In 1928, Alexander Fleming discovered penicillin, but the revolutionary antibiotic didn’t reach the masses until 1945, after two Oxford scientists developed the necessary large-scale production method.
In the intervening 17 years between discovery and distribution, Fleming continued to experiment with small batches of penicillin on several bacterial pathogens, including Staphylococcus. In the process, he unearthed the earliest signs of a phenomenon that now plagues medicine almost a century later: the ability of bacteria to become resistant, even immune, to antibiotics.
He identified this potential for resistance in 1940, just five years before penicillin became available for widespread use, and he received the Nobel Prize in Medicine for its discovery.
‘‘I would like to sound one note of warning. ... It is not difficult to make microbes resistant to penicillin in the laboratory by exposing them to concentrations not sufficient to kill them, and the same thing has occasionally happened in the body.’’
— Alexander Fleming, 1945
