L8. Pathogenesis Flashcards
What does “commensal” mean?
An organism found in normal flora
What is a pathogen?
An organism capable of causing disease
What is pathogenicity?
The ability to cause disease.
What is virulence?
The ability to cause HARMFUL disease.
Is colonisation the same as infection? Why?
No.
Colonisation occurs when microbes find a new host to multiply on.
Give the term used to describe disease caused by colonised bacteria.
Infection
What is an endogenous infection?
When the microbe originated from the patient’s own flora
What is an exogenous infection?
When the microbe’s source is outwith the patient’s flora.
Describe the 4 pillars which make up “Koch’s Postulates”.
- The microbe must be present in every case of the disease.
- It is isolated and grown in culture.
- The disease reproduces and can be inserted into an animal host.
- The microbe must be recoverable from the new host.
Which microbe is commonly linked to UTIs?
E. Coli
Why is E.coli commonly linked to UTIs?
There is an easy connection between their pili and the bladder.
Briefly describe the parasitic cycle.
Parasites enter, attach and colonise so avoid the host’s immunity.
They produce harmful proteins which spread and are released from the host.
Give 2 examples of micro organisms.
Bacteria
Fungi
Which type of bacteria have capsules?
Gram positive bacteria
How does the host’s immune system fight encapsulated bacteria?
It cannot attack the bacteria due to its capsule. There is an inflammatory response eg. meningitis, sinusitis
