Questions and Answers
What is the acronym for IMViC?
Why is the IMViC test used?
Because it is a fast, inexpensive way to distinguish between most enteric bacteria.
What are the IMViC tests frequently used for?
To check for the possibility of fecal contamination of food or water supplies.
What bacteria is associated with fecal contamination?
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What bacteria is associated with soil?
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What is E. coli positive for in the IMViC tests?
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What is E. coli negative for in the IMViC tests?
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What is E. aerogenes positive for in the IMViC tests?
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What is E. aerogenes negative for in the IMViC tests?
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What color is a positive Indole test?
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What color is a negative Indole test?
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What color is a positive Methyl Red test?
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What color is a negative Methyl Red test?
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What color is a positive Voges-Proskauer test?
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What color is a negative Voges-Proskauer test?
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What color is a positive Citrate Utilization test?
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What color is a negative Citrate Utilization test?
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_____ is a component of the amino acid tryptophan.
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When tryptophan is broken down, the presence of indole can be detected through the use of _________.
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What color is Kovac's reagent?
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Kovac's reagent reacts with indole to produce a _____ color on the surface of the broth in the test tube.
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What family does the IMViC test distinguish between?
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What media is used for the Indole test?
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What media is used for the Methyl Red test?
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What media is used for the Voges-Proskauer test?
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What is the Methyl Red test used for?
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At what pH does Methyl Red change red?
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Organisms that lower the pH of the culture to 5 in a Methyl Red test are _____.
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Organisms that do not lower the pH of the culture to 5 in a Methyl Red test are _____.
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What does the Methyl Red test check for?
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What does the Voges-Proskauer test check for?
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What is acetoin?
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How is the VP test performed?
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What does a Citrate Utilization test check for?
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What media is used for the Citrate Utilization test?
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What does bromthymol blue mean in the Citrate test?
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What does green mean in the Citrate test?
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Study Notes
IMViC Tests Overview
- Acronym IMViC stands for Indole, Methyl Red, Voges-Proskauer, and Citrate Utilization.
- Used for distinguishing most enteric bacteria quickly and cost-effectively.
- Frequently checks for fecal contamination in food or water, indicating hygiene levels.
Key Bacteria
- Escherichia coli (E. coli): Commonly associated with fecal contamination.
- Enterobacter aerogenes: Typically found in soil environments.
Test Results for E. coli
- Positive results: Indole and Methyl Red.
- Negative results: Voges-Proskauer and Citrate Utilization.
Test Results for E. aerogenes
- Positive results: Voges-Proskauer and Citrate Utilization.
- Negative results: Indole and Methyl Red.
Color Indicators in IMViC Tests
-
Indole test:
- Positive: Red
- Negative: Yellow
-
Methyl Red test:
- Positive: Red
- Negative: Yellow
-
Voges-Proskauer test:
- Positive: Pink
- Negative: No color
-
Citrate Utilization test:
- Positive: Blue
Additional Information
- Indole is a component derived from tryptophan.
- Kovac's reagent is used to detect indole, producing a red color when reacting.
- Kovac's reagent itself is yellow.
Test Media
- Indole test: Tryptone broth is used.
- Methyl Red test: MRVP broth is utilized.
- Voges-Proskauer test: Also conducted in MRVP broth.
- Citrate Utilization test: Simmon's citrate agar is employed.
Methyl Red Test Specifics
- Detects if the pH lowers below 5, indicating glucose fermentation.
- Organisms that acidify the culture to a pH of 5 are considered positive, while those that do not are negative.
Voges-Proskauer Test Specifics
- Tests for the presence of acetoin, a neutral product from fermentation.
- Conducted by adding Barrit's reagent to the culture.
Citrate Utilization Test Mechanism
- Assesses the ability of organisms to use citrate as their carbon source.
- Bromthymol blue indicates increasing pH during the test.
- A green result indicates no change in pH.
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Description
This quiz focuses on the IMViC tests, which are crucial for distinguishing between enteric bacteria. Test your knowledge on the acronym, usage, and significance of these tests in public health and microbiology. Great for students studying microbiology or related fields!
