A rapid method for phase recovery in Salmonella cultures.

Many methods have been proposed for the isolation of temporarily suppressed phases of diphasic Salmonella (Craigie, 1931; Gard, 1938; Hajna, 1944). These absorption methods are effective but require incubation for at least two days and considerable manual labor. Juenker (1946) suggested a procedure by which broth was inoculated with the organisms of the desired phase by passing them through a semisolid agar in a pipette, thus shortening the absorption period by 24 hours. Because this method requires considerable manipulation it has not been used, to our knowledge, in Army or Public Health Laboratories. Direct inoculation of broth for identification of a desired flagellar phase from primary isolation plates apparently has not been recorded in the literature. The advantage of this technic would seem to be limited by the possibility that absorption of the antigen without subsequent growth of the organism would leave such meager amount of the sought phase that no further serology would be possible. Direct absorption from broth incubated for 24 hours in this laboratory, however, has given complete antigenic formula of some 20 diphasic Salmonella in less than 48 hours.