n.
Any of a group of generally low-oxygenutilizing bacteria identified by a branching growth pattern that results in large threadlike structures.
The filaments may break apart to form rods or spheroidal shapes. Some actinomycetes can form spores. Many species occur in soil and are harmless to animals and higher plants; others are important disease-causing agents. For diagnostic purposes in human infections, the presence of sulfur granules is used.