SIGNIFICANCE OF SALMONELLAE ISOLATED FROM APPARENTLY HEALTHY MICE.

Morello, Josephine A. (Boston University School of Medicine, Boston, Mass.), Teresa A. DiGenio, and Edgar E. Baker. Significance of salmonellae isolated from apparently healthy mice. J. Bacteriol. 89:1460-1464. 1965.-Three species of Salmonella were isolated from three groups of apparently healthy laboratory mice. The host-parasite relationship of one of these, a mutant S. typhimurium (lacks I and i antigens), was studied to determine the significance of these pathogens. Mice were fed undiluted broth cultures, and the infection was followed by means of fecal and organ cultures and a hemolytic serological test. Tissue invasion occurred during the early stages of the disease, but, within 1 week, the organism usually was localized in the intestinal tract. After 1 month, most of the mice had eliminated the organism completely. Antibody response to this organism was generally variable. Conditions of stress, including heat, cold, and cortisone administration, did not precipitate more severe disease in infected animals. The infection was maintained for longer periods of time in animals housed in groups than in those in individual cages. The presence of such salmonellae in laboratory animals appears to be of limited significance.