C.E.M.O. Agar Base

(Contagious Equine Metritis Organism)

LAB 78

Description

This medium is a selective isolation medium for Taylorella equigenitalis the causative organism of contagious equine metritis. The medium is a sugar free base with a mixture of high grade casein and soy peptones as nutrients and with L-cystine and sodium sulphite as supplements and reducing agents. The medium is made selective with the addition of amphotericin (5 mg/L) and trimethoprim (10 mg/L). Streptomycin (200 mg/L) can also be used but sensitive variants of T. equigenitalis have been described.

1.10

Method for reconstitution

Weigh 37.5 grams of powder, disperse in 1 litre of deionised water. Allow to soak for 10 minutes, swirl to mix then sterilise by autoclaving at 121˚C for 15 minutes. Allow to cool to 80˚C, add 50ml of sterile horse blood and allow to ‘chocolate'. Further cool to 47˚C before adding antibiotic selective agents. Mix well and pour into Petri dishes.

Appearance: Chocolated Blood Agar.

pH: 7.3 ± 0.2

Minimum Q.C. organisms: T. equigenitalis

E. coli (inhibition) NCIMB 50034

Storage of Prepared Medium: Plates - up to 7 days at 2-8˚C in the dark.

Inoculation: Surface, streaking out for single colonies.

Incubation: 37˚C in 10% CO₂ for 2-3 days.

Growth Characteristics

colony size    shape &
organism        (mm)       surface       colour         other

T. equigenitalis   0.1-1.0       CV.E.G.

References

United States Pharmacopoeia XXI. 1985.

Brown V.I., Lowbury E.J.L. (1965). Use of an improved Cetrimide Agar Medium and other culture methods for Pseudomonas aeruginosa. J. Clin. Pathol. 18, 752-756.