Characteristics Of Genital Microbiome In Healthy And Infertile Reproductive Women

Background and purpose:Microbiota in human body play a critical role in establishing and maintaining our daily well-being and are associated with pathogenesis of various diseases.These bacterial communities can be found in skin,respiratory tract,alimentary tract,and other tissue sites,each with their own ecosystems to carry out multiple functions.Previous studies have shown that female genital tract（FGT）microbiota is considered to be one of the simplest yet most important,as it has unique impacts on the reproductive health of women.However,the commonness and specificity of different parts of the female reproductive tract are not clear,and the composition and diversity of reproductive tract microorganisms and their internal relationship with female reproductive health have not been fully analyzed.Materials and methods:The 16s r RNA gene sequencing of the specimens from the FGT was conducted to identify and quantify the microorganisms.The bioinformatics methods including clustering analysis,differential analysis,and correlation analysis were employed to classify and quantify the microbiota,and characterized the representative microbiota for the clusters.Furthermore,the differential microbiota analysis was conducted to identify microbiota and pathways related to female infertility.Through the isolation and culture of vaginal secretions from healthy reproductive age women,dominant Lactobacilli were screened out,then their acid production capacity,H₂O₂ production capacity,physiological and biochemical characteristics and antibacterial properties were studied.Results:Based on the analysis of the genital tract flora,the subjects were clustered into different subgroups by the bacteria in the vagina,cervix,and uterus.The microbial composition and proportion of the vagina and cervix showed high similarity and divided the samples into four groups,respectively.Consistently,the two classifications by vagina and cervix also had high similarity,and were characterized by highly heterogeneous flora at genus（Heterogeneous）,Lactobacillus crispatus（L.crispatus）,Lactobacillus inners（L.iners）,and a variety of Lactobacilli species（L.heterogeneous）.In addition,the samples could be divided into three groups by the flora in uterine cavity,which were characterized by gram-negative bacteria,species such as Brevundimonas nasdae,Brevundimonas aurantiaca,Acinetobacter sp.,Pseudomonas stutzer,Methyloversatilis universalis,and species of Lactobacillus crispatus,Lactobacillus inners,respectively.Propionibacterium acnes,Acinetobacter junii,Lactobacillus crispatus and Lactobacillus inners may be associated with infertility.Functionally,metabolism-related pathway,neurotrophin signaling pathway and adipocytokine signaling pathway were predominantly dysregulated in the uterine cavity of infertile patients.Through the isolation and culture of female reproductive tract secretions,two strains of L.crispatus（C1 C3）and two strains of Lactobacillus gasseri（L.gasseri）（G3G7）were screened out,which had a strong ability to produce lactic acid and H₂O₂,and both could effectively inhibit the reproduction of pathogenic bacteria in vitro experiments,such as Escherichia coli（E.coli）,Staphylococcus aureus,pseudomonas aeruginosa.Discussion:We characterized a comprehensive microbial landscape in FGT and the microbiological characteristics of different parts of the FGT of normal population.Moreover,the potential pathogenic bacteria and biological signaling pathways related to infertility in the uterine cavity were explored.This study has enhanced our understanding of the characteristics of flora and the sterility associated flora in FGT.In this study,Lactobacillus strains with good efficacy and productivity were isolated from female reproductive tract,and we expected that studying microbial agents would contribute to improve the reproductive tract microecology and obtain better reproductive outcomes in the future.