Flashcards in Staphylococcus Deck (15):
What are physical characteristics of Staph?
Gram Positive cocci, nonmotile
Where is staph normally located in our normal flora?
Upper Respiratory Tract. 25% of people are carriers
What is a key difference between S. Aureus and S. Saprophyticus/Epidermidis?
S. Aureus is coagulase positive and the others are not.
Difference between Staph and Strep?
Staph is Catalase Positive
Strep is Catalase Negative
-Can use peroxide to see if bubbles
What is the unique morphology of S. Aureus?
Protein A on its outer surface bound to peptioglycan, which bind the Fc regions of IgG molecules preventing opsonization/phagocytosis.
What are the toxins that S. Aureus can produce?
What can enterotoxins cause and where are they from?
Enterotoxins are super toxins usually from contaminated food and cause intoxication to the person n/v/d between 2-6 hours after ingestion that resolve shortly there after.
What is super antigen and how does it work?
Superantigens are enterotoxins that can cause intoxication and toxic shock syndrome. The toxin can nonspecifically bind the MHC receptor and TCR causing mass activation and cytokine release.
How do exfoliative toxins work and what can they cause?
Exfoliative toxins are proteases that cleave the intracellular attachment of epithelial cells. ETA/ETB forms.
SCALDED SKIN SYNDROME
How is Staph typically transferred?
Transferred via direct contact on the hands. Can reside on the skin since oxygen tolerant.
What are common infections of Staph?
Folliculitis, Abscesses, Impetigo (mixed staph/strep), scalded skin syndrome, and Pneumonia (immunocompromised)
Where is the primary site of infection of Staph?
Skin infections. Primary barrier of protection is intact skin.
How can Staph Aureus become resistant to penicillin/methicillin? How is it treated?
Changes in the PBP (Penicillin Binding Proteins)
Treated with Vancomycin.
What is a characteristic of S. Epidermidis?
Typically gotten while in the hospital localized at surgical sites and can bind to plastics. Multiple Drug Resistance.