Flow chart Aerobic Gram positive organisms
Gram stain morphology
Rods
Regular rods
Cocci
Catalase +
Irregular, coryneform
Beta hemolytic on Day 2
Beta hemolytic
Coagulase +
Catalase negative
Coag Neg
• Listeria
• Bacillus
• Lactobacillus
Yes
Catalase negative
Coag negative
staphylococcus
or Micrococcus
No
Staphylococcus
aureus
Arcanobacterium
Corynebacterium
Yes
No
See Strep chart
S. pneumoniae.other
viridans strep, or
Enterococcus