Indirect induction of a Staphylococcus aureus prophage by P11de a plasmid phage hybrid

The ability to mediate indirect induction of staphylococcal prophages was found to be a property of the cryptic high frequency transducing phage P11de but not of three other phages tested. P11de is the product of a recombination between a P11 phage and a gamma plasmid. Irradiated P11de preparations could not induce prophage development in strains which contained either a P11 prophage or a gamma plasmid. The establishment of P11de in a strain was not, however, inhibited by the presence of a P11 prophage. It is inferred that the inhibition of indirect induction exerted by the resident P11 prophage occurs at a stage other than the establishment of the P11de replicon.