Interaction of genital microbiota in infertile couples

Abstract

Abstract Background Bacteria colonise most of the human body and the genital tract is not an exception. While it has been known for decades that a vaginal microbiota exists, other genital sites have traditionally been viewed as sterile environments, with bacterial presence associated only with pathological conditions. However, recent studies identified specific patterns of bacterial colonisation in most genital sites. Shifts in the bacterial colonisation of the female genital tract have been linked to impairment of reproduction and adverse pregnancy outcomes, such as preterm birth. The goal of this project is to understand the association between the genital microbiota of couples seeking assisted procreation aid and the outcome of this treatment. Male and female partners were considered as a unit (“couple microbiota”) and the interaction between their microbiota will be evaluated. Results We have characterised microbial samples coming from vaginal and penile swabs, as well as follicular fluid and semen, using next generation sequencing (16S rRNA profiling). The results revealed variability in bacterial biomass across different sample types, with Lactobacillus spp. dominating in vaginal and follicular fluid samples. Male samples exhibited higher diversity and harboured bacterial genera previously associated with negative obstetrical and gynecological outcomes. In addition, we found evidence of inter-partner microbiota interaction, indicating possible bacterial transmission between partners. Conclusions With this project, we aimed to gain a better understanding of how the male genital microbiota could influence the lower (vagina) and upper (follicular fluid) female genital tracts. Our results suggest a very limited impact of male microbiota on the female bacterial colonisation, although the information about the sexual activity of the couples involved in the study was missing. Future research should focus on understanding the influence of sexual activity on microbial composition and stability in different genital sites, especially in the case of infertile couples.