About Tetracycline A broad-spectrum polyketide antibiotic,Tetracycline Derivative. Mechanism of Action of Tetracycline Tetracycline is a broad spectrum antibiotic which has more specific action against gram positive organisms than gram negative organisms. It exerts its bacteriostatic action by accumulating inside the bacteria through specific transporter protein & inhibits bacterial protein synthesis by attaching to 30 S subunit of bacterial ribosome (which are absent in mammals). It chelates cations like Ca &Mg and inhibits functioning of various enzymes & ribosome. It is used in some areas for the treatment of Chloroquine-resistant falciparum malaria