Lysogenic conversion of O antigens in Salmonella group C1

Abstract

Lysogenic conversion among certain serotypes in Salmonella O group C1 reveals that all 62,7 strains of S. choleraesuis var. kunzendorf, except for a unique strain of the same biotype, can be converted to 61,7 by phages released spontaneously from 61,7 strains of S. choleraesuis and S. choleraesuis var. kunzendorf but absent in 62,7 variants of the same species. An exceptional strain of S. montevideo (61,7) is lysogenic for a phage which converts all 62,7 strains of S. choleraesuis var. kunzendorf to 61,7. The 62,7 strain of S. choleraesuis var. kunzendorf, which is resistant to conversion only by phages released from 61,7 strains of the same biotype, is in turn lysogenic for a "blocking phage" which lysogenizes all other 62,7 strains, converting them so that they are no longer susceptible to the phages from 617 strain of S. choleraesuis and S. choleraesuis var. kunzendorf; however, they are still susceptible to conversion by the 61,7-Montevideo phage. Many strains from other Salmonella C1-group serotypes are also lysogenic, and their temperate phages lysogenize susceptible strains which are within the same group, but no converting properties could be determined. An attempt was made to differentiate these phages according to various criteria.