Microbiota, Microbiome, and Gut Flora - What's the Difference?

The microbiota refers to all microorganisms located in a specific area. In the case of the intestinal microbiota, also known as gut flora, these are bacteria, viruses, and fungi that settle in the gut.

The microbiome, on the other hand, is the entirety of all genomes of these microorganisms. Therefore, we talk about microbiome analyses because new analysis methods can examine all genomes in a sample. These analysis methods, known as Next Generation Sequencing, thus determine the entire collected DNA from all microorganisms in a sample and thus enable an overview of all microorganisms in a (stool) sample, which is not possible with traditional analysis methods.

The entirety of all genomes of the intestinal microbiota is therefore the intestinal microbiome.

For the purpose of our analyses, we often use the terms microbiota, microbiome, and gut flora synonymously, referring to the bacteria that colonize the gut.

Different sections of the gastrointestinal tract harbor different bacteria, which are perfectly adapted to each section of the gut depending on pH levels and the presence of oxygen. About 10^14 microbes live in the human gastrointestinal tract, which is 100 trillion! The colon is the most densely populated section of the gut. The gut microbiota is unique to each person. Even in healthy identical twins living in the same household, the gut microbiota is similar, but differences can still be found.

Gut bacteria play an important role in our health. Beneficial bacteria, for example, prevent the colonization of disease-causing bacteria by occupying space in the gut or strengthening the gut mucosal barrier. They can also metabolize components of our food that the human body cannot digest, such as certain plant fibers. These components are also generally referred to as dietary fibers or, when specifically intended for the metabolism of bacteria, as prebiotics. In return for providing the bacteria with food and a comfortable "living space," certain bacteria supply us with important metabolic products, such as short-chain fatty acids, which we cannot produce ourselves. In addition, bacteria in the gut play an important role in the immune system, as well as effects on the nervous system and our brain. It has been scientifically proven that the microbial ecosystem in the gut can influence neurological diseases, mood, and mental health through the so-called gut-brain axis.

The human body mostly lives in harmony with its microbiota and benefits from their abilities. In some cases, however, a bacterial imbalance or infection can disrupt this harmony. Through the use of microbiome analyses, which can provide a holistic picture of the intestinal microbiota, these imbalances are to be recognized early and prevented proactively.

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