title: Multiple locus VNTR analysis highlights that geographical clustering and distribution of Dichelobacter nodosus, the causal agent of footrot in sheep, correlates with inter-country movements.
abstract: Dichelobacter nodosus is a Gram-negative, anaerobic bacterium and the causal agent of footrot in sheep. Multiple locus variable number tandem repeat (VNTR) analysis (MLVA) is a portable technique that involves the identification and enumeration of polymorphic tandem repeats across the genome. The aims of this study were to develop an MLVA scheme for D. nodosus suitable for use as a molecular typing tool, and to apply it to a global collection of isolates. Seventy-seven isolates selected from regions with a long history of footrot (GB, Australia) and regions where footrot has recently been reported (India, Scandinavia), were characterised. From an initial 61 potential VNTR regions, four loci were identified as usable and in combination had the attributes required of a typing method for use in bacterial epidemiology: high discriminatory power (D>0.95), typeability and reproducibility. Results from the analysis indicate that D. nodosus appears to have evolved via recombinational exchanges and clonal diversification. This has resulted in some clonal complexes that contain isolates from multiple countries and continents; and others that contain isolates from a single geographic location (country or region). The distribution of alleles between countries matches historical accounts of sheep movements, suggesting that the MLVA technique is sufficiently specific and sensitive for an epidemiological investigation of the global distribution of D. nodosus.
authors.affiliation: Department of Clinical Veterinary Sciences, University of Bristol, Langford House, Langford, Bristol BS40 5DU, England, United Kingdom. Electronic address: Claire.Russell@imerys.com.
authors.forename: Claire L
authors.initials: CL
authors.lastname: Russell
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, England, United Kingdom. Electronic address: Edward.Smith@warwick.ac.uk.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Smith
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, England, United Kingdom. Electronic address: L.A.Calvo-Bado@warwick.ac.uk.
authors.forename: Leonides A
authors.initials: LA
authors.lastname: Calvo-Bado
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, England, United Kingdom. Electronic address: Laura.Green@warwick.ac.uk.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Green
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, England, United Kingdom. Electronic address: E.M.H.Wellington@warwick.ac.uk.
authors.forename: Elizabeth M H
authors.initials: EM
authors.lastname: Wellington
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, England, United Kingdom. Electronic address: Graham.Medley@warwick.ac.uk.
authors.forename: Graham F
authors.initials: GF
authors.lastname: Medley
authors.affiliation: Department of Clinical Veterinary Sciences, University of Bristol, Langford House, Langford, Bristol BS40 5DU, England, United Kingdom. Electronic address: lynda.moore@iah.ac.uk.
authors.forename: Lynda J
authors.initials: LJ
authors.lastname: Moore
authors.affiliation: Department of Clinical Veterinary Sciences, University of Bristol, Langford House, Langford, Bristol BS40 5DU, England, United Kingdom. Electronic address: R.Grogono-Thomas@bristol.ac.uk.
authors.forename: Rosemary
authors.initials: R
authors.lastname: Grogono-Thomas
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D020376:Dichelobacter nodosus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D005060:Europe / Q000453:epidemiology; D005535:Foot Rot / Q000453:epidemiology / Q000382:microbiology*; D018598:Minisatellite Repeats / Q000235:genetics*; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial
keywords: Dichelobacter nodosus; Global distribution; MLVA; Ovine footrot