[Influence of hemolytic plasmids on the development of the "killing" effect in various species of enterobacteria].

Experiments on isogenic strains of different enterobacterial species, both carrying hemolytic plasmids and free from them, have demonstrated that their "killing" effect on mice is linked with the yield of hemolysin and does not depend on the origin of Hly plasmids or the chemotype of bacteria. Plasmid p IE 567 coding the synthesis of alpha-hemolysin has been shown to be capable of expression in Enterobacter aerogenes, Hafnia alvei and Salmonella typhimurium strains, but E. aerogenes 3/43, H. alvei alpha 773 and Escherichia coli J53 carrying p IE 567, in contrast to E. coli P 678 and S. typhimurium 415 carrying the same plasmid, produce less alpha-hemolysin and have no pronounced effect in reducing the survival time of intranasally infected mice.