Many ecosystems thrive and help us stay healthy. What is the role of these bacteria? What if there is a conflict? Focus on the different groups of microbes whose secrets we haven’t yet uncovered. A unique microbiota is like a fingerprint
Severe infections lead to disease, infection and resistance to infection. Others will perform biological functions (at the metabolic level, vitamin synthesis, food breakdown, etc.). Each microbiota (skin, intestine, genitals, oropharynx) groups certain bacteria according to the characteristics of the environment in which they evolved (presence or absence of oxygen, acidity, etc.).
Although most of the major families of bacteria are found in every human body, each of us has our own microbiome, as unique as our fingerprints. This ecosystem is slowly evolving. When a baby is born, it first encounters the mother’s bacterial flora. If the baby is born during birth, it will benefit from the mother’s stomach and vaginal bacteria (mostly lactobacilli in the genital area). If it is born by Caesarean section, it will absorb skin changes. “As it grows, for example, when it comes into contact with other children in the nursery, its body will see other types of bacteria and its microbiota will become more diverse people of this type,” said bacteriologist Jacques Kreuz.
Intestinal microbiota (gut microbiota)
Composition of the intestinal microbiota
Varies depending on the location in the digestive tract. For example, since the stomach environment is acidic, there are very few bacteria in the stomach. On the other hand, there are more plants in the small intestine and large intestine or colon.
The gut microbiome contains 100 trillion different bacterial species.
There are 800 to 1,000 different species. Among the largest and most famous families, we can count Firmicutes and Bacteroidetes. Our lifestyle and diet play an important role in balancing and catching some diseases over others. “Vegetarians have many species of Prevotella in their microbiome, part of the Bacteroidetes phylum,” explains Dr. Anne-Marie Casade. The more diverse and varied the bacteria, the better it is for our microbiome and our health.
Bacteria have different functions:
Some synthesize vitamins (such as vitamin K) or insects;
Some are associated with the production of antibodies;
Others produce hormones that play a role in gut-brain communication;
Other factors can also cause food to deteriorate
AND SO ON.
When our stomach is balanced, everything is fine and our immune system works well. Remember that 85% of our immune system is in the intestines.
Gut flora imbalance
If it is not balanced, many problems can occur, from simple bloating to gastrointestinal problems such as irritable bowel syndrome. However, the research team is investigating the functioning of the intestines further and predicts that intestinal deficiency can lead to more serious diseases such as diabetes, asthma, allergies or worm autoimmune diseases (Crohn’s disease, lupus erythematosus, multiple sclerosis, etc.).
Dietary changes, stress and antibiotic use are enough to create imbalances in delicate systems. Make sure to eat a variety of high-fiber foods (fruits and vegetables) to take care of your microbiome. A range of probiotics (food supplements) can also help. “However, the beneficial effects of probiotics still need to be confirmed by good research,” added Karin Clement, professor of nutrition.
Vaginal microbiota (or vaginal flora)
The composition of the vaginal microbiota
It is related to hormones and is produced during puberty. Depending on the age of life, there can be differences in the flora found in the environment. This is what happens during major hormonal changes (puberty, pregnancy, menopause). Did you know that our unique odor comes from the type of bacteria in our body? The vaginal microbiota consists of approximately 90% of different types of lactobacilli (L. crispatus, L. gasseri, etc.). These bacteria, called bacillus or delineae flora, need estrogen to survive and develop. This is why this ecosystem is affected by hormonal disorders (pregnancy, pregnancy and menopause). These lactic acid bacteria help to keep the pH at a low (acidic) pH by secreting lactic acid, thus limiting bacterial growth and the risk of infection. “In addition to these bacteria, there are also Candida albicans bacteria that live in the vaginal mucosa,” added Dr. Anne-Marie Casade.
Vaginal microbiome imbalance
Therefore, the vaginal flora has antifungal and antibacterial properties in balance. When the balance is disrupted (decrease in good bacteria and/or increase in bad bacteria), negative symptoms can occur: urinary tract or genital infections, yeast infections, etc.
Many things can affect the balance of the vaginal flora:
wearing very tight clothes;
excessive hygiene or use of inappropriate products;
taking medications;
high;
diseases (diabetes, thyroid problems, etc.);
smoking;
certain birth control methods (low dose estrogen).
Use appropriate hygiene products to maintain the balance of your genital area. If you are using probiotics regularly, your doctor may also prescribe probiotics in the form of vaginal pessaries to prevent infection.
Skin microbiota (or skin flora)
Our skin microbiota is found everywhere on the skin and also consists of many bacteria. It feeds on sebum and dead keratinocytes (epidermis cells). Skin cells also protect against viruses and other diseases.
For example,
some people will be more attracted to mosquitoes than others due to crowding. Skin bacteria consist of Firmicutes, Proteobacteria and Actinobacteria. Some parts of the body, especially wet areas (glasses, feet, etc.) contain large amounts of bacteria.
Propionibacterium acne is especially common in young people, and the scalp often contains yeast, the main culprit of acne. This ecosystem changes depending on age and climate. Therefore, skin flora decreases with age.
In order to protect the skin in the best way, it is recommended to be strict but not too strict in hygiene. Ideally, choose bath products that are as pH neutral as possible and free of chemicals (dyes, preservatives, parabens, etc.).
Oropharyngeal microbiota (or respiratory bacteria)
Bacteria in the nose, throat, and lungs are numerous and diverse. These include Staphylococcus aureus, Streptococcus, Neisseria, Lactobacillus, and others. Thanks to DNA sequencing, scientists were able to determine the composition of the lung microbiota in 2025. That’s why science has yet to uncover all the mysteries of our diverse microbiomes.