Bacterial Mediums Review

Blood Agar

Blood Agar

Differencial

Eosine methelyne blue

 

Selective(for gram-, inhibited by eosin and methelyne blue) Differencial(ability to ferment lactose)

Gelatin Deep Agar

Differencial

Lysine Decarboxylase Broth

Differencial

MacConkey Agar

Selective (Gram -) Differencial (ability to ferment lactose)

 

Mannitol Salt Agar

Selective(Halotolerance) Differencial (Staphylococcus species)

 Nitrate Reduction Broth

 

Differencial(reducing nitrate -nitrite/ other nitrogenous compounds)

Phenol Red Fermentation Broth

 

Differencial(ability of organsim to ferment carbohydrates)

Rabbit plasma

Differencial

SIM Agar

Differencial

Simmons Citrate Agar

Selective

Starch Agar

Differencial

Triple Sugar Iron Agar

Differencial

Methyl Red Test

Differencial

Voges Proskauer Test

Differencial

Urea Agar

Differencial

Catalase

Differencial

Oxidase

Differencial

• Alpha Hemolysis - surrounded by clear zone(complete lyis)

• Beta Hemolysis - green, olive or brown color(partially lyse)

• Gamma Hemolysis - also known as negative hemolysis

Blood Agar

 

• Positive lactose fermentation if Green/Purple

• Negative if No color

Eosine methelyne blue

 

Gelatinase Positive if medium is liquified

 

Gelatin Deep Agar

 

• Positive if Purple

• Negative if Yellow

Lysine Decarboxylase Broth

 

• Positive for lactose fermentaion if Pink

• Negative if colorless

MacConkey Agar

• Positive Fermentation if Gas present, turns yellow

• Negative if Pink or Red

Mannitol Salt Agar

 

• Positive if gas present,

• Positive if turns pink after reagents A & B,

• Positive if no color chage after zinc is added

• ONLY DENTRIFICATION POSITIVE IF GAS PRESENT

 

Nitrate Reduction Broth

• Positive If medium solidifies

• Negative If stays Liquid

Rabbit Plasma

• Sulfur Reduction = Positive if Black;

• Negative if Yellow. Indole Test = Positive if layer turns Red;

• Negative if layer is Yellow Motility = Positive if growth radiates away from stabline;

• Negative if growth is only along stabline

SIM Agar

 

• Positive if Blue (citrate permease positive)

• Negative if Green

Simmons Citrate Agar

• Positive If Halo/light color ring around the bacteria

• Negative if Purple/Black around growth after iodine

Starch Agar

 

• Positive if Red/Yellow; Yellow/Yellow (for fermentaion)]

• Positive if Black( for H2S

Triple Sugar Iron Agar

• After Methyl red is added Positive if Red

• Negative if Yellow

Methyl Red Test

• Positive if Red

• Negative if color is unchanged

Voges Proskauer Test

 

Positive if turn pink

Urea Agar

 

Positive If Bubbles and white products are formed

Catalase

 

Positive if Square turns Blue

Oxidase