Fleming grew this fungal mold in a pure culture and found that the result killed a range of disease-causing bacteria. The mold was from the Penicillium genus, so he called it penicillin. It was left to Drs. Howard Florey and Ernst Chain to figure out penicillin’s structure and transform it into a lifesaving medical agent. The three pioneers shared the Nobel Prize in Physiology or Medicine in 1945.
