Objectives: It is still controversial whether or not a mycobacterial infection may be a cause of Crohn's disease. Mycobacterium paratuberculosis may be very difficult to detect using routine culture techniques. To clarify this, we detected mycobacterial DNA in patients with inflammatory bowel disease.
Methods: IS900 sequences highly specific to M. paratuberculosis and the groEL gene encoding a conserved mycobacterial antigen were studied in colonic mucosa using polymerase chain reaction (PCR). PCR products were analyzed by Southern blot hybridization.
Results: IS900 sequences were detected in all (100%) of 10 patients with Crohn's disease, in 11 (61.1%) of 18 patients with ulcerative colitis, and in 14 (87.5%) of 16 control patients with noninflammatory bowel disease. All IS900 positive samples had groEL PCR products.
Conclusions: Our results, on the basis of the prevalence, do not support the hypothesis that M. paratuberculosis is involved in the pathogenesis of Crohn's disease.