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December 1, 1945


JAMA. 1945;129(14):953-954. doi:10.1001/jama.1945.02860480033010

In a study of the bacterial flora of contaminated wounds, Johnson and his associates1 of the departments of surgery and biochemistry, Columbia University College of Physicians and Surgeons, found that pathogenic micro-organisms appeared at times on blood agar plates following direct plating of the injured tissues; these were not demonstrable in broth cultures made at the same time from the same material. This occurred most frequently when the broth cultures contained nonpathogenic contaminants of the Bacillus subtilis group. Many of these contaminants had an inhibiting action on subsequent platings with gram positive cocci, one strain being of particularly high antibiotic titer. The active principle of a cell free filtrate from this strain has been named "bacitracin" by the Columbia University investigators.

"Bacitracin" is formed by surface growth of this strain on a variety of liquid mediums but not in submerged growths, the maximum titer being reached after three to