Effect of the transfer of the R plasmids of resistant Salmonella typhimurium strains of different origins on the phage sensitivity of Salmonella typhimurium

It has been shown that after the transfer of R-plasmids from S. typhimurium strains of different origin to S typhimurium strains sensitive to antibiotics these latter strains, as a rule, cannot be typed according to the scheme of Felix and Kellow These strains retain sensitivity to phages from I. G. Chiarkadze's collection, but the spectrum of their phage sensitivity is narrower. In one case the recipient was noted to change its phagovar to that of the donor. S. typhimurium donor strains, differing in the degree of their influence on the virulence of recipients, do not differ in their capacity for changing their sensitivity to the phages from the international collection of Felix and Kellow and from I. G. Chirakadze's collection.