Seminovaginal microbiome in couples. ReproTAKcouples1

Genital tract microbiome is tightly associated with reproductive health. Although vaginal microbiome has been researched a lot, the current knowledge about male microbiome is scarce, and parallel studies examining couples are extremely rare. In this work, we aimed to compare seminal and vaginal microbiome in couples and to assess the influence of sexual intercourse on vaginal microbiome. The study included 23 couples. Microbiomes of semen and vaginal fluid (pre- and post-intercourse) were profiled using Illumina HiSeq2000 sequencing of the V6 region of 16S rRNA gene. Seminal communities were significantly more diverse but with lower total bacterial concentrations than vaginal ones. G. vaginalis was the predominant in half of women whose partners had significant leukocytospermia but only in one of 17 women who had a partner without leukocytospermia. There was significant decrease in relative abundance of L. crispatus after intercourse and high concordance between semen and vaginal samples. In couples that had more similar genital tract microbiome before intercourse, the similarity decreased after intercourse and vice versa. Our data supported the hypothesis that semen influences vaginal microbiome: predominance of G. vaginalis in female partner is associated with inflammation in male genital tract.