IMViC Tests Flashcards
What are the IMViC tests?
A series of 4 tests to differentiate Enterobacteriaceae (Gram (-) rod)
What are the names of the four tests of the IMViC tests?
I= indole production test M= methyl red test V= voges proscaur test C= citrate utilization test
What is the purpose of the indole production test?
determine if an organism has the enzyme tryptophanase
What media is used in the indole production test?
tryptone broth
What is the inoculation and incubation guide for the indole production test? What do you do after incubation?
loopful, 37C for 48 Hours, add Kovac’s reagent and indole (yellow) rosindole= pink
What are the results of the indole production test?
+=pink - = yellow
What is the purpose of the MRVP test?
to determine if your organism ferments glucose into mixed acids (MR test) or a neutral product called acetoin (VP test)
What media is used for the MRVP tests?
glucose supplemented nutrient broth
What is the inoculation and incubation guide for the MRVP test?
loopful, 37C for 48 hours
What is the theory for the indole production test?
tryptophanase turns tryptophan into pyruvic acid, NH3 (ammonia) and indole
What is the theory of the MR test?
glucose is fermented to mixed acid
What do you do after incubation during the MR test?
add methyl red (pH indicator) Acidic: red, neutral/basic: yellow
What are the results of the MR test?
(+)- red (-) - yellow
What is the theory for the VP test?
glucose is fermented into a neutral product
What do you add after incubation for the VP test to detect acetoin?
alpha-naphthol and KOH (potassium hydroxide)
What are the results of the VP test?
(+)-red (-)- yellow or color of media
What is the purpose of the citrate utilization test?
to determine if your organism can use sodium-citrate as the only carbon source
What media is used for the citrate utilization test? What are the three parts of it?
simmons citrate agar slant -sodium citrate is the only carbon source -ammonium phosphate is the only nitrate source - Bromthymol Blue (pH indicator) -acidic: yellow - neutral: green -basic: blue
What is the inoculation guide for the citrate utilization test?
1 loopful streak on slant
What is the incubation period for the citrate utilization test?
37C for 48 hours
What is the theory for the citrate utilization test?
if the organism can use ammonium phosphate and NA citrate as only C and N course then ammonia is produced (NH3)
What are the results of the citrate utilization test?
(+) growth, blue (-) no growth, green
Which is positive for being able to use sodium-citrate as the only carbon source?
Blue
Which is postive for pyruvic acid, NH3, and indole?
The one with the pink line at the top
