SHIGELLOSIS IN CYNOMOLGUS MONKEYS (MACACA IRUS) IV. BACTERIOLOGICAL AND HISTOPATHOLOGICAL OBSERVATIONS ON THE EARLIER STAGE OF EXPERIMENTAL INFECTION WITH SHIGELLA FLEXNERI 2A

Abstract

The locality of mulplication of S. flexneri 2a in the alimentary tract and the causal relation between the distribution of the fluorescing bacilli in the tissue and the appearence of inflammatory response were investigated on 4 cynomolgus monkeys in the earlier stage of 12 and 24 hr after an oral administration of the bacilli.
The results of the present observations suggested the importance of the involvement of the large intestine, particularly of epithelial cells, for the multiplication of the bacilli. In the small intestine, there was evidence neither of penetration of the bacilli into the epithelial cells nor of a pronounced increase in the number of the bacilli in the lumen.
The degeneration of the epithelial cells had already taken place when the bacilli penetrated into the cells. This fact would suggest that some preconditioning on epithelial cells by certain cytotoxic substances seems to be necessary for the penetration of the bacilli into them.
The penetration of the bacilli into the lamina propria via the intact epithelial barrier was not observed in the earlier stage of infection; this phenomenon appeared 3 to 4 days after infection when the surface mucosa degenerated to necrosis and desquamated.
The presence of the bacilli does not necessarily coincide with the locality of the lesions.