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32 Cards in this Set
- Front
- Back
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What does staph look like?
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Gram +
Cocci clustered (grapes) non-motile |
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Where is the most common place to find staph?
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anterior nares
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What is the importance of coagulase?
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differentiates s. aureus from other staph
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What does coagulase do?
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contributes to the clotting of plasma
converts fibrinogen to fibrin |
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What type of metab does s. aureus have?
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facultative anaerobe
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Fermentation of mannitol in acid would show what in s. aureus? s. epidermidis?
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S. aureus +
S. epidermidis - |
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Which is catalase + staph or strep?
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STAPH!
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What are the 3 main structures in the cell envelope of Staph?
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peptidoglycan
teichoic acid protien A |
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What is protien A?
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major component of cell wall of staph that is covalently bound to peptidoglycan
*** binds Fc region of IgG |
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What is the clinical use of protein A?
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used to detect Ab levels
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What are some enzymes in staph aureus that help in establishing an infection?
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coagulase
lipase Hyaluronidase staphylokinase nuclease |
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Coagulase
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clotting of plasma
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lipase
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assist in establishing coloniazation but breaking down the cell wall
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Hyaluronidase
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hydrolysis of HA to facilitate spreading of infection
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Staphylokinase
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dissolution of clots
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Nuclease
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unique to s. aureus!
endo-exo nuclease activity for DNA or RNA |
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Toxins produced by staph aureus
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hemolysins
leukotoxins enterotoxins exfolative toxins |
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Leukotoxin
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2 protein toxin that attacts leukocytes and macrophages
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Enterotoxins
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preformed - food posioning
heat stable |
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Toxic Shock Syndrome
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Staph grows in vag normally and tampon has things to help grow... super antigen!
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Enterotoxins and TSST bind
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MCH II and TCR independent of antigen -> cytokines!
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Exfolative toxins
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2 forms: ETA ETB proteases
stim lysis of intracellular attatchment btwn cells of the epidermis |
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What disease does exfolative toxin cause?
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scalded skin syndrome
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What are 5 types of infection that staph can cause?
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folliculitis
boils impetigo scaled skin syndrome pneumonia |
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methicillin resistant s. aureus (MRSA) is due to?
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mutations with in PBPs
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What is used for s. aureus infections?
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vancomycin
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What is the main problem caused by enterococcus?
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vancomycin resistance
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What are the characteristics of enterococcus bacteria?
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not very aggressive but hard to treat because of vancomycin resistance
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What 2 gene products are needed for vancomycin resistance spread?
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VanH - a reductase
VanA - a ligase |
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How does vancomycin resistance work?
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puts a lactate on the C-term instead of a D-ala therefore vancomysin wont be able to stop cross bridging casue it wont see the d-lac
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S. epidermis characteristics
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coagulase negative
low virulence hospital aquired |
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S. saprophyticus characteristics
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coagulase negative
UTIs |
