5.18 SIM medium Flashcards
What does the “S” in SIM medium stand for?
-sulfur
In SIM medium, what does a negative result for indole production look like?
-A yellow coloring after adding the Kovacs reagent.
In the SIM test, what is the reagent used to detect the presence of indole?
-Kovac’s reagent
The ferrous ammonium sulfate in the SIM medium functions to
-Produce a visible result when hydrogen sulfide is produced.
What is the name of the enzyme responsible for converting tryptophan into indole in SIM medium?
-Tryptophanase
What is the role of the “Indole” component in SIM medium?
-To detect the production of indole from tryptophan
SIM medium will assay for:
-all of the above
-(sulfur reduction, indole production, motility)
If the addition of Kovac’s reagent produces a floating red layer on a SIM medium culture, this indicates the organism is:
-Positive for tryptophanase.
What is the significance of motility in the SIM test?
-It assesses the ability of bacteria to move through a semisolid medium
What is the primary purpose of SIM medium in microbiology?
-To detect the production of hydrogen sulfide, indole, and assess motility
SIM medium tests for the ?? family
-Enterobacteriaceae
Kligler Iron Agar (KIA) tests for :
-glucose and lactose fermentation and sulfur reduction
-(gram negative organisms)
Sulfur reduction to H2S can be accomplished by bacteria in two different enzymes:
-cystine desulfurase
-thiosulfate reductase
The H2S produced combines with iron, in the form of ferrous
ammonium sulfate, to form ferric sulfide (FeS) producing a:
-black precipitate
-positive result
Positive result for indole production:
Negative result for indole production:
-red color
-no color
