The female upper reproductive tract harbors endogenous microbial profiles

Abstract

IntroductionThe female reproductive tract harbours unique microbial communities (known as microbiota) which have been associated with reproductive functions in health and disease. While endometrial microbiome studies have shown that the uterus possesses higher bacterial diversity and richness compared to the vagina, the knowledge regarding the composition of the Fallopian tubes (FT) is lacking, especially in fertile women without any underlying conditions.MethodsTo address this gap, our study included 19 patients who underwent abdominal hysterectomy for benign uterine pathology, and 5 women who underwent tubal ligation as a permanent contraceptive method at Hospital Clínico Universitario Virgen de la Arrixaca (HCUVA). We analyzed the microbiome of samples collected from the FT and endometrium using 16S rRNA gene sequencing.ResultsOur findings revealed distinct microbiome profiles in the endometrial and FT samples, indicating that the upper reproductive tract harbors an endogenous microbiome. However, these two sites also shared some similarities, with 69% of the detected taxa Being common to both. Interestingly, we identified seventeen bacterial taxa exclusively present in the FT samples, including the genera Enhydrobacter, Granulicatella, Haemophilus, Rhizobium, Alistipes, and Paracoccus, among others. On the other hand, 10 bacterial taxa were only found in the endometrium, including the genera Klebsiella, Olsenella, Oscillibacter and Veillonella (FDR <0.05). Furthermore, our study highlighted the influence of the endometrial collection method on the findings. Samples obtained transcervically showed a dominance of the genus Lactobacillus, which may indicate potential vaginal contamination. In contrast, uterine samples obtained through hysterescopy revealed higher abundance of the genera Acinetobacter, Arthrobacter, Coprococcus, Methylobacterium, Prevotella, Roseburia, Staphylococcus, and Streptococcus.DiscussionAlthough the upper reproductive tract appears to have a low microbial biomass, our results suggest that the endometrial and FT microbiome is unique to each individual. In fact, samples obtained from the same individual showed more microbial similarity between the endometrium and FT compared to samples from different women. Understanding the composition of the female upper reproductive microbiome provides valuable insights into the natural microenvironment where processes such as oocyte fertilization, embryo development and implantation occur. This knowledge can improve in vitro fertilization and embryo culture conditions for the treatment of infertility.

Deciphering the role of female reproductive tract microbiome in reproductive health: a review

“…Compared to the lower reproductive tract and the uterus, there are relatively few studies on the tubal microbiome ( Miles et al., 2017 ; Zhou et al., 2019 ; Walther-António et al., 2016 ; Pelzer et al., 2018a ; Canha-Gouveia et al., 2023 ). Walther-António et al.…”

“…In most studies on the tubal microbiome, the selected subjects tended to have benign diseases of the uterus and cervix that may affect the cervical physiological barrier, making it easy for bacteria (such as Lactobacillus ) that colonize the lower reproductive tract to migrate upward ( Walther-António et al., 2016 ; Pelzer et al., 2018a ). A recent study comparing the microbiome of the fallopian tube in women who underwent tubal ligation (normal controls) and those who underwent hysterectomy for benign disease (cases) showed no significant differences in microbial diversity or differential abundance analysis ( Canha-Gouveia et al., 2023 ). It was also found that the most prevalent genera among fallopian tube samples were Lactobacillus , Prevotella , Acinetobacter , Propionibacterium , and Faecalibacterium ( Canha-Gouveia et al., 2023 ).…”

“…A recent study comparing the microbiome of the fallopian tube in women who underwent tubal ligation (normal controls) and those who underwent hysterectomy for benign disease (cases) showed no significant differences in microbial diversity or differential abundance analysis ( Canha-Gouveia et al., 2023 ). It was also found that the most prevalent genera among fallopian tube samples were Lactobacillus , Prevotella , Acinetobacter , Propionibacterium , and Faecalibacterium ( Canha-Gouveia et al., 2023 ). This study is a significant impetus for further investigation into the microbial communities within the fallopian tubes.…”

Microenvironment of the Lower Reproductive Tract: Focus on the Cervical Mucus Plug

“…59 During the transfer of fresh/frozen embryos, the dominance of Lactobacillus in the vagina, cervix and including uterus can have better reproductive outcomes, and the decrease in Lactobacillus at the endometrial level can be associated with worse embryo implantation rates. 39 59 60 61 62 Nevertheless, the presence and dominance of alive Lactobacilli inside the uterus is an active topic of debate, 38 63 64 65 which requires clarification.…”

Advanced Technologies for Studying Microbiome–Female Reproductive Tract Interactions: Organoids, Organoids-on-a-Chip, and Beyond

“…3 However, it was shown that 70% of the microbial communities of the endometrium and the fallopian tubes (FTs) are shared within a patient. 4 It is acknowledged that the microbiome plays a role in the process of becoming pregnant and maintaining a healthy pregnancy. 5 Consequently, alterations in microbial homeostasis, sometimes referred to as dysbiosis, can lead to various reproductive disorders, ranging from bacterial vaginosis and pelvic inflammatory disease (PID) to infertility and pregnancy complications.…”