STUDIES ON ENTEROPATHOGENIC ACTIVITY OF VIBRIO PARAHAEMOLYTICUS USING LIGATED GUT LOOP MODEL IN RABBITS

Abstract
Enteropathogenic activity of Vibrio parahaemolyticus was studied with the ligated gut loop model in rabbits. Positive reaction of the gut loop was mostly produced with Kanagawa-positive organisms. Reaction was also induced by the cell-free filtrate from brain heart infusion cultures of the vibrio, thus suggesting the presence of an enterotoxic substance. With the filtrate from broth cultures, however, dilatation of the gut loop and inflammatory changes in the intestinal mucosa occurred regardless of the Kanagawa reaction of the original culture. The substance responsible for these changes was thermolabile, being different from the Kanagawa-hemolysin which failed to produce pathological changes in the gut loop. On the other hand, massive inocula acetone-killed, chloroform-killed, or heated cultures did not produce dilatation or pathological changes in the gut loops. When the pathological changes in the intestinal mucosa of loops inoculated with cell-free filtrate from broth cultures were compared with those inoculated with live cultures, the only difference observed was less marked infiltration of granulocytes in the mucosa in the former. These findings suggest that the ability of V. parahaemolyticus to multiply in the intestine which is generally associated with the Kanagawa reaction of the organism may possibly be essential to its enteropathogenicity, although an enterotoxin-like substance produced by the vibrio regardless of the Kanagawa reaction may play a role in inducing gastroenteritis and diarrhea.