Streptomyces griseus

Streptomyces griseus holds a unique place in medical history: it's the source of streptomycin, the first antibiotic effective against tuberculosis. Discovered by Albert Schatz in Selman Waksman's laboratory in 1943, streptomycin transformed TB from a death sentence into a treatable disease. This single discovery from soil bacteria eventually led to the Nobel Prize and established Streptomyces as the primary source of medically useful antibiotics.

The discovery process—systematically screening soil actinomycetes for antibacterial compounds—established a paradigm that dominated antibiotic discovery for decades. S. griseus demonstrated that soil bacteria produce potent antimicrobial compounds as ecological weapons against competitors. Mining this evolved chemical warfare for human medicine proved extraordinarily productive: most antibiotic classes were discovered from Streptomyces or related actinomycetes in the following decades.

S. griseus also pioneered understanding of Streptomyces developmental biology. The bacterium produces A-factor, a signaling molecule that triggers both antibiotic production and morphological differentiation. This link between secondary metabolism and development—chemical production tied to lifecycle transitions—appears throughout Streptomyces. Understanding A-factor regulation enabled manipulation of antibiotic production, demonstrating that secondary metabolism isn't random but precisely controlled. The ecological logic: produce antibiotics during sporulation to clear competitors from the space spores will colonize.