Remel™ Ehrlich's Indole Reagent

Detect indole production by nonfermenters and anaerobes grown in indole broth with Thermo Scientific™ Remel™ Ehrlich's Indole Reagent.Ehrlich's reagent contains p-dimethylaminobenzaldehyde that acts as an indicator to identify indoles. The use of ρ-dimethylaminobenzaldehyde in the indole test was first reported by Vracko and Sherris1. Ehrlich's Indole Reagent is recommended for detecting indole production by nonfermenting gram negative bacilli and for anaerobes2-4.

Use Ehrlich’s Indole Reagent to detect indole production by nonfermenters and anaerobes grown in indole broth.Ready to use: liquid reagent.Easy to interpret:Positive test: pink-red ring between broth and solvent within 15 minutes.Negative test: no color development in the form of a ring within 15 minutes.Tryptophanases are intracellular enzymes that mediate indole production by hydrolysing the amino acid tryptophan. Indole combines with dimethyl-aminobenzaldehyde to form a red compound. This is a condensation product formed by an acid splitting of a protein. When Ehrlich’s reagent is used, small amounts of indole are produced from the breakdown of tryptophan by tryptophanase. These must be extracted first with xylene or a xylene substitute before they are detectable5Ehrlich's Indole Reagent contains ρ-dimethylaminobenzaldehyde (CAS 100-10-7), hydrochloric acid (Concentrated) (CAS 7647-01-0) and 95% ethyl alcohol (CAS 64-17-5). Ehrlich’s Indole Reagent is not specific for indole. When a solvent like xylene is used to extract indole, the red color that develops in the solvent layer occurs only with indole and skatole6. Use of inadequate peptone broth or glucose-containing medium may cause aberrant results6. Not all products are available for sale in all territories. Please inquire.Remel™ and Oxoid™ products are now part of the Thermo Scientific brand.