MR VP test

stands for methyl red and voges proskauer test
same medium ,sort of clear or colourless broth before inoculation
test is used to differentiate between E coli and Enterobacter
if E coli is positive in one test, then it will be negative in the other

add methyl red reagent to MR
look for red colour which is positive which is E coli
add VP1 and VP2 to voges proskauer
red colour is positive which is Enterobacter

methyl red
looking for breakdown of glucose to acidic end products at ph4
non acidic end products at ph 6 is negative

voges proskauer
non acidic end products at ph 6 is positive
acidic end products at ph 4 is negative

easy way to remember
acid 4 ME
(acidic end products ph 4 MR E coli)