Fecal bacteriology and reservoir ileitis in patients operated on for ulcerative colitis.

To investigate the etiology of ileal reservoir inflammation, fecal bacteriology and ileal wall morphology were compared in three groups of 15 patients operated on for ulcerative colitis: 1) conventional ileostomy, 2) Kock ileostomy; and 3) pelvic ileal pouch. Total bacterial counts showed overgrowth of fecal bacteria in each group, but the anaerobic bacterial counts were significantly higher (P less than .05) in the two pouch groups than in the conventional ileostomy group. Mucosal morphology did not differ among the three groups showing either normal mucosa or mild chronic inflammatory changes in most patients. In contrast, five of the six patients with clinical pouchitis had acute inflammatory changes in histologic specimens. Fecal bacteriologic findings in these patients did not differ quantitatively or qualitatively from others. It is concluded that proctocolectomy for ulcerative colitis predisposes to ileal bacterial overgrowth, and after pouch operations especially, anaerobic overgrowth may be one factor in the development of pouch inflammation. Acute clinical pouchitis with clear histologic changes was, however, not connected with specific changes in fecal bacteriology.