The fallopian tube microbiome: implications for reproductive health

Abstract

ObjectiveThere is a paucity of data characterizing the microbiota of the female upper genital tract, which controversially is described as a sterile site. We examine whether the fallopian tube harbours an endogenous microbial community.DesignThis prospective study collected from women undergoing total hysterectomy or salpingectomy-oophorectomy.SettingPrivate hospital gynaecology department.PatientsFallopian tubes were collected from women diagnosed with benign disease or for prophylaxis.InterventionsSamples were interrogated for the presence of microbial DNA using a next generation sequencing technology approach to exploit the V5 to V9 regions of the 16S rRNA gene.Main outcome measuresThe fallopian tube microbiota was characterized using traditional culture techniques and next generation sequencing.ResultsBacteria were isolated from 50% of cultured samples, and 100% of samples returned positive PCR results. Only 68% of the culture isolates could be confidently identified using automated diagnostic equipment in a clinical microbiology laboratory. Monomicrobial communities were identified only for cultured isolates (50%). Pyrosequencing revealed that all communities were polymicrobial. Lactobacillus spp. were not present in all groups, nor were they the most dominant isolates. Distinct differences in the microbial communities were evident for left compared to right fallopian tubes, ampulla versus isthmus, pre- and post- menopausal tissue, and in secretory phase fallopian tubes with and without Mirena intrauterine devices in situ (all p < 0.05).ConclusionThe female upper genital tract is not sterile. Distinct microbial community profiles in the fallopian tubes of healthy women suggest that this genital tract site supports an endogenous microbiota.

Modulation of Placental Gene Expression in Small-for-Gestational-Age Infants

“…The lack of understanding and characterisation of the placental associated microbial components (such as bacterial DNA) compared to the most well-characterised microbial communities such as those located at mucosal sites (the gut, oral and vaginal mucosa) is attributed to the fact the placenta is a low biomass organ, and microbial DNA at this site may well represent only remnants of exposure rather than living microorganisms. Recent evidence also confirms the presence of microbial communities throughout the continuum of the female genital tract including the fallopian tubes and uterine cavity, previously thought to be sterile like the placenta [91][92][93][94][95][96]. This suggests that the upper genital tract is not sterile and that microbial components may have potential physiological roles in these reproductive niches.…”

Commentary: Uterine Microbiota: Residents, Tourists, or Invaders?

“…In addition, there are two new studies published that support the concept of microbial changes throughout the menstrual cycle, where bacterial continuum between proliferative and secretory phases differed in (1) endometria from dysmenorrhea and menorrhagia patients ( 19 ) and (2) in the fallopian tubes ( 20 ). Clearly, more studies are required for identifying the “baseline” microbial continuum in the uterus, nevertheless the first studies are showing the uterine microbiota differences along the menstrual cycle.…”

The hologenome concept of evolution: do mothers matter most?

“…Breast cancer is associated with relative changes in the microbiota within genera and species . The female reproductive tract also harbours distinct microbiota in its different parts, with the Lactobacillus genus (Firmicutes) dominating the vagina, cervical canal, and to a smaller degree also the uterus . These findings indicate a non‐sterile environment that undergoes qualitative changes during the menstrual cycle and in states such as adenomyosis and endometriosis .…”