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Penicillin has got its popularity due to the victory in the fight against infectious diseases. It is the oldest of practically applicable antibiotics excreted from the green mould. Microbiologists, biochemists, pharmacologists, physicians, veterinarians, agronomists and engineers have made their contribution to the improvement of penicillin qualities while studying the antibiotic properties. The history of this breakthrough is extremely interesting.
History of Penicillin
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Most of scientific discoveries are a result of deliberate experiments. However, a large part of breakthroughs in science were made due to pure luck. Story of the penicillin discovery is an illustrative example that proves this fact (Bartfai & Lees 2006). Scottish bacteriologist Alexander Fleming was desperately looking for a substance that could destroy the pathogens without harming patient’s cells.
In 1928, Fleming agreed to write an article about staphylococcus for an omnibus ‘System of Bacteriology’. Melvin Price had studied involution forms of these microbes shortly before his colleague decided to write the article. Fleming liked to emphasize the merits of young scientists in his works. That is why he wanted to mention colleague’s name in the future article. However, Melvin refused as he did not finish the studies because he had left his job. Moreover, he was going to test findings once more, but he could not do this quickly at his new workplace. Therefore, Fleming had to continue the work of Price and to investigate staphylococcus.
Over time, Price visited Fleming in his laboratory. He jokingly blamed Melvin for being forced to do painstaking job. Unlike his neat colleagues, Fleming did not throw cups with bacterial cultures. He collected them until his lab table got cluttered with cups. Many of them were covered with the mould, which was a common phenomenon. However, in one of the cups Fleming found the mould, which had dissolved the colonies of staphylococcus. He saw the drops resembling dew instead of yellow turbid mass. Fleming showed it to another colleague. His colleague examined the cup, but he was not surprised. Nevertheless, Fleming temporarily put off the work on staphylococcus and devoted himself to the study of the unusual mould.
Fleming left the cup on the table and took a vacation. The onset of cold snap in London created the favourable conditions for the mould growth, and the subsequent warming facilitated the bacteria growth. It turned out that the coincidence of these circumstances promoted the breakthrough in science. In other words, scientist’s untidiness and his observation were two factors in a series of accidents that contributed to the discovery of penicillin (Bud 2007).
What is mould? This is a tiny fungus of green, brown, yellow or black colour that grows in the damp places. This organism reproduces itself by spores that are in the air. If one of these spores gets in a favourable environment, it grows, forms the swelling and turns into a solid mass.
In order to test the assumption for the mould’s bactericidal effect, Fleming transplanted a few spores from the cup into the growth-supporting microenvironment in a flask, and left them to germinate at room temperature. A week later, the mould extensively covered the entire surface of the growth-supporting microenvironment. Fleming tested liquid for antibacterial properties. It emerged that diluted in 500-800 times bacterial culture can inhibit the growth of staphylococcus and other bacteria. Thus, the exceptionally strong antagonistic effect of this type of fungus was proven.
Fleming tested the antibiotic properties of penicillin in the following way. He prepared a cup with a gelated nutrient agar and made a hole in the substance to the cup bottom. Fleming filled the gap with yellow liquid. Then he seeded the edges of the cup with different types of bacteria. As a result, the selective effect of the new antibacterial agent was revealed.
Antibiotics suppressed to a greater or lesser extent the growth of staphylococcus, streptococcus, pneumococcus, gonococcus, diphtheria bacilli and anthrax. Penicillin left unaffected collibacillus, typhoid, influenza pathogens, paratyphoid and cholera (Hatt 2007). An extremely important finding was the discovery of the fact that the substance was not harmful to human white blood cells even at high doses.
Fleming was working with a young bacteriologist named Stuart Craddock for some time. Firstly, they grew penicillium in the meat broth at 37 ° F. However, later on Craddock placed mould spores into the flat bottles and left them in an incubator at 20° F for a week. Thus, they were able to receive daily from two to three hundreds cubic centimetres of broth with the penicillin. This broth was infiltrated through Seitz’s filter by means of air pump.
Fleming studied the culture and tried to find out the favourable conditions, which could provide the greatest effect. He noticed that the bactericidal property of broth quickly disappeared at laboratory temperature. Hence, the substance was very unstable (Hatt 2007). Finally, Fleming managed to bring his broth to the test which could not stand any antiseptic, namely the determination of toxicity. It turned out that the antibacterial infiltration was not toxic. Intravenous administration of twenty-five cubic centimetres of this substance to rabbit did not cause any toxic effect. Semicubical centimetres of broth introduced into the abdominal cavity of mice did not cause any symptoms of intoxication, as well. What is more, hourly irrigation of conjunctiva during the day did not cause even irritation.
Scientist discovered the substance which even in diluted form provided bactericidal, bacteriostatic and bacteriolytic action without causing harm to the body. At that time, Craddock suffered from sinusitis, an inflammation of the paranasal sinuses. Fleming irrigated Craddock’s sinus with penicillin broth and took a swab three hours later. He saw that all bacteria were phagocytosed. The first modest attempt of treatment by means of penicillin gave good results. Patient's condition improved within 3 hours.
Fleming asked permission of his colleagues in the hospital to try the impact of the filtrate on the patients with infected wounds. The second Fleming’s patient after Craddock was a woman who slipped, leaving Paddington Station, and had been hit by a bus. She was brought to St. Mary's hospital with a terrible wound on her leg. Afterwards, the leg was amputated. Women began to suffer from sepsis. All doctors were expecting the patient’s death. Fleming examined the women and found out that she was hopeless. However, he soaked bandage in mould broth and put it on the amputated surface. He did not put high hopes on that attempt as the penicillin concentration was too low and the disease had spread throughout the body. As a result, he accomplished nothing.
In 1926, Fleming asked Frederick Ridley along with Craddock to extract antibacterial active principle. It was necessary to do that before starting a serious test of penicillin in the clinic. Scientists had to learn about the method of extraction from books. They read the description of the conventional method. Scientists knew that heat destroyed the substance. That is why the broth had to be evaporated at a fairly low temperature (Bartfai 2006). In fact, they knew almost nothing when they started this work.
Nevertheless, young scientists prepared apparatus from laboratory equipment. They evaporated broth in a vacuum and got the syrupy brown mass. Penicillin concentration was about ten times higher than in the broth. However, this mass could not be applied. Scientist’s task was to produce penicillin in pure crystal form. Time went by. They had the same viscous mass, which was unstable. Concentrate maintained its properties only for a week.
In 1929, Fleming reported his discovery at the Medical Research Club. Scientist did not know how to present his findings. Fleming described penicillin discovery very modestly as he was very shy. Nevertheless, his observations made a good impression on the attendees.
Fleming also wrote an article about penicillin for the scientific journal Experimental Pathology. He presented main facts on a few pages. Fleming claimed that penicillin was not an enzyme or protein since it dissolved in absolute alcohol. That is why the substance could be safely administered in the blood. Penicillin was more effective than any other antiseptic and could be used to treat infected areas.
Fleming continued his experiments in the hospital. The results were quite good, but they were not miraculous. In 1934, Fleming showed Dr. Holt the impact of penicillin on a mixture of blood and bacteria. Antibiotics killed the bacteria and left white blood cells unharmed. Holt promised to allocate perfect penicillin. However, after a series of failures, he refused further attempts. In 1939, a young English professor Howard Walter Florey and biochemist Ernst Chain, tried to get the pure penicillin. They managed to get a few grams of the brown powder after two years of frustration and defeat.
In1940, the experiment was held at the fifty white mice. Each of them was administrated virulent streptococcus. Twenty five of them were treated with penicillin, which was administered every three hours for two days. Treated mice survived while others died within sixteen hours.
The first injections were administrated to the patient who suffered from septicaemia. Doctors introduced intravenously 200 ml penicillin and administrated 100 ml penicillin every three hours. The patient's condition improved on the next day. However, doctors quickly run out of penicillin. The disease resumed and the patient died. Nevertheless, it was proven that penicillin works against blood poisoning.
Fifteen years old boy who suffered from blood poisoning was the first patient rescued by penicillin treatment. At that time, the whole world was on fire of war for three years. Thousands wounded died of blood poisoning and gangrene. Generous amount of penicillin was needed (Bud 2007).
Every day, scientists invent a new type of antibiotics. However, there is no other drug in the history of mankind that saved so many lives.
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