Abstract
By the cultivation of Salmonella typhi in broth containing antiserum derived from the specific phase of Salmonella muenchen, Kauffmann 1 was able to isolate a variant which possessed altered flagellar antigens and which was no longer agglutinable in S. muenchen antiserum. The variant was obtained from only one culture and was not reversible. It was designated as a beta phase of the theretofore supposedly monophasic typhoid bacillus. Through cultivation in immune serums, beta phases were also obtained by Kauffmann and Tesdal 2 from Salmonella schleissheim and by Gard 3 from Salmonella abortus-canis. None of these induced phases were reverted to the naturally occurring phases of the bacilli and it is questionable whether they represented phase-variation as it is observed in naturally diphasic species, or whether they were mutants produced by exposure to antiserums.
It was found by Bruner and Edwards 4 that the technic of Wassén 5 was very effective in the isolation of suppressed specific phases in the so-called monophasic nonspecific Salmonella types. Therefore 7 cultures of S. typhi in our possession were examined by this method. The organisms were cultivated in agglutination-tubes containing semi-solid agar to which had been added sufficient S. muenchen antiserum to confine the growth of the normal, or alpha, phase of the bacilli to the line of inoculation. The medium was inoculated by stabbing at one side of the tube. Outgrowths from this line represented variation in the flagellar antigens of the bacilli. By this method beta phases similar to the one described by Kauffmann 1 were obtained from all the cultures on the first trial. Subsequently, the experiment was twice repeated with the same results.
The variants were transferred several times in semi-solid agar containing S. muenchen antiserum to free them of the alpha phase.
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