- A family of nonsporeforming, nonmotile, ordinarily facultatively anaerobic (some species are aerobic and others are anaerobic) bacteria (order Actinomycetales) containing Gram-positive, nonacidfast, predominantly diphtheroid cells which tend to form branched filaments in tissue or in some stages of cultural development; the filaments readily fragment, producing diphtheroid or coccoid forms. The metabolism of these chemoheterotrophic bacteria is fermentative. This family contains the genera Actinomyces (type genus), Arachnia, Bacterionema, Bifidobacterium, and Rothia.
* * *Ac·ti·no·my·ce·ta·ce·ae -.mī-sə-'tā-sē-.ē n pl a family of filamentous or rod-shaped bacteria of the order Actinomycetales that are often branched, sometimes produce conidia, and sometimes form a mycelium that readily breaks up into bacillary elements
* * *Ac·ti·no·my·ce·ta·ceae (ak″tĭ-no-mi″sə-taґse-e) a family of bacteria of the suborder Actinomycineae, order Actinomycetales, consisting of gram-positive, nonsporulating, irregularly shaped rods that tend to form branched filaments. It contains the genera Actinobaculum, Actinomyces, Arcanobacterium, and Mobiluncus.
Medical dictionary. 2011.