Tetracycline is a broad-spectrum antibiotic produced by the Streptomyces genus of actinobacteria. It has a bacteriostatic effect on a wide range of gram-positive and gram-negative pathogens. It is used to treat a number of infections. These include acne, cholera, brucellosis, plague, malaria, and syphilis. It is taken by mouth. Tetracycline requires a prescription and is on the World Health Organization's list of essential medicines.