MANNITOL TRYPTOPHAN LAURYL SULFATE BROTH
CAT Nº: 1267
For the differentiation of indol producers microorganisms
FORMULA IN g/l
Casein Peptone
20.00
Monopotassium Phosphate
2.75
Mannitol
5.00
Sodium Lauryl Sulfate
0.10
Sodium Chloride
5.00
L-Tryptophan
0.20
Dipotassium Phosphate
2.75
Final pH 6.8 ± 0.2 at 25ºC
PREPARATION
Suspend 35.8 grams of the medium in one liter of distilled water. Mix well and dissolve by heating with frequent
agitation. Boil for one minute until complete dissolution. Dispense a amount of 5 ml per tube with Durham gas collecting
tubes for gas detection. Sterilize in autoclave at 115°C for 10 minutes. The prepared medium should be stored at 2-8°C.
The color of the prepared medium is light amber.
The dehydrated medium should be homogeneous, free-flowing and cream in color. If there are any physical changes,
discard the medium.
USES
MANNITOL TRYPTOPHAN LAURYL SULFATE BROTH is used for the differentiation of microorganisms that produce indol.
Casein peptone provides nitrogen, vitamins, minerals and amino acids essential for growth. Mannitol is the fermentable
carbohydrate providing carbon and energy. Sodium chloride supplies essential electrolytes for transport and osmotic
balance. Potassium phosphates act as a buffer system. Sodium lauryl sulfate is an inhibitor of Gram-positive bacteria. LTryptophan is an essential amino acid and is converted to skatole and indole.
Inoculate and incubate at 37± 2°C for 24 hours. The test for indole should be conducted after incubation by adding a
few drops of Kovacs Reagent (Cat. 5205). Kovacs reagent detects the microorganism capable of cleaving the tryptophan.
When these microorganisms are present in the medium they liberate indole that reacts with 4dimethylaminobenzaldehyde to form a pink-to-red color in the reagent layer after a few minutes.
MICROBIOLOGICAL TEST
The following results were obtained from type cultures in the performance of the medium, after incubation at a
temperature of 37± 2°C and observed after 24 hours.
Growth
Gas
Indol
Escherichia coli ATCC 25922
Good
+
+
Citrobacter freundii ATCC 8090
Good
+
-
Enterococcus faecalis ATCC 11700
Good
-
-
Microorganisms
BIBLIOGRAPHY
Schubert,R. (1956). Die coliform Bacterian in der Wasserdiagnostik und ihre Differenzierrengen. Zeitschrift fur Hygiene und
Infektinskrankheiten 142, 476-486.
1
LABORATORIOS CONDA, S.A.
www.condalab.com
Pugsley, A. P., Evison, L. M. & James, A. (1973). A simple technique for the differentiationof Escherichia coli in water. Water Research
7, 1431-1437.
STORAGE
25ºC
Once opened keep powdered medium closed to avoid hydration.
2ºC
2
LABORATORIOS CONDA, S.A.
www.condalab.com