Microbial Triggers to Sepsis

Question 1

How do bacteria attach to epithelia?

Answer 1

Non-specific electrostatic interactions
Tethering via projections “fimbriae” or pili
Attachment via special receptors on human cell surfaces
Internalisation into the epithelial cell

Question 2

How do bacteria penetrate epithelial/endothelial barriers?

Answer 2

Artificial penetration- breach of epithelium
Entry into and through the cell
Transit in between cell layers

Question 3

Response to meningococcal infection

Answer 3

Release of inflammatory mediators by human cells e.g. TNF, IL8
Recruitment of innate immune response

Question 4

Clearance of Gram negative bacteria

Answer 4

Opsonisation
Complement activation
Chemotaxis of neutrophils

Question 5

What receptor recognises staphylococcal infection?

Answer 5

Toll-like receptors

Question 6

How do superantigens work?

Answer 6

It is not processed by APC but binds directly to MHC class 2 activating more T cells than a normal immune response ​

Question 7

Streptococcus pyogenes evasion of immunity mechanisms

Answer 7

Anti-neutrophil strategies
Anti-opsonisation strategies
Toxins which interfere with immune responses e.g superantigens

Question 8

Neisseria meningitides evasion of immunity mechanisms

Answer 8

Anti-complement/MAC strategies e.g Capsule

Question 9

Staphylococcus aureus evasion of immunity mechanisms

Answer 9

Anti-neutrophil strategies
Anti-opsonisation strategies
Toxins which interfere with immune responses e.g superantigens

Question 10

What produces the panton valentine leucocidin enzyme?

Answer 10

Staphylococcus aureus

Question 11

What does Panton Valentine Leukocidin do?

Answer 11

Forms pores in neutrophils to kill them

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Question 12

Which toxins cause superantigen toxic shock and by which bacteria?

Answer 12

Staphylococcus aureus

Toxic shock syndrome toxin-1 (TSST-1), staph enterotoxin A, B, C (SEA, B, C)