Erythromycin Ethylsuccinate, an oral macrolide antibiotic produced byStreptomyces erythreus, reversibly binds to the50S ribosomeof bacteria, and inhibits protein synthesis. In vitro
Erythromycin displays antibacterial activity against Staphylococcus aureus, streptococcus pneumonia, Streptococcus pyogenes, Haemophilus influenza, Moraxella catarrhalis, Bordetella pertussis, Neisseria gonorrhoeae, Campylobacter jejuni, Helicobacter pylori, and Borrelia burgdorferi. Erythromycin is a motilin receptor agonist, which is a potent stimulator of gastrointestinal motor activity. The concentrations of Erythromycin required to induce 50% of the maximum contractile response to a supramaximal dose of acetylcholine is 2 μM. The concentrations of Erythromycin required to displace 50% of the labeled motilin is 13 μM. Erythromycin has no effect on muscle strips of rat or dog duodenum but induces contractions in human strips.