01a: Staph, Strep

Question 1

Staph: Gram (pos/neg), catalase (pos/neg) (aerobes/anaerobes).

Answer 1

Pos; pos; facultative anaerobes

Question 2

T/F: Staph is non-motile.

Answer 2

True

Question 3

Staph aureus typically found where on body?

Answer 3

Anterior nares

Question 4

T/F: Staph Aureus, S. Epidermidis, and S. Sapropyticus are all beta-hemolytic.

Answer 4

False - only S. Aureus (other are non-hemolytic)

Question 5

Clinical hallmark of S. Aureus infection.

Answer 5

Abscess formation

Question 6

Coagulase positive test is important to distinguish Staph (X) from…

Answer 6

X = Aureus

Other Staph species (ex: S. Epidermidis and S. Saprophyticus)

Question 7

List the exotoxins of S. Aureus.

Answer 7

1. Enterotoxin
2. TSST
3. ET (Exfoliative Toxins)
4. PV Leukocidin
5. Alpha, beta, delta, gamma toxins

Question 8

List the exotoxins of S. Epidermidis.

Answer 8

NONE

Question 9

T/F: All S. Aureus strains carry TSST.

Answer 9

False - only 5-25%

Question 10

Which (endo/exo)-toxin(s) in Staph (X) responsible for WBC and RBC lysis?

Answer 10

Exotoxin;
X = Aureus

PV Leukocidin and alpha, beta, delta, gamma toxins

Question 11

Which bacteria is leading cause of osteomyelitis, aka (X).

Answer 11

X = infection of bone

S. Aureus

Question 12

Which (endo/exo)-toxin(s) in Staph (X) responsible for Scalded Skin Syndrome? What’s the mechanism?

Answer 12

Exotoxin;
X = Aureus

ET (Exfoliative Toxins); Ser proteases that cleave cell adhesion molecules (separate epidermis)

Question 13

T/F: There are no vaccines for any Staph species.

Answer 13

True

Question 14

Most common method of transmission of S. Aureus.

Answer 14

Direct contact or fomites

Question 15

Most common method of transmission of S. Epidermidis.

Answer 15

Endogenous

Question 16

Most common method of transmission of S. Saprophyticus.

Answer 16

Sexual contact

Question 17

How are S. Epidermidis and S. Saprophyticus distinguished?

Answer 17

S. Epidermidis: Novobiocin-sensitive

S. Saprophyticus: Novobiocin-resistent

Question 18

What is the most common cause of septic arthritis in adults?

Answer 18

S. Aureus

Question 19

Staph (X) can ferment mannitol, turning the agar plate (Y) color.

Answer 19

X = aureus
Y = yellow

Question 20

Favored treatment of Chlamydia is (X) because it’s a one-time treatment, but (Y) is also given.

Answer 20

X = azithromycin (macrolides)
Y = doxycycline

Question 21

T/F: Chlamydiaceae is facultative intracellular parasite.

Answer 21

False - obligate intracellular parasite

Question 22

T/F: Ceftriaxone is given as treatment in patient with Chlamydia.

Answer 22

True, but to treat potential Gonorrhea

Question 23

Which beta lactams can be used to treat Chlamydia?

Answer 23

None! No peptidoglycan in cell wall of Chlamydiaceae!!

Question 24

Stain used to visualize Chlamydiaceae. And best method of diagnosis via (X).

Answer 24

Giemsa

X = NAAT

Question 25

T/F: Chlamydia is most commonly reported STI in US.

Answer 25

True

Question 26

Neonate with "stacatto" cough has (X) disease, secondary to (Y) infection. What else would you expect to see in this neonate?

Answer 26

``` X = pneumonia Y = transmitted chlamydia ceae trachomatis infection ``` Conjunctivitis

Question 27

T/F: Both Chlamydophila pneumoniae and C. psittaci infections present with pneumonia.

Answer 27

True

Question 28

Elderly male smoke presents with pneumonia and diarrhea. What infectious agent is at the top of your differential? What other signs will verify this?

Answer 28

Legionella pneumophila Hyponatremia, HA, confusion, high fever