Toxigenesis and Infection of Mice by Salmonella enteritidis

Abstract

Summary

Toxigenesis and infection studies caused by S. enteritidis (LD_50/48hr = 7.1 × 10⁸ cell) were evaluated. Mice were fed per os 10³ or 10⁸ viable cells harvested from an 18- or 36-hr culture. Time of toxigenic onset, duration, and persistence of test organisms in organ tissues were confirmed bacteriologically, physiologically and by pathological differences between infected and control mice. No toxigenesis and/or infection was noted in mice fed 10³ cells of either culture, while severe syndrome was observed within 3 hr in mice fed 10⁸ cells of both cultures. Feeding 10⁸ cells harvested after 36 hr of growth produced short-lived toxigenic manifestation (less than 5 hr PF), but mice receiving 10⁸ cells obtained after 18 hr of growth had a longer toxigenic syndrome, and organisms persisted in the GI tract for 72 hr PF. High incidence of recovery of the test organism from the liver, spleen, and blood of mice was noted in mice fed 10⁸ cells of the 18-hr culture but not from the 36-hr culture. It appeared that toxigenesis and infection of 5. enteritidis required a minimum of 3 hr PF and 10⁸ cells of the 18-hr culture to induce salmonellosis in mice.