Action Mechanism Of Antibiotics

There are four main mechanisms for the bactericidal effect of antibiotics, namely, inhibition of bacterial cell wall synthesis, interaction with cell membrane, interference with protein synthesis, and inhibition of nucleic acid replication and transcription. [6]

Inhibition of cell wall synthesis

The cell wall of bacteria is mainly composed of polysaccharides, proteins and lipids, which have important functions of maintaining morphology and resisting osmotic pressure changes. [12] Therefore, inhibition of cell wall synthesis will lead to bacterial cell rupture and death; Mammalian cells have no cell wall, so they are not affected by these drugs. This effect depends on a protein of the bacterial cell wall, usually called penicillin binding proteins (PBPs), β Lactam antibiotics can bind with this protein to inhibit the synthesis of cell wall, so PBPs are also the target of such drugs. Antibacterial drugs acting in this way include penicillins and cephalosporins, but frequent use will lead to enhanced drug resistance of bacteria. [6]

Interaction with cell membrane

Some antibiotics interact with the cell membrane to affect the permeability of the membrane, causing the leakage of salt ions, proteins, nucleic acids, amino acids and other important substances in the bacteria, which has a fatal effect on cells. However, there are some similarities between the basic structure of bacterial cell membrane and that of human cell membrane, so this kind of antibiotics has certain toxicity to human beings. Antibiotics acting in this way are polymyxin and brevibacterium. [6]

Interfering with protein synthesis

Interfering with protein synthesis means that enzymes necessary for cell survival cannot be synthesized. Antibiotics acting in this manner include fomycin (actinomycins), aminoglycosides, tetracyclines, and chloramphenicol. The protein is synthesized on the ribosome, which consists of 50S and 30S subunits. Among them, aminoglycosides and tetracyclines act on the 30S subunit, while chloramphenicol, macrolides and lincomycin mainly act on the 50S subunit, inhibiting the initiation, peptide chain extension and termination of protein synthesis. [6]

Inhibition of nucleic acid replication and transcription

Inhibiting the transcription and replication of nucleic acid can inhibit the function of bacterial nucleic acid, thereby preventing cell division and/or the synthesis of required enzymes. Antibiotics acting in this way include naphthyric acid and dichloroacridine, rifampicin