Learn all about microbiota

Did you know that in your body you have trillions of (sidenote: Microorganisms Living organisms that are too small to be seen with the naked eye. They include bacteria, viruses, fungi, archaea and protozoa, and are commonly referred to as “microbes”. ) , including bacteria, viruses, and fungi1?

The human microbiota plays a key role in your health: a balanced microbiota contributes to our good health. 
You may have already heard about the gut microbiota, or “gut flora”, it is the most popular one.

But did you know that other microbiota are living in your body? In your skin2, your urinary tract3, your vagina4, your mouth5, your ears6...

Find out more about each of these microbiota!

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    6 microbiota described in this page

    trillions the human microbiota is estimated to be trillions of microorganisms

    What are microbiota?

    The human microbiota corresponds to all the microorganisms that have colonized your body and with which you cohabitate: mainly bacteria, but also viruses, fungi, yeast and protozoa. Its composition differs according to the surfaces colonized: cutaneous microbiota, vaginal microbiota, urinary microbiota,  respiratory microbiota, ENT microbiota and intestinal microbiota, also called the intestinal flora, by far the largest with 100 trillion microorganisms1.

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    What microbiota are found in our bodies?

    We have trillions7 of bacteria that populate our intestine with fascinating powers on the human body. Let’s understand how your intestinal microbiota works and why you should take care of it!

    In a nutshell

    • It consists of trillions7 of  (sidenote: Microorganisms Living organisms that are too small to be seen with the naked eye. They include bacteria, viruses, fungi, archaea and protozoa, and are commonly referred to as “microbes”. )  that populate your intestines like bacteria, viruses, fungi (including yeasts), and even parasites.
    • Each one of us has a unique microbiota, like a fingerprint.7
    • The gut microbiota can be considered a functional organ of the human body, it works closely with your intestines.
    • Some diseases associated with intestinal (sidenote: Dysbiosis Generally defined as an alteration in the composition and function of the microbiota caused by a combination of environmental and individual-specific factors. ) are: antibiotic-associated diarrhea8, infantile colic9, gastroenteritis10, inflammatory bowel diseases11 (IBS)...
    • You have several ways of positively affecting the balance and the diversity of the gut microbiota: diet, prebiotics, probiotics, transplant...

    Hundreds of bacteria populate the vagina.4 Let’s see how they work and why we should take care of our microbiota!

    In a nutshell

    • The vaginal microbiota is balanced when its diversity is low.4
    • All women have a microbiota in their vagina, but it is different for each one of us.
    • The body evolves throughout life, and so does the vaginal microbiota.
    • For women, taking care of our microbiota is more than important. Daily intimate health is crucial to stay away from (sidenote: Dysbiosis Generally defined as an alteration in the composition and function of the microbiota caused by a combination of environmental and individual-specific factors. ) and unbalancing the microbiota.

    The cutaneous microbiota is a very complex ecosystem, composed of an ensemble of living (sidenote: Microorganisms Living organisms that are too small to be seen with the naked eye. They include bacteria, viruses, fungi, archaea and protozoa, and are commonly referred to as “microbes”. ) (bacteria, fungi, viruses, and parasites), which contribute to the olfactory signature of human skin.

    In a nutshell

    • The skin acts as a triple protective barrier.4,12
    • The skin microbiota is relatively stable over time4,13 and only changes at the major stages of life. 
    • The skin microbiota also plays a key role in immunity: it stimulates the immune defense mechanisms of the epidermis and the body as a whole and calms inflammation where necessary.14
    • (sidenote: Dysbiosis Generally defined as an alteration in the composition and function of the microbiota caused by a combination of environmental and individual-specific factors. ) is often associated with pathological skin conditions such as acne,15 atopic dermatitis,16 psoriasis,17 seborrheic dermatitis,18 rosacea,19 or skin cancer.20

    It was long believed that healthy lungs contained no microorganisms. That’s been called into question since the recent discovery of the pulmonary microbiota.

    In a nutshell,

    The human urinary tract is inhabited by numerous (sidenote: Microorganisms Living organisms that are too small to be seen with the naked eye. They include bacteria, viruses, fungi, archaea and protozoa, and are commonly referred to as “microbes”. ) that can play a protective role in our health.21 Reduced diversity in the urinary flora may also be a risk factor for disease.22 In fact, urine was once thought to be sterile, but recent scientific research has shown the opposite to be the case.22

    In a nutshell

    The ENT (ear, nose, throat) microbiota is made up of three distinct bacterial floras: the oral microbiota, the auricular microbiota, and the nasopharyngeal microbiota.

    In a nutshell

    • The oral microbiota brings together more than 700 bacterial species, which contribute to oral health.
    • In the ear canal, the composition of the auricular microbiota is closely related to that of the skin.
    • The nasopharyngeal microbiota, which covers the nasal airways and the pharynx, is composed of very different germs.
    Sources
    1. Kho ZY, Lal SK. The Human Gut Microbiome - A Potential Controller of Wellness and Disease. Front Microbiol. 2018 Aug 14;9:1835
    2. Bay L, Barnes CJ, Fritz BG, et al. Universal Dermal Microbiome in Human Skin. mBio. 2020 Feb 11;11(1):e02945-19.
    3. Neugent ML, Hulyalkar NV, Nguyen VH, et al. Advances in Understanding the Human Urinary Microbiome and Its Potential Role in Urinary Tract Infection. mBio. 2020 Apr 28;11(2):e00218-20.
    4. Greenbaum S, Greenbaum G, Moran-Gilad J, et al. Ecological dynamics of the vaginal microbiome in relation to health and disease. Am J Obstet Gynecol. 2019 Apr;220(4):324-335.
    5. Radaic A, Kapila YL. The oralome and its dysbiosis: New insights into oral microbiome-host interactions. Comput Struct Biotechnol J. 2021 Feb 27;19:1335-1360.
    6. Xu Q, Gill S, Xu L, et al. Comparative Analysis of Microbiome in Nasopharynx and Middle Ear in Young Children With Acute Otitis Media. Front Genet. 2019;10:1176.
    7. Ley RE, Peterson DA, Gordon JI. Ecological and evolutionary forces shaping microbial diversity in the human intestine. Cell. 2006 Feb 24;124(4):837-48.
    8. McFarland LV. Antibiotic-associated Diarrhea: Epidemiology, Trends and Treatment. Future Microbiol. 2008 Oct;3(5):563-78.
    9. Perceval C, Szajewska H, Indrio F, et al. Prophylactic use of probiotics for gastrointestinal disorders in children. Lancet Child Adolesc Health. 2019 Sep;3(9):655-662
    10. Stuempfig ND, Seroy J. Viral Gastroenteritis. [Updated 2020 Nov 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-
    11. Oka P, Parr H, Barberio B, et al. Global prevalence of irritable bowel syndrome according to Rome III or IV criteria: a systematic review and meta-analysis. Lancet Gastroenterol Hepatol. 2020 Oct;5(10):908-917
    12. Petrova MI, Lievens E, Malik S, Imholz N and Lebeer S (2015) Lactobacillus species as biomarkers and agents that can promote various aspects of vaginal health. Front. Physiol. 6:81.
    13. Reid G, Bruce AW, Fraser N, Heinemann C, Owen J, Henning B. Oral probiotics can resolve urogenital infections. FEMS Immunol Med Microbiol 2001;30: 49–52.
    14. Petricevic L, Domig KJ, Nierscher FJ, et al. Characterisation of the oral, vaginal and rectal Lactobacillus flora in healthy pregnant and postmenopausal women. Eur J Obstet Gynecol Reprod Biol 2012;160:93–9.
    15. Gupta P, Singh MP, Goyal K. Diversity of Vaginal Microbiome in Pregnancy: Deciphering the Obscurity. Front Public Health. 2020 Jul 24;8:326.
    16. Petrova MI, van den Broek M, Balzarini J, Vanderleyden J, Lebeer S. Vaginal microbiota and its role in HIV transmission and infection. FEMS Microbiol Rev. 2013;37(5):762-792.
    17. Younes JA, Lievens E, Hummelen R, van der Westen R, Reid G, Petrova MI. Women and Their Microbes: The Unexpected Friendship. Trends Microbiol. 2018 Jan;26(1):16-32.
    18. Kovachev S. Defence factors of vaginal lactobacilli. Crit Rev Microbiol. 2018 Feb;44(1):31-39.
    19. Riepl M. Compounding to Prevent and Treat Dysbiosis of the Human Vaginal Microbiome. Int J Pharm Compd. 2018 Nov-Dec;22(6):456-465.
    20. Torcia MG. Interplay among Vaginal Microbiome, Immune Response and Sexually Transmitted Viral Infections. Int J Mol Sci. 2019;20(2):266.
    21. Whiteside SA, Razvi H, Dave S, et al. The microbiome of the urinary tract--a role beyond infection. Nat Rev Urol. 2015 Feb;12(2):81-90.
    22. Morand A, Cornu F, Dufour JC, et al. Human Bacterial Repertoire of the Urinary Tract: a Potential Paradigm Shift. J Clin Microbiol. 2019 Feb 27;57(3).
    23. Lewis DA, Brown R, Williams J, et al. The human urinary microbiome; bacterial DNA in voided urine of asymptomatic adults. Front Cell Infect Microbiol. 2013 Aug 15;3:41.
    24. Aragón IM, Herrera-Imbroda B, Queipo-Ortuño MI, et al. The Urinary Tract Microbiome in Health and Disease. Eur Urol Focus. 2018 Jan;4(1):128-138.
    25. Antunes-Lopes T, Vale L, Coelho AM, et al. The Role of Urinary Microbiota in Lower Urinary Tract Dysfunction: A Systematic Review. Eur Urol Focus. 2020 Mar 15;6(2):361-369.