6. Germ theory of disease begin to accumulate in 19th century.
Agostino Bassi(1773-1856) first showed a microorganism could
cause disease.
Demonstrated-1853 Silk worm disease was due to fungal infection.
1845 M.J.Berkeley proved that the great potato blight of Ireland
was caused by a water mould.
1853 Heinrich de Bary showed that smut & rust fungi caused
cereal crop disease.
Pasteur showed that disease caused due to silkworm was due to
a Protozoan parasite.
Joseph Lister(1827-1912) developed a system of antiseptic
surgery designed to prevent microorganisms from entering the
wounds.
Robert Koch -The 1st direct demonstration of the role of bacteria
in causing disease .
Prescott microbiology
6
7. Photograph of Robert Koch looking through a microscope
with colleague Richard Pfeiffer looking on.
8. Robert Heinrich Hermann Koch
(11 Dec 1843- 27 May 1910)
The founder of Modern Bacteriology.
“magic-bullets”- Chemicals developed to attack specific bacteria.
Nobel Prize in medicine in 1905 (research on TB).
1.Discovery of Bacteriology,
2. Koch’s postulates of grem theory
3.Isolation of Anthrax, TB & Cholera.
Known for identifying the specific causative agents of :-
Tuberculosis, Cholera & Anthrax.
Created & improved laboratory technologies & techniques in the field of
microbiology, & made key discoveries in public health.
wikipedia
12. Introduction to the Koch’s Postulates
4 criteria designed to established a causative relationship between a
microbe & a disease. The postulates were formulated by Robert &
Freidrich Loeffler in1884, based on earlier concepts described by Jakob
Henle.
To describe the etiology of Cholera & Tuberculosis.
They were developed in the 19th century as general guidelines to
identify the pathogens that could be isolated with the techniques of
the day.
12
13. Koch’s Postulates
1.The microorganism must be found in abundance in all
organisms suffering from the disease, but should not be found in
healthy organisms.
2. The microorganism must be isolated from a diseased
organism & grown in pure culture.
3. The cultured microorganism should cause disease when
introduced in to a healthy organism.
4. The microorganism must be re-isolated from the inoculated,
diseased experimental host & identified as being identical to
the original specific causative agent.
13
17. A Molecular approach to Koch’s Posulates
1. The virulence trait under study should be associated much
more with pathogenic strains of the species than with non-
pathogenic strains.
2. Inactivation of the gene or genes associated with the
suspected virulence trait should substantially decrease
pathogenicity.
3. Replacement of the mutated gene with the normal wild type
gene should fully restore pathogenicity
4. The gene should be expressed at some point during the
infection and disease process.
5. Antibodies or immune system cells directed against the gene
products should protect the host.
Prescott microbiology
17
18. Let’s test your knowledge…
1.What is Pasteurization ?
2.Which food items undergo the process of Pasteurization ?
3.What is the name of the bacteria which converts alcohol to acetic acid ?
4.Name the microorganism causing disease Anthrax.
5.What are the Koch’s postulates ?
6.Why is Koch called as “The founder of modern bacteriology” ?
18
