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

pH (2.5%):
7.5± 0.2

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