Antibiotics In 1940 Howard Walter Florey (1898–1968) and Ernst Boris Chain (1906–1979) announced their development of the first useful antibiotic drug, using the penicillin that Alexander Fleming (1881–1955) had discovered in a mold culture in 1928. Earlier, the discovery of antibacterial sulfonamide drugs had provided a helpful tool for fighting infectious disease. Later antibiotics and antifungal medicines would lead to effective treatment of many infectious diseases. In recent time, pharmaceutical science has been challenged by the evolution of antibiotic-resistant bacteria.