The Role of Chemistry in History

The Role of Chemistry in History header image 2

A Brief History of Penicillin

March 26th, 2008 · 20 Comments ·

Introduction| Irish Luck|A Brief History of Penicillin|

Penicillin and Bacteria| Penicillin Affects History: Thanks to Penicillin, He will Come Home!!|

History Affects Penicillin:|References|


Alexander Fleming was not the first one to discover penicillin. In 1875 an English distinguished physician named John Tyndall was busily engaged in his study about germs and Bacteria. He was trying to find if there was a systematic dispersion of bacteria in the atmosphere i.e. whether or not bacteria aggregated and evenly distributed in ‘clouds.’ In order to do this, Tyndall sat up a number of open test tubes containing broth. Depending on his theory about bacteria, he believed that all of the tubes should become thick and muddy because of the growth of bacteria falling into them from the air.

Tyndall prepared one hundred tubes of broth, placed them comparatively close to each other. He kept the tubes open in order to be exposed to the air for twenty four hours. The next day, Tyndall noticed that the broth in some tubes remained clear which proved that no bacteria had fallen into these tubes despite the fact that all the tubes were kept open. This also indicated that Tyndall’s theory about the even distribution of bacteria in the atmosphere was wrong.

Tyndall also observed that on the surface of other tubes there was a penicillium. Tyndall thought that the penicillium was “exquisitely beautiful.” Tyndall believed that there was a battle between the bacteria and the mold, and “in every case where the mold was thick and coherent, the bacteria died or became dormant and fell to the bottom as a sediment”
(J. Tyndall, 1876).

Tyndall only marked and studied the physical properties of penicillium, or what we now know as (Penicillium notatum). He observed that penicillium was able to destroy bacteria falling into the tubes from the air, but he did not know at that time that bacteria could cause disease (Friedman, 1998, p. 169).

Around 1896, doctors and physicians were unable to help patients suffering from a serious infection. The only thing they could do was to amputate a leg, remove an appendix. In case of other serious infections, the doctors waited and depended only on the patients’ immune system to fight the infection (Friedman, 1998, p. 169). However, many patients died while waiting for their bodies to fight bacteria.

Alexander Fleming accidentally rediscovered penicillin when he was engaged in studying different kinds of bacteria and molds in his laboratory. He once opened one of his Petri dishes for a few seconds to smear it with a strain of staphylococcus which is a bacterium that typically occurs in clusters resembling grapes. Fleming noticed a halo of inhibition of bacterial growth around a contaminant blue-green mold staphylococcus plate culture. Fleming concluded that the mold was releasing a substance that was inhibiting bacterial growth and lysing the bacteria. He grew a pure culture of the mold and discovered that it was a penisillium mold, now known to be penicillium notatum. This was surprising because it was too short a time for a penicillium spore or two to find the dish. Tyndall waited 24 hours before he observed the existence of penicillium in some of his test tubes containing broth, whereas Fleming only left his dish exposed to the air for a few seconds and he observed a strain of staphylococcus being attacked by penicillium. On Fleming’s occasion, probably billions of penicillium spores happened to be floating in the atmosphere of Fleming’s laboratory. An expert on mold was growing penicillium notatum just one floor below Fleming’s laboratory. Because at that time there was no sufficient method to prevent spores from floating away, the light spores, ascended the elevator shaft and the staircase to Fleming’s laboratory door, which he habitually kept open (Hare, 1970, p. 199).

Fleming was interested in what he saw on his Petri dish. Unlike Tyndall who was only interested in the physical properties of penicillium, Fleming wanted to know the functional properties of penicillium. He wanted to find out the strange ability of penicillium to stop the growth of staphylococci. Fleming applied a simple screening method in order to observe the functional properties of penicillin.

Without doubt, this was a great discovery that would help the physicians to cure dangerous infections. However, there was a problem in applying Fleming’s discovery in the real life because some distinguished physicians in addition to Fleming’s colleagues believed that “antibacterial drugs are a delusion” (Wilson, 1976, p. 147).Despite this common belief, Fleming took a big step when he injected the penicillium broth filtrate into a rabbit and a mouse. He then observed that there was no ill results were present after the injection. Fleming further tried penicillin on human being when he irrigated an infected human eye, an inflamed maxillary sinus, and the infected surface of an amputated leg with a penicillin solution. None of these three cases showed any toxic effects of penicillin. However, only the first two tissues lost their infections and were totally cured. The infected tissue on the amputated leg did not show any sign of positive change or healing. This was the only applicable experiment of Fleming on penicillin.

The development of penicillin for the medical use is attributed to an Australian nobleman called Howard Walter Florey who worked with a team at Oxford University Florey’s team wanted to investigate the biochemical and biological properties of antibacterial substances that microorganisms might possess. The team eventually discovered that penicillin was a molecule and not an enzyme as physicians used to consider it. The team also discovered that penicillin was very unstable unlike other simple molecules. Florey’s team members were able to produce stable penicillin by “reducing the temperature of a water solution of penicillin by freeze drying it (Freidman, 1998, p. 179). Then, Florey experimented penicillin on animals, especially white mice, before he applied it on human beings.

Tags: Penicillin