Positive and negative bacteria.

Bacteria are found literally everywhere. Some of them are simply necessary for a person, others are harmful. Those that constantly live in the human body are considered an obligatory microflora. These organisms create an invisible barrier that prevents infection from entering our body. Bifidobacteria living in our intestines do not allow toxins to enter the bloodstream, and also maintain a habitat in it, in which pathogenic microorganisms cannot live. Dangerous bacteria are a source of serious infectious diseases. The most common are staphylococci, shigella and Escherichia coli.