II. Background

  1. Staphylococcus is derived from Staphyle (Greek for bunch of grapes)

III. Labs: Characteristics

  1. Gram Positive Cocci in irregular clusters
  2. Facultative Anaerobes
  3. Non-spore forming
  4. Non-motile
  5. Glucose fermentation
  6. Size: 0.7 to 1.2 microns
  7. Beta hemolytic
    1. As with Beta Hemolytic Streptococcus, hemolyze RBCs on sheep blood agar plate (BAL)
    2. Staphylococcus Aureus is named for its gold coloration on BAL
  8. Catalase positive
    1. Catalase converts Hydrogen Peroxide (from Macrophages, PMNs) into water and oxygen
    2. Catalase positive organisms on a culture plate will bubble when exposed to Hydrogen Peroxide

IV. Organisms

  1. Coagulase-Positive Organisms (activates plasmin, inducing Clot Formation)
    1. Staphylococcus Aureus
  2. Coagulase-Negative Organisms
    1. Staphylococcus Epidermidis (IV catheter infections)
    2. Staphylococcus Saprophyticus (UTI in women)

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