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Nobel Prize for Penicillin

Sir Alexander Fleming

This paragraph from Sir Alexander Fleming’s Nobel prize acceptance speech is perhaps the origin of the “radical pathogen cure” (Read and colleagues PNAS, 2011):

“But I would like to sound one note of warning. Penicillin is to all intents and purposes non-poisonous so there is no need to worry about giving an overdose and poisoning the patient. There may be a danger, though, in underdosage. It is not difficult to make microbes resistant to penicillin in the laboratory by exposing them to concentrations not sufficient to kill them, and the same thing has occasionally happened in the body.
The time may come when penicillin can be bought by anyone in the shops. Then there is the danger that the ignorant man may easily underdose himself and by exposing his microbes to non-lethal quantities of the drug make them resistant. Here is a hypothetical illustration. Mr. X. has a sore throat. He buys some penicillin and gives himself, not enough to kill the streptococci but enough to educate them to resist penicillin. He then infects his wife. Mrs. X gets pneumonia and is treated with penicillin. As the streptococci are now resistant to penicillin the treatment fails. Mrs. X dies. Who is primarily responsible for Mrs. X’s death? Why Mr. X whose negligent use of penicillin changed the nature of the microbe. Moral: If you use penicillin, use enough.”

Excerpted from the 1945 Nobel Prize lecture by Alexander Fleming, the discoverer of Penicillin (entire article accessible at

Writing question due October 23, 2012:

Doctors and nurses have taken Alexander Fleming’s advice to heart, and we always ask patients to complete their course of penicillin, or any other antibiotic.
What is the downside of Fleming’s advice? Was he wrong?


1) Hastings

2) Antibiotic Strategy


Important, if you were in group 2 and presented this topic last week, you must answer the following question in addition to the one above (you will be given an extra 1/2 page if you need it):

Doctors are taught that the best way to avoid evolution of resistance is to restrict antibiotic use to only those patients with bacterial infections. The problem is that we often do not know who has a bacterial infection. I want you to tell me which scenario is more likely to result in the evolution of resistance: 1) Over-the counter – making penicillin an over the counter medication and letting patients decide when and how long to take it. 2) Standard care – prescribing penicillin only by doctors to patients suspected of having a bacterial infection. for both scenarios 1 and 2, assume that the pharmaceutical company manufactures the same amount per year, 100 tons of penicillin, and it all gets sold in both scenarios…

Categories: Uncategorized

Joe Alcock

Emergency Physician, Educator, Researcher, interested in the microbiome, evolution, and medicine

3 replies

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