Abstract
Seven strains antagonistic to indicator coryne-bacteria on solid media were found among 100 Staphylococcus aureus strains of human origin. These inhibitory strains all gave sharply defined inhibition zones, belonged to bacteriophage type-71 and were isolated from superficial infections. They were strongly active in direct antagonism tests against all the other "aureus" strains, and against some coagulase-negative staphylococci, streptococci and other gram-positive species; gram-negative organisms were not susceptible. S. aureus strains producing hazy inhibition zones with corynebacteria showed similar though less extensive antibacterial activity. Inhibition by both kinds of staphylococci occurred under several different environmental conditions but not in the presence of oleic-acid. The antagonistic agents were relatively heat resistant, passed readily through cellophan and showed considerable specificity in their action.