Antibiotics are the products of the life of microorganisms, animals and plants, as well as their semi-synthetic derivatives and synthetic products of this series that destroy or stop the development of pathogens in the human or animal body. Antibiotics also affect the intensity of biochemical reactions. To date, many different antibiotics have been synthesized, but only some of them are used in practical medicine. This is due to their high toxicity. Below are the main groups of antibiotics that are derived from microorganisms, animal and plant tissues.
The main raw materials for the preparation of antibiotics are mold fungi (griseofulvin, penicillin), actinomycetes (tetracyclines, rifamycins, streptomycins, levomycetins, cephalosporins, aminoglycosides, polyenes), fungi (fusidine), bacteria (gramicidin, polymyxin), lichens (usnic acid), plants (Rafanine, imanine, phytoncides), animals (lysozyme, erythrine, leukin, interferon, ekmolin, gamma globulins).
Antifungal antibiotics are groups of various bio-compounds that are capable of destroying the biological membranes of microscopic fungi, causing their death. The most popular are such drugs as "Levorin", "Natamycin", "Nystatin". These days, these drugs are not very often prescribed, due to low efficiency and high toxicity. Modern pharmacy offers a large number of highly effective synthetic fungicidal drugs, which gradually displace antifungal antibiotics.
Given the chemical structure, distinguish such groups of antibiotics: cephalosporins, penicillins, macrolides, levomycitins, tetracyclines, polymyxins, aminoglycosides, rifamycins and polyenes. Antibiotics, unlike chemical antiseptics, getting on the surface of a microbial cell or penetrating inside, even in small concentrations, disturb its osmotic vital functions (reproduction, respiration, nutrition) showing bactericidal and bacteriostatic action.
Groups of antibiotics by the mechanism of action: inhibitors of the cell membrane (cephalosporins, penicillins); Inhibitors of different stages of biosynthesis of protein and nucleic acids (levomycetins, streptomycins, aminoglycosides, tetracyclines, macrolides, rifamycins, chloromycins, actinomycins). The most dangerous drugs from this group of antibiotics are levomycetins and aminoglycosides, which can cause damage to the red bone marrow, liver and kidneys.
Thanks to modern technologies, the mechanism of antimicrobial action of antibiotics at the molecular level was studied, which increased the understanding of the underlying processes that occur under their influence. For example, researchers found that a violation of the synthesis of proteins under the influence of drugs of teracycline, levomycetin and erythromycin occurs at different stages. Levomycetins inhibit the activity of the enzyme peptidyl transferase, erythromycin acts on the enzyme translocase, and tetracyclines - the process of attachment of transport ribonucleic acid to the ribosome.
Groups of antibiotics given the range of antimicrobial activity. All antibiotics are classified into narrow and broad spectrum drugs. Such narrow-spectrum drugs, like "Erythromycin", "Oleandomycin" - act mainly on gram-positive microflora, and polymyxin - on gram-negative, and polyenes - on fungi.
Drugs with a wide spectrum of action (streptomycins, levomycitins, tetracyclines, aminoglycosides) act on both gram-positive and gram-negative microflora, as well as some viruses, fungi, rickettsia, leptospira, protozoa.