Darmmikroben

Darmmikroben, or gut microbiota, are the community of microorganisms living in the digestive tracts of humans and many other animals. The ecosystem comprises bacteria, archaea, viruses, and fungi, with bacteria making up the largest proportion. In a healthy adult, the gut harbors trillions of cells and a vast gene repertoire, far exceeding the human genome. The densest populations reside in the colon, where microbial metabolism of indigestible carbohydrates produces short-chain fatty acids such as acetate, propionate, and butyrate, which feed colonocytes and influence host metabolism and immunity.

Composition varies between individuals and is influenced by birth mode, diet, antibiotics, age, metabolism, and geography. Dominant bacterial phyla include Firmicutes and Bacteroidetes, with others such as Actinobacteria and Proteobacteria present in smaller numbers.

Functions of Darmmikroben include aiding digestion and nutrient extraction, synthesizing vitamins, training and regulating the immune system, protecting against pathogens by competitive exclusion, maintaining gut barrier integrity, and communicating with other organs through the gut-brain axis.

Dysbiosis refers to disruptions of this ecosystem that are associated with diseases such as obesity, type 2 diabetes, inflammatory bowel disease, allergies, and certain mental health conditions. Studying the gut microbiota relies on sequencing-based approaches (16S rRNA profiling, metagenomics), culture-based methods, and functional assays. Interventions include probiotics, prebiotics, synbiotics, and fecal microbiota transplantation, especially for recurrent Clostridioides difficile infection, though safety and individual response vary. Research continues to clarify causal relationships and develop personalized microbiome-based therapies.