Discrimination of isolates of Mycobacterium bovis in Northern Ireland on the basis of variable numbers of tandem repeats (VNTRs)

Abstract

The ability to reproducibly discriminate Mycobacterium bovis isolates and trace their transmission has the potential to clarify sources of infection and major routes of transmission for bovine tuberculosis (TB). A PCR-based genotyping assay has been developed to discriminate between strains of M bovis by examining multiple sites in its genome that consist of variable numbers of tandem repeats (VNTRS). The discriminatory power and reproducibility of this VNTR typing has been compared with that of the established PCR-based spoligotyping technique by using a panel of 461 isolates of M bovis prevalent in Northern Ireland. The VNTR assay discriminated 40 different profiles, the most prevalent of which constituted 21 per cent of the total, compared with 14 profiles discriminated by spoligotyping, the most prevalent of which constituted 65 per cent. No significant differences were observed between the prevalences of the VNTR profiles in the years from 1999 to 2003. A preliminary evaluation indicated that most genotypes predominated in particular areas of the country. This VTNR typing assay was found to be highly discriminating, with the performance characteristics to support its systematic application to the molecular epidemiology of bovine TB.

Genotyping North American Animal Mycobacterium Bovis Isolates Using Multilocus Variable Number Tandem Repeat Analysis

“…1,9,12,[16][17][18] A previous study, 18 based on a worldwide collection of M. tuberculosis isolates, proposed an optimized set of 24 VNTR loci, which included a subset of 15 discriminatory loci, for use as a first-line typing method. However, the determination of which markers and groups of markers will prove to be the most useful for local application should be determined empirically.…”

Molecular Epidemiology of Multidrug-ResistantMycobacterium bovisIsolates with the Same Spoligotyping Profile as Isolates from Animals

“…Polymorphic MIRU-VNTR loci have been exploited for M. bovis typing (14,26,29,30), although in this study only two out of the nine loci tested were able to distinguish both groups of isolates. VNTR typing could be a good discriminatory typing method, nevertheless, this technique is not yet standardized, and it is necessary to assess the discriminatory power of each polymorphic locus alone and in combination with others before its extended use.…”

Bovine tuberculosis: herd-level surveillance of Mycobacterium bovis genotypes in Northern Ireland (2003-2008)

“…M. bovis was isolated and confirmed using standard procedures. The first (disclosing) M. bovis isolate per herd was subjected to genotyping (Skuce et al 2005). VNTR profiling, spoligotyping, nomenclature, reference isolates and quality control were as described (Skuce et al 2005).…”

“…The first (disclosing) M. bovis isolate per herd was subjected to genotyping (Skuce et al 2005). VNTR profiling, spoligotyping, nomenclature, reference isolates and quality control were as described (Skuce et al 2005). Animal-level data (movements and test records) were derived from the Animal and Public Health Information System (APHIS, Houston 2001).…”

“…The maintenance and spread of infection within and between populations of cattle and populations of wildlife is poorly understood, with investigations hampered by difficulties in accurately defining epidemiologically-linked cases. The recent development of M. bovis genotyping schemes, based on recording DNA repeat copy number variation (variable number tandem repeats or VNTRs) offers highly-discriminating tools for investigating the spread of M. bovis (Skuce et al 2005, Smith et al 2006. Systematic application of M. bovis genotyping in conjunction with tracing of cattle movements and wildlife surveillance can be expected to provide valuable insights into disease source and spread.…”