VMC 311: Systematic Veterinary Bacteriology and Mycology (2+1)

STAINING AND CULTURAL CHARACTERS

Staining

• A small amount of pus is placed in a Petridish and washed to expose the small 1 to 3 mm sulfur granules associated with the disease.
• The actinomycotic granules are larger than the grey-white granules seen in actinobacillosis.
• A granule is transferred to a slide, and a drop of 10% sodium hydroxide is added.
• A coverslip is placed on the granule, and it is crushed by gentle pressure.
• In actinomycosis the characteristic “ray fungi” with club-shaped margins can be seen under low power microscopy.
• The coverslip is removed and the material spread to make a smear. This is dried, fixed, and stained by the Gram method.
• If the granules are from an actinomycotic lesion, delicate, intertwined, branching, Gram-positive filaments are seen.
• Gram-stained smears from growth on solid or fluid media reveal masses of Gram-positive rods and slightly branched filaments.

Cultural characters

• A.bovis grows well on ordinary laboratory media at 37°C, under anaerobic conditions.
• The colonies which appear in about 5 to 7 days are white, rough, raised and firmly embedded into the medium.
• The branching mycelium breaks into arthrospores, which give an appearance of pleomorphic rods.
• Small cottony colonies may be seen suspended discretely in thioglycolate broth.

Bio chemical properties of Actinomyces bovis

Motility	-
Catalase	-
Nitrate	-
Gelatinase	-
CAMP	-
Lactose	-
Sucrose	+
Mannitol	-

Laboratory Indications of Actinomyces bovis

Indole	-
Catalase	-
Lipase	-
DNAse	-