Actinobacteria (Actinomycetes; Actinomycota) A phylum of Gram-positive mostly anaerobic nonmotile bacteria. Many species are fungus-like, with filamentous cells producing reproductive spores on aerial branches similar to the spores of certain moulds. The phylum includes bacteria of the genera Actinomyces, some species of which cause disease in animals (including humans); and Streptomyces, which are a source of many important antibiotics (including streptomycin).

Actinomycetes See Actinobacteria.