In vitro Studies of Aureomycin,a New Antibiotic Agent. ∗

Abstract

Summary

A new antibiotic, aureomycin, is effective in vitro against both gram positive and gram negative bacteria. Although its activity is of a lower order than that of penicillin for gram positive cocci or polymyxin for gram negative bacilli, it is effective against both classes of bacteria in concentrations close to those required of streptomycin. Inhibition at such concentrations, however, is fleeting in the case of aureomycin, much larger amounts being required for permanent suppression of growth. The new agent is bacteriostatic rather than bactericidal in its effect. Its antibacterial action is greatly diminished in the presence of serum, in vitro, and deterioration at room temperature is marked. Differences in the size of the inoculum have a moderate effect upon the minimal inhibitory concentration.