USE OF A REPETITIVE ELEMENT ISOLATED FROM MYCOBACTERIUM-TUBERCULOSIS IN HYBRIDIZATION STUDIES WITH MYCOBACTERIUM-BOVIS - A NEW TOOL FOR EPIDEMIOLOGIC STUDIES OF BOVINE TUBERCULOSIS

Typing of M. bovis isolates for epidemiological purposes is possible u sing restriction endonuclease analysis (REA). However, the DNA fragmen t patterns obtained are complex and difficult to analyse due to the la rge number of bands produced. In an attempt to develop a less complica ted typing scheme two DNA probes were used in hybridization studies to detect restriction fragment length polymorphisms (RFLP) in M. bovis. An oligonucleotide probe which matches part of the insertion sequence IS6110 produced few bands and failed to discriminate between bovine is olates of M. bovis. A probe prepared from a highly repeated DNA sequen ce, cloned from M. tuberculosis when used on southern blots of AluI di gested M. bovis DNA, resulted in a discriminating typing scheme which was easier to perform and analyse than the REA. The RFLP typing scheme identified 27 different strains from a total of 36 isolates of M. bov is and 7 reference strains from the M. tuberculosis complex. Using REA , 24 types were identified using Bc/I and PvuII digests and 23 differe nt types using BstEII digests. When results of all 3 enzyme digests we re combined, the REA identified 27 types from the same strains. Ten is olates of M. bovis from 5 properties involved in an outbreak of bovine tuberculosis were all identified as the same type with both technique s.