Symposium - Nature and Pathogenesis of Infection

Question 1

What do gram negative cocci in pairs indicate?

Answer 1

Neisseria meningitidis

Question 2

What is the clinical syndrome for skin infections? What 2 pathogens can cause this?

Answer 2

Cellulitis
Bacteria (gram positive)
- Streptococcus pyogenes, gram +ve chain (most likely)
- Staphylococcus aureus, gram +ve clusters

Question 3

What is the clinical syndrome for brain infections? What pathogens can cause this?

Answer 3

Meningitis
Virus or Bacteria
- Haemophilus Influenza - rare due to vaccination
- Streptococci pneumoniae
- Neisseria meningitidis (bacterial, more severe)
- Herpes Simplex Virus

Question 4

What is the clinical syndrome for lung infections? What pathogens can cause this?

Answer 4

pneumonia
can be viral or bacterial. Bacterial:
- streptococcus pneumonia, more likely (gram positive)
- haemophilus influenza (gram positive)

Question 5

What is the clinical syndrome for bladder infections? What pathogens can cause this?

Answer 5

cystitis
bacterial
- e-coli (most likely)

Question 6

What is the clinical syndrome for mouth infections? What pathogens can cause this?

Answer 6

pharyngitis
respiratory viruses and bacteria
- streptococcus pyogenes
- Corynebacterium diphtheria
- EBV

Question 7

What is the clinical syndrome for heart infections? What pathogens can cause this?

Answer 7

endocarditis
- virdian streptococci
- streptococcus aureus

Question 8

What is the clinical syndrome for eye infections? What pathogens can cause this?

Answer 8

conjunctivitis
- adenovirus
- staphylococcus aureus

Question 9

What are the causes of disease in infection?

Answer 9

• damage caused directly by parasite
• damage mediated via inappropriate innate immune mechanisms
• damage mediated via inappropriate adaptive immune mechanisms

Question 10

How do pathogens cause damage?

Answer 10

• cytotoxic - cause lysis of cells
• bacteria releasing toxins that directly damage tissues

Question 11

How do pathogens cause damage via the innate immune system?

Answer 11

• endotoxins (PAMPS)
• activate innate immune cells
• enzymes released
• activates complement system

Question 12

What is noticeable in patients where the innate immune system is causing damage as a result of infection?

Answer 12

• high CRP
• fever, coma
• high lactate
• low oxygen stats
• hypotension
• acute respiratory distress
• disseminated intravascular coagulation

Question 12

How do pathogens cause damage via the adaptive immune system?

Answer 12

• gell and coombs
  1. anaphylactic
  2. antigen on bacteria activates inflammatory cascade
  3. immune complex mediated
  4. cell-mediated