Media Mikro SIM Medium 500 gr, Oxoid CM0435

Description A motility-indole medium has been found to be helpful in the identification of the Enterobacteriaceae; e.g. in the differentiation of Klebsiella from Enterobacter and Serratia species1. For convenience, these two important tests have been combined with sulphide-production in one tube. The production of hydrogen sulphide is a useful diagnostic test in the identification of enteric bacteria and is helpful in the differentiation between Salmonella and Shigella. The sulphate-reducing bacteria will produce hydrogen sulphide and further chemical substitution results in ferrous sulphide being formed along the line of inoculation. The presence of fermentable sugars may suppress the enzyme mechanism which forms hydrogen sulphide, as a result of the acid products formed (Bulmash and Fulton2 ) and therefore sugars are not included in the medium. Oxoid SIM Medium can be used in conjunction with Triple Sugar Iron Agar CM0277 to assess the ability of the culture to ferment lactose, sucrose and glucose. The production of indole from tryptophan is one of the diagnostic tests used in identifying enteric bacteria. For example, unless it is an unusual form, a Salmonella culture never produces indole from tryptophan in amounts detectable in usual tests. Tryptone is incorporated into the medium since it is a tryptophan-rich peptone, and after incubation, indole can be identified by a red dye complex reaction with one of several reagents, e.g. Kovac’s Reagent which consists of amyl alcohol, para-dimethylaminobenzaldehyde and concentrated hydrochloric acid3.