Actinomyces

A genus of slow-growing, nonmotile, nonsporeforming, anaerobic to facultatively anaerobic bacteria (family Actinomycetaceae) containing Gram-positive, irregularly staining filaments; diphtheroid cells may be predominant. They exhibit true branching while forming mycelial type colonies. Most of the species produce a filamentous microcolony. The metabolism of these chemoheterotrophs is fermentative; the products of glucose fermentation include acetic, formic, lactic, and succinic acid s but not propionic acid. A. may have characteristic sulfur granules in purulent drainage. These organisms are pathogenic for humans and other animals and can cause chronic suppurative infection in humans. Over 16 species have been described; type species is A. bovis. [actino- + G. mykes, fungus]

- A. bovis a species of bacteria causing actinomycosis in cattle; infection in humans is not established; it is the type species of its genus.

- A. israelii the most common species of a. causing human actinomycosis and, occasionally, infections in cattle.

- A. naeslundii a species whose natural habitat is the oral cavity; human infections occur and it produces periodontal destruction in some species of animals.

- A. odontolyticus a species whose normal habitat is the human oral cavity; it has been isolated from deep dental caries.

- A. viscosus a species that has been isolated from the oral cavity of humans and some species of other animals; it produces periodontal disease in animals and has been isolated from human dental calculus and root surface caries.

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ac·ti·no·my·ces .ak-tə-(.)nō-'mī-.sēz, ak-.tin-ō- n

1) cap a genus of filamentous or rod-shaped gram-positive bacteria of the family Actinomycetaceae that includes usu. commensal and sometimes pathogenic forms inhabiting mucosal surfaces esp. of the oral cavity compare ACTINOMYCOSIS

2) pl actinomyces a bacterium of the genus Actinomyces

ac·ti·no·my·ce·tal -.mī-'sēt-əl adj

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n.

a genus of Gram-positive nonmotile fungus-like bacteria that cause disease in animals and humans. The species A. israelii is the causative organism of human actinomycosis.

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Ac·ti·no·my·ces (ak″tĭ-no-miґsēz) [actino- + Gr. mykēs fungus] a genus of bacteria of the family Actinomycetaceae, consisting of gram-positive, irregularly staining, straight or slightly curved rods that form branched filaments; organisms are asporogenous, non–acid-fast, nonmotile, and chemo-organotrophic. The type species is A. boґvis.