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Medicine Term One > Pathogens of the host > Flashcards

Flashcards in Pathogens of the host Deck (25)
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1
Q

What is a commensal

A

Organism part of normal flora

2
Q

Pathogenicity

A

The capacity of a micro-organism to cause an infection

3
Q

Pathogenicity requires

A

Infectivity -Ability to become established

Virulence - Ability to cause harmful effects once established

4
Q

The ability to become established within a host dependant on

A

Pathogens attachment

pathogens acid resistance (e.g. high acidic level in the stomach)

5
Q

Pathogen

A

organism that causes a disease

6
Q

What is virulence

A

ability to cause harmful effects once established

7
Q

What are the three virulence factors

A

Invasivness
Toxin production
evasion of immune system

8
Q

What is virulence specific to

A

strains not species

9
Q

What is invasiveness

A

Multiplies and spreads around the body

10
Q

what is toxin production

A

release toxins extracellular

11
Q

Streptococcus pyogenes is an invasive bacteria causes what disorders

A

Necrotising fasciitis
Cellulitis
Connective tissue breakdown
Fibrinolysis - the enzymatic breakdown of the fibrin in blood clots

12
Q

What is released extracellularly by the micrograms

A

exotoxins

13
Q

what are enterotoxins

A

more specific exotoxins which act on the GI tract

14
Q

what is endotoxin

A

structurally part of the Gram negative cell wall that is release when disintegrates

15
Q

What bacteria causes tetnus and what does it produce

A

clostridium tetani

an exotoxin

16
Q

When and what does tetanus do

How is death caused?

A

Happens through contaminated wounds
toxin production binds to nerve synapse and inhibits release of inhibitory neurotransmitters.
death = respiratory paralysis

17
Q

How is tetanus treated

A

debridement (removal of damaged tissue), antibiotics and antitoxin

18
Q

What bacteria is cholera and what does it produce

A

Vibrio cholerae, enterotoxin

19
Q

What does cholera enterotoxin do

A

Increases cAMP levels which inhibits uptake of Na and Cl ions causes outflow of water into GI tract resulting in dehydration due to watery diarrhoea

20
Q

What are the two example of bacteria which produce superantigens

A

Strep pyogenes and Staph aureus

21
Q

What are two examples of the commensal flora in the gut and nose

A

E. Coli - Gut

Staph. aureus - Nose

22
Q

What do super antigens do

A

able to stimulate t cells proliferation therefore increasing cytosine resulting in toxic shock

23
Q

What part of the gram negative bacterial cell wall is the endotoxin

A

Lipid A

24
Q

What are the seven things that characterise infection

A
Inflammation 
Pain
Pyrexia (fever)
Tachycardia 
Rigors (sustained shaking)
Increased white cell count 
Increased C reactive protein (markers of infection)
25
Q

What does it mean if someone is asymptomatic

A

Shows no symptoms

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