Microbes are everywhere. They populate the air, the water, the soil, and have even evolved intimate relationships with plants and animals.
The human body is inhabited by millions of tiny living organisms, which, all together, are called the human microbiota. Bacteria are microbes found on the skin, in the nose, mouth, and especially in the gut. We acquire these bacteria during birth and the first years of life, and they live with us throughout our lives
On the other hand, areas of the body such as the brain, the circulatory system and the lungs are intended to remain sterile (microbe free). The human body provides many unique environments for different bacterial communities to live.
