Evaluation of the Growth of Salmonellae in Rappaport's Broth and in Muller-Kauffmann's Tetrathionate Broth

S ummary . The behaviour of 70 strains of salmonellae belonging to 44 serotypes in Rappaport's broth and in Muller-Kauffmann's tetrathionate broth was examined. With an inoculum of 5–25 cells, 5 strains did not grow in Rappaport's medium, 2 multiplied slowly and 63 grew strongly in 24 h. With an inoculum of 100–500 organisms all but one strain grew readily in 24 h. In Muller–Kauffmann's tetrathionate broth inoculated with pure cultures of salmonellae, growth of many strains was markedly inhibited, in the absence of added faeces, at 37° and 43°. This inhibition was more severe with light inocula at 43°. The addition of 0.05% (w/v) of salmonella-free human faeces to Muller–Kauffmann's tetrathionate broth, did not stimulate growth of salmonellae. In contrast, the addition of 5% (w/v) of human stools to this medium resulted in a heavy growth of the added salmonellae, especially at 43°.