Antibiotics are the waste products of microorganisms, animals and plants, as well as their semisynthetic derivatives and synthetic products of this series, which in the human or animal body destroy or stop the development of pathogens. Antibiotics also affect the intensity of biochemical reactions. To date, many different antibiotics have been synthesized, but in practical medicine only a few of them are used. This is due to their high toxicity. Below are the main groups of antibiotics that are obtained from microorganisms, animal and plant tissues.
The main raw materials for obtaining antibiotics are mold fungi (griseofulvin, penicillin), actinomycetes (tetracyclines, rifamycins, streptomycins, chloramphenicol, cephalosporins, aminoglycosides, polyenes), fungi (fusidine), bacteria (gramicidin, plants polymexin) (rafanin, imanine, phytoncides), animals (lysozyme, erythrin, leukin, interferon, ecmoline, gamma globulins).
Antifungal antibiotics are groups of diverse biocompounds that can destroy the biological membranes of microscopic fungi, causing their death. The most popular drugs are 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 that are gradually replacing antifungal antibiotics.
Given the chemical structure, the following antibiotic groups are distinguished: cephalosporins, penicillins, macrolides, levomycetins, 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 disrupt its osmotic life functions (reproduction, respiration, nutrition), showing a bactericidal and bacteriostatic effect.
Groups of antibiotics by the mechanism of action: cell membrane inhibitors (cephalosporins, penicillins); inhibitors of different stages of protein and nucleic acid biosynthesis (chloramphenicol, streptomycin, aminoglycosides, tetracyclines, macrolides, rifamycins, chloromycins, actinomycin). The most dangerous drugs from this group of antibiotics are chloramphenicol and aminoglycosides, which can cause damage to the red bone marrow, liver and kidneys.
Thanks to modern technologies, the mechanism of the antimicrobial action of antibiotics at the molecular level was studied, which expanded the understanding of the underlying processes that occur under their influence. For example, the researchers found that the violation of protein synthesis under the influence of teracycline, chloramphenicol and erythromycin preparations occurs at different stages. Chloramphenicol inhibits the activity of the peptidyl transferase enzyme, 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 drugs with a narrow and wide spectrum of action. Narrow-spectrum drugs such as Erythromycin, Oleandomycin act primarily on gram-positive microflora, and polymyxin on gram-negative, and polyenes on fungi.
Preparations with a wide spectrum of action (streptomycin, chloramphenicol, tetracyclines, aminoglycosides) act on both gram-positive and gram-negative microflora, as well as on some viruses, fungi, rickettsia, leptospira, protozoa.