what is an infection?

Question 1

what is an infection?

Answer 1

the invasion and growth of microorganism in tissue

Question 2

how do microorganisms cause symptoms?

Answer 2

1. exposure
2. adherence
3. invasian
4. multiplication
5. dissemination
6. cellular damage through virulence factors

Question 3

what are the different types of virulence factors?

Answer 3

endotoxins
exotoxins

Question 4

what are the different types of exotoxins?

Answer 4

1. cytolytic - membrane damaging
2. AB toxins - 2 part toxins where B binds to the cell and delivers an enzyme A to cytosol which is often an enzyme that interferes with cell function
3. super antigens - microbial proteins that bind both class II MHC molecules and T cell receptors (activation of T cells)
4. enzymes - destroy tissue into which bacteria is trying to invade

Question 5

what are endotoxins?

Answer 5

• cell wall components in particular lipopolysaccharide-protein complexes
• all of which cause host cell damage either directly or as a result of the immune response to the virulence factor

Question 6

what factors determine if a pathogen will cause a disease in an individual?

Answer 6

pathogens virulence factors
inoculum size
antimcrobial resistance

Question 7

how do we know if a patient has an infection?

Answer 7

symptoms and history
specific investigations: bacteriology + virology
supportive investigations: FBC, CRP, LFT