Evaluation of the discriminatory power of variable number tandem repeat (VNTR) typing of Mycobacterium bovis strains
2005
Hilty, M. | Diguimbaye, C. | Schelling, E. | Baggi, F. | Tanner, M. | Zinsstag, J.
The discriminatory power of variable number tandem repeat (VNTR) typing based on 16 known loci (12 MIRUs, 3 ETRs and VNTR 3232) was assessed for Mycobacterium bovis strains collected sequentially at the slaughterhouse of N'Djaména, Chad. Of 67 M. bovis strains analyzed, 67% were clustered. In this study, VNTR typing was highly discriminative with an overall allelic diversity (h(oa)) of 0.922. We defined five loci (ETR A, B, C and MIRU 26, 27) as highly (h > 0.25), two loci (MIRU 4, and VNTR 3232) as moderately (0.11 < h < 0.25) and three loci (MIRU 16, 20, 31) as poorly (0.01 < h < 0.11) discriminative. Six loci (MIRU 2, 10, 23, 24, 39, and 40) showed no polymorphism at all. VNTR typing of the five highly discriminative loci (h = 0.917) proved to be most appropriate for first line typing of M. bovis strains of Chad and superior than spoligotyping (h(sp) = 0.789). In contrast to Mycobacterium tuberculosis strains, a consensus on VNTR loci needs to be found for M. bovis strains. The selection of a generally agreed set of VNTR loci for molecular discrimination of M. bovis in different geographical settings is discussed.
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