Staph

Question 1

Identify this organism

Answer 1

Staph. aureus

See Grape-like clusters, Gram +

Question 2

What is the coagulase status of Staph epidermidis, and Staph saprophyticus?

Answer 2

Negative

Question 3

Which Staph is novobiocin resistant?

Answer 3

S. saprophyticus

Question 4

MecA gene encodes for

Answer 4

PBP2a (decreased binding affinity for B-lactam antibiotic)

This is a resistance factor for MRSA.

Question 5

A _____ Year Study at Brigham & Women’s Hospital in Boston (January 1996 – December 2004)

Answer 5

9

Question 6

MRSA infection is becoming more common in the ____ setting

Answer 6

community

Question 7

What is the most important reservoir of methicillin resistant Staphylococcus aureus (MRSA) in hospitals?

Answer 7

Patients themselves!!!

Question 8

Name 4 important species of Staphylococci

Answer 8

1. S. Aureus 2. S. epidermidis 3. S. lugdunensis 4. S. saprophyticus

Question 9

What is this?

Answer 9

Pyoderma.

This could be due to Staphylococcus aureus infection.

It could also be autoimmune (pyoderma gangrenosum)

Question 10

What’s this?

Answer 10

Furuncle (boil)

Staph. aureus infection.

Question 11

What’s this?

Answer 11

Carbuncle - serious Staph aureus infection

Question 12

Name 3 toxin-mediated infections via Staph aureus

Answer 12

1. Scalded-skin syndrome
2. Toxic-shock syndrome
3. Food poisoning

Question 13

During a localized infection, Staph aureus can metastasize to other sites via blood, resulting in:

Answer 13

–Pneumonia
–Bacteremia
–Endocarditis
–Osteomyelitis
–Septic arthritis
–Septic embolization
–Metastatic infections

Question 14

Capsules, Protein A, Panton-Valentine Leukocidin (PVL), Coagulase. These are all examples of what?

Answer 14

Staphylococcus aureus virulence factors, that interfere with phagocytosis

Question 15

What is this?

Answer 15

Staphylococcal scalded skin syndrome.

Exfoliatins or epidermolytic toxins dissolve mucopolysaccharide matrix of epidemis…separation of skin layers! Rare in adults.

Question 16

Staphylococcal food poisoning involves what type of toxin?

Answer 16

Enterotoxins

Question 17

Staph aureas is coagulase positive, or negative?

Answer 17

Positive!

Coagulase reacts with
substance in plasma
called coagulase-reacting
factor that converts fibrinogen to fibrin

Question 18

Alternative coagulase test is called

Answer 18

Latex aggluination test

Question 19

This bug is often first detected as clusters of abscesses or “spider bites”

Answer 19

MRSA

Question 20

What are we screening for here?

Answer 20

MRSA.

This screening resulted in:

A 75% decrease in MRSA bacteremia in ICUs

And a 67% drop hospital wide

Question 21

–Abscesses, pustular lesions, “boils”
–“Spider bites”
–Cellulitis

Answer 21

Think MRSA!

•MRSA belongs in the differential diagnosis of skin and soft tissue infections (SSTI’s) compatible with S. aureus infection

Question 22

What is the catalase status of Staph?

Answer 22

Catalase positive (whereas Strep. is negative)

Question 23

What is the only Staph species that is PYR and ornithine POSITIVE?

Answer 23

S. lugdunensis

Question 24

An organism identified as gram-positive cocci in clusters is isolated from the urine of a 21 year female with symptoms of acute cystitis. The laboratory reports that the organism is coagulase-negative, furozolidone susceptible and novobiocin resistant. What is the most likely identification of this bacterium?

Answer 24

Staphylococcus saprophyticus

Question 25

MSPM - men who play sports with men

MSM - men who have sex with men

These are risk factors for?

Answer 25

MRSA