Co-transduction by a Staphylococcal Phage of the Genes Responsible for Penicillinase Synthesis and Resistance to Mercury Salts

Abstract

STRAINS of Staphylococcus aureus endemic in hospitals are usually resistant to several antibiotics, including penicillin, and to mercury salts¹. A recent survey² showed a correlation between multiple resistance to antibiotics and the ability to produce large amounts of penicillinase under appropriate conditions. The highest correlation, however, was between high penicillinase activity and mercury resistance. It has been known for some time that penicillinase-producing strains of S. aureus readily revert to the penicillin-sensitive state³. Novick⁴ has shown that this process can occur as frequently as once every 10³ generations, and that the step involves loss both of the gene responsible for synthesis of the penicillinase molecule itself and the genes conferring inducible properties on penicillinase synthesis.