Salmonella titers

Table 6 contains the mean value of three separate experiments. A comparison of the intestinal and peritoneal cell counts reveals that the ampicillin treatment reduced the intestinal cell counts approximately a hundred-fold without affecting the Salmonella titer. Cycasin alone (positive control) resulted in the anticipated rise in MF for typhimurium ampicillin alone did not alter the spontaneous MF, and mice treated with both ampicillin and cycasin were approximately the same as the negative control. The reduction of intestinal microorganisms by ampicillin and the resultant inability to detect mutagenic activity after administration of cycasin parallel the finding in carcinogenic studies. In germ-free animals no tumors were found after administration of cycasin (Spatz et aL, 1967). 

Figure 10. IgG antibody titers against three Salmonella O-antigen 4-containing antigens as estimated by ELISA in serum samplesfrom a patient with S. typhimurium infection. Key A, Salmonella BO LPS IO OX m, AMRC-BSA and o, AM-(CH -BSA.

Salmonella typhi contain antigen O (somatic) and antigen H (flagellar) which give rise to host antibodies. The antigens are lipopolysaccharides which are located in the outer membrane of Salmonella baciUi. Salmonella typhi is further identified by the additional presence of antigen Vi (capsular). A fourfold or over rise of antibody titers to O and H antigens. A 2-weeks apart in paired samples is indicative of typhoid fever. 

Transfer 1 mL of preenrichment culture to 10 mL of TT broth. Transfer a second 1-mL aliquot to 10 mL of SC broth. Both broths are required to ensure that acceptable titers of various Salmonella can be obtained. Failure to use both broths may lead to inaccurate results with some strains of Salmonella,... 

Remove the TT and SC cultures from the incubator and transfer 1 mL of each culture to separate tubes, each containing 10 mL of GN broth in order to increase the titer of Salmonella (if present) to detectable levels. Although, in some cases. Salmonella can be detected directly for the TT and SC broths, broad screening of many different food types is most accurately conducted by using the complete enrichment scheme. Failure to do so could lead to an increase m the incidence of false negative results. 

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