Bismuth Sulfite Agar (Powder)
Selective medium for isolation of Salmonella.
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.
Appearance
Greenish beige, homogeneous, free flowing powder
Solubility
Greenish-yellow, opaque
Microbiological Analysis
Escherichia coli (ATCC 25922): Poor to excellent growth. Green to brown colonies with sheen
Enterococcus faecalis (ATCC 29212): No growth
Salmonella typhi (ATCC 19430): Good to excellent growth. Olive black to blank w/ or w/o metallic sheen
Salmonella typhimurium (ATCC 14028): Good to excellent growth. Olive black to blank w/ or w/o metallic sheen
Directions per Liter
Dissolve 52g in 800-900ml of ddH2O stirring gently until completely solubilized. Adjust pH of the medium to 0.1-0.3 pH unit below the desired level. Add additional water to bring the solution to1L Filter-sterilize using a 0.22 micron membrane filter. Aliquot into sterile containers. Do not autoclave. Contains heat-labile compounds that can be damaged with autoclaving.
Storage and Stability
Store powdered media at RT. Stable for 12 months after receipt. Opened bottles should be capped tightly and kept in a dark, low humidity environment. Prepared media should be kept at 4°C and used within a short period of time.
| Components shown as | g/liter |
| Casein Digest Peptone | 5.0 |
| Peptic Digest of Animal | 5.0 |
| Beef Extract | 5.0 |
| Dextrose | 5.0 |
| Disodium Phosphate | 4.0 |
| Ferrous Sulfate | 0.3 |
| Bismuth Sulfite Indicator | 8.0 |
| Brilliant Green | 0.025 |
| Agar | 20.0 |
