Who is credited with inventing penicillin?
Originally Englishman Alexander Fleming noticed the activity of penicillin when it had accidentally contaminated a culture he was working on. He made a note of it and did no further work with it. Howard florey an Australian and Ernst Chain got wind of Flemings discovery and went to work to isolate penicillin. They succeeded in producing the drug. however it took the backing and infrastructure of the US department of defense to bring the final development of penicillin to fruition. Once all of the work was completed Fleming stepped in to share in the credit for the discovery.
In 1928, Sir Alexander Fleming observed that colonies of the bacterium Staphylococcus aureus could be destroyed by the mold Penicillium notatum, proving that there was an antibacterial agent there in principle. This principle later lead to medicines that could kill certain types of disease-causing bacteria inside the body. At the time, however, the importance of Alexander Fleming's discovery was not known. Use of penicillin did not begin until the 1940s when Howard Florey and Ernst Chain isolated the active ingredient and developed a powdery form of the medicine.
Penicillin wasn't invented. It was discovered by accident by Sir Alexander Fleming in 1928 that penicillin killed bacteria. It was discovered at St Mary's Hospital, England.
Wikipedia lists Sir Alexander Fleming discovering Penicillin. It was further developed by Howard Walter Florey.
Alexander Fleming. It might be apocryphal (almost true !) that had Pennicillin not been invented twice as many people would have died in WW2 than actually did.