Microbic superinfection in relapse of inflammatory bowel disease.

To assess the association between symptomatic relapse of inflammatory bowel disease (IBD) and superinfection with enteropathogenic microorganisms, we determined prospectively the incidence of infections with enteropathogenic bacteria, protozoa, and helminths in patients with confirmed longstanding IBD. Sixty-four patients with IBD (49 with Crohn's disease [CD] and 15 with ulcerative colitis [UC]) were consecutively enrolled in the study when relapse occurred. Multiple biopsies for histological and microbiological investigations were taken from all patients who were evaluated by colonoscopy. Parallel stool specimens were investigated for the presence of enteropathogenic bacteria, protozoa, and helminths. In six patients, we detected Clostridium difficile or toxin B (five CD, one UC), in one patient Campylobacter jejuni (CD), and in another patient Salmonella typhimurium (UC). Enteropathogenic Escherichia coli were isolated from three patients. Investigation of biopsies for Mycobacteria, microscopic examination of stool samples for helminths, and immunofluorescence for chlamydia were negative in all patients. In summary, as we found enteropathogenic microorganisms so infrequently in patients with relapse of IBD, despite intensive microbiological screening by tissue sampling for detection of gut adherent bacteria, we believe that microorganisms play only a minor role in the exacerbation of IBD.