ID Board Review/Bacterial Diseases/Gram-positive cocci (GPC)

Medically Significant GPC

• Staphylococcus spp
  • Staphylococcus aureus
  • Coagulase Negative Staphylococcus (CoNS)
    • Staphylococcus epidermidis
• Streptococcus spp
  • Streptococcus pneumoniae
  • Streptococcus viridans
  • Streptococcus pyogenes (GAS)
  • Streptococcus agalactiae (GBS)
• Enterococcus spp

Gram Positive Cocci Characteristics

Bacteria	Histology	Catalase	Coagulase	Hemolysis	Optochin	Bacitracin
Staphylococcus spp	"Grape-like" clusters	Positive	Positive
CONS	-	Positive	Negative
Streptococcus spp	Pairs and chains	Negative	-
S. pneumoniae	Pairs and chains	Negative	-	α-hemolysis	Sensitive
S. viridans	Pairs and Chains	Negative	-	α-hemolysis	Resistant
S. pyogenes	Pairs and Chains	Negative	-	β-hemolysis		Sensitive
S. agalactiae	Pairs and Chains	Negative	-	β-hemolysis		Resistant

CONS- Coagulase Negative Staph