Week 1

A: Definition

Microbiology is the study of:

Small living organisms or microbes ubiquitous (found almost everywhere).

*Since viruses are acellular (not composed of cells) they’re often referred as ‘infectious agents’ or ‘infectious particles’ rather than microorganism.

Microbes that cause disease are known as pathogens. Those that do not cause disease are called nonpathogens.

B: Classification of microbiology

• Bacteriology (Study of bacteria) i.e antrax, chloera, diarrhea
• Mycology (Study of fungi) i.e tinea, yeast vaginitis
• Virology (Study of viruses) i.e AIDS
• Phycology (Study of algae) i.e a rare cause of infections; intoxications (result from ingestion of toxin).
• Protozoology (Study of protozoan/protozoa) i.e toxoplasmosis

*EXTRA NOTES

Importance of Microbes

• Microbes are important as decomposers or saprophytes since they aid in fertilization by returning inorganic nutrients into the soil.
• Microbes are used in bioremediation to clean up/ decompose industrial wastes i.e oil spills.
• Microorganisms are involved in elemental cycles [carbon, nitrogen, oxygen, sulfur and phosphorus]
• Microbes serve as food for smaller animals; important part of the food chain.
• Microbes aid in food digestion and some produces beneficial substances or solutions.
• Microbes are used in various industries such as food, beverage, chemical and antibiotic industries. Also known as BIOTECHNOLOGY [i.e yogurt, yakult drink, wine and cheese] *small bacteria and fungi produce antibiotics.
• Microbes are used in genetic engineering.
• Microbes are used as cell models.
• Microbes cause either infection diseases or intoxication.

Reasons for nurse to study Microbiology

• Nurse must have an idea of how infections spread.
• Nurse should know which surfaces are most susceptible to infectious agents.
• Nurse should know how to keep instruments aseptic and contaminant-free.
• Nurse should know how to recognize the symptoms of an infection.
• Nurse should know how to recognize the type of infection as soon as it occurs.
• Nurse must know how to carefully take care of an open wound without infecting it.

C: History of Microbiology

1. Anthony Van Leeuwenhoek  (1632 - 1723)

The Father of Microbiology (The first to explore microbiology)

Born: In Delft on 24 October 1632.

In 1676:

• 1st to see bacteria [bacterium] and protozoa [field of lenses]
• He observed water closely and was surprised to see tiny organisms. The first bacteria observed by man. 
• Also, laid the foundations of plant anatomy and became an expert on animal reproduction.
• Discovered blood cells and microscopic nematodes, and studied the structure of wood and crystals.
• Made over 500 microscopes to view specific objects.
• Discovered sperm, which he considered one of the most important discoveries of his career, and described the spermatozoa from molluscs, fish, amphibians, birds and mammals. 
• Conclude that fertilisation occurred when the spermatozoa penetrated the egg.

Van Leeuwenhoek died on 30 August 1723.

2. Edward Jenner (1759 – 1833):

The Father of Immunology (The first to explore smallpox vaccination).

Born: In Berkeley, Gloucestershire on 17 May 1749

He lived through exciting times, with the first balloon flights and new machines such as steam engines. But Jenner was happy to work as a country doctor in the west of England.

• The first doctor to vaccinate people against smallpox. Smallpox was a dangerous disease. A disease that once killed thousands of people every year.  Jenner found a way to prevent people catching smallpox so fewer people got ill, and the disease became rare. Today smallpox has died out.

Some people laughed at his ideas, but Jenner was not put off. And people all over the world are grateful for what he did.

He died on 26 January 1823.

3. Louis Pasteur (1822 – 1895):

A French chemist and biologist

Proved the germ theory of disease

Invented the process of pasteurisation.

Born:  In Dole in the Jura region of France on 27 December 1822  .

In 1847:

•  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 called pasteurisation.
• Finder of where these bacteria came from, and was able to prove that they were introduced from the environment.
• Discovered infectious agents causing silkworm disease. (Parasitic infections as the cause)à Advocated that only disease-free eggs should be selected.
• Contributed to the germ theory of disease (which holds that germs attack the body from outside). Extended this theory to explain the causes of many diseases. (i.e anthrax, cholera, TB and smallpox) & and their prevention by vaccination.
• Best known for his work on the development of vaccines for rabies.

In 1888:

A special institute was founded in Paris for the treatment of diseases. It became known as the Institute Pasteur.

Pasteur was its director until his death on 28 September 1895.

He was a national hero and was given a state funeral.

4. Joseph Lister (1827 – 1912):

The Father of antiseptic surgery.

He was a professor of surgery.

Born: In Upton Essex  on 5 April 1827

• He recognised that over half of his amputation patients in Glasgow died as a result of post-operative infection and it was against this background.
• So he began his experimental work with antisepsis and was deeply interested in the prevention of post-operative sepsis.
• He was attracted by Pasteur’s germ theory of disease and concluded that sepsis or wound infection may be due to microbial growth, derived from the atmosphere.
• He successfully prevented post-operative sepsis by introducing antiseptic techniques.
• He chose carbolic acid (Phenol) and used as spray on the wound or during surgery. He applied dressings soaked in carbolic acid on wounds.
• As a result, there was a marked reduction of post-operative sepsis, wound inflammation and suppuration.
• It saved millions of lives from the jaws of death due to wound infections.
•  Lister’s antiseptic surgery later led to the development of aspetic surgery.
• He suffered many criticism but never lose courage and followed his own ideas and revolutionized the science of surgery by introducing antiseptic system in 1867.

He died on 10 February 1912 in Walmer, Kent.

5. Robert Koch (1843 – 1910):

The Father of Modern Bacteriology.

Born: In December 1843

• His discoveries made a significant contribution to the development of the first ‘magic bullets’ - chemicals developed to attack specific bacteria
• Koch developed a new experimental method to test whether a particular micro-organism is the cause of a disease.
• Building on Pasteur's work on germ theory, Koch used experiments to prove that the bacterium Bacillus anthracis was the cause of anthrax - the bacterium could be observed in the tissue of anthrax victims.
• He extracted this bacterium from a sheep which had died of anthrax, grew it and injected a mouse with it. The mouse developed the disease as well.
• Koch repeated this process over 20 generations of mice, before he announced in 1876 that he had proved this bacterium caused anthrax.
• Koch continued to improve his methods and techniques by solidifying liquids such as broth with gelatine and agar, for instance, he created a solid medium for growing bacteria which was easier to handle than the liquids used by Pasteur.
• Koch's assistant Julius Richard Petri developed the Petri dish, which made the observation of bacteria even easier.
• Koch and his team also developed ways of staining bacteria to improve the bacteria’s visibility under the microscope, and were able to identify the bacterial causes of tuberculosis and cholera.

In addition,  he:

• Discovered the germ theory of disease [Koch’s postulates] bacillus anthracic produces spores capable of resisting adverse conditions.
• Developed method of fixing, staining and photographing bacteria
• Developed methods of cultivating bacteria on solid media
• Discovered mycobacterium tuberculosis and vibrio cholera
• Worked on tuberculin which led to the development of a skin test valuable in diagnosing tuberculosis.

Adopting Koch's method, other researchers were able to identify the bacteria that caused diseases such as typhus, tetanus and the plague.

Dr. Koch died on May 27, 1910, in Baden-Baden.

6. Paul Ehrlich (1854 – 1915):

The Father of Chemotherapy (treatment of disease with medicine)

He was a german bacteriologist.

Born:  In Strzelin, Poland on 14 March 1854

• From his discovery that certain tissues have a specific affinity, he reasoned that organisms causing diseases could be selectively killed with chemical drugs.
• This led him to produce “arsphenamine” (an arsenic compound), the first synthetic drug, which destroyed the syphilis microbe in the body.
• Ehrlich observed that organic arsenicals killed trypanosomes in an infected animal, but, if smaller doses were administered, the trypanosomes acquired tolerance to the drug.
• Therefore, he aimed at “therapia magna sterilans” (i.e.the introduction into the blood of a single dose of chemotherapeutic agent sufficient to kill the parasite).
• He also observed that drug would undergo certain changes in the body after it would produce the desired action.
•  During the later years of his life, Ehrlich was concerned with experimental work on tumours and on his view that sarcoma may develop from carcinoma, also on his theory of athreptic immunity to cancer.

He died on 20th August 1915.

7. Alexander Fleming (1881 – 1955):

The Father of Vaccine Therapy (His discovery of penicillin)

Born: In Ayrshire on 6 August 1881.

• Early in his medical life, Fleming became interested in the natural bacterial action of the blood and in antiseptics.
• He was able to continue his studies throughout his military career and on demobilization he settled to work on antibacterial substances which would not be toxic to animal tissues.
•  In 1921, he discovered in «tissues and secretions» an important bacteriolytic substance which he named Lysozyme.
• About this time, he devised sensitivity titration methods and assays in human blood and other body fluids, which he subsequently used for the titration of penicillin.
• In 1928, while working on influenza virus, he observed that mould had developed accidently on a staphylococcus culture plate and that the mould had created a bacteria-free circle around itself/
• He was inspired to further experiment and he found that a mould culture prevented growth of staphylococci, even when diluted 800 times. He named the active substance penicillin
• He wrote numerous papers on bacteriology, immunology and chemotherapy, including original descriptions of lysozyme and penicillin.

Dr Fleming died on March 11th in 1955 and is buried in St. Paul's Cathedral.