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Uterine microbiome


Source: http://en.wikipedia.org/wiki/Uterine_microbiome
Updated: 2017-06-03T13:26Z
Microbiome analysis flowchart

The uterine microbiome is the commensal, nonpathogenic, bacteria present in a healthy uterus, amniotic fluid and endometrium and the specific environment which they inhabit. It has been only recently confirmed that the uterus and its tissues are not sterile.[1][2] Due to improved 16S rRNA gene sequencing techniques, detection of bacteria that are present in low numbers is possible.[3] Using this procedure that allows the detection of bacteria that cannot be cultured outside the body, studies of microbiota present in the uterus are expected to increase.[4]

Characteristics

Bacteria, viruses and one genus of yeasts are a normal part of the uterus before and during pregnancy.[2][5] The uterus has been found to possess its own characteristic microbiome that differs significantly from the vaginal microbiome. Despite its close spatial connection with the vagina, the microbiome of the uterus more closely resembles the commensal bacteria found in the oral cavity.[2] In addition, the immune system is able to differentiate between those bacteria normally found in the uterus and those that are pathogenic. Hormonal changes have an effect on the microbiota of the uterus.[6]

Taxa

Epstein-Barr virus

The organisms listed below have been identified as commensals. Some also have the potential for growing to the point of causing disease:

OrganismCommensalTransientPotential
pathogen
References
Escherichia colixx[2][6][7]
Escherichia spp.xx[2][6][7]
Ureaplasma parvumxx[2][6]
Fusobacterium nucleatumx[8]
Prevotella tanneraex[5]
Bacteroides spp.x[5]
Streptomyces avermitilisx[2][6]
Mycoplasma spp.xx[5]
Neisseria lactamicax[2][6]
Neisseria polysacchareax[2][6]
Epstein-Barr virusxx[5]
Respiratory-Syncytial virusxx[5]
Adenovirusxx[5]
Candida spp.xx[5]

Other taxa, while not causing signs or symptoms of disease, are associated with a negative birth outcome.[2][5][6]

Clinical significance

Prophylactic antibiotics have been injected into the uterus to treat infertility. This has been done before the transfer of embryos with the intent to improve implantation rates. No association exists between successful implantation and antibiotic treatment.[9] Infertility treatments often progress to the point where a microbiological analysis of the uterine microbiota is performed.[2]

Immune response

The healthy uterine microbiota at the mucosal-epithelium and trophoblast implantation site is regulated by macrophages. These macrophages control the microbiota and secrete antimicrobial substances that regulate the population of the commensal bacteria and help to prevent infection with pathogenic bacteria.[2]

History

Investigations into reproductive-associated microbiomes began around 1885 by Theodor Escherich. He wrote that meconium from the newborn was free of bacteria. This was interpreted as the uterine environment was sterile. Other investigations used sterile diapers for meconium collection. No bacteria were able to be cultured from the samples. Bacteria were detected and were directly proportional to the time between birth and the passage of meconium.[1]

Research

Investigations into the role of the uterine microbiome in the development of the infant microbiome are ongoing.[1]

References and notes

  1. ^ a b c Perez-Muñoz, Maria Elisa; Arrieta, Marie-Claire; Ramer-Tait, Amanda E.; Walter, Jens (2017). "A critical assessment of the “sterile womb” and “in utero colonization” hypotheses: implications for research on the pioneer infant microbiome". Microbiome. 5 (1). ISSN 2049-2618. doi:10.1186/s40168-017-0268-4. 
  2. ^ a b c d e f g h i j k l Mor, Gil; Kwon, Ja-Young (2015). "Trophoblast-microbiome interaction: a new paradigm on immune regulation". American Journal of Obstetrics and Gynecology. 213 (4): S131–S137. ISSN 0002-9378. PMID 26428492. doi:10.1016/j.ajog.2015.06.039. 
  3. ^ Verstraelen, Hans; Vilchez-Vargas, Ramiro; Desimpel, Fabian; Jauregui, Ruy; Vankeirsbilck, Nele; Weyers, Steven; Verhelst, Rita; De Sutter, Petra; Pieper, Dietmar H.; Van De Wiele, Tom (2016). "Characterisation of the human uterine microbiome in non-pregnant women through deep sequencing of the V1-2 region of the 16S rRNA gene". PeerJ. 4: e1602. ISSN 2167-8359. PMC 4730988Freely accessible. PMID 26823997. doi:10.7717/peerj.1602. 
  4. ^ Wassenaar, T.M.; Panigrahi, P. (2014). "Is a foetus developing in a sterile environment?". Letters in Applied Microbiology. 59 (6): 572–579. ISSN 0266-8254. PMID 25273890. doi:10.1111/lam.12334. 
  5. ^ a b c d e f g h i Payne, Matthew S.; Bayatibojakhi, Sara (2014). "Exploring Preterm Birth as a Polymicrobial Disease: An Overview of the Uterine Microbiome". Frontiers in Immunology. 5: 595. ISSN 1664-3224. PMC 4245917Freely accessible. PMID 25505898. doi:10.3389/fimmu.2014.00595. 
  6. ^ a b c d e f g h Yarbrough, V. L.; Winkle, S.; Herbst-Kralovetz, M. M. (2014). "Antimicrobial peptides in the female reproductive tract: a critical component of the mucosal immune barrier with physiological and clinical implications". Human Reproduction Update. 21 (3): 353–377. ISSN 1355-4786. PMID 25547201. doi:10.1093/humupd/dmu065. 
  7. ^ a b Todar, K. "Pathogenic E. coli". Online Textbook of Bacteriology. University of Wisconsin–Madison Department of Bacteriology. Retrieved 2007-11-30. 
  8. ^ Prince, Amanda L.; Antony, Kathleen M.; Chu, Derrick M.; Aagaard, Kjersti M. (2014). "The microbiome, parturition, and timing of birth: more questions than answers". Journal of ReproductiveImmunology. 104–105: 12–19. ISSN 0165-0378. PMC 4157949Freely accessible. PMID 24793619. doi:10.1016/j.jri.2014.03.006. 
  9. ^ Franasiak, Jason M.; Scott, Richard T. (2015). "Reproductive tract microbiome in assisted reproductive technologies". Fertility and Sterility. 104 (6): 1364–1371. ISSN 0015-0282. PMID 26597628. doi:10.1016/j.fertnstert.2015.10.012. 

See also

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