• Tests for hemolytic reaction
  • Beta-hemolysis - clear zone (complete hemolysis)
  • Alpha-hemolysis - greenish zone (partial hemolysis)
• Gamma-hemolysis - unchanged (no reaction)
• Alpha and Gamma are typically normal flora
• Beta is streptococci pathogen, most common is Streptococcus pyogenes.
• Differential - three types of hemolysis
• Enrichment - sheep blood nutrients enhance growth.

• Enzymes catalase produced by MO reacts with H₂O₂ (hydrogen peroxide) to produce oxygen and water.
• The observation is bubbles or none.
• Primary differentiation is GM+
  • cocci (staphylo - pos. & strept-neg.)
  • bacilli (Bacillus-pos. & Lactobacillus-neg.)

Citrate Agar

• Slant - streak and stab
• MO uses citric acid as source for carbon as carbon is consumed pH changes and turn bromythomol blue to green color.
• Blue is positive for citric acid consumption.
• Differentiates on GM- rods.

• All liquid media (red)
• Fructose, Glucose, Lactose, Mannitol
• Test for MO's ability to ferment sugars.
• Observations:
  • growth (turbidity)
  • acid (ph indicator turns from red to yellow)
  • gas (bubbles inside inverted vial)
• Differentiates sugar fermentaion and gas production

• Certain MOs produce H₂S
• The media has ferrous sulfate that reacts witht H₂S and produces a black precipitate.
• Differentiates GM- rods

• Slant
• If MO produces enzyme urease it creates a bright pink color.
• Differentiates between GM- Rod Proteus mirabilis (pos) and Salmonella typhimurium (neg)

• Poured over inoculated medium
• Seals MO from oxygen
• Differentiates aerobic or anaerobic

• Plate
• Differentiates for lactose fermentation.
  • Positive - bright pink colonies
  • Negative - dull or colorless colonies
• Selective for GM-, surpress GM+

Tyrptic Soy Agar (TSA)

• Plate or tube 
• Nutrient for growth of GM+ and GM-
• Used to produced isolated colonies
• Overgrowth can occur.

• Plate or tube 
• Nutrient
• Selective for GM+, antibiotic surpress GM- growth.

• Eosin-methylene blue agar.
• Differentiates based on lactose fermentation
  • Colored colonies (pink or metalic green) ferment lactose
  • Colorless do not ferment lactose.
• Selects for gram negative - EMB inhibits GM+ growth.

• Prepared on slant - inoculated by streaking and then stabbing.
• Contains glucose, lactose, sucrose, ferrous sulfate, phenol red and nutrient agar.
Differentiates sugar fermentation. 
Yellow is acid, Red is alkaline. 
R/Y - Ferments glucose only.
• Glucose is consumed and amino acids acids are used for energy which oxidize change pH.
Y/Y - Ferments glucose, lactose, and/or sucrose
R/R - does not ferment any sugar (double