Mycobactocidin, a New Antibiotic Active against Mycobacteria.

Fregnan, G. B. (University of Wisconsin, Madison) and D. W. Smith. Mycobactocidin, a new antiboitic active against mycobacteria. J. Bacteriol. 83:1069-1076. 1962.-A new antibiotic, produced by a strain of Staphylococcus epidermidis, is described. The name mycobactocidin is proposed because of the specificity of the antibiotic against mycobacteria. Methods for extraction and purification of the antibiotic are described. The water-soluble fraction is shown to be active in vitro. No toxicity could be detected in mice after intraperitoneal or subcutaneous injection. Enzymatic hydrolysis suggests a glyco-protein nature for the antibiotic. Mycobactocidin is soluble in distilled water at neutrality but is generally insoluble in organic solvents. The antibiotic is precipitated from aqueous solution by heavy metals. It is stable in the pH range of 2 to 8, but is precipitated at pH 3 to 4. An aqueous solution of the antibiotic is stable for several days at 5 C, and for longer periods if lyophilized and stored at -20 C. It does not pass through a dialysis membrane and its activity is retained after 15 to 20 hr of dialysis at 5 C. The activity was shown to be unrelated to the formation of hydrogen peroxide.