The Acquired Resistance of Staphylococcus aureus to Bacteriophage

Abstract

Twenty phages and their propagating strains of S. aureus were grown on solid and fluid medium and any secondary growth was examined for phage sensitivity, for acquired lysogenicity, and for cross resistance to other phages. Wide differences in the capacity to acquire resistance were observed. All but one of the resistant staphylococci acquire lysogenicity for the parent strain, and all but one are capable of absorbing the phage to which they had become resistant. Lysates of a staphylococcus which showed sensitive secondary growth in zones of lysis cause non-specific inhibition of phage lysis on agar medium. The results are discussed with reference to phage typing and therapy.