The Microbiota Continuum along the Reproductive Tract in Women with Infertility

Abstract

Introduction. At present, the question of commensal, including opportunistic, microflora participation in  infertility development remains debatable. In a number of studies, the translocation of the vaginal microflora into the endometrial tissue is considered as a factor contributing to inflammation development. In addition, the connection of some reproductive losses with the persistence of certain conditionally pathogenic microorganisms is shown. Today, to solve this issue, molecular genetic research methods are being actively introduced that surpass the routine cultivation techniques in a number of positions.The aim of the study was to assess the taxonomic diversity of microorganisms in the vaginal biotope with infertility.Material and methods. For the study samples of vaginal contents obtained from the posterior vaginal fornix of 15 women, consisting of barren marriage, were used. A metagenomic study of 16S ribosomal RNA samples was carried out on the Illumina MiSeq platform, using the MiSeq Reagent Kits v3 kit (600-Cycle Kit), as recommended by the manufacturer. Libraries for sequencing plots of the V3-V4 gene of the 16S ribosomal RNA were prepared according to the 16S Metagenomic Sequencing Library Preparation Illumina. In bioinformatics assessment, Kraken Metagenomics version 2.0.0 software for metagenomic analysis (classifier of reads — short nucleotide sequences) was used using a standard database.Results. It was shown that the occurrence of representatives of the Lactobacillaceae family in the vaginal biotope varies from 12 to 84%. The genus Lactobacillus with the dominance of L. jensenii, L. delbrueckii and L. amylolyticus occupied the leading position among the members of the family. In all samples, Moraxella spp. was found in large numbers, with M. osloensis leading among the representatives of the entire community. In half of the cases, the joint presence of M. osloensis and G. vaginalis was revealed.Conclusion. It has been established that in infertility in the vaginal microbiota the number of representatives of the genus Lactobacillus is significantly reduced, and there is also a change in the leading species to L. jensenii, whose functional activity does not fully ensure the colonization resistance of the vaginal biotope, allowing for excessive reproduction of oppotrunistic microorganisms, in particular, M. osloensis.