09/28/2016 12:19 pm ET Updated Sep 29, 2017

Giving a Face to Penicillin

By Drs. David Niesel and Norbert Herzog

Most people are familiar with the story of the discovery of penicillin by Alexander Fleming. He was not known for being tidy and did not clean up petri plates containing bacterial agar with growing bacteria before leaving on a trip. He discovered that where there was fungus growing on the plate, the bacteria did not grow. He surmised that the fungus produced a substance that inhibited bacterial growth. This is a classic example of serendipity leading to a major discovery in science.

Fleming was the son of a Scottish pig farmer and was born on August 6, 1881. His academic potential was recognized early and he was awarded a scholarship to the Kilmarnock Academy before moving to London. There he attended the Polytechnic School studying business and commerce and he graduated at 16. In 1901, an inheritance allowed him to enroll and graduate from London's St. Mary's Hospital Medical School in 1903. He joined Almroth Wright, a bacteriologist and immunologist doing laboratory research. Wright and Fleming were interested in our body's natural defenses that protect against infections. When World War I broke out, Fleming joined the Royal Army Medical Corps. Treating wounds involved using antiseptics such as carbolic acid, boric acid or hydrogen peroxide. He proved that this practice was killing soldiers by interfering with their natural immune responses. After the war, he returned to research convinced that the only antimicrobial agents that work with natural defenses should be used. One day he had a cold and a drop of mucus from his nose fell onto bacteria growing on the petri plate. Almost instantly, the bacteria were destroyed. He discovered the active ingredient, was an enzyme called lysozyme. Unfortunately, lysozyme was not a very useful antibiotic.

Now back to his greatest discovery, when he noticed a clearing of bacteria on a petri dish where a mold was growing. He identified the fungus as a Penicillium species and on March 7, 1929, he named this new antibiotic, penicillin. He demonstrated that penicillin killed human bacterial pathogens, but unfortunately it did not work well when applied to the skin. He published his results, but the discovery was largely unappreciated because of his inability to produce much of the antibiotic and its apparent slow action.

Dr. Ernest Chain stumbled across Fleming's paper in 1938 and began pursuing penicillin research with Dr. Howard Florey. They soon showed that penicillin saved mice from deadly bacterial infections and successfully treated a few humans. When World War II began the two scientists knew the demand for penicillin would be great. The Rockefeller Foundation in the US provided resources to continue their research, which lead to the production of 500 times the amount of penicillin. The first person in the US treated with penicillin was Anne Miller, in March 1942. She had bacterial blood poisoning and was near death. Another patient at the hospital knew a scientist working on penicillin and Ms. Miller's physician obtained a tablespoon of penicillin, which was used to treat and cure her. Early in 1943, only 400 million units of penicillin had been produced. By wars end, US companies were making 650 billion units per month. That was the beginning of the era of antibiotics.

Medical Discovery News is hosted by professors Norbert Herzog at Quinnipiac University, and David Niesel of the University of Texas Medical Branch. Learn more at