Properties of Brucella-phages lytic for non-smooth Brucella strains.

A series of host-range mutants has been selected for brucella-phage R. Two of these mutants designated R/O and R/C have been used for typing purposes. Phage R/O is lytic for non-smooth strains of Brucella abortus and for B. ovis. It is genetically unstable however and produces mutants lytic for smooth B. obortus and B. suis. Phage R/C is lytic for non-smooth B. abortus and for B. ovis and B. canis. It is much more stable than phages R or R/O and shows little or no lytic activity on smooth Brucella strains. It has been effective in differentiating B. canis from B. suis in tests on a limited number of strains. In their properties, all of the brucella-phages of the R series resemble their parent phage.