Actinomyces

A genus of non-acid-fast, gram-positive organisms that form a mycelium of branching filaments that fragment into irregular-sized fragments.

• A. bovis — the cause of actinomycosis of cattle and sheep.
• A. congolensis, A. dermatonomus — see dermatophilus congolensis.
• A. hordeovulneris — a cause of abscesses, pleuritis and systemic infections in dogs where it is often associated with penetration by grass awns (foxtails) of Hordeum spp.
• A. israelii — an uncommon cause of actinomycosis in cattle and pigs.
• A. necrophorus — see fusobacterium necrophorum.
• A. pyogenes — now called Arcanobacterium pyogenes.
• A. suis — the cause of actinomycosis of the swine mammary gland.
• A. viscosus — the cause of periodontal disease in hamsters, and opportunistic infections of dogs.