[Hospital strains of Salmonella serotype typhimurium with particular biological properties].

93 cultures of Salmonella typhimurium (STm) were isolated from the infants (under one year old) admitted into a pediatrics ward. All the cultures had only flagellation antigens in phase I, a common sensitivity spectrum to antibiotics and the same sensitivity to the sets of bacteriophages for typing of this serotype. Of these, 10 strains were negative H2S and 6 immobile. Using as carrier a strain of E. coli, K12Nxr, an experimental transfer of multiple resistance to the antibiotics obtained from strains of Salmonella, agona serotype (with special resistance markers) to STm strains was made. The transfer was equally possible to monophasic and diphasic strains of STm. In the transfer to the diphasic strains, the modification of the phage type was noticed. The results suggest the possibility of the in vivo transfer of R plasmids from the agona serum to the typhimurium serum of Salmonella.