Comparative study of Mycobacterium paratuberculosis strains isolated from Crohn's disease and Johne's disease using restriction fragment length polymorphism and arbitrarily primed polymerase chain reaction.

To obtain insights into the pathogenic mechanisms involving Mycobacterium paratuberculosis in Crohn's disease (CD) we questioned if the strains of M. paratuberculosis isolated from CD are distinguishable from those involved in Johne's disease (JD), a chronic granulomatous enteritis in cattle. Accordingly we compared human and animal strains at the DNA level, both by the analysis of restriction fragment length polymorphism (RFLP) in and around the insertion sequence IS 900 and by the arbitrarily primed chain reaction (AP-PCR). Results are in favour of a common clonal origin for the 4 strains isolated from CD and for 8 of the 11 strains isolated from cattle and sheep JD.