What Is the Principle of the IMViC Test?

IMViC tests are actually four different tests that are used for identification and differentiation of enteric bacteria (of the family enterobacteriaceae). IMViC is an acronym that stands for the indole, methyl red, Voges-Proskauer, and citrate utilization tests.

The indole test is performed on a SIM medium or in tryptophan broth and a positive or negative result is obtained after adding Kovac's reagent. Methyl red and Voges-Proskauer tests are both done in a MR-VP broth. A positive or negative result is obtained after adding a methyl red reagent for the methyl red test, or after adding Barritt's A and Barritt's B reagents for the Voges-Proskauer test. Citrate utilization is performed on Simmon's citrate agar and tests positive or negative by bacterial growth and color.

The enterobacteria can be identified by the combination of positive and negative results in the IMViC tests.