Use of Organic Acids for the Differentiation of Salmonella pullorum and Salmonella gallinarum.

Abstract

Brown, Duncan and Henry 1 demonstrated that the sodium salts of 4 organic acids, tartaric, mucic, fumaric and citric, were utilized as food by some members of the paratyphoid group, thus making it possible to separate certain members of this group through the use of this agency. The utilization of the acids as foods was measured in a liquid medium by precipitation of the residual acid by lead acetate. Using this procedure they were able to separate Salmonella aertrycke and Sal. schotmülleri. In a personal communication, Henry and Duncan 2 reported the separation of Sal. pullorum and Sal. gallinarum as follows:

Jordan and Harmon 3 demonstrated that sodium tartrate peptone medium containing phenol red separated Sal. aertrycke and Sal. schotmülleri by a color change due to difference in pH.

Using a method of procedure similar to that of Jordan and Harmon, the writer tested the sodium salts of citric, d-tartaric, fumaric and mucic acids on Sal. pullorum and Sal. gallinarum together with a few closely related organisms. Fumaric and citric acids were found unsatisfactory as the pH changes induced were very inconstant. On the other hand, the reactions obtained with d-tartaric and mucic acids were very constant. The data on the latter 2 acids are presented in Table I.

The data show that both sodium salts of d-tartaric and mucic acids differentiated between Sal. pullorum and Sal. gallinarum. Using these salts on a number of strains of both organisms over a period of 3 years, no variations or exceptions in the reactions listed above were obtained with either the tartrate or mucate media. Liquid and agar stab cultures gave the same reactions. The data on Sal. aertrycke and Sal. schotmülleri confirmed the work of Jordan and Harmon.