Question

What confirmation test do you do to confirm your unknown sample is S. typhimurium?

Answer 1

The various tests performed, the unknown organism was determined to be S.
typhimurium. Two plates, EMB (eosin methylene blue), and standard nutrient agar, were
inoculated with samples of the organism, incubated, and observed. On the EMB plate, the
bacteria appeared to be off-white and slightly translucent. No indicative green metallic sheen was observed, so the organism was not a lactose fermenter. On the nutrient agar plate, the
organism also showed an off-white color. The individual colonies were circular with diameters ranging from 1-2 mm.
A nutrient broth was also inoculated and incubated, and samples were taken from
it in order to perform various tests. When a gram stain was performed, the organism was
revealed to be Gram-negative, in the form of red rods (bacilli) against a mostly colorless
background.