2: Intro to Infectious Disease

Question 1

how do you get infectious from endogenous bacteria?

Answer 1

secondary to some other alteration in tissue structure or function

• organisms go where they don’t belong
• obstruction of draining pathways w/ overgrowth
• alteration in host defenses

Question 2

4 common organisms for sinusitis, OM, and pneumonia

Answer 2

• H. influenzae (non-B)
• S. pneumoniae
• M. catarhallis
• S. aureus

Question 3

95% of bacterial pneumonias are from what organism

Answer 3

S. pneumoniae

Question 4

what are 3 organisms not commonly found in the mouth, nose, or oropharynx?

Answer 4

• b-hemolytic streptococci (S. pyogenes)
• H. influenza type B
• N. meningitidis

Question 5

what do capsules help bacteria do?

Answer 5

evade the innate immune system, so they need opsonization to be phagocytized

Question 6

what can you tell by the time to onset of symptoms?

Answer 6

immune response for sx -> incubation 7-10d

neutrophil response for sx -> 12-24 h

Question 7

4 major routes humans become infected with organisms:

Answer 7

• contact with virulent dude
• colonizing dude gets past a barrier (somewhere it’s not supposed to be)
• changes in local conditions - overgrowth
• some combination of the first three

Question 8

inability to produce Ig’s makes one susceptible to what?

Answer 8

encapsulated organisms

Question 9

lack of cellular immunity makes one susceptible to what?

Answer 9

intracellular organisms

Question 10

lack of neutrophil fxn makes one susceptible to what?

Answer 10

staph, strep

Question 11

lack of phagocytic clearing mechanisms makes one susceptible to what?

Answer 11

encapsulated organisms

Question 12

two principles of containing contagion

Answer 12

• limit exposure

- not allowing colonization

Question 13

what determines the pathology associated with a given organism?

Answer 13

nature of the host-organism interaction

Question 14

given that signs and symptoms can often be attributed to the host response to an organism, what are the implications for an immunocompromised person?

Answer 14

patients with altered immune response or vascular insufficiency may not show typical signs and symptoms!

Question 15

5 components to therapeutic intervention in infectious disease

Answer 15

• treat underlying disease
• prevent contagious spread
• shore up natural barriers
• alter immune response (either stimulate or suppress)
• educate patient