Phage-Host Relationships in Vibrio Cholerae

Only 3 of 246 isolates of typical Vibrio cholerae were found to be lysogenic. In contrast, prophages were detected in 23 of 27 El Tor vibrio strains. Virulent phage stocks possessed extremely wide host ranges, but temperate phages lysed only a few hosts. Although there was little variety in the lysis patterns of these phages, the differences were distinct enough to identify separate groups of V. cholerae and to indicate the feasibility of a phage typing scheme. Particularly promising was the distinct differentiation of El Tor strains from typical V , cholerae. Virulent (clear plaque) mutants obtained from temperate El Tor phages possessed altered host ranges. The new host ranges of the mutants resembled those of the virulent phages.