In 1926 Wilson and Blair used Bismuth and Sodium Sulfite in a culture formulation for the isolation of typhoid-paratyphoid groups of bacteria bacteria. Further modifications of the formula were described by Hajna and Damon. The current recommended formulation is found in the USP. Bismuth and brilliant green dye acts as inhibitors to most enteric bacteria and Gram positive bacteria. Salmonella typhi produces black colonies surrounded by a metallic sheen. Other Salmonella produce green or black colonies. Some Shigella sp. may grow on this medium. Highly selective agar medium for the isolation of Salmonella, particularly Salmonella typhi from clinical and environmental specimens. (Alpha Biosciences # B02-108-500gm)
Use: Highly selective agar medium for the isolation of Salmonella, particularly Salmonella typhi from clinical and environmental specimens.
Description: In 1926 Wilson and Blair used Bismuth and Sodium Sulfite in a culture formulation for the isolation of typhoid-paratyphoid groups of bacteria bacteria. Further modifications of the formula were described by Hajna and Damon. The current recommended formulation is found in the USP. Bismuth and brilliant green dye acts as inhibitors to most enteric bacteria and Gram positive bacteria. Salmonella typhi produces black colonies surrounded by a metallic sheen. Other Salmonella produce green or black colonies. Some Shigella sp. may grow on this medium.
Formula* per Liter:
- Casein Digest Peptone .........….……... 5.0g
- Glucose .........................…..……........ 5.0g
- Peptic Digest of Animal Tissue ….…... 5.0g
- Beef Extract ...............……................. 5.0g
- Disodium Phosphate ..............……...... 4.0g
- Ferrous Sulfate ..........….…................ 0.3g
- Bismuth Sulfite Indicator ........……...... 8.0g
- Brilliant Green ............……............. 0.025g
- Agar .......................................……..... 20.0g
Final pH: 7.5 ± 0.2 at 25.0°C
* Grams per liter may be adj. or formula supplemented to obtain desired performance
Preparation: Mix 52.0 grams of the medium in one Liter of purified water until evenly dispersed. Heat with repeated stirring and boil for one minute to dissolve completely. Distribute and autoclave at 121.0°C for 15 minutes.
Quality Control Specifications:
- The powder is homogeneous, free flowing and light beige.
- Visually the prepared medium is greenish-yellow and opaque.
- Expected cultural response after 40-48 hours at 35.0°C.
Organism                                              Growth                        Colony Color
Escherichia coli ATCC 25922          Partial Inhibition                 Brown to Green
Enterococcus faecalis ATCC 29212     Inhibited                                  -
Salmonella typhi ATCC 19430              Good                Black with metallic sheen
Salmonella typhimurium ATCC 14028  Good                     Black-Greenish/Grey
Shigella flexneri ATCC 12022        Partial Inhibition              Greenish-Brown
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.
Â
