Staphylococci and Similar Organisms Flashcards
S. aureus isolated from where?
- Abscesses
- Wound infections
- Carbuncles
S. aureus disease association
- food poisoning via enterotoxin
- pneumonia
- osteomyelitis
- endocarditis
- wounds
- staphylococcal scalded skin syndrome
- toxic shock syndrome
Name the enterotoxin associated with toxic shock syndrome
toxic shock syndrome toxin-1 (TSST-1)
S. aureus gram stain/morphology
GPC in clusters
S. aureus colony morphology
- opaque/smooth
- beta hemolytic on SBA
S. aureus biochemical traits
catalase
coagulase
PYR
ornithine
MSA growth
- catalase pos
- coagulase pos
- PYR neg
- ornithine neg
- grows on MSA and ferments mannitol to make yellow colonies
Latex agglutination assay detects ____ and ___ on the surface of S. aureus
- clumping factor
- protein A
Most coag-neg staph do not ferment mannitol and thus produce ___ colonies on MSA
red
coag-neg staph normal environment
normal skin flora
coag-neg staph disease association
- immunosuppressed pt
- neutropenic pt
- UTIs
- catheter/shunt infections
coag-neg staph colony morphology
white to gray colonies and non-hemolytic
Common coag-neg staph examples
- S. epidermidis
- S. saprophyticus
- S. lugdunensis
S. lugdunensis can ferment mannitol and is slide coagulase pos because of clumping factor just like S. aureus. How to distinguish?
- PYR test
- S. lugdunensis is PYR pos while S. aureus is PYR neg
How to distinguish between S. epidermidis and S. saprophyticus?
- Novobiocin susceptibility test
- S. epidermidis is susceptible while S. saprophyticus is resistant
Micrococcus normal environment
normal skin and mucous membrane flora
