Absence of mycobacterium avium subsp. paratuberculosis in Crohn's patients.

Background: Mycobacterium avium subspecies paratuberculosis (MAP) has been suspected of involvement in Crohn's disease (CD). We investigated this potential association by testing whole blood from CD patients and healthy controls for the presence of MAP by culture and molecular methods. In addition, each blood sample was analyzed for polymorphisms in the NOD2/CARD15 gene previously associated with CD.