Avian colibacillosis is an economically important bacterial disease of domestic poultry which despite efforts to control the disease, has increased with intensification of farming practises and the emergence of antibiotic resistance. E. cola isolates implicated in avian colibacillosis commonly elaborate surface organelles known as fimbriae and flagella and it has been hypothesisedt hat these surface appendagesm ay be important in pathogenesis. To investigate the role of fimbriae and flagella of E. coil 078: K80 in the pathogenesis of avian colibacillosis, defined isogenic single and multiple afimbriate and aflagellate mutants were constructed in a well characterised avian E. coli 078: K80 isolate (EC34195) and tested in various in vitro and in vivo models. In in vitro adhesion studies type 1 fimbriae were found to contribute significantly to adhesion of E. coli 078: K80 to cultured epithelial cells and tracheal and gut tissue explants. Curli fimbriae contributed significantly to adhesion to gut tissue explants whereas flagella contributed significantly to adhesion in the presence of mucus. In in vivo colonisation and invasion studies where day-old SPF chicks were dosed with the wild-type or isogenic afimbriate and aflagellate mutants type 1 fimbriae, curli fimbriae and flagella all contributed to colonisation and invasion. In in vivo persistence studies type 1 fimbriae, curli fimbriae and flagella all contributed to the persistence of E. coli 078: K80 in the chick. In a competition persistence model where day-old SPF chicks were dosed with wild-type and isogenic afimbriate or aflagellate mutantsf lagella>curli>type I were significant for the persistenceo f E. coli 078: K80 in the chick. 2
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:394403 |
| Date | January 2000 |
| Creators | La Ragione, Roberto Marcello |
| Publisher | Royal Holloway, University of London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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