Discovery of Penicillin

Penicillin is a group of antibiotics derived from Penicillium fungi. Penicillin antibiotics are historically significant because they are the first drugs that were effective against many previously serious deseases, such as syphilis and infections. They are still widely used today, though many types of bacteria are now resistant and are less needed. It is said that penicillin heralded the dawn of the antibiotic age; because before its discovery, there was no treatment for diseases such as pneumonia, gonorrhea, or rheumatic fever.

Penicillin was discovered by the Scottish scientist and Nobel laureate Alexander Fleming, in 1928. He began to sort through petri dishes with colonies of Staphylococcus, bacteria that caused boils, sore throats, and abscesses. In one dish he noticed something unusual: it was dotted with colonies, save for one area where a blob of mold was growing. The zone around the mold (penicillium notatum) was clear, as if the mold had secreted something that inhibited bacterial growth.

He later detected that the mold possessed properties that could kill a wide range of harmful bacteria cells without harming human blood cells. He determined this by isolating pure penicillin from the mold juice. It proved to be very unstable, and they were only able to prepare solutions of crude material to work with.

In June 1929, Fleming published his findings in the British Journal of Experimental Pathology, with only a passing reference to penicillin’s potential therapeutic benefits. This was of practical benefit to bacteriologists, and kept interest in penicillin going. Other scientists, including Harold Raistrick, Professor of Biochemistry at the London School of Hygiene and Tropical Medicine, tried to purify penicillin but failed.

The chemical structure of penicillin was determined by the British chemist Dorothy Crowfoot Hodgkin in 1945.  Ever since, penicillin has become the most widely used antibiotic, and it is still used for many bacterial infections. A team of Oxford research scientists devised a method of mass-producing this drug. In this same year, the Australian scientists Howard Florey and Ernst Boris Chain shared the Nobel Prize in Medicine with Fleming for their work.