Avian Pathogenic Escherichia coli (APEC) is an important pathogen of the poultry industry, responsible for 43% of condemnations of broiler birds at slaughter and annual losses of between 1-8% of a laying flock. APEC is also a public health concern; consumption of poultry meat has been linked with urinary tract infections (UTI) in humans, and also as a reservoir of potential antimicrobial resistance genes. In this study of strain 3770, a reproductive tract associated isolate of APEC, the isolate was characterised for typical APEC virulence phenotypes, and also underwent full-genome sequencing in order to further advance our understanding of the pathogenomics of reproductive tract associated APEC infections. Additionally, a population study examined the virulence gene profiles within a population of reproductive tract associated E. coli, with a particular focus on virulence factors associated with infections in avian species and UTI in humans. It was found that 3770 exhibited characteristic extra-intestinal pathogenic E. coli (ExPEC) virulence phenotypes; serum resistant, adhesive, and able to persist in the short term within phagocytic cells. It was also able to induce reproductive tract infections via the aerosol route. The genome sequence was 5.02Mb in size with a high number of virulence genes. The most closely related E. coli was an adherent-invasive E. coli isolate associated with Crohn's Disease. The population study of reproductive tract infections revealed a high level of variance within the population, and a higher prevalence of ibeA and K1 capsule genes than seen in other populations. These results provide further evidence that there is no one single APEC pathotype. It is likely that virulence in APEC isolates is a complex relationship between the virulence profile of the bacterium and the health status of the host.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:721995 |
| Date | January 2016 |
| Creators | Collingwood, Charlotte Rose |
| Publisher | University of Liverpool |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://livrepository.liverpool.ac.uk/3007233/ |
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