S rRNA sequencing. Local inflammatory response was evaluated via interleukin-6 levels in the swab samples. Following one month of probiotic use, a decrease was observed in rectal bacterial richness (median number of taxa 38 vs. 37; p  = 0.03) and rectal IL-6 levels (median 1.1 pg/mL vs. 0.6 pg/mL; p  = 0.02), as well as a decrease in vaginal bacterial diversity (median inverse Simpson index 1.1 vs. 1.0; p  = 0.03) The distribution of vaginal community state types remained unchanged. Among the probiotic strains, L. crispatus and L. rhamnosus were detected in post-intervention only in the vaginal swab samples of women who harbored them at baseline; B. animalis was not detected in any vaginal or rectal samples. To conclude, the use of a multi-strain oral probiotic containing microbial lysates and fructooligosaccharides did not alter the vaginal microbiota community state type in healthy premenopausal women, but it was associated with a modest modulation of rectal and vaginal microbial environments and a reduction in a local rectal inflammatory response.