Genetic relatedness among Mycobacterium paratuberculosis and M. avium complex.

Total DNA was extracted from M. paratuberculosis (ATCC 19698) and from M. avium complex (ATCC 25291) cultivated on RVB-10 enriched liquid media. Restriction endonuclease analysis of total DNA was performed with 34 enzymes and DNA digestion profiles were compared. Fifteen enzymes revealed important differences between the two species. Two pairs of enzymes (EcoRII, BstNI) and (MboI, Sau3AI) provide evidence for the presence of dcmI and dam methylation in DNA of M. avium complex and M. paratuberculosis. The differences in DNA fragments of these two species could be of potential value in differentiating these clinically significant mycobacteria.