The History of Microbiology

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"The History of Microbiology"
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I would like to begin this article by paying tribute to all the healers down through the ages who tried their best to help the sick without knowing what actually caused disease. They didn't know about microorganisms, but they still found ways to ease the sufferings of sick people. Before the technology was available to see microorganisms, diseases were attributed to 'bad air' or miasmas, curses or the power of witches or just living a bad life and being struck down by the gods. This limited the ability of healers to help their patients.

The history of microbiology begins with the discovery of the magnifying power of lenses, because this was the technology that allowed the discovery of the microorganisms that cause disease. Robert Hooke made lenses in 1665 which allowed him to see the structure of cork. He published a book, Micrographia, in which he described the tiny compartments in cork as "cellulae", Latin for tiny rooms, and from this, we get the word cell. A few years later, in 1677, van Leeuwenhoek invented a single lens microscope that could magnify 300 times and with this he observed "little animals" (bacteria and protozoa) in pond water. Once people could see these organisms, they could study them and the science of microbiology was born.

In the 1700's small pox was a major killer. In Turkey, they practiced a primitive form of vaccination where people who did not have the pox were cut with a knife and then the cut was smeared with smallpox pus. As revolting as this sounds, it did in fact give some immunity to the dreadful disease. In 1796, Edward Jenner, who had heard of this practice and had also observed that milkmaids who contracted 'cow pox' seldom succumbed to small pox, performed the first scientific vaccinations against small pox. He inoculated people with pox cells and showed that they developed an immunity to the full blown disease. Thus microbiology took a giant step forward.

However not much progress was made for the next fifty years because doctors still did not accept that 'germs' caused disease and many were absolutely filthy in their habits. Surgeons never changed their gowns and aprons and the more covered in blood and pus the apron was, the better the surgeon was supposed to be. Not surprisingly many people died in hospital from infections and women did not want to go to hospitals to have their babies for fear of death by 'childbed fever'. In 1850 a doctor named Semmelweise advocated the revolutionary idea that doctors should wash their hands in order to stop the spread of disease but it wasn't until the 1860's that the great Louis Pasteur was finally able to offer the first proofs of the germ theory of disease.

Pasteur was a giant in the field of microbiology. His experiments disproved the theory of spontaneous generation and showed that life has to come from life and does not just appear out of nowhere. He supported the theory that disease comes from 'germs' and he developed this theory through experimentation, so that it finally gained widespread acceptance. He developed the process of pasteurisation to kill bacteria in milk and other food products. He showed that fermentation is caused by microorganisms. Pasteur coined the word virus and developed a vaccine to immunise against a form of cholera. Later, in 1885, Pasteur developed the first vaccination for rabies.

Progress quickened in the latter half of the 19th century. Lister practiced antiseptic surgery in his hospital and greatly increased post-surgical survival rates. In 1875 Cohn initiated the study of bacteriology when he began classifying various types of bacteria by their shapes. in 1876, Robert Koch discovered that the cause of anthrax was a bacteria, Bacillus anthracis, thereby offering the first positive proof of the germ theory of disease. In 1881 Koch grew bacteria on solid media for the first time. He studied tuberculosis and was awarded the Nobel Prize in Medicine in 1905 for his efforts.

Other important discoveries of the late 1800's included the development of Gram Stains for bacteria by Christian Gram (1884); the invention of the Petri dish (1887) for growing microorganisms safely by Petri; and the discovery of viruses by Ivanovski(1892).

In 1900 Walter Reed proved that mosquitoes carried yellow fever, the first evidence of the importance of animal vectors in disease transmission. In 1908 Metchnikoff and Paul Ehrlich demonstrated that antibodies in a host can consume bacteria and foreign particles by the process of phagocytosis, which enhanced our knowledge of the disease-fighting processes of our bodies. Ehrlich went on to find the first cure for syphilis in 1910.

In 1928 Alexander Fleming discovered penicillin by serendipity. Fungal hyphae contaminated his penicillin colonies and he noticed that the bacteria were killed by the fungi. He isolated the chemical from the fungi and the first and most important antibiotic was born.

Women have also played a role in the field of microbiology. Margaret Pittman identified the cause of whooping cough and was the first woman to be a director of a National Institute of Health laboratory. Alice Evans became the first female president of the American Society of Microbiology in 1928 after she identified the bacteria that live in fresh milk. She went on to study meningitis. In 1933, Ruth Moore became the first African-American to get a PhD in microbiology and later she was the first woman ever to chair a medical school department. She studied tuberculosis bacteria.

The discovery of the structure of DNA in the 1950's was an important step in all fields of biology but has been a particularly powerful tool in microbiology. In 1977, Gilbert and Sanger published the first report of DNA sequencing and in 1995 the first microbial gene sequence was published for H. influenzae. DNA sequencing is important in microbial identification because so many bacteria look exactly alike even though they are different at a genetic level.

A major milestone in microbiology occurred in 1979, when the first microbial disease organism was officially driven to extinction. Smallpox (Variola virus) now only exists in the laboratory and could be totally eliminated if we choose to do so. Such is the power of the science of microbiology that we can now not only prevent and control diseases, but in some cases we can even eliminate them.

The work must continue and the field is growing because microorganisms evolve very quickly. Already many pathogens are developing immunities to common antibiotics. We will never win this war. We will always be fighting the pathogens, but at least now we understand what we are up against and are not blaming disease on gods or curses or bad air.

References: www.theguardians.com/Microbiology/gm_mbi02.htm


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