ChEBI: Tetracycline is a broad-spectrum polyketide antibiotic produced by the Streptomyces genus of actinobacteria. It has a role as an antimicrobial agent, an antibacterial drug, an antiprotozoal drug, a protein synthesis inhibitor and an Escherichia coli metabolite. It is a tertiary alpha-hydroxy ketone and a member of tetracyclines. It is a conjugate acid of a tetracycline(1-) and a tetracycline zwitterion.