Classification of antibiotics

Antibiotics (from other Greek, ἀντί "against" + βίος "life") are substances of natural, semisynthetic or synthetic origin that suppress the growth of living cells, most often prokaryotic or protozoans.

Classification A huge variety of antibiotics and their effects on the human body was the reason for the classification and separation of antibiotics into groups. By the nature of the effect on the bacterial cell, antibiotics can be divided into two groups:

-Bacteriostatic (bacteria remain alive, but not able to reproduce), -Bactericidal (bacteria die, and then are excreted from the body). Classification of the chemical structure, which is widely used in the medical environment, consists of the following groups:

Beta-lactam antibiotics, divided into three subgroups: Penicillins - are produced by the colonies of the mold fungus Penicillinum; Cephalosporins - have a similar structure with penicillins. Used in relation to penicillin-resistant bacteria. Carbapenems - the structure is more resistant to lactamases than penicillins and cephalosporins, which greatly expands the spectrum of action. Macrolides are antibiotics with complex cyclic structure. The action is bacteriostatic. Tetracyclines - are used to treat infections of the respiratory and urinary tract, treatment of severe infections such as anthrax, tularemia, brucellosis. The action is bacteriostatic. Aminoglycosides - have a high toxicity. Used to treat severe infections such as blood or peritonitis infection. The action is bactericidal. Levomycetins - Use is limited due to the increased risk of serious complications - damage to the bone marrow that produces blood cells. The action is bacteriostatic. Glycopeptide antibiotics disrupt the synthesis of the bacterial cell wall. They have a bactericidal effect, but against enterococci, some streptococci and staphylococci act bacteriostatically. Lincosamides have a bacteriostatic effect, which is due to inhibition of protein synthesis by ribosomes. In high concentrations against highly sensitive microorganisms may exhibit a bactericidal effect. Anti-TB drugs - Isoniazid, Ftivazid, Salusid, Metazide, Ethionamide, Prothionamide. Antibiotics of different groups - Rifamycin, Ristomycin sulfate, Fusidine-sodium, Polymyxinum M sulfate, Polymyxin B sulfate, Gramicidin, Heliomycin. Antifungal antibiotics - destroy the membrane of the fungal cells and cause their death. Action - the lytic. Gradually replaced by highly effective synthetic antifungal drugs. Anti-leprosy drugs - Diphenylsulfone, Solesulfone, Dyuzifon. Beta-lactam antibiotics Beta-lactam antibiotics (β-lactam antibiotics, β-lactams) are a group of antibiotics that combine the presence of a β-lactam ring in the structure. To beta-lactams are subgroups of penicillins, cephalosporins, carbapenems and monobactams. The similarity of the chemical structure predetermines the same mechanism of action of all β-lactams (disruption of bacterial cell wall synthesis), as well as cross-allergy to them in some patients.

Penicillins

Penicillins are antimicrobials belonging to the class of β-lactam antibiotics. The ancestor of penicillins is benzylpenicillin (penicillin G, or just penicillin), used in clinical practice since the early 1940s.

Cephalosporins

Cephalosporins is a class of β-lactam antibiotics, whose chemical structure is based on 7-aminocephalosporanic acid (7-ACS). The main features of cephalosporins in comparison with penicillins are their greater resistance to β-lactamases - enzymes produced by microorganisms. As it turned out, the first antibiotics - cephalosporins, having high antibacterial activity, do not possess complete resistance to β-lactamases. Being resistant to plasmid lactamases, they are destroyed by chromosomal lactamases, which are produced by gram-negative bacteria. To increase the stability of cephalosporins, expand the spectrum of antimicrobial activity, improve pharmacokinetic parameters, their numerous semi-synthetic derivatives were synthesized.

Carbapenems

Carbapenems (English carbapenems) are a class of β-lactam antibiotics, with a wide range of actions, having a structure that determines their high resistance to beta-lactamases. Not resistant against a new type of beta-lactamase NDM1

Macrolides

Macrolides are a group of drugs, mostly antibiotics, the basis of the chemical structure of which is a macrocyclic 14- or 16-membered lactone ring to which one or more carbohydrate residues are attached. The effect of macrolides is due to a violation of protein synthesis on the ribosomes of microorganisms. Macrolides belong to the class of polyketides, compounds of natural origin. Macrolides are among the least toxic antibiotics.

Also macrolides include:

azalides, which are a 15-membered macrocyclic structure obtained by incorporating a nitrogen atom into a 14-membered lactone ring between 9 and 10 carbon atoms; Ketolides are 14-membered macrolides, in which a keto group is attached to the lactone ring at the 3-carbon atom. In addition, the group of macrolides nominally includes the drug tacrolimus related to immunosuppressants, the chemical structure of which is the 23-membered lactone ring.

Tetracyclines

Tetracyclines - a group of antibiotics belonging to the class of polyketides, close in chemical structure and biological properties. Representatives of this family are characterized by a common spectrum and mechanism of antimicrobial action, full cross-resistance, close pharmacological characteristics. The differences relate to certain physico-chemical properties, the degree of antibacterial effect, the characteristics of absorption, distribution, metabolism in the macroorganism, and tolerability.