A new enrichment medium for certain Salmonellae.

A great number of enrichment media for Salmonellae have been described in the medical literature. Some of them have gained wide acceptance in many clinical laboratories. Two of the most frequently used enrichment media are tetrathionate broth in various modifications (Muller, 1923; Kauffmann, 1930; Preuss, 1949; Knox, Gell, and Pollock, 1942) and selenite broth (Hobbs and Allison, 1945). The purpose of an enrichment medium for Salmonellae is twofold: it has to enable the pathogens to multiply freely and it should inhibit or kill all accompanying coliform organisms. Particularly troublesome are Proteus, Pseudomonas pyocyanea and Aerobacter aerogenes, which are not always inhibited in the enrichment media mentioned. These organisms grow after subculturing on solid indicator media such as Salmonella shigella medium (SS) and a great number of lactose-negative colonies must be examined in order to detect Salmonella. A medium which satisfies both criteria of enrichment has been developed in this laboratory. The use of this medium was responsible for the detection of almost twice as many cases of salmonellosis as when the two other standard enrichmnent media were used.