Scientists And Discoveries

Louis Pasteurs Contributions to Medical Microbiology

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There are two men given the name, “Founder of microbiology”, one is Robert Koch and the other Louis Pasteur. Pasteur was born in the town of Dole, which is in the Jura region of France, on December 27 1822. His interest in sciences led him to study for a master’s degree then a doctorate at the Ecole Normale in Paris.

In 1848, having finished his education, he started work as a teacher and researcher in Dijon and Strasbourg. His early research was in the field of chemistry rather than microbiology. In particular, he demonstrated that some compounds could produce two different shaped crystals. This was in contradiction to the belief of the time, which was that a compound could have only one crystal shape. With this experiment, he started the science of stereochemistry.

In 1854, he took up the appointment of Professor of Chemistry at Lille University.  At the time, the faculty of science at the university also undertook problem-solving tasks for the local industries. It was this part of his job that led him into the developing field of microbiology.

The wine and beer makers of the area were having problems with the souring of their products and Pasteur studied the problem. He found that bacteria were responsible for the spoiling of the local alcoholic beverages. He also found the solution, which involved heating the wine or beer after fermentation had finished. This would kill the microorganisms before they could damage the product.

He also found that bacteria were also responsible for the spoiling of milk and that his heating process would also prevent the rapid spoiling of milk. This process is still in use today and bears his name – pasteurization.

Many scientists at the time believed that the bacteria that caused this spoilage were produced spontaneously. Pasteur was not so sure and set about to disprove this theory. In 1864, Pasteur used a specially made swan-necked vessel to prove that the bacteria had come from the air thus disproving the theory of spontaneous generation of bacteria.

His work with the local brewers and wine makers also allowed him to prove that yeasts were responsible for the fermentation process. At the time the theory of fermentation being a chemical process, as proposed by Justus von Liebig, was the accepted theory. So he disproved a second erroneous theory.

In 1865, he returned to Paris to become the director of Scientific Studies at the Ecole Normale. At this time, the French silk industry was being destroyed by an illness afflicting the silkworms. Although outside of anything he had ever worked upon before, Pasteur attempted to find the cause as well as provide a solution. He found a parasite was infecting the silkworms. When all the affected worms and mulberry bushes were destroyed a healthy silk industry was restarted.

His interest in microorganisms led him to the study of anthrax. At the time, the disease caused numerous animal deaths as well as several human fatalities annually in Europe. He also looked for the cause of gas gangrene. This terrible infection of wounds often led to the loss of a limb and frequently death. He found that the organism, now known as Clostridium perfringens, would only grow in an anaerobic atmosphere. To study these microorganisms Pasteur had to develop the aseptic techniques still used by bacteriology laboratories to this day. These techniques are used to prevent contamination of a bacterial culture with unwanted bacteria from the air or the microbiologist’s skin.

His growing knowledge of bacteria led him to advocate the use of heat sterilized instruments and bandages by surgeons to decrease the incidence of postoperative infections. This simple instruction, now so common in our hospitals, saved thousands if not millions of lives by preventing post-operative infections.

Pasteur wrote a paper on his investigations into bacteria and the germ theory called “The Germ Theory and its Application to Medicine and Surgery”. He read this before a meeting of the French Academy of Sciences on April 29 1878, and had it published in Comptes rendus de l'Academie des Sciences, lxxxvi, pp. 1037-43. An English translation of this paper is available from the Modern History Sourcebook. This paper provides a foundation for the modern science of medical microbiology

Furthering his work on anthrax, he produced the first vaccine containing killed bacteria with this he demonstrated the ability of non-viable microorganisms to produce immunity to an infection. He went on to produce similar vaccines for use against chicken cholera and rabies. He used his new rabies vaccine to save the life of a young boy, Joseph Meister, in July 1895 after a rabid dog had bitten the child.  The use of killed organisms as a vaccine source is still common practice today.

He developed specialized glassware that is still in use in microbiology laboratories today. He invented the Pasteur pipette. This pipette made from a piece of sterilized glass tube, which, after heating the central part until it melts, is pulled to form a thin nozzle. This valuable tool is still in use worldwide. Though these are now mass-produced, there are still some microbiologists, including the author of this article, who were trained to make these for themselves.

In 1888, his work on disease and microorganisms was rewarded when the French government appointed him to the directorship of a new institute in Paris, which had been set up to study the treatment of diseases. He was the director of the Pasteur Institute until his death in 1895.

The French Government accorded him the honor of a State Funeral in honor of his work in microbiology and it application to medicine.

More about this author: Alison Bowler

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