Virtual Lab 3 | BCTC

Virtual Lab 3


Gram Stain

  • organism: Staphylococcus aureus
  • reaction: gram positive
  • morphology/arrangement: staphylo/cocci...clusters, round bacteria

lab 3 - Staphylococcous Aureus

Catalase Test

  • catalase reaction formula
  • Staphylococci are typically strongly positive for the reaction

lab 3 - Catalase Reaction

Mannitol Salt Agar Plate (MSA)

  • selective component: high salt
  • differential component: mannitol

MSA plate

Caption Text Goes Here
Sector Growth? Fermentation of mannitol? Interpretation
A  +++ Yes (reduction of phenol red - yellow) Presumptive ID of Staphylococcus aureus
B +++ No Staphylococcus species (but not S. aureus)
C --- No Not a Staphylococcus species


Coagulase Test

  • detects the presence of coagulase enzyme that can coagulate plasma
  • is a definitive test for Staphylococcus aureus

lab 3 - Coagulase Reaction




Representative Streptococcus

  • Gram stain reaction: Gram positive
  • Morphology, arrangement: coccus-shaped organism in chains

Strepto arrangements  diagram

Blood Agar Plate

Organism: Streptococcus pyogenes

  • Hemolysis type: Beta ()
  • Optochin (P disc) sensitivity: Resistant
  • Bacitracin (A disc) sensitivity: Sensitive

lab 3 - S Pyogenes Plate

Representative Streptococcus

lab 3 - Representative Stretococcus


S. agalactiae Plate

lab 3 - S Agalactiae Plate

S. agalactiae Biochemical Tests

lab 3 - S Agalactiae Biochemical Test

S. pyogenes Plate

lab 3 - S Pyogenes Plate

S. pyogenes Biochemical Tests

lab 3 - S Pyogenes Biochemical Test

S. pneumonia Plate

lab 3 - S Pneumonia Plate

S. pneumonia Biochemical Tests

lab 3 - S Pneumonia Biochemical test

Viridans Group Representative Plate

lab 3 - Viridian Group Plate

Viridans Group Representative, Biochemical Tests

lab 3 - Viridian Group Biochemical Test

Enterococcus Plate

lab 3 - Enterococcus Plate

Enterococcus Biochemical Tests

lab 3 - Enterococcus Biochemical test