SIM agar (Sulfite-IndoleMotility agar)
For in vitro diagnostic use.
KM0159 SIM Medium is a multi-purpose medium for the differentiation of Enterobacteriaceae.
This is best described as a multi-purpose medium for the differentiation of Enterobacteriaceae that combines three individual tests into a single medium (hydrogen sulphide production, indole formation and motility).
The presence of motility is apparent by the organism tracking out from the line of inoculation and often turning the medium turbid. Non-motile organisms generally grow within the stab line leaving the surrounding medium clear.
H₂S positive organisms turn the medium black due to the formation of hydrogen sulphide in the presence of the sodium thiosulfate and ferric ammonium citrate often making it difficult to determine the other parameters.
Indole production is tested for by layering a small amount of Indole Reagent (Kovac’s) onto the surface of the medium. A positive result is indicated by the formation of a pink colour at the interface of the reagent and the medium. The enzymatic digest of casein and enzymatic digest of animal tissue provide the required carbon, nitrogen, and vitamins in this medium. Ferric ammonium citrate and sodium thiosulfate are used to detect hydrogen sulphide production. The low concentration of agar allows for a semisolid media which is used for motility detection