Learn all about microbiota

Did you know that in your body you have trillions of microorganisms (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

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What microbiota are found in our bodies?

In a nutshell

It consists of trillions⁷ of microorganisms (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 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 dysbiosis (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. Levy M, Kolodziejczyk AA, Thaiss CA, et al. Dysbiosis and the immune system. Nat Rev Immunol. 2017;17(4):219-232. ) are: antibiotic-associated diarrhea,⁸ infantile colic,⁹ gastroenteritis,¹⁰ inflammatory bowel diseases¹¹ (IBS)...
You have several ways of positively affecting the balance and the diversity of the gut microbiota: diet, prebiotics, probiotics, transplant...

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 dysbiosis (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. Levy M, Kolodziejczyk AA, Thaiss CA, et al. Dysbiosis and the immune system. Nat Rev Immunol. 2017;17(4):219-232. ) and unbalancing the microbiota.

The cutaneous microbiota is a very complex ecosystem, composed of an ensemble of living microorganisms (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

The skin acts as a triple protective barrier.^4,12
The skin microbiota is relatively stable over time^4,13 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
Dysbiosis (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. Levy M, Kolodziejczyk AA, Thaiss CA, et al. Dysbiosis and the immune system. Nat Rev Immunol. 2017;17(4):219-232. ) 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

In a nutshell,

The composition of the pulmonary microbiota is shaped primarily by environment.
Imbalance (dysbiosis (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. Levy M, Kolodziejczyk AA, Thaiss CA, et al. Dysbiosis and the immune system. Nat Rev Immunol. 2017;17(4):219-232. ) ) in the pulmonary microbiota may promote the emergence of pathogenic (sidenote: Pathogen A pathogen is a microorganism that causes, or may cause, disease. Pirofski LA, Casadevall A. Q and A: What is a pathogen? A question that begs the point. BMC Biol. 2012 Jan 31;10:6. ) bacteria or fungi, and contribute to the development of chronic respiratory diseases.

The human urinary tract is inhabited by numerous microorganisms (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 composition of urinary microbiota of women is different from the composition of the microbiota of men.²³
The urinary microbiota acts as a barrier against pathogens (sidenote: Pathogen A pathogen is a microorganism that causes, or may cause, disease. Pirofski LA, Casadevall A. Q and A: What is a pathogen? A question that begs the point. BMC Biol. 2012 Jan 31;10:6. ) .²¹
Studies published to date have demonstrated the clear role played by the urinary microbiota in urinary tract infections.^24,25

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.