Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/18/2008
Publication Date: 4/18/2008
Citation: Li, L., Amonsin, A., Sreevatsan, S., Bannantine, J.P., Sevilla, I., Juste, R., Kapur, V. 2008. Development and Evaluation of a Variable-number Tandem Repeat (VNTR) Method for Subtyping of Mycobacterium avium subspecies paratuberculosis Isolates [abstract]. Johne's Disease Integrated Program. p. 30. Interpretive Summary:
Technical Abstract: Mycobacterium avium subsp. paratuberculosis (Map) is the causative agent of Johne’s disease in cattle and other ruminants. Because of the apparent ease by which Map can spread to susceptible animals within a dairy herd, a better understanding of the epidemiology of Map infections is required. In this study, we have developed and evaluated a new method, variable-number tandem repeats (VNTR) analysis, for subtyping isolates of Map. A genomics and PCR-based screen of 124 tandem repeat loci in the Map genome identified at total of 19 VNTR loci. These loci were then used for subtyping 36 Map isolates recovered from different host species including cattle (n=9), goat (n=15), sheep (n=3), human (n=4), and bison (n=5) from Spain, India and USA. The analysis shows that the 36 Map isolates could be grouped as12 VNTR types, with overall index of discrimination (D) of 0.837. The isolates were grouped into 3 distinct clusters: cattle (C), sheep (S), and bison (B) strains. These results are consistent with assignments by IS1311 PCR-REA, and provide further evidence that the B type strains are distinct from the cattle and sheep type isolates. Importantly, each cluster could be further divided into different subcluster based on their VNTR types, suggesting a higher discriminatory power for VNTR typing than that of IS1311 PCR-REA. VNTR typing also showed good concordance with the multi-locus short sequence repeat (MLSSR), although the discriminatory power of VNTRs is slightly lower than that of MLSSR (0.873 compared to 0.929 of MLSSR). In contrast to MLSSR, VNTR based typing does not require sequence analysis, is substantially less expensive to implement, and will add considerably to the tools available for high-throughput epidemiological investigations of Map.