II. Background
- Staphylococcus is derived from Staphyle (Greek for bunch of grapes)
III. Labs: Characteristics
- Gram Positive Cocci in irregular clusters
- Facultative Anaerobes
- Non-spore forming
- Non-motile
- Glucose fermentation
- Size: 0.7 to 1.2 microns
- Beta hemolytic
- As with Beta Hemolytic Streptococcus, hemolyze RBCs on sheep blood agar plate (BAL)
- Staphylococcus Aureus is named for its gold coloration on BAL
- Catalase positive
- Catalase converts Hydrogen Peroxide (from Macrophages, PMNs) into water and oxygen
- Catalase positive organisms on a culture plate will bubble when exposed to Hydrogen Peroxide
IV. Organisms
- Coagulase-Positive Organisms (activates plasmin, inducing Clot Formation)
- Coagulase-Negative Organisms
- Staphylococcus Epidermidis (IV catheter infections)
- Staphylococcus Saprophyticus (UTI in women)