Pathogens

Question 1

Differentiate a pathogen from a commensal

Answer 1

Pathogen - a disease-causing organism

Commensal - an organism that’s part of the normal flora of the body

Question 2

What is meant by the pathogenicity of a pathogen?

Answer 2

It’s capacity to cause infection

Question 3

What two factors dictate pathogenicity?

Answer 3

Infectivity

Virulence

Question 4

What two factors dictate infectivity?

Answer 4

Attachment

Acid resistance

Question 5

What is infectivity?

Answer 5

Ability of a pathogen to become established

Question 6

What is virulence?

Answer 6

Ability of a pathogen to cause harm once established

Question 7

What three factors dictate virulence?

Answer 7

Invasiveness
Toxicity
Immune evasion

Question 8

Name the three classes of pathogenic toxin

Answer 8

Exotoxin
Enterotoxin
Endotoxin

Question 9

What is an exotoxin?

Answer 9

Released extracellulary (e.g. tetanus)

Question 10

What is an enterotoxin?

Answer 10

An endotoxin that acts on the GI tract (e.g. cholera)

Question 11

What is an endotoxin?

Answer 11

Part of the cell wall of a Gram negative bacteria (the lipopolysaccharide)