Studies on Crohn's disease. 1. The relationship between Yersinia enterocolitica infection and terminal ileitis.

Patients with terminal ileitis or regional enterocolitis have been examined for signs of infection due to Yersinia enterocolitica serotype 3. The patients were grouped according to the length of preoperative history. Among 18 patients with preoperative symptoms of one week or less there were nine with positive signs of Yersinia enterocolitica infection. None of these patients developed the chronic form of Crohn's disease while two of the primarily Yersinia negative patients progressed to the chronic form. Among nine patients with preoperative symptoms of one week to three months there was one patient with positive signs of Yersinia enterocolitica infection. This patient has remained healthy whereas seven of the negative ones progressed to the chronic form of Crohn's disease. None of the patients with established Crohn's disease of the chronic form had signs of recent Yersinia infection. The findings indicate that patients with acute terminal ileitis and positive signs of Yersinia infection are not likely to progress to the chronic form of Crohn's disease. Bacteriologic and serologic investigation for Yersinia infection are therefore of prognostic value.