Purpose: Mycobacterium paratuberculosis has been proposed as a causative agent in patients with Crohn's disease. The purpose of this study was to determine whether M. paratuberculosis was present in tissue from patients with Crohn's disease in a defined geographic area.
Methods: We prospectively evaluated, using polymerase chain reaction and culture, whether M. paratuberculosis was present in 44 specimens (37 from intestinal mucosal biopsies and 7 from surgical resections) from patients with Crohn's disease, ulcerative colitis, or normal colonic mucosa.
Results: Of the 25 specimens tested from the 21 Crohn's patients, only 1 positive specimen was noted, whereas the 8 specimens from the 5 ulcerative colitis patients and the 11 specimens from the 11 control patients failed to demonstrate a positive result with polymerase chain reaction. Cultures of all specimens revealed no growth of M. paratuberculosis.
Conclusion: M. paratuberculosis was only rarely detected in biopsy or surgical specimens from patients with Crohn's disease. These results do not support a common causative role of M. paratuberculosis in Crohn's disease.