Detection of Mycobacteria in Crohn's Disease by a Broad Spectrum Polymerase Chain Reaction

The role of mycobacterial infection, particularly related to Mycobacterium avium subsp paratuberculosis (Map), in Crohn's disease has long been debated. We developed primer pairs capable of detecting a broad spectrum of mycobacterium and employed them to investigate surgical specimens from patients with Crohn's disease. Pan mycobacterium primers of the 65-kDa heat shock protein gene (Hsp65) were used in a polymerase chain reaction (PCR) to examine 12 surgically-resected, formalin-fixed, paraffin-embedded specimens from 11 patients with Crohn's disease. The DNA sequences of amplicons were aligned with those in GenBank. Mycobacterial DNA was found in specimens from three of 11 patients. M. mucogenicum was identified in a specimen from one patient and M. tuberculosis in two, but Map was not identified in any. Hsp65-based PCR can be employed to search for occult mycobacterial infection of the gastrointestinal tract in patients with a diagnosis or suspicion of Crohn's disease. This approach may have a therapeutic implication.