Natural or synthetic substances that have a killing (bactericidal) or inhibiting (bacteriostatic) effect on pathogenic microorganisms, usually bacteria. Antibiotics attack the microbes e.g. at the cell wall(penicillins, cephalosporins), cell membrane permeability(polymyxins), nucleic and protein synthesis(tetracyclines, gyrase inhibitors, pleuromutilins, oxazolidinone, chloramphenicol, aminoglycosides, lincosamides, macrolides, glycylclines). Cyclic lipopeptides penetrate the bacterial cytoplasmic membrane via lipid side chains and, in the presence of calcium, form pores (ion channels) that lead to cytolysis of the pathogens (see also daptomycin).
Due to their inhibition of nucleic acid and protein synthesis, some antibiotics are also used as cytostatics, and in some cases also as immunosuppressants (e.g. Adria-, Dauno-, Mito-, Actinomycin).
Topical antibiotics are mostly used to treat wounds or for eradication in cases of MRSA/ORSA colonization (e.g., mupirocin). Topical antibiotics also play a role in acne therapy (e.g., erythromycin).
The following active ingredients play a role in dermatology (see also active ingredients, dermatological):