Staphylococci

Categorization
Cell Wall: Gram Positive Shape: Cocci
Biochemistry: Catalase Positive Metabolism: Facultative Anaerobe
Classification
  • Overview
    • Both Staphylococci and Streptococci are Gram Positive Cocci; therefore, it is important to understand how these organisms are differentiated. Additionally, it is important to appreciate how different strains of staphylococci are differentiated from one another.
  • Differentiation from Streptococci
    • Gram Stain: Staphylococci appear as grape-like clusters on gram stain while streptococci appear as strings of beads.
    • Catalase: All staphylococci are catalase positive, possessing catalase enzyme and thus bubble when exposed to Hydrogen Peroxide (H2O2) while all streptococci are Catalase Negative.
  • Differentiation between Staph Strains
    • Coagulase: Only Staphylococcus aureus produces coagulase
    • Color: Only S. aureus produces a pigment which gives colonies a golden color whereas other strains produce white colonies
    • Hemolysis: Only S. aureus can hemolyze RBCs and is thus beta-hemolytic.
Member Organisms