Bacteria, infection and the scientists who discovered ways to combat them.

Bacteria are microscopic organisms whose single cells have neither a membrane-bounded nucleus nor other membrane-bounded organelles like mitochondria and chloroplasts. Another group of microbes, the archaea, meet these criteria but are so different from the bacteria in other ways that they must have had a long, independent evolutionary history since close to the dawn of life. In fact, there is considerable evidence that you are more closely related to the archaea than they are to the bacteria!

Louis Pasteur (1822 - 1895)

Pasteur was a French chemist and biologist who proved the germ theory of disease and invented the process of pasteurisation. He was able to demonstrate that organisms such as bacteria were responsible for souring wine and beer (he later extended his studies to prove that milk was the same), and that the bacteria could be removed by boiling and then cooling the liquid. This process is now called pasteurisation.

Pasteur's various investigations convinced him of the rightness of the germ theory of disease, which holds that germs attack the body from outside. Many felt that such tiny organisms as germs could not possibly kill larger ones such as humans. Pasteur now extended this theory to explain the causes of many diseases - including anthrax, cholera, TB and smallpox - and their prevention by vaccination. He is best known for his work on the development of vaccines for rabies.

The process of boiling a liquid to destroy germs is still used today; most dairy products are pasteurized so this helps ...

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The process of boiling a liquid to destroy germs is still used today; most dairy products are pasteurized so this helps us treat disease as they are killed. Also surgery could be done with out further complications due to germs on the surgical equipment being killed. Doctors developed a better understanding of the cause of infection.

Alexander Fleming (1881-1955)

In 1928 Fleming was research assistant to Sir Almroth Wright working on bacteria. He accidentally discovered a mould on a set of culture dishes, which were being used to grow the staphylococci germ (which turns wounds septic). Fleming noticed that where there was mould the germs had stopped developing.
It was one of Fleming's colleagues who identified the mould as penicillin. Fleming subsequently tested the penicillin on animals, with no ill effects, and also used it to cure a colleague's eye infection. Fleming had discovered the first antibiotic. By World War II it was being mass-produced by the American drugs industry, and given to all soldiers before active service. People could now be protected against infection on a day to day basis.

Joseph Lister (1827-1912)

He argued that if a doctor went from one patient to another after doing surgery, that doctor would pass on to the next visited patient a potentially life threatening disease. He insisted that those doctors who worked for him wash their hands in calcium chloride after an operation and before visiting a new patient.

Lister believed that it was microbes carried in the air that caused diseases to be spread in wards. Peoples operated on bodies were weak and their skin had been cut open so that germs could get into the body with more ease. Lister decided that the wound itself had to be thoroughly cleaned, covering it with a piece of lint which had carbolic acid on it. He used this treatment on patients who had a compound fracture. Death by gangrene was common after such an accident. Lister covered the wound made with lint soaked in carbolic acid. His success rate for survival was very high. Lister then developed his idea further by devising a machine that pumped out a fine mist of carbolic acid into the air around an operation. The number of patients operated on by Lister who died fell dramatically.

Lister helped disease, the science of disinfectants was born. Man’s desire to end disease has led to the development of many different chemical compounds that kill pathogenic microorganisms. Joseph Lister did not discover a new drug but he did make the like between lack of cleanliness in hospitals and deaths after operations. For this reason, he is known as the ‘Father of Antiseptic Surgery.

Peer Reviews

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skatealexia

30th of Jul 2012

Quality of writing

Different font sizes used throughout with looks untidy. Punctuation, grammar and spelling good throughout. Good subtitles and use of paragraphs to make the different sections clear.

Level of analysis

The candidate outlines basically what a bacteria is, but should go into more detail about the structure so that we can identify more with the bacteria. The bit about archaea is not directly relevant so should not be included. The candidate provides good depth about each major scientist in the development of the ways to combat bacteria. To develop this further they could have gone into the uses of bacteria in genetic engineering.

Response to question

A good response to a simple question. To expand on the question the candidate should have gone into greater scientific detail behind the work of each scientist. Such as the process of pasteurisation and the experiments that were used to exactly discover each method.

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