[Role of phage in the transfer of plasmids in mixed cultures of Staphylococcus aureus (author's transl)].

Lysogenicity with phages of serogroup B is a prerequisite to the transfer of drug resistance plasmids in mixed cultures of Staphylococcus aureus. This is demonstrated by experiments with transfer of the plasmids pII 147, pC 221, pT 127, pE 2222 to strain 8325-4 which was lysogenized for different phages of different serogroups (Table 2). The transfer is also possible, when the donor strain or the recipient strain are lysogenic for the phage mutant phi 11, M 28, which is able to lyse strain 8325-4 but unable to form phage heads (Kretschmer and Egan, 1975). The fact that the induction of prophage phi 11 and steps of phage-propagation are necessary for the transfer, is evident from negative results obtained by use of the rec--mutant of strain 8325 (RN 981) as donor and by use of strain 8325-4 lysogenic for the phage mutant phi 11, A 4 as donor. The phage mutant phi 11, A 4 is defective at an early step of phage propagation. These experiments are shown in Tables 3 and 4. The possibility of transfer using donor or recipient strains which are lysogenic for a phage-mutant but unable to form phage heads clearly shows that the transfer is not based on transduction. Incubation of non lysogenic donor and recipient cells in the culture supernatant of strain 8325-4 (phi 11, M 28) or in the lysate of strain 8325-4 obtained after infection with phage phi 11, M 28 also allows the transfer of plasmids. Obviously one of the components of serogroup B phages is essential for the transfer.