Phenotypic and genotypic analysis of intestinal spirochacies

  • Sarah J. Rayment

Student thesis: Doctoral ThesisDoctor of Philosophy


Pulsed field gel electrophoresis of 82 intestinal spirochaete isolates showed
specific differentiation of Serpulina pilosicoli and Serpulina hyodysenteriae although considerable heterogeneity was observed, especially amongst S. pilosicoli isolates. In several cases genotypically similar isolates originated from different animals suggesting that cross-species transmission may have occurred.
The Caco-2 and Caco-21HT29 cell models have been proposed as potentially
realistic models of intestinal infection. Quantitation of adhesion to the cells showed
isolate 3 82/91 (from a bacteraemia) to adhere at significantly greater numbers than any other isolate tested. This isolate produced a PFGE profile which differed from other S. pilosicoli isolates and so would be of interest for further study. Comparison of bacteraemic and other S. pilosicoli isolates suggested that bacteraemic isolates were not more specifically adapted for adhesion to, or invasion of the epithelial cell layer than other S. pilosicoli isolates. Genotypically similar isolates from differing animal origins adhered to the Caco-2 model at similar levels.
Generation of a random genomic library of S. pilosicoli and screening with
species specific monoclonal antibody has enabled the identification of a gene sequence encoding a protein which showed significant homology with an ancestral form of the enzyme pyruvate oxidoreductase. Immunoscreening with polyclonal serum identified the sequences of two gene clusters and a probable arylsulphatase. One gene cluster represented a ribosomal gene cluster which has a similar molecular arrangement to Borrelia burgdorjeri, Treponema pallidum and Thermatoga maritima. The other gene cluster contained an ABC transporter protein, sorbitol dehydrogenase and phosphomannose isomerase.
An ELISA type assay was used to demonstrate that isolates of S. pilosicoli
could adhere to components of the extracellular matrix such as collagen (type 1),
fibronectin, laminin, and porcine gastric mucin.
Date of AwardNov 1998
Original languageEnglish
SupervisorM. Anne Livesley (Supervisor)


  • intestinal spirochaete
  • pulsed-field gel electrophoresis
  • genomic library
  • pyruvate oxidoreductase
  • arylsulphatase
  • sorbitol dehydrogenase
  • ABC transporter
  • ribosomal protein
  • extracellular matrix
  • adhesion
  • Caco-2
  • Co-culture

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