“We are entering a post-antibiotic era”, the head of WHO stressed, “and every antibiotic developed at any time can become useless”. Cascade model of resistance occurrence includes at the fi rst stage, there is a circulation of plasmids of soil fungi, actinomyces and bacteria to the plants and invertebrate animals in biofi lms and symbioses, which represent complex cascade systems; at the next stage, there is circulation of plasmids from invertebrate animals to higher animals, from animals to humans and from humans to animals – and this contributes to fast spreading of drug resistance all over the world. The key role belongs to the genes which are contained in R-plasmids. Anthropogenic stress infl uences counteract the most important function of the biosphere – the regular recreation of living matter and energy accumulated in it. During the formation of the biosphere, a cascade of population structures was formed in the form of biological fi lms and symbioses of plants, animals and microorganisms. These structures are united by a single genetic system, which because of the circulation of plasmids regulates the expression of genes under stress and leads to the emergence of resistance.