Histopathologic characterization of acute gastritis and duodenitis induced by inoculation of Escherichia coli O157 in mice

Abstract

Objective: To examine the effect of intragastric inoculation of an Escherichia coli O157 strain, which does not have such pathogenic factors as the stx, eae and EHEC-hlyA genes, on the induction of acute gastritis and duodenitis in BALB/c mice. Design: Time-dependent histopathologic changes were characterized in stomach and duodenum mucoepithelium by light and transmission electron microscopy. Results: The acute gastritis was characterized by inflammation and polymorphonuclear leukocyte infiltration that was followed by lymphocyte infiltration of the lamina propria, mucoepithelial erosions, mucoepithelial cell necrosis and haemorrhage from 1.5 to 24 h after inoculation. At 24 h, lymphocytes infiltrated the mucoepithelium. The acute duodenitis was characterized by polymorphonuclear leukocytic and lymphocytic infiltration of the lamina propria and by vacuolar degeneration of columnar epithelial cells from 1.5 to 24 h after inoculation. Inflammatory cells, including eosinophils, infiltrated mainly the lamina propria from 1.5 to 6 h after inoculation in both stomach and duodenum. Conclusions: our results showed that E. coli O157 inoculation icduced acute gastritis and duodenitis, independent of such pathogenic factors as stx, eae and EHEC-hlyA.