USE OF 4 DNA INSERTION SEQUENCES TO CHARACTERIZE STRAINS OF THE MYCOBACTERIUM-AVIUM COMPLEX ISOLATED FROM ANIMALS

The Mycobacterium avium complex (MAC) includes the closely related spe cies M. avium, M. intracellulare and M. paratuberculosis. The insertio n elements IS900, IS901, lS1245 and IS1311 were used as DNA probes to characterize by restriction fragment polymorphisms (RFLPs) eight refer ence strains, three animal isolates of M. paratuberculosis from outsid e New Zealand and 61 selected New Zealand MAC isolates from cattle, de er, pigs, sheep and humans. IS900 was found only in strains of M. para tuberculosis. All MAC strains contained IS1311 and the RFLPs associate d with this insertion element divided M. paratuberculosis strains into the same groups as IS900 RFLPs. Except for M. paratuberculosis, all M AC strains contained IS 1245 and the majority of those from lesions in cattle, deer and pigs also contained IS901. All animal strains contai ning IS901 had the same RFLPs with IS901, IS1245 and lS1311. In three cases, these apparently identical strains could be differentiated by r estriction fragment analysis with BstEII. IS901 was not present in fou r human isolates or in isolates from deer without lesions. These resul ts indicate that a very closely related group of strains causes the ma jority of non-paratuberculosis MAC lesions in animals in New Zealand. (C) 1997 Academic Press Limited.