This experiment is from the official website of the Fourth Military Medical University

Operation method

Bacterial indole test

Materials and Instruments

Escherichia coli Enterobacter aerogenes Proteus vulgaris Bacillus subtilis
NaOH solution Creatine Methyl red reagent Indole reagent Ether Bromomethylphenol violet indicator
Ultra-clean bench Constant temperature incubator Autoclave Test tubes Pipettes Duchenne cannulae Glucose peptone water medium Peptone water medium Sugar fermentation medium

Move

1. Test tube marking

Take a test tube containing peptone water culture solution and mark it according to the bacteria to be cultured.

2. Inoculation culture

Aseptically inoculate a small amount of bacterial moss into the above corresponding test tubes, the fifth tube as a blank control is not inoculated, placed in a 37 ℃ thermostat incubator culture 24 ~ 48h.

3. Observation record

Add 5-10 drops of indole reagent into the culture solution, make the reagent float on the surface of the culture, form two layers, observe the results: if there is indole, the ether layer shows rose red, this is a positive reaction of indole test, otherwise it is a negative reaction, the positive is indicated by "＋", the negative is indicated by " -". Positive reaction is indicated by "+" and negative reaction by " - ".

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