Sulfanilylguanidine in Control of Salmonella Infection and Carrier State in Mice

Abstract

The presence of an enzootic Salmonella infection in our laboratory colonies of mice has prompted an investigation into the etiology, control, and nature of this disease. Data gathered from animal autopsies and bacteriological studies indicate that in 2 strains the infection follows different courses. The 2 strains of mice, Akh and Rfi, were developed by Furth of Cornell University Medical School for his studies of leukemia. Seventy to 80% of the Akh animals die of lymphoid leukemia if they live to be over 8 months of age. The Rfi mice carry myeloid leukemia and 1% die of the disease. Bacteriological studies of stool cultures revealed a significantly higher incidence of infection in Rfi mice than in Akh animals. Autopsies performed on 26 Akh mice in a 2-months'period revealed gross evidence of Salmonella infection in only 2, whereas gross evidence of this disease was seen in 17 animals in a series of 35 Rfi mice autopsied during the same period. The typical lesions seen at autopsy were numerous, irregularly distributed, white areas of focal necrosis, variable in shape, 0.5 to 5 mm in diameter, occurring most frequently in the liver and spleen. Small hemorrhagic areas and minute ulcerations were occasionally present in the intestinal tract. In every instance where attempted, an organism identified as Salmonella enteritidis was isolated from the lesions in both strains of mice. On the basis of preliminary studies, to be completed and reported later, the organisms isolated from both strains of mice appeared to be identical.

Cultures from individual animals were made as follows: Fecal pellets were collected directly from the animals on sterile swabs and emulsified in 2 cc of sterile tryptose broth before streaking on brilliant green lactose agar plates 1 (extract agar (pH 7.0), 1% lactose, 0.1% dextrose, 1% Andrades indicator, brilliant green 1-250,000).