IMViC Reactions Flashcards
What are IMViC reactions?
Biochemical tests.
What type of metabolic activity is happening in IMViC reactions?
Fermentation
What does IMViC stand for?
Represents the order of the four tests…
Indole, Methyl red, Voges-Proskauer, and Citrate.
What are IMViC tests designed to determine?
Specific physiological properties of microorganisms.
What types of bacteria are these tests useful for?
Coilform such as E. Coli and Enterobacter-Klebsiella groups as well as Enterobacteriaceae. Any gram (-) bacterium.
What is indole?
A breakdown product of the amino acid tryptophan.
What group of bacteria typically have a positive indole test?
Typical strains of E. Coli. Enterobacter-Klebsiella does not.
What bacteria was used for the indole test?
E. Coli and Enterobacter aerogenes.
What is the incubation requirements for the indole test?
35 degrees C for 24hrs.
What media and inculcating process was used for the indole test?
SIM was used and a single stab was administered.
What reagent was used in the indole test?
Kovac’s indole reagent was used.
Describe a positive indole test.
After the reagent is added the amyl alcohol of the reagent will separate and turn a BRIGHT RED color if indole is present.
Describe a negative indole test.
There will be no color change.
What media is used in the methyl red test?
MR-VP broth.
What does MR-VP broth contain?
Peptone, glucose, and a phosphate buffer.
What does the methyl red test depend on?
Depends on the ability if the organism to produce acid from glucose.
What are the incubation requirement for the methyl red test?
Incubate at 35 degree C for 5days.
What reagent is added the the media after 5days of incubation in the methyl red test?
Methyl red
Describe a positive test for Methyl Red.
There will be a red color that indicates acid below a pH of 4.4.
Describe a negative test for methyl red.
A yellow color.
What is the citrate test designed to determine?
Whether or not a bacterium has a cell membrane transport protein to carry citrate to the cell. If protein is present it grows, if not it doesn’t grow.
What type of bacteria typically utilizes the citrate?
Enterobacter-Kelbsiella
What media and process was used in this lab?
Simmons citrate agar (green) and we used the stab and streak method.
What are the intermediates of the IMViC tests?
Organisms not typical with E. Coli (++–) or E. Aerogenes (–++) are considered intermediates.
Describe a positive citrate test (organism was able to transport citrate in the cell and grow)
Growth on the slant and change in color from green to a deep blue.
Describe a negative citrate test (organism unable to transport citrate into the cell)
No growth, and green color.
What type of bacteria typically does NOT utilize citrate?
E. Coli.
