1. Medical Microbiology
The History

2. What is Microbiology? It is the study of microbes or microorganisms
Microbes, or microorganisms are minute living things that are usually unable to be viewed with the naked eye.

3. What is Microbiology continued
What are some examples of microbes?
Bacteria, fungi, protozoa, algae, viruses, and some are parasites (helminths)
Some are pathogenic
Microbiology also involves processes that include immunology, epidemiology, bacterial physiology

4. History of Microbiology
First microbes were observed in 1673
Robert Hooke- In 1665 reported that living things were composed of little boxes or cells
devised the compound microscope and illumination system
Antoni van Leeuwenhoek- ( )
He is considered the father of bacteriology
Made simple microscopes and began observing with them
Discovered bacteria (he called them animalcules)

5. Leeuwenhoek's microscope consisted simply of:
A) a screw for adjusting the height of the object being examined
B) a metal plate serving as the body
C) a skewer to impale the object and rotate it
D) the lens itself, which was spherical

6. History of Microbiology
Many believed in spontaneous generation:
Aristotle synthesized the hypothesis which stated that some vital force contained in given to organic matter can create living organisms from inanimate objects.
In basic terms spontaneous generation stated that living organisms arise from non living matter.

7. History of Microbiology
Spontaneous generation was disproved in 1668 by Italian Scientist, Francesco Redi.
Here he used three pieces of meat. One piece of meat was placed under a piece of paper. The flies could not lay eggs onto the meat and no maggots developed. The second piece was left in the open air, resulting in maggots. In the final test, a third piece of meat was overlaid with cheesecloth. The flies were able to lay the eggs into the cheesecloth and when this was removed no maggots developed. However, if the cheesecloth containing the eggs was placed on a fresh piece of meat, maggots developed, showing it was the eggs that "caused" flies and not spontaneous generation.

8. History of Microbiology
John Needham- revived the theory of spontaneous generation in 1745
Needham theorized that if he took chicken broth and heated it, all living things in it would die.
After heating some broth, he let a flask cool and sit at a constant temperature. The development of a thick turbid solution of microorganisms in the flask was strong proof to Needham of the existence of spontaneous generation.
Lazzaro Spallanzani ( )
He demonstrated that microorganisms were already in the solution, the container, or the air
He took solutions which he knew would "breed" organisms and boiled them for up to an hour. The flasks were hermetically sealed to keep out contaminated air.
Proponents of spontaneous generation discounted the experiment by asserting that air was required for the vital force to work.

9. History of Microbiology
Theory of biogenesis later arose
In 1858 German scientist, Rudolf Virchow challenged spontaneous generation with his concept of biogenesis
Living organisms arise from pre-existing life
Virchow presented his idea to the scientific community, but could not back it up with a convincing experiment

10. History of Microbiology
In 1861, a French scientist by the name of Louis Pasteur demonstrated where microorganisms came from
Father of Medical Microbiology
Demonstrated the microorganisms exist in the air and could contaminate sterile solutions by passing air through cotton filters
The filter trapped tiny particles floating in the air
History of pasteurization
He first showed that the air is full of microorganisms by passing air through gun cotton filters. The filter trapped tiny particles floating in the air. By dissolving the cotton with a mixture of ether and alcohol, the particles were released and then settled to the bottom of the liquid. Inspection of this material revealed numerous microbes that resembled the types of bacteria often found in putrefying media. Pasteur realized that if these bacteria were present in the air then they would likely land on and contaminate any material exposed to it.

11. History of Microbiology
Louis Pasteur performed numerous experiments to discover why wine and dairy products became sour
He found that bacteria were to blame
Pasteur called attention to the importance of microorganisms in everyday life and stirred scientists to think that if bacteria could make the wine “sick,” then perhaps they could cause human illness.
Pasteur looked at wine under the microscope and noticed that when aged properly (in a sealed bottle at lower temperature) the liquid contained little spherical yeast cells. But when the wine turned sour, there was a proliferation of bacterial cells which were producing lactic acid (increasing the sour taste). Pasteur suggested that heating the wine gently at about 120°F would kill the bacteria that produced lactic acid and let the wine age properly.

12. Louis Pasteur’s Swan neck flask experiment
He filled a number of short-necked flasks with beef broth and then boiled their contents. He immediately sealed the mouths of some of the flasks while he left the others open and allowed to cool. After few days, the contents of the unsealed flasks were found to be contaminated with microorganisms. No evidences of growing microorganisms were found on the sealed flasks. Pasteur concluded that the microorganisms in the air were responsible in contaminating non-living matter like the broths in John Needham’s flask.
Pasteur filled a flask with medium, heated it to kill all life, and then drew out the neck of the flask into a long S shape. This prevented microorganisms in the air from easily entering the flask, yet allowed some air interchange. If the swan neck was broken, microbes readily entered the flask and grew.

13. Golden Age of Microbiology 1857- 1914
Beginning with Pasteur’s work, discoveries included the relationship between microbes and disease, immunity and antimicrobial medicine
Germ theory of disease
Pasteur showed that microbes are responsible for fermentation
Microbial growth is also responsible for spoilage of food
Pasteur demonstrated that spoilage bacteria could be killed with heat (pasteurization)
Developed vaccines for anthrax (1881)and rabies (1885)
Application of a high heat for a short time is called pasteurization

14. Germ theory disease
1835: Agostino Bassi- showed a silkworm diseases was caused by a fungus
1865: Pasteur- believed that another silkworm disease was caused by a protozoan
1840s: Ignaz Semmelwise- advocated hand washing to prevent transmission of fever from one OB patient to another
Demonstrated that hand washing prevented the spread of childbirth fever.
At the time (early 19th century) doctors would deliver babies without first washing their hands and, worse, would do so after performing autopsies on patients who had died from childbirth fever. This not only assured transmission, but biased that transmission so that the most virulent forms of the organism (i.e., those that killed women while they were still in the hospital) would be transmitted.

15. Germ theory disease
1860s: Joseph Lister- He is the father of antiseptic surgery.
He used a chemical disinfectant (carbolic acid) to prevent surgical wound infections after Pasteur’s work showing microbes are in the air, can spoil food, and cause animal disease.
1867: Robert Koch- provided proof that bacterium causes anthrax and provided the experimental steps, Koch’s postulates, used to prove that a specific microbe causes a specific disease.
Lister washed surgical wounds with phenol
He is considered the father of antiseptic surgery
What Koch accomplished in brief was to demonstrate for the first time that in any human disease a strict relation between a micro-organism and a disease

16. Koch’s postulates Pathogen must be present in all cases of disease
Pathogen must be isolated and grown in lab in pure culture
Pathogen from pure cultures must cause disease when inoculated into healthy, susceptible lab animal
Same pathogen must be isolated from the diseased lab animal

17. History of Vaccination
A precursor of smallpox vaccination was variolation
An early Asian method which introduced dried scabs of smallpox patients and was later modified in Europe
Modification consisted of injecting infectious material under the skin
First tested among abandoned children and prisoners
When it was declared safe, members of the English royal family were inoculated
Precursor-variolation, referred to an early Asian method of conferring immunity to smallpox by introducing dried scabs from smallpox patients into the noses of potential victims who wished to be protected from this disease. Variolation often produced a milder case of disease with a much lower fatality rate than that caused by community acquired small pox. This method gained popularity in Europe during the early 1700s. In Europe the procedure was modified by injecting infectious material under the skin; first tested among abandoned children and prisoners. When it was declared safe, members of the English royal family were inoculated.

18. Vaccination continued:
1796: Edward Jenner is credited with the development of the smallpox vaccine
Folk wisdom suggested that dairy maids who had contracted cowpox seemed to be immune to smallpox
Infection with the cowpox virus produced a much less sever form of disease that smallpox

19. Vaccination continued
Jenner conducted an experiment in which he used scabs from the cowpox lesions on the arm of a dairy maid, Sarah Nelmes to create a small pox vaccine
He then used the material to vaccinate an 8 year old boy, James Phipps
After being vaccinated Phipps appeared to develop immunity to the smallpox virus.

20. Vaccination continued
Later Jenner vaccinated his own son and several other children
He obtained similar results
Worldwide elimination of smallpox was achieved in 1978
Called vaccination from vacca for cow
The protection is called immunity

21. Antibiotics 1928: Alexander Fleming discovered the first antibiotic.
He observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus.
1940s: Penicillin was tested clinically and mass produced and was available towards the end of World War II
Flemming discovered the antimicrobial properties of the mold Penicillium notatum in 1928

22. Development of Agar
Angelina Hesse developed the use of Agar to grow microorganisms.
She was the wife of Walter Hesse who worked in Koch’s laboratory
Advantages of agar- It was not attacked by most bacteria.
Agar is better than gelatin because of its higher melting point (96°c) and solidifying (40–45°c) points.
Walter asked Fanny about the jellies and puddings that she made and how they managed to stay gelled even in warm weather. Fannie told him about how she learned about the seaweed product, agar-agar, from a Dutch neighbor of hers while she was growing up in New York City. Her neighbor had emigrated from Indonesia, where it was the local custom to use agar in their cooking. Fannie suggested that they try this out in their laboratory.
The rest is history. Agar turned out to be an ideal gelling agent that stayed firm even in the incubator and could not be digested by any bacterial enzymes. Walter Hesse notified Koch of this new technique, who immediately added agar to his nutrient broths.

23. Petri Dish Richard Petri (1887)
He developed the Petri dish (plate), a container used for solid culture media