These antibiotics first affect the outer membranes of sensitive bacteria. The amino acid of the ring polypeptide part of the drug and the 2valic ion binding point of bacterial epiphany produce electrostatic interaction, so that the integrity of the membrane is destroyed, the fatty acid part of the drug can penetrate the outer membrane, and thus increase the permeability of the cell plasma membrane, resulting in phosphoric acid, nucleosides and other small molecules in the plasma, causing cell dysfunction to die directly.
Because gram-positive bacteria have a thick cell wall outside, preventing drugs from entering the bacteria, such antibiotics have no effect on them. The mechanism of action of polypeptide antibiotics is also different, polymycoccal class can change the function of bacterial plasma membrane, while bacillus peptides act on cell walls and cytoplasm. The biggest advantage of peptide antibiotics is that bacteria are not easy to produce resistance, but the disadvantageis is greater toxicity, in addition to the damage to bacterial cell membrane, animal cell membrane also works, mainly on the kidneys, nervous system has a certain toxicity.