Virulence regions and virulence factors of the ovine footrot pathogen, Dichelobacter nodosus

Stephen J. Billington, Joanne L. Johnston, Julian I. Rood

Research output: Contribution to journalShort SurveyOtherpeer-review

54 Citations (Scopus)

Abstract

Ovine footrot is a debilitating and highly infectious disease that is primarily caused by the Gram-negative, anaerobic bacterium Dichelobacter nodosus. The major antigens implicated in virulence are the type IV fimbriae and extracellular proteases. The fimbriae show sequence and structural similarity to other type IV fimbriae, this similarity extends to genes that are involved in fimbrial biogenesis. Several acidic and basic extracellular serine proteases are produced by both virulent and benign isolates of D. nodosus. Subtle functional differences in these proteases appear to be important in virulence. In addition, there are two chromosomal regions that have a genotypic association with virulence. The partially duplicated and rearranged vap regions appear to have arisen from the insertion of a plasmid into a tRNA gene via an integrase-mediated site-specific insertion event. The 27 kb vrl region has several genes often found on bacteriophages and has inserted into an ssrA gene that may have a regulatory role in the cell. The determination of the precise role that each of these genes and gene regions has in virulence awaits the development of methods for the genetic analysis and manipulation of D. nodosus.

Original languageEnglish
Pages (from-to)147-156
Number of pages10
JournalFEMS Microbiology Letters
Volume145
Issue number2
DOIs
Publication statusPublished - 1 Dec 1996

Keywords

  • Dichelobacter nodosus
  • Fimbria
  • Footrot
  • Protease
  • Vap region
  • Virulence
  • Vrl region

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