Actinomyces is a genus of bacteria. The bacteria that grouped in this genus share several characteristics. The bacteria are rod-like in shape. Under the light microscope, Actinomyces appear fungus-like. They are thin and joined together to form branching networks. Bacteria of this genus retain the primary stain in the Gram stain reaction, and so are classified as being Gram positive. Actinomycetes are not able to form the dormant form known as a spore. Finally, the bacteria are able to grow in the absence of oxygen.

Members of the genus Actinomyces are normal residents of the mouth, throat, and intestinal tract. But they are capable of causing infections both in humans and in cattle if they are able to enter other regions. This can occur as the result of an...