Asculine is a glycoside and it is incorporated with a nutrient base a ferric salt. Aesculin hydrolysis means the breakdown of aesculin. This hydrolysis is indicated by a BROWN coloration.
It occurs due to the reaction of aglycone (6.7 Dihydroxycoumarin) with iron. Sometimes another chemical (SODIUM AZIDE) is added. It acts as a preservative.
The Aesculin hydrolysis test is used to identify the enterococci, anaerobic cocci, streptococci, and others.
Aesculin hydrolysis test principle
Some organism hydrolyse aesculine. It results in the formation of a substance called AGLYCONE. It reacts with iron and forms a compound that is BROWN to BLACK in color.
Aesculin hydrolysis test procedure
Following are the steps in the aesculin test procedure.
- First, inoculate the aesculin broth or agar.
- Incubate that agar at 37 C temperature.
- Examine daily for up to 5 days.
- If you notice blackening, the result is positive.
Aesculin hydrolysis test positive bacteria / negative bacteria list
Aesculin hydrolysis Positive bacteria list
- Enterococci
- Anaerobic cocci
- Streptococcus porcinous
- S. uberis
- S.Suis
- S.Sanguis
- S.Bovis
- S.Eequinus
- S.Mutans
- S.Salivarius
- Listeria
A. hydrolysis Negative bacteria list
All other streptococci
How to prepare aesculin hydrolysis agar?
Dissolve the masculine and iron salt in the peptone water and sterilize it at 115 C for 10 minutes.
How to prepare Aesculin cooked meat broth
Aesculin cooked meat broth accordingly, 1% aesculin is added before autoclave. Then 0.5% ml of an aqueous solution of ferric ammonium citrate solution is added.
Which bacterias show aesculin hydrolysis test positive?
The following bacterias show aesculin hydrolysis test positive.
Enterococci
Anaerobic cocci
Streptococcus porcinous
S. uberis
S.Suis
Enterococci
Anaerobic cocci
Streptococcus porcinous
S. uberis
S.Suis