Hôpital Saint-Antoine, Assistance publique-Hôpitaux de Paris, Laboratoire Clostridium difficile associé au Centre national de référence des anaérobies, 184, rue du Faubourg-Saint-Antoine, 75012 Paris, France, EA 2392 antibiotiques et flore digestive, Université Pierre-et-Marie-Curie, site Saint-Antoine, 27, rue de Chaligny, 75012 Paris, France, Hôpital Beaujon, Université Paris-VII, Centre labellisé pour les maladies intestinales rares, Gastroentérologie, MICI et assistance nutritive, Pôle des maladies de l'appareil digestif (PMAD), 100, boulevard du Général-Leclerc, 92110 Clichy, France
The intestinal microbiota (or intestinal microflora) includes about 10
14 micro-organisms in symbiosis with the host. New techniques of molecular analysis revealed that each individual is characterized by a specific microbiota whose composition is stable over the time. Despite this apparent diversity, 99% of fecal bacteria belong to three major phylogenetic lineages: Firmicutes, Bacteroidetes and Actinobacteria. Gut microbiota displays various functions which are essential for maintaining the host's health. In particular, intestinal micro-organisms possess a great metabolic potential. This microbial community is indeed able to convert a large variety of substrates (including sugars, proteins and lipids) leading to the production of a wide range of metabolites. Most of these metabolites have a beneficial effect on the host's health. New methods to study the microbiota can better demonstrate the relationship between changes in this complex ecosystem and digestive diseases. Effectively, the equilibrium of this ecosystem can be altered in inflammatory Bowel disease, short Bowel syndrome, infectious diarrhea or irritable Bowel disease. Numerous clinical trials plead in favour of certain probiotics micro-organisms to restore this equilibrium of the intestinal microbiota and correct the phenomena of dysbiosis.