Transcript Plate 5 – Koch`s Postulates

Warm-Up
Your pet dog gets sick and
dies. You suspect it may
have been a bacterial
disease. How can you
prove it?
Plate 5 – Koch’s Postulates
If olive oil comes
from olives, where
does baby oil come
from?
Some Background Info
• Robert Koch was born in
1843 in Clausthal, Germany
• 1862, he went to the
University of Göttingen to
study medicine
• He studied under Professor
Jacob Henle, who believed
that diseases were caused
by living, parasitic
organisms
Anthrax
• The disease anthrax was very prevalent
amongst farm animals near Koch
• Anthrax was so called because it
coagulated and darkened the blood of
infected animals (anthrac: “coal”)
• Koch believed that the bacteria Bacillus
anthracis was the cause of the disease
Koch’s Experiment
• Took blood from the spleen of
infected farm animals and inoculated
mice
– All mice contracted anthrax and died
• Took blood from spleens of healthy
farm animals and inoculated mice
– All mice did not contract anthrax and
survived
• This experiment showed that anthrax
can be transmitted through the blood
of infected animals
Koch’s Experiment
• Koch also wanted to know if anthrax
bacteria that had never been in contact
with an animal could cause the disease
Koch’s Experiment
1. Collect the bacteria from a dead animal
2. Isolate and grow the bacteria in a nutrient
medium
3. Inject the bacteria into a healthy animal
4. Collect the bacteria from now-dead animal
5. Isolate and grow the bacteria in a nutrient
medium
6. Compare the bacteria with the original bacteria
Koch’s Results
• Bacteria can be isolated
• Bacteria can be grown in pure cultures (all
cells genetically identical)
• Sample bacteria can regenerate disease
in animals
• Bacteria from blood of infected animal is
genetically identical to original bacteria
Koch’s Postulates
1.
2.
3.
4.
The microorganism must be found in abundance in all
organisms suffering from the disease, but should not
be found in healthy animals.
The microorganism must be isolated from a diseased
organism and grown in pure culture.
The cultured microorganism should cause disease
when introduced into a healthy organism.
The microorganism must be reisolated from the
inoculated, diseased experimental host and identified
as being identical to the original microorganism.
Bioterrorism/Bioethics
• Let’s pretend that an “anthrax-bomb” was
released on Philadelphia
– If there is only a limited quantity of a vaccine:
who should receive prophylactic treatment
first?
– If a vaccine hasn’t been FDA-approved yet,
should the government allow people to
receive this medication?
– If the government has citizens sign a waiver
stating that “refusing treatment may result in
the patient’s death”, is that being too
coercive?