Complementary seminovaginal microbiome in couples.

The genital tract microbiome is tightly associated with reproductive health. Although many research studies have been performed on the vaginal microbiome, current knowledge of the male microbiome is scarce, and parallel studies examining couples are extremely rare. In this work, we aimed to compare seminal and vaginal microbiomes 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 those of the vagina. Gardnerella vaginalis was predominant in half of the women whose partners had significant leukocytospermia, but only in one of 17 women who had a partner without leukocytospermia. There was significant decrease in the relative abundance of Lactobacillus crispatus after intercourse, and high concordance between semen and vaginal samples. Our data support the hypothesis that semen and vaginal microbiomes are in association, inasmuch as the predominance of G. vaginalis in female partners was significantly related to inflammation in male genital tracts.