The original penicillin (antibiotic) molecule, discovered by Alexander Fleming in the 1920s, on spoiled bread (mold). In the 1940s, scientists at the U.S. Department of Agriculture in Peoria, Illinois (in America) discovered how to produce commercial quantities of Penicillin G by utilizing the fungus Penicillium chrysogenum, which they found on a cantelope in Peoria, Illinois. Penicillin kills bacteria by blocking an enzyme which is crucial to growth and repair of the bacteria’s cell wall (peptidoglycan layer), but penicillin does not harm other species, so it is species-specific to bacteria.
An antibacterial drug used against streptococcal infections, meningococcal meningitis and other serious infections.