(AB) Columbia Cna Agar 500G

Eliner et al. added colistin and nalidixic acid to Columbia Agar to suppress the growth of Gram negative bacteria. The addition of 5-10% sheep red blood cells to the base demonstrates hemolytic patterns of the staphylococci and streptococci. Selective Agar medium used for the isolation of Gram positive staphylococci and streptococci from clinical specimens. (Alpha Biosciences # C03-113-500gm)

Use: Selective Agar medium used for the isolation of Gram positive staphylococci and streptococci from clinical specimens.

Description: Eliner et al. added colistin and nalidixic acid to Columbia Agar to suppress the growth of Gram negative bacteria. The addition of 5-10% sheep red blood cells to the base demonstrates hemolytic patterns of the staphylococci and streptococci.

Formula* per Liter:

• Casein Digest Peptone .................. 5.0g
• Corn Starch ................................... 1.0g
• Peptic Digest of Animal Tissue ..... 8.0g
• Sodium Chloride ........................... 5.0g
• Yeast Enriched Peptone .............. 10.0g
• Colistin ....................................... 0.015g
• Nalidixic Acid.............................. 0.010g
• Agar ...............................................14.0g

Final pH: 7.3 ± 0.2 at 25.0°C

* Grams per liter may be adj. or formula supplemented to obtain desired performance

Preperation: Mix 44 grams of the medium in a Liter of purified water until evenly dispersed. Heat with repeated stirring and boil for one minute to dissolve completely. Distribute and autoclave at 121°C for 15 minutes. Prepare 5 to 10% blood agar by adding the appropriate volume of sterile defibrinated blood to melted sterile agar medium, cooled to 45-50°C. Dispense into Petri dishes or tubes

Quality Control Specifications:

1. The powder is homogeneous, free flowing and light beige.
2. Visually the prepared medium is opaque and cherry red.
3. Expected cultural response after 18-24 hours at 35.0°C under 5-10 CO2.

Organism                                                                 Result                        Hemolysis

Proteus mirabilis ATCC 12453                                Inhibited                              -

Staphylococcus aureus ATCC 25923                      Growth                            Beta

Streptococcus pneumonia ATCC 6305                    Growth                           Alpha

Streptococcus pyogenes ATCC 19615                    Growth                            Beta

Storage: Store the sealed bottle containing the dehydrated medium at 2 to 30.0°C. Once opened and recapped, place the container in a low humidity environment at the same storage temperature. Protect it from moisture and light. The dehydrated medium should be discarded if it is not free flowing or if the color has changed from the original light beige color.