NO MYCOBACTERIUM-PARATUBERCULOSIS FOUND IN CROHNS-DISEASE USING THE POLYMERASE CHAIN-REACTION

M. paratuberculosis has been considered as a putative causative factor of Crohn's disease. However, its detection in diseased tissue samples using the polymerase chain reaction yielded conflicting results. We v alidated this technique for the detection of mycobacteria (any species ) and M. paratuberculosis before applying it to 72 intestinal biopsies from patients with Crohn's disease (N = 36), ulcerative colitis (N = 13), and control subjects (N = 23). Possible polymerase chain reaction inhibitors were detected by spiking template DNA with the equivalent of two M. paratuberculosis genomes. Mycobacteria were found in 17/36 ( 47%), 6/13 (46%), and 13/23 (57%) tissue samples of Crohn's disease, u lcerative colitis, and controls, respectively. No M. paratuberculosis were detected in any sample. It is concluded that mycobacteria are pre sent with a similar frequency in the intestinal tissues or luminal inc lusions of patients with inflammatory bowel disease and of those unaff ected by the disease. Our data do not support a role for M. paratuberc ulosis in Crohn's disease.