LAB 2, September 24, 26
Regarding lab 3: check mannual page 20 ;1/3 of
the students will need to a culturette swab today for next week's lab
Related Material
Koch was the first to apply the new oil immersion
microscope, using glass slides and aniline dye staining; introduced
the first solid growth media (sliced boiled potato), and then
gelatin as a sterile semi-solid medium used in pure colony isolation,
and coagulated blood sera for growth of fastidious organisms.
These advances in scientific method and in techniques were major
factors in the rapid advance discovery of several important pathogenic
bacteria:
Bacillus anthracis
- Proved to be the cause of anthrax - by KOCH, Pasteur, 1877.
Neisseria gonorrhoeae
(Gonococcus) - proved to be germ of gonorrhea. - Neisser, 1879.
Streptococcus pneumoniae
(Pneumococcus, Diplococcus) - lobar pneumonia - Pasteur, 1880.
Salmonella typhosa
- typhoid fever, 1880.
Staphylococcus aureus
- abscesses, Pasteur,1880.
Streptococcus pyogenes
- acute infections including septicemia, KOCH, Ogston,
1882.
Mycobacterium tuberculosis -
tuberculosis, KOCH, 1882.
Vibrio cholerae
- Asiatic cholera, KOCH, 1883.
Corynebacterium diphtheriae
- diphtheria,1883.
Clostridium tetani -
tetanus, 1884.
Neisseria meningitidis
- (Meningococcus); epidemic meningitidis, 1887.
Pasteurella pestis
- plague, 1894.
On page 7 in your manual you learned that Robert
Koch is credited with the first reliable methods for isolation
of bacteria in pures cultures. Here are some of his other scientific accomplishments.
Robert Koch was born in Germany, took his degree
in medicine in 1866 and began a general practice in a small country
town. He became interested in microscopic studies, and focused
on the cause of anthrax. His studies were reported in 1876 and
were so complete and well ordered that he and his methods soon
were telegraphed throughout the medical world.
Robert Koch made rigorous use of a logical scientific method in the pursuit of
human pathogens and was so successful that his research:
proved the germ theory of disease established a set of four postulates
that guided microbiologists world wide in the isolation of pathogenic
organisms and has influenced medical microbial research for over
100 years.
The postulates are listed here followed by some pathogens in today's news.
1. The microorganism must be observed in association with the disease.
2. The microorganism must be isolated and grown in pure culture.
3. The disease is reproduced in an animal by inoculation with the microorganism
in pure culture.
4. The microorganism is observed in the diseased animal and shown to be the same
microorganism as that inoculated.
During our course we will cover several organisms
that have presented challenges in the proof of their pathogenicity.
As a pretest on modern microbiology, can you suggest difficulties
in applying these postulates to the pathogens E.coli O157:H7
and HIV?
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