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ALEXANDER FLEMING - DISCOVERER OF PENICILLIN

Dr sci. SIMO JELAČA

During the Peloponnesian War (430 BC), the plague entered Athens and raged for the next 2300 years. The plague was caused by the bacterium Yersinia pestis. Rats transmitted it to humans, and then it spread further among the population. In the fourteenth century it was called the "Black Death". In that period, the plague destroyed a quarter of the European population, about 25 million. From 1894 to 1914, it appeared in China and took the next ten million inhabitants.

Other diseases that killed 20 to 40 million people worldwide since 1918 were: pneumonia, syphilis, typhoid, diphtheria, meningitis, gonorrhea, hepatitis, polio, smallpox, measles, cholera, tetanus, and yellow fever.

Tuberculosis appeared when the bacterium Mycobacterium tuberculosis began to destroy human lung tissue. Throughout history, tuberculosis has become a major problem, meaning it has claimed more lives than any other disease.

During 1928, the Scottish biologist Alexander Fleming worked in the laboratory of St. Mary's Hospital Medical School, London, when he noticed something unusual in one of his"Petri dishes" with a colony of Staphylococcus bacteria, which was contaminated (infected) with foamy, white molds. As his container was open, it was exposed to air, thereby exposing it to other microorganisms, and infection was possible. But in this case that was not the case. The staphylococcus was clear as a tear. Some bacteria can infect food and become poisonous, while others cause disease. In this case, Fleming was like a highly respected expert, and he was very calm and modest. He left his containers of bacteria for about a week, then examined them thoroughly to see if there was anything unusual or interesting. He found that the appearance of mold was a surprise. He moved them and began to examine them in detail. That foamy mass changed colors, from dark green to light yellow. At room temperature (20 degrees C) they grew quite quickly. Flemig called this mold Penicillium fungus. He covered those fungi with bouillon molds and stated that it was Penicillium fungus, a bacterium that kills streptococcal pneumonia infection, syphilis, genotyping, gangrene, meningitis and diphtheria. And a very important fact is that mold is not toxic. Then Fleming injected this mass into a rabbit and a mouse and determined that no harmful phenomena occurred, on the contrary, they destroyed the white blood cells of the animals, their immune system.

Penicillin, as Fleming called it, was an active component of his mold and a good antiseptic. But it will be a long time before his invention is sufficiently concentrated, purified and stabilized for medical use. He was not a chemist to be able to do it successfully himself. When Fleming was visited by his friend in a biological laboratory, completely surrounded by Petri dishes, and open doors, where anyone could walk in and see what he was doing, Fleming said to his friend; "Look", "This fell from the sky".

While Fleming was working with Petri dishes, he kept many of them open, exposing them to air, so many became infected with different microorganisms and he examined them all. He found that the broth in which the mold grew at room temperature acquires resistant bacteriological properties against many pathogenic bacteria during one or two weeks. The colony of foam mass increased rapidly, and after a few days it changed color, from green to yellow to almost black. It was about Penicillium. As many as 8 types of penicillium have been found, but not all of them are the same in all molds.

Heat up to 80 degrees C has no significant effect on penicillin, while boiling for one hour has an effect, reducing its effect by about a quarter of its strength, when the fluid is alkaline. And, when the fluid is acidic, the power reduction is weaker. If it is kept in an autoclave for 20 minutes, at 115 degrees C, its strength is almost completely destroyed.

Penicillin contains a bacterial-inhibitory substance that is very active against some microbes, while it has no effect on others. Penicillin completely inhibits the growth of staphylococcus in vitro at a dilution of 1 in 600 and does not affect leukocytes to a greater extent. Penicillin has an advantage over chemical antiseptics. It works well at a dilution of 1 in 800. Penicillin is not toxic to living things at higher doses. The broth in which the mold grew at room temperature for one to two weeks acquired resistant bacteriological properties against many pathogenic bacteria. According to its morphology, it was Penicillium, and according to its characteristics, Penicillium rubrum. It was determined that only "Penicillium" broth should be used. Fleming measured the potency of penicillin at different concentrations and determined the toxicity of penicillin, considering that almost all antibacterial agents kill leukocytes.

Alexander Fleming was born in Ayrshire, Scotland, in 1881, as the son of a farmer. He walked 6 miles to school every day. At the age of thirteen he went to London and lived with his brothers and sister. He joined the army in 1900, where he remained until 1914. There were 12 medical schools in London, and Fleming enrolled in the one closest to him. He received a scholarship from St. Mary's school, which he finished in 1908 and entered the university. He was a brilliant student. His initial work was as an immunologist, with Edward Wright, who had already created a vaccine against thyroid fever. During the First World War, Fleming was accepted into the Royal Army Medical Corp., in the laboratory, where he worked on antibacterial methods. In 1921 Fleming was promoted to the position of assistant director of the inoculation department at St. Mary's, where he continued to work under the direction of Professor Wright. Fleming was elected professor of St. Mary's University in 1928, and later earned the status of Emeritus Professor in the field of Bacteriology. In 1943, he was elected to the Royal Society, where he was promoted to the status of Sera (Sir).

He published numerous scientific works, including the first works on lysozyme and Penicillin. He was the president of the Association of Microbiologists and a member of the Academy of Sciences. He was also Chancellor of the University of Edinburgh from 1951 to 1954. He died in 1955. Fleming is considered a national hero, he saved the lives of millions of people in the world (at list 200 million).

Penicillin is used to treat infections of the throat, ear, urinary tract, and to prevent skin infections caused by cuts or burns. Penicillin kills bacteria or prevents their occurrence. There are people whose body is allergic to penicillin, so it is necessary to emphasize this to the doctor during the treatment, because, otherwise, they can even die. Penicillin, by the way, begins to work immediately after reception. It has been found that penicillin can kill other bacteria, which are more sensitive. In a published paper, Fleming compared penicillin with other antibacterial agents, both bacterial and chemical, and found penicillin to be stronger and less harmful. And, as the most important claim, he states that penicillin is an effective antiseptic for administration in the form of injections into an infected part of the body. Fleming read his work at the Medical Research Club in London on February 13, 1929, to which there were no professional objections. He seemed very modest and shy on that occasion.

When receiving the Nobel Prize in 1945, Fleming emphasized the advantage of the medical use of penicillin instead of chemotherapy. Penicillin was used during the Second World War, and in 1943 the American microbiologist Selman Abraham Waksman found and isolated Streptomycin, so that millions of people were saved with those two drugs. And, finally, Fleming's way of working in laboratories completely changed the work in the field of bacteriology, and penicillin contributed to the strengthening of science and the human race advanced one step further in the pursuit of immortality.

Great discoveries in science are sometimes accidental and sometimes intentional. In his first paper on penicillin, in 1929, Fleming noted that his discovery was accidental. This showed his modesty and his work style. Fleming described the material he worked with as a white foamy mass that turns light-yellow in color, which is different from the description given by physicists. He eventually named his active agent Penicillium.

Alexander Fleming

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