For many years, microbes, e.g. bacteria, fungi, viruses and other microorganisms, have solely been associated with diseases and unhygienic conditions. In response, mankind has spared little effort to eradicate these organisms, be it in everyday life through ubiquitously available disinfectants or in a medical setting, e.g. through antibiotics or antifungal medication. While there are places where a germ-free environment is vital, e.g. an operation room, one needs to differentiate between spaces in which microorganisms physiologically should not exist (e.g. in our bloodstream) or spaces in which they should flourish (e.g. the colon).
Bearing this in mind, in recent years, researchers have found that the microorganisms living on and in our body (i.e. any surface connected to the outside world, e.g. skin, nasal and oral cavities, our gastrointestinal tract et cetera), our microbiota, are, in fact, not harmful to us. On the contrary, they may contribute to our health and well-being and protect us against actual pathogens (by forming a so-called “colonization resistance" ). In addition, research has revealed the complexity and diversity of our gut microbiota which may be in part responsible for the development of certain diseases including obesity and type 2 diabetes .