• The streptonycetes are a large group of filamentous, gram positive bacteria that form spores at the end of aerial filaments. • They have the highest GC percentagein the DNA base composition of any bacteria known. • Many clinically important antibiotics have come from Streptomycetes species Concept:• The streptonycetes are a large group of filamentous, gram positive bacteria that form spores at the end of aerial filaments. • They have the highest GC percentagein the DNA base composition of any bacteria known. • Many clinically important antibiotics have come from Streptomycetes species Concept: