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25 Cards in this Set
- Front
- Back
What does the "Aureus" in "Staph Aureus" refer to?
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The gold ring that forms when Staph is cultured on blood agar plates
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What is a simple test to distinguish between Staph and Strep?
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Catalase test
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Are staphylococci alpha, beta, or gamma hemolytic?
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All are beta-hemolytic (they completely lyse blood)
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How do you distinguish between Staph Aureus and the other Staphylococci?
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Staph Aureus makes a golden color on agar plates, and it is the ONLY catalase positive staphylococcus.
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What are the 6 proteins that Staph Aureus can use to disable the immune system?
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Protein A, Coagulase, Hemolysins, Leukocydins, Penicillinase, Novel Penicillin Binding Protein
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Where does protein A come from and what does it do?
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Staph Aureus… it binds to the Fc region of attacking antibodies so they cannot opsonize the bacteria.
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What are the 4 proteins Staph Aureus uses to burrow through tissue?
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Hyaluronidase (destroys connective tissue proteoglycans), Staphylokinase (like streptokinase, lyses fibrin clots), Lipase (allows staph Aureus to colonize sebaceous glands), Protease.
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What causes scalded skin syndrome, and how?
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Staph Aureus by the exotoxin, "exfoliatin"
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What are the 3 exotoxins produced by staph aureus?
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Exfoliatin, enterotoxin, TSST-1 (toxis schock syndrome toxin - 1)
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TSST-1 from staph aureus is analagous to what toxin from Strep Pyogenes?
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Pyogenic Toxin (both are superantigens)
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What are the 3 diseases caused by staph aureus exotoxins?
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Scalded Skin Syndrome, Food Poisoning, Toxic Shock Syndrome
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What are some of the features of enterotoxin food poisoning?
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nasea, vomiting, diarrhea, abdominal pain, occasional fever
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What are some causes of toxic shock syndrome?
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TSST-1 is introduced to patient through, surgical wound or super-absorbent tampon
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What are some features of toxic shock syndrome?
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diffuse erythematous rash, fever, septic shock, vomiting/diarrhea, desquamation of palms
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What are six diseases caused by staph aureus (not by staph exotoxins)?
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Remember the wizard with his Staph… Pneumonia, Meningitis/Brain Abcess, Osteomyelitis, Acute Endocarditis, Septic Arthritis, Skin Infections
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Describe Impetigo
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Small vesicles give rise to pustules, which crust over and become honey-colored, wet, and flakey
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Describe Cellulitis
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Deep skin infection… skin becomes red, hot, shiny, and swollen
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What are carbuncles?
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Multiple painful infected lesions communicating under the skin
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How does Staph Aureus get into the blood or urine?
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Catheter infections
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Methicillin Resistant Staph Aureus (MRSA) is resistant to penicillin and a lot of penicillin derivatives. What is an antibiotic that is still effective agains Staph A.?
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Vancomycin… which is only used in the most critical of cases.
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Where is Staph EPIDERMIDIS usually found?
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On the skin… is normally harmless
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Staph Epidermidis frequently causes what kinds of problems?
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Infected prosthetic joints, and catheter based infections (causes bacteremia / UTI's)
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How do you determine than a blood culture positive with Staph Epidermidis is not a contamination?
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Do a second blood culture from another source
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What is the name of the third pathogenic staph bug… (not Aureus, and not Epidermidis)
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Staphylococcus Saprophyticus
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What are the clinical manifestations of Staph Saprophyticus infections?
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UTI's in sexually active females (very rarely contracted in hospitals)
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