George B. Kauffman
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California State University Fresno, CA 93740
The Discovery of Penicillin Twentieth century wonder drug
The discovery of penicillin, the first of the miracle drugs and the one that has been hailed as “the greatest contribution medical science ever made to humanity,” stems from an accidental observation made in 1928 by the Scottish bacteriologist Sir Alexander Fleming (1881-1955) (J, 2,4-7, 9,10). His fortuitous observation, which was a direct result of his apparently disorderly habit of not discarding culture plates promptly, led to his discovery of a chemical substance which would destroy infectious bacteria without destroying tissues or weakening the body’s defenses. Fleming noted that on a Petri dish of staphylococci a mold (Penicillium notatum) which had been introduced by accidental contamination had dissolved the colonies of staphylococci. Such ruining of a pure culture of a bacterium by inadvertent exposure to air borne contaminants is a common annoyance well-known to bacteriologists, for which the customary procedure is to discard the culture and to repeat the experiment. In Fleming’s own words, however, “It was fortunate that... 1 was always on the lookout for new bacterial inhibitors, and when 1 noticed on a culture plate that the st aphylococcal colonies in the neighborhood of the mold faded away, I was sufficiently interested in the antibacterial substance produced by the mold to pursue the subject” (1). This simple account has been uncritically accepted and disseminated by most historians of science and biographers of Fleming with the notable exception of Ronald Hare, who had worked in the same institute as Fleming and who has written a book demonstrating “that far from the phenomenon that led to the discovery being a comparatively common event that had previously escaped detection, it must be so unusual an occurrence that it is doubtful whether it can have happened very often since bacteria were first cultivated in the laboratory” (4, p. 56). Thus, once again we find that, as Lord Byron asserted, truth is stranger than fiction, for the discovery, as reconstructed experimentally by Hare, is much more improbable, complex, and interesting than the “official” version. By nature, Fleming was extremely taciturn and unable to express himself either orally or in print. All that is known about the details of Fleming’s discovery of penicillin is given in the opening paragraph of his original paper: “While working with staphylococcal variants, a number of culture plates were set aside on the laboratory bench and examined from time to time. In the examinations, these plates were necessarily exposed to the air and they became contaminated with various microorganisms. It was noticed that around a large colony of a contaminating mold, the staphylococcal colonies became transparent and were obviously undergoing lysis” (3). Fleming did not specify the type of medium used, whether the plate had been incubated and at what temperature, how long it had been on the bench, or even what species of staphylococci was used. In fact, he himself was unable to “re-discover” penicillin despite many attempts to do so (4, p. 79), and Hare, attempting to reproduce Fleming’s work, using Fleming’s strain of Penicillium and the Oxford strain of Staphylococcus that is highly sensitive to penicillin, found that rather than being inhibited by the mold, the fully developed staphylococcal colonies prevented the mold from growing, confirming a fact known since 1942, namely, that penicillin can only act on microbes while they are young and actively multiplying. Hare, therefore, concluded that in the original discovery the mold .
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must have developed into a colony that had begun to produce penicillin before any staphylococci had begun to multiply, a situation which he was able to duplicate experimentally. However, no bacteriologist would have used a culture plate with a large colony of mold already growing on it. Hare theorized that if the mold spore had reached the plate at the same time or within a few hours of being seeded with staphylococci, penicillin might have been discovered if multiplication of the staphylococci could have been delayed until the mold had started to grow and produce penicillin. This could have occurred if the plate had been kept at an intermediate temperature such as room temperature—too low to prevent growth of the staphylococci which grow only above 12°C (53°F) while allowing growth of the mold, the growth of which is not greatly affected by temperature. Beginning on August 1,1966, Hare began a series of ingenious experiments in a successful attempt to determine the exact conditions of Fleming’s discovery. The exciting tale of his investigations reads like a detective story, and while space does not permit us to detail his deductions and experiments here (He devotes two chapters to this), we can at least summarize his conclusions. Fleming’s discovery of penicillin certainly was an accidental observation but one that depended on an entire series of apparently unrelated events. If only one of these events failed to occur, he would not have made his discovery. Because of his knowledge of staphylococci, Fleming was chosen to write a chapter on them for the large 9-volume “System of Bacteriology” to be published by the Medical Research Council. Late in 1927, in the course of writing this chapter, he read an article by J. W. Bigger, C. R. Boland, and R. A. Q. O'Meara (“Variant colonies of Staphylococcus aureus,” J. Path. Bad., 30, 261 (1927)), which prompted him to study variant colonies of these microorganisms, a task with which he was assisted by D. M. Pryce, a Research Scholar. In February 1928, Pryce accepted a position in the Department of Pathology, and Fleming continued the work himself. Several months earlier, Dr. Storm van Leeuwen, the eminent Dutch allergist, had come to London and lectured at St. Thomas’ Hospital, where he advanced a theory, that some asthma patients are allergic to molds growing in the foundations and floorboards of their houses. Dr. John Freeman, an allergist who was in charge of routine bacteriological investigations at St. Mary’s Hospital where Fleming worked, was impressed by van Leeuwen’s lectures and persuaded Sir Almroth Wright, the Head of the Innoculation Department at St. Mary’s Medical School at Paddington (now the Wright-Fleming Institute of Microbiology), to appoint a young Irish mycologist Dr. C. J. La Touche to isolate molds from houses. La Touche was assigned to a makeshift laboratory immediately below Fleming’s laboratory. Both laboratories had doors opening onto the same flight of stairs, and, since it was virtually impossible to open his window, Fleming usually kept his door open. La Touche was lucky enough to isolate an unusually powerful penicillin-producing strain of mold. Since his laboratory had no fume hood under which to work, the atmosphere became contaminated with spores which were probably wafted up to Fleming’s labora-
tory.
Several fortuitous factors resulted in the highly critical temperature conditions required for the discovery that we have already mentioned. Fleming either forgot to incubate his culture plate or purposely omitted to do so. His laboratory,
of the an exposed turret in the southeast corner building, was particularly sensitive to outside temperatures. During Fleming’s vacation, which he took during late July and early August of 1928 when the plate was standing in the lab, a 9-day cold spell occurred at a time of year generally unsuitable for the discovery (five days is the minimum time required for the Penicillium colonies to grow and produce penicillin). When Fleming returned from vacation in September, he discarded the plates, but at that time the Innoculation Department used only shallow enamel trays containing a little antiseptic for this purpose. If deep buckets filled with antiseptic had been used, as is the case in properly equipped bacteriological laboratories, the microorganisms would have been destroyed at once, but Fleming placed the plate in question on top of other plates in the tray. Early in September Pryce returned and asked Fleming how the work was progressing. Fleming complained about having to do all the work himself and showed him the cluttered condition of the laboratory. In so doing, he looked at a plate that he had already inspected and discarded but that had as yet escaped the antiseptic because of inadequate methods for disposing of used culture plates. And the rest, as they say, is history. When all the above fortuitous events are taken into account, the odds located in
against Fleming’s discovery appear almost astronomical, and than it is his discovery is seen to be a much rarer occurrence normally assumed to be in the literature. In fact, Hare has called it “the supreme example in all scientific history, of the part that luck may play in the advancement of knowledge” (4, p. 87). Although penicillin is the archetypal antibiotic, many similar cases of antibiosis (cxvtl', against; jSt'os, life) had been recorded previously (e.g., Pasteur’s discovery that certain saprophytic bacteria can kill Bacillus anthracis, the bacte-
rium that causes anthrax), but none resulted in practical antibiotics. Fleming tried to isolate the bactericidal substance (penicillin) produced by the mold but found it to be unstable and to lose its activity rapidly. Also, it could not be used for injections until freed of foreign proteins. Recognizing that a method for extracting and concentrating the crude substance was required but having no chemist or biochemist on his staff, he encouraged others to accept the task. An attempt to isolate the antibiotic, made by Dr. Harold Raistrick at the London School of Hygiene and Tropical Medicine, with Fleming’s cooperation, ended in failure. Knowing that he possessed a potentially life-saving drug in his laboratory, Fleming patiently maintained his cultures for a dozen years (8).
Finally, in 1939 at Oxford University, Howard W. Florey, Australian experimental pathologist, and Ernst B. Chain, a Jewish chemist who had fled from Nazi Germany, used the relatively new technique of lyophilization (freeze-drying) to isolate penicillin from Fleming’s own cultures in a completely purified form that was one million times more active than Fleming’s crude substance of 1928. In contrast with Fleming, who had worked alone with micro methods, they employed no less than six co-workers and numerous technicians and produced mold juice by the gallon. In 1940 they published the results of their successful treatment of infected white mice, but a completely successful test involving a human being was not accomplished until 1942 because of the limited supply of the drug. By 1943 English and American factories were producing penicillin on a large scale, and it became available for military use. By 1944 it became available for civilian use, and the following year Fleming, Florey, and Chain were jointly awarded the Nobel Prize in Medicine and Physiology. Andre Maurois wrote of Fleming, “No man, except Einstein in another field, and before him Pasteur, has had a more profound influence on the contemporary history of the human race” an
(7).
Acknowledgment Financial Support of the National Science Foundation (Grant SOC76-11267) is gratefully acknowledged. Literature Cited (1) “Accidental Scientific Discoveries,” Sohaar and Co., Chicago, III., 1955, p. 35. (2) Dolman, C. E., "Alexander Fleming,” in C. C. Gillispie (Editor), "Dictionary of Scientific Biography,” Charles Scribner's Sons, New York, N.Y., 1972, Vol. 5, pp. 28-31. (3) Fleming, A.. “On the antibacterial action of cult ures of a Penicillium with special ref erence to their use for the isolation of B. influenzae," Brit. J. Exp. Path., 10, 226 (1929). (4) Hare. R.,“The Birth of Penicillin and the Disarming of Microbes,” George Allen and
Unwin, Ltd., London, 1970. (5) Kauffman, G. B., "A. Fleming," in “Encyclopedia of World Biography," McGraw-Hill Book Co., New York, N.Y., 1973, Vol. 4. p. 136. (6) Ludovici, L. J., “Fleming—Discoverer of Penicillin,” Indiana University Press,
Bloomington, Ind., 1955.
(7) Maurois, A., “The Life of Sir Alexander Fleming, Discoverer of Penicillin,” Jonathan Cape, London, England, 1959. (8) Missildine, W. H., “Your Inner Child of the Past,” Simon and Schuster, New York, N.Y., 1963, p. 28. (9) Ratcliff, J. D., “Yellow Magic: The Story of Penicillin," Random House, New York.
N.Y., 1945. (1ft) Rowland, J., “The Penicillin Man: The Story of Sir Alexander Fleming,” Roy Publishers, New York, N.Y., 1957. (11) Stevenson, L. G., “Nobel Prize Winners in Medicine and Physiology 1901-1950," Henry Schuman, New York, N.Y.. 1953.
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