Question

In the IMViC test series, what result combination is unlikely and why?

Answer 1

There are four test performed in IMVic

1)Indole test

2) Methyl Red Test

3) Vogus Proskauer Test

4)Citrate Utilization Test

These test are performed to analyse the presence of bacteria family enterobacteriaceae & their ability to metabolize different compounds

• In Methyl red test , we can differentiate E.coli & Enterobacter aerogenes

Ecoli utilise glucose & produce mixed acid in phosphate broth buffer & brings the PH = 4 showing postive test while E. aerogenes produce acid in phosphate broth buffer bringd the PH=6 showing negative test

• In Vogus Proskauer Test , we can differentiate E.coli & Enterobacter aerogenes & Klebsiellla

E. aerogenes & KLebsiella will metabolise acetoin following butylene glycol pathway which can be indicated by Barrittes reagent giving rose red colour due to formation of compound Diacetyl showing positive test while E.coli is unable to form diacetyl & shows no colour giving negative test.