L-33

Question 1

What are Koch’s postulates for?

Answer 1

Guidelines used to demonstrate that a specific pathogen causes specific disease symptoms

Question 2

What are Koch’s postulates?

Answer 2

1. The pathogen must be present in every individual with the disease
2. A sample of the microorganism taken from the diseased host can grow in pure culture
3. A sample of the pure culture causes the same disease when injected into a healthy host
4. The microorganism can be recovered from the experimentally infected host

Question 3

What are the exceptions to Koch’s postulates?

Answer 3

• microbes that can’t be cultured

- pathogens that also can be found in healthy subjects

Question 4

What are the key stages of microbial pathogenesis?

Answer 4

1. Exposure to pathogens
2. Adherence to host cells (skin or mucus)
3. Invasion of host tissues (through epithelium)
4. Colonisation and growth, production of viralence factors, replication within host tissues
5. Disease causing damage to host tissues through toxicity and invasiveness

Question 5

What are the 4 key stages of microbial pathogenesis:

Answer 5

1. Adherence to host cells (adherence such as fimbrae)
2. Invasion of host tissues ( using flagella and internalin related proteins that help to burrow into cell)
3. Replication within host tissues (siderophores and capsules used)
4. Disease causing damage to host tissues using endotoxins and exotoxins

Question 6

What are endotoxins?

Answer 6

Lipopolysaccharide components found in the outer membrane of gram negative bacteria, and elicit strong immune responses

Question 7

What are exotoxins?

Answer 7

Toxins produced within living bacteria and then released into the surrounding medium

Question 8

What are the 3 types of exotoxins?

Answer 8

• cytotoxins
• neurotoxins
• enterotoxins