Imbalance of the Intestinal Flora (Dysbiosis)

“Intestinal flora imbalance (dysbiosis)” (synonyms: Intestinal dysbiosis; intestinal flora disorder; intestinal intoxication; intestinal poisoning; symbiosis disorder; Small Intestinal Bacterial Overgrowth, SIBO; ICD-10-GM K63.8: Other Specified Diseases of the Intestine) refers to a disease process that is triggered by a bacterial flora in the intestine that deviates qualitatively and/or quantitatively from the norm. In dysbiosis, there is an imbalance in the structural or functional composition of the microbiota. Microbiotia is the term used to describe the totality of microorganisms that colonize the intestine and are essential for the host organism. The body needs these microorganisms because they perform important functions in our body. Already at the beginning of the last century, the Nobel Prize winner E. Metchnikow stated that a high number of lactobacilli in the intestine has a positive effect on health and promotes a long life. At the same time, H. Tissier found that diarrhea in infants could be successfully treated using bifidobacteria. This was the beginning of the study of human intestinal flora. The human intestine harbors more than 1014 microorganisms. The small intestine has a relatively low bacterial colonization. Bacterial colonization density increases from the duodenum (small intestine) to the jejunum (small intestine) to the ileum (small intestine) and colon (large intestine). The intestinal flora is subject to individual variations – about 400 species can be detected regularly. The microorganisms of the colon can be assigned to 400 different species. Among the quantitatively most important species are Bacteroides, Eubacterium and Bifidobacterium. They are an essential part of the “microbiome” which further includes bacteria of the skin and the urogenital tract, but also of the mouth, throat and nose. The dry mass of stool consists of 30-75% bacteria. The biodiversity of these microbes is large and their roles are diverse:

  • Prevent bacterial overgrowth (microbial barrier) – protection against settlement and multiplication of pathogens; growth inhibition through the production and release of microstatic and microcidal substances such as short-chain fatty acids, hydrogen sulfide and hydrogen peroxide.
  • Immunomodulation and stimulation – constant training of the natural immune defenses, that is, stimulation of antibody formation and production of macrophages (phagocytes).
  • Vitamin production – vitamin K by coli bacteria, vitamins B3, B5 and folic acid by Clostridia species, vitamin B12 by some species of lactobacilli and biotin by germs of the genus Bacteroides. However, the amounts produced in the process are only of minor importance and contribute far from covering the daily requirement of these vital substances.
  • Nutrient and vital substance supply (macro- and micronutrients) of the large intestine mucosa.
  • Promoting the metabolism of the intestinal wall by substances formed by the bacteria.

At the same time, our intestine provides habitat and food for microorganisms. This give and take between humans and microorganisms is called symbiosis (living together). A symbiosis is always characterized by the fact that both humans and bacteria derive a benefit from this coexistence. Course and prognosis: Many chronic diseases are preceded or accompanied by dysbiosis. The maintenance of a eubiotic intestinal flora (undisturbed balance of bacterial flora in the intestine) is essential for the entire organism. The supply of probiotic food (e.g. lactic fermented sauerkraut, beans, etc.) or probiotic cultures (probiotics; mainly apathogenic (not pathogenic) germ groups of lactobacilli and bifidobacteria) via dietary supplements can favorably influence the environment in the intestine. Comorbidities (concomitant diseases): associated with dysbiosis are: