Selman Waksman, a microbiologist at Rutgers University specializing in the study of soil microorganisms, leads from the late 1930s onward a systematic search for antibacterial substances produced by bacteria of the genus Streptomyces, abundantly present in soil. Albert Schatz, a doctoral student under Waksman's supervision, isolates in 1943 a strain of Streptomyces griseus capable of producing a substance active against gram-negative bacteria — a type of bacteria against which penicillin, discovered fifteen years earlier, proves ineffective. The substance, named streptomycin, also proves effective against Mycobacterium tuberculosis, becoming the first antibiotic capable of treating tuberculosis, then one of the leading causes of death worldwide, responsible for large-scale sanatoriums and quarantines in numerous countries. The discovery also consolidates the systematic search for antibiotics in soils as a pharmaceutical research strategy, a method that would produce most of the known antibiotics over the following decades.