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”. What is microbiology? Microbiology Society. ) , including bacteria, viruses, and fungi?1

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 skin,2 your urinary tract,3 your vagina,4 your mouth,5 your ears...6

Find out more about each of these microbiota!

    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 microorganisms.1


    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

    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 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”. What is microbiology? Microbiology Society. ) (bacteria, fungi, viruses, and parasites), which contribute to the olfactory signature of human skin.

    In a nutshell

    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”. What is microbiology? Microbiology Society. ) 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 flora: 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.

    Kho ZY, Lal SK. The Human Gut Microbiome - A Potential Controller of Wellness and Disease. Front Microbiol. 2018 Aug 14;9:1835

    Bay L, Barnes CJ, Fritz BG, et al. Universal Dermal Microbiome in Human Skin. mBio. 2020 Feb 11;11(1):e02945-19.

    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.

    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.

    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.

    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.

    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, et al. Lactobacillus species as biomarkers and agents that can promote various aspects of vaginal health. Front Physiol. 2015 Mar 25;6:81.

    13 Reid G, Bruce AW, Fraser N, et al. 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, et al. 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, et al. 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.