YERSINIA SELECTIVE AGAR BASE ISO 10273
CAT Nº: 1126
Selective medium for Yersinia enterocolitica used with supplement
FORMULA IN g/l
D-Mannitol
20.00
Sodium Desoxycholate
0.5
Enzymatic Digest of Gelatin
17.00
Neutral Red
0.03
Enzymatic Digest of Casein
and Animal Tissues
3.0
Magnesium Sulfate Anhydrous
0.01
Yeast Extract
2.0
Crystal Violet
0.001
Sodium Pyruvate
2.0
Bacteriological Agar
12.50
Sodium Chloride
1.0
Final pH 7.4 ± 0.2 at 25ºC
Yersinia enterocolitica
ATCC 27729
PREPARATION
Suspend 29 grams of the medium in 500 ml of distilled water. Mix well and dissolve by heating with frequent agitation.
Boil for one minute until complete dissolution. Sterilize in autoclave at 121ºC for 15 minutes. Cool to 45-50ºC and
aseptically add one vial of Yersinia selective supplement (Cat. 6033), previously reconstituted in 5 ml of sterile distilled
water. Homogenize gently and dispense into Petri dishes. The prepared medium should be stored at 8-15°C. The color is
purple-red.
The dehydrated medium should be homogeneous, free-flowing and beige in color. If there are any physical changes,
discard the medium.
Yersinia Selective Supplement (CIN) Cat. 6033
(Composition: each vial for 500 ml)
Cefsulodin…………………………………..….7.5 mg
Irgasan………………………………….……...2.0 mg
Novobiocine…………………..…………….1.25 mg
USES
Yersinia Selective Agar Base (SO 10273 is a selective and differential medium when used with supplement. The formula
is based on CIN (Cefsulodin-Irgasan-Novobiocine) Agar of Schiemann, and is recommended by ISO 10273 for the
isolation of Yersinia enterocolitica from a variety of clinical samples and food.
The accompanying flora are inhibited by the addition of antibiotics to the supplement. Yersinia growth is promoted by
pyruvate as well as by the high nutrients content in the base. Yersinia degrades the mannitol in the medium to an acid;
the colonies turning a red color due to the neutral red indicator.
D-Mannitol is the fermentable carbohydrate. Mannitol fermentation in the presence of neutral red produces a
characteristic “bull’s-eye” colony, colorless with a red center. Enzymatic digest of gelatin and Enzymatic digest of casein
and animal tissues provide nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of
vitamins, particularly of the B-group. Sodium pyruvate is added as a source of energy and as a protective substance in
order to overcome oxygen toxicity biologically produced by the organisms. Selective inhibition of Gram-negative and
Gram-positive organisms is obtained through crystal violet, sodium desoxycholate and Irgasan (triclosan). Cefsulodin and
1
LABORATORIOS CONDA, S.A.
www.condalab.com
novobiocin improve the inhibition of normal enteric organisms. Sodium chloride supplies essential electrolytes for
transport and osmotic balance. Magnesium sulphate is a magnesium ion required in a large variation of enzymatic
reactions, including DNA replication. Neutral red is the pH indicator
ISO 10273 norm recommends the use of this medium for the detection of presumptive pathogenic Yersinia
enterocolitica, after incubation of the enrichment media PSB, at a temperature of 22ºC to 25 ºC for 48 to 72 hours or 5
days without agitation, and ITC medium at a temperature of 25 ºC for 48 hours. Inoculate and incubate at 30ºC for 2448 hours.
Typical colonies of Y. enterocolitica, will appear colorless, with dark red centers, like bull's eye, surrounded by a
transparent border.
MICROBIOLOGICAL TEST
The following results were obtained in the performance of the medium from type cultures, with Yersinia Selective
Supplement (Cat. 6033) added, after incubation at a temperature of 30ºC and observed after 24-48 hours
Growth
Microorganisms
Good
Yersinia enterocolitica ATCC 27729
Inhibited
Escherichia coli ATCC 25922
According ISO 11133 24h/30 ºC (Productivity)
Microorganisms
Yersinia enterocolitica ATCC 23715
Inoculum
(cfu/ml)
103-104
Productivity
Quanlitative
Good growth
Specificity
pink
BIBLIOGRAPHY
American Public Health Association: Compendium of Methods for the microbiological Examination of Foods.
Schiemann, D:A: Synthesis of a selective agar medium for Yersinia enterocolitica.- Canad.J.Microbiol,25 1298-1304
ISO 10273 Microbiology of food and
animal stuffs. Horizontal method for the detection of presumptive pathogenic Yersinia
enterocolitica
ISO
STORAGE
25ºC
Once opened keep powdered medium closed to avoid hydration.
2ºC
2
LABORATORIOS CONDA, S.A.
www.condalab.com