Staphylococcus aureus

Gram-Positive cocci; arranged in grape-like clusters

Beta-Hemolytic

Catalase Positive

Coagulase Positive

Penicillin Resistant

Genus Staphylococcus

Appear in clusters

Non-Motile, Gram-Positive Cocci

Catalase Positive

Modified Oxidase Negative

Mannitol Fermentation Negative

Bacitracin Resistant                        Furazolidone Susceptible

Oxidase Production Negative            Lysostaphin Susceptible

Staphylococcus saprophyticus

Gram-Positive Cocci

Novobiocin Resistant

Coagulase Negative

Catalase Positive

Very Glossy, opaque, smooth, butyrous (butter-like), convex colonies

Pigmented colonies ranging from cream to yellow-orange

Staphylococcus epidermidis

Gram-Positive cocci, arranged in clusters

Catalase Positive                             Coagulase Negative

PYR Negative                                  Beta- or non-Hemolytic

Ornithine decarboxylase Negative

Nonpigmented, smooth, glistening, slightly raised to convex, and opaque

Many strains drug resistant

Beta-Hemolytic Streptococci: Group A

(S. pyogenes)

Gram-Positive                                 Catalase Negative

Bacitracin Susceptible                      PYR Test Positive

Bile-Esculin Negative                        6.5% NaCl Negative

Penicllin drug of choice for treatment

Opaque or pearly gray appearance              Beta-Hemolytic

Beta-Hemolytic Streptococci:  Group B

(S. agalactiae)

Gram-Positive cocci; usually arranged in chains

Beta-Hemolysis with a narrow zone with a soft outer edge

Bacitracin Resistant                          CAMP Test Positive

Bile-Esculin Hydrolysis Negative           Hippurate Hydrolysis Positive

Catalase Negative                            Does Not grow in 6.5% NaCl

Produce large, gray-white, mucoid, creamy colonies

Alpha-Hemolytic Streptococci:  Group A

(S. pneumoniae)

Alpha Hemolytic (green zone)

Gram-Positive cocci, usually arranged in lancet-shaped pairs

Smooth, glistening, wet-looking

Penicillin resistant

Optochin Disk (P-Disk) Susceptible

Highly encapsulated producing mucoid colonies with depressed centers 

Genus Enterococcus

Streptococcus Group D

Gram-Positive cocci or coccobacilli arranged in pairs and chains

Alpha- or Gamma-Hemolytic

Catalase Negative                             Oxidase Negative

Bile-Esculin Positive                           PYR Positive

6.5% NaCl Positive

Vancomycin and Ampicillin Resistant

Form small, gray colonies                  Growth stimulated by CO2

Growth at 45 degrees Celcius