Effect of Mannose on Salmonella typhimurium-Mediated Loss of Mucosal Epithelial Integrity in Cultured Chick Intestinal Segments

Abstract

The effect of incubating Salmonella typhimurium and S. typhimurium cell-free extracts with isolated intestinal segments from 1-day-old chicks was evaluated using scanning electron microscopy. Incubation of segments with intact bacteria or with cell-free extract resulted in the loss of mucosal epithelial integrity after as little as 30 min incubation. Loss of mucosal epithelial integrity was evidenced by the complete shedding of the epithelium. The addition of 2.5% D-mannose to the incubation medium inhibited the loss of epithelial cells, whether intestinal segments were incubated with intact bacteria or with cell-free extract. These results indicate that S. typhimurium exerts a D-mannose-sensitive cytotoxic effect on the mucosal epithelium of isolated intestinal segments and that the cytotoxic effector is present in cell-free extracts of the bacteria.