Brown Checkpoint 2

Question 1

2. How are members of S. viridans and S. pneumoniae distinguishable?

Answer 1

a. Viridans is optochin resistant, S. pneumoniae diplococci

Question 2

3. In patients with pre-existing heart diseases, why are dental procedures a potential risk for IE?

Answer 2

a. Normal flora in oral cavity can cause IE and enter bloodstream with dental procedures

Question 3

4. Which member of S. viridans group is the most frequently isolated in cases of IE? Which one causes brain and liver abscesses? Which is frequently associated with dental caries?

Answer 3

a. S. sanguinis most common for IE
b. S. mutans dental caries
c. S. intermedius, liver and brain abscesses

Question 4

5. What is the quellung reaction and which virulence factor does it detect?

Answer 4

a. Identification of a capsule, antibodies (antiserum) generated against bacterial capsule antigens are mixed with bacteria, cause capsule to swell

Question 5

6. What are some of the common infections caused by Group D streptococci and the enterococci?

Answer 5

a. Subacture IE, biliarty tract infections, UTI, wound infections

Question 6

7. Which species of the enterococci cause the most clinical cases?

Answer 6

a. Enterococcus faecalis (85%) and faecium(5-10%), normal flora of GI tract and female repro tract

Question 7

8. Which species in Group D streptococci cause the most clinical cases?

Answer 7

a. S. gallolyticus (normal GI tract flora, frequently goun in blood of ppl with colon malignancies), to a lesser extent S. equinus

Question 8

9. Which culture conditions can the enterococci grown in but members of Group D streptococci cannot?

Answer 8

a. Group D will not grow in 40% bile and 6.5% NaCL

Question 9

10. How does protein M contribute to the onset of rheumatic fever?

Answer 9

a. Similar to myosin proteins of heart, molecular mimicry

Question 10

11. What are the major and minor Jones criteria and how many major and minor criteria must be met in order to diagnose rheumatic fever?

Answer 10

a. 2 major or 1 major 2 minon
b. Major
i. Carditis, polyarthritis, sydenham’s chorea, erythema marinatum, subcutaneous nodules
c. Minor
i. Fever, arthralgia, previous rhematic fever or rheumatic heart disease, acte phare rxn: ESR/CRP/leukocytosis, prolonged PR interval

Question 11

12. Why are people with a history of rheumatic fever commonly placed on prophylactic antibiotics?

Answer 11

a. Each future S. pyogenes infection will retrigger production of cross-reactive antibodies

Question 12

13. Why is rheumatic fever a risk factor for infective endocarditis?

Answer 12

a. Damage to heart is permanent, most frequent sites of damage are mitral valve followed by aortic valve

Question 13

14. What are some of the common disease caused by Coxiella burnetii?

Answer 13

a. Q fever, IE, arterial infections, osteomyelitis

Question 14

15. How is C. burnetii commonly transmitted? Who are the most at-risk groups?

Answer 14

a. Can be aerosolized, found in feces, skin, fur and milk of cows, goats and sheep. Also found in placenta of those animals. Pregnant women and farmers, vets, and slaughterhouse workers

Question 15

16. Why are cultures not used in routine laboratory identification of Q fever? What are the two most common methods of lab ID?

Answer 15

a. Isolating pathogen is difficult and dangerous (biosafety level 3, PCR may be used to confirm in culture-neg IE, serology is gold standard