SIM, Indole, Sulfer reduction tests (week 6)

Which bacteria are especially differentiated using the SIM test?

• Escherichia coli and Bacillus

• Salmonella and Shigella

• Staphylococcus and Streptococcus

• Pseudomonas and Clostridium

What does the sulfur test in the SIM test detect?

• Reduction of sulfur to sulfur dioxide

• Reduction of sulfur to hydrogen sulfide gas

• Oxidation of sulfur to sulfuric acid

• Conversion of sulfur to sulfate ions

What compound in the media reacts with hydrogen sulfide gas in the sulfur test?

• Sodium chloride

• Ferrous ammonium sulfate

• Potassium nitrate

• Calcium carbonate

What is the visual indicator of a positive sulfur reduction in the SIM test?

• Media turns yellow

• Media turns black

• Media turns red

• Media turns blue

What enzyme do some organisms have that breaks down the amino acid tryptophan?

• Tryptophanase

• Amylase

• Lactase

• Protease

What are the products of the breakdown of tryptophan by tryptophanase?

• Indole and pyruvate

• Glucose and fructose

• Lactose and galactose

• Maltose and sucrose

What reagent is used to test for the presence of indole?

• Kovac’s Reagent

• Benedict’s Reagent

• Biuret Reagent

• Fehling’s Solution

What color indicates a positive indole test when using Kovac’s Reagent?

• Cherry red

• Blue

• Green

• Yellow

What does the motility test in the SIM test detect in bacteria?

• Presence of sulfur

• Ability to move through the environment

• Production of indole

• Resistance to antibiotics

What indicates a motile-positive result in the motility test?

• Growth only at the stab line

• No growth in the medium

• Growth radiating outward from the stab line and/or cloudy media

• Clear medium with no growth