The discovery in 1928 that revolutionized the field of antibiotics was penicillin. Alexander Fleming, a Scottish bacteriologist, discovered penicillin accidentally when he noticed that mold (Penicillium chrysogenum) contaminated one of his bacterial cultures, inhibiting bacterial growth around it. This discovery led to the development of penicillin as a powerful antibiotic, which transformed the treatment of bacterial infections and saved countless lives during and after World War II. Penicillin paved the way for the creation of more antibiotics and marked a turning point in medical science, greatly influencing public health and clinical practices.