Why you use creatine in VP test?

Creatine is used in the VP (Voges-Proskauer) test to help detect the presence of acetoin, a product of fermentation by certain bacteria. In this test, the addition of reagents (alpha-naphthol and potassium hydroxide) reacts with acetoin to produce a red color, indicating a positive result. Creatine serves as a substrate that can enhance the metabolic activity of the tested microorganisms, potentially increasing the sensitivity and accuracy of the test.