(AB) Selective Strep Agar, 500 grams

Selective Streptococcus Agar was devised by Roantree et al. for the isolation of group A beta-hemolytic streptococci. Other workers improved the medium by the addition of yeast nucleic acid and maltose which promoted increased colony size and enhanced clarity and sharpness of hemolytic zones produced by Group A streptococci. Selective Streptococcus Agar is used for isolation and detection of pathogenic streptococci, especially Group A streptococci. (Alpha Biosciences # S19-106-500gm)

Use: Selective Streptococcus Agar is used for isolation and detection of pathogenic streptococci, especially Group A streptococci.

Description: Selective Streptococcus Agar was devised by Roantree et al. for the isolation of group A beta-hemolytic streptococci. Other workers improved the medium by the addition of yeast nucleic acid and maltose which promoted increased colony size and enhanced clarity and sharpness of hemolytic zones produced by Group A streptococci.

Formula* per Liter:

• Casein Digest Peptone ................ 15.0g
• Beef Extract ................................... 6.7g
• Nucleic Acid ..................................... 6.0g
• Sodium Chloride ........................... 5.0g
• Maltose ........................................... 0.25g
• Polymyxin B Sulfate .................. 0.024g
• Neomycin Sulfate ........................ 0.002g
• Agar ...............................................15.0g

Final pH: 7.3 ± 0.2 at 25.0°C

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

Preparation: Mix 43 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. The medium may be used with or without blood. 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.

Organism                                                        Result                          Hemolysis

Escherichia coli ATCC 25922                         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.