Identification of a repetitive DNA sequence specific to Mycobacterium paratuberculosis.

A 0.2-kb DNA sequence specific to Mycobacterium paratuberculosis, the causative organism of Johne's disease, was isolated from a partial genomic library. The sequence was part of a larger repetitive DNA element and was present in strains of M. paratuberculosis from cattle, sheep, goat, deer and also a woman with Crohn's disease but not in M. paratuberculosis strain 18. The sequence was not present in strains of 19 other mycobacterial species including 31 reference serotype strains of the M. avium-M. intracellular-M. scrofulaceum (MAIS) complex, some strains of which are closely related to M. paratuberculosis. The sequence may be useful for developing a diagnostic test for Johne's disease.