Staph Flashcards
Identify this organism
Staph. aureus
See Grape-like clusters, Gram +
What is the coagulase status of Staph epidermidis, and Staph saprophyticus?
Negative
Which Staph is novobiocin resistant?
S. saprophyticus
MecA gene encodes for
PBP2a (decreased binding affinity for B-lactam antibiotic)
This is a resistance factor for MRSA.
A _____ Year Study at Brigham & Women’s Hospital in Boston (January 1996 – December 2004)
9
MRSA infection is becoming more common in the ____ setting
community
What is the most important reservoir of methicillin resistant Staphylococcus aureus (MRSA) in hospitals?
Patients themselves!!!
Name 4 important species of Staphylococci
- S. Aureus 2. S. epidermidis 3. S. lugdunensis 4. S. saprophyticus
What is this?
Pyoderma.
This could be due to Staphylococcus aureus infection.
It could also be autoimmune (pyoderma gangrenosum)
What’s this?
Furuncle (boil)
Staph. aureus infection.
What’s this?
Carbuncle - serious Staph aureus infection
Name 3 toxin-mediated infections via Staph aureus
- Scalded-skin syndrome
- Toxic-shock syndrome
- Food poisoning
During a localized infection, Staph aureus can metastasize to other sites via blood, resulting in:
–Pneumonia
–Bacteremia
–Endocarditis
–Osteomyelitis
–Septic arthritis
–Septic embolization
–Metastatic infections
Capsules, Protein A, Panton-Valentine Leukocidin (PVL), Coagulase. These are all examples of what?
Staphylococcus aureus virulence factors, that interfere with phagocytosis
What is this?
Staphylococcal scalded skin syndrome.
Exfoliatins or epidermolytic toxins dissolve mucopolysaccharide matrix of epidemis…separation of skin layers! Rare in adults.
Staphylococcal food poisoning involves what type of toxin?
Enterotoxins
Staph aureas is coagulase positive, or negative?
Positive!
Coagulase reacts with
substance in plasma
called coagulase-reacting
factor that converts fibrinogen to fibrin
Alternative coagulase test is called
Latex aggluination test
This bug is often first detected as clusters of abscesses or “spider bites”
MRSA
What are we screening for here?
MRSA.
This screening resulted in:
A 75% decrease in MRSA bacteremia in ICUs
And a 67% drop hospital wide
–Abscesses, pustular lesions, “boils”
–“Spider bites”
–Cellulitis
Think MRSA!
•MRSA belongs in the differential diagnosis of skin and soft tissue infections (SSTI’s) compatible with S. aureus infection
What is the catalase status of Staph?
Catalase positive (whereas Strep. is negative)
What is the only Staph species that is PYR and ornithine POSITIVE?
S. lugdunensis
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?
Staphylococcus saprophyticus
