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Flashcards in Part 1 Deck (18)
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0
Q

Example of opportunistic pathogen

A

Staphylococci - commensals of skin and mucous membranes but pathogens through broken skin.

E.Coli - commensals in Colon but pathogens in urinary tract

1
Q

How do bacteria cause disease?

A

Invasion, toxigenicity (production of microbial toxins), immunopathology (host damage from body’s response to infection)

2
Q

What’s a nosocomial infection?

A

Hospital acquired

3
Q

Where is clostridium tetani found?

A

Faeces and soil- environmental source

4
Q

Where is the source of streptococcus equi infections?

A

Another animal (upper respiratory trAct of horses.

5
Q

What’s an endogenous infection?

A

When source on body already- commensals

6
Q

How does Bordatella Bronchiseptica avoid ‘flushing’ action of body fluids?

A

Sticks to ciliated epithelium in trachea- stops mucociliary escalator moving. End of fimbriae recognise receptors.

7
Q

What does moraxella bovis cause?

A

Conjunctivitis of cows.

8
Q

What are K88 fimbriae, what bacteria has them and why are they important?

A

E.Coli use them to adhere to mucosal surface of small intestine by K88 receptor binding. Important in clearance- antibody blocks receptor and stops binding.

9
Q

How to pathogenic bacteria acquire iron?

A

Siderophores - put out into environment, bind iron and bring back.

Transferin- binding proteins - binds to iron and steals it from other molecules in body

10
Q

What are siderophores?

A

Put out into environment to acquire iron.

11
Q

What’s endotoxin?

A

Lipopolysaccharide only. Found in gram -ve cell walls

12
Q

Obligate intracellular pathogens?

A

Chlamydia, lawsonia

13
Q

How is antibody mediated opsonophagocytosis avoided?

A

Molecular mimicry - surface components which appear to be self. Eg. K1 antigen of E.Coli is sialic acid.
Hyaluronic capsule of beta-haemolytic streptococci

14
Q

Examples of exotoxins produced by gram positive bacteria

A

Gram positive digest surroundings for nutrition:
Phospholipase, protease, collagenase, hyaluronidase

Clostridial toxins
Tetanus toxin
Botulinum toxin

Leucocidin, haemolysin, antichrmotaxins, C5a protease

15
Q

Exotoxins produced by gram negative bacteria

A

Cholera toxins, LT, ST, shiga-like toxin of E. Coli etc

16
Q

What does endotoxin cause?

A

LPS- initial fever,

Thrombosis 
Leucopaenia
Compliment activation
Hypotension
Circulatory collapse
Death
17
Q

How does Mycobacterium in TB cause injury?

A

Immune-mediated - invade but no known toxin secreted. Tissue destruction and cytokine damage