Characterization and comparison of Campylobacter bacteriophages

Al Kandari, Sharifa (2013) Characterization and comparison of Campylobacter bacteriophages. PhD thesis, University of Nottingham.

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Members of the genus Campylobacter are a major cause of food-borne disease worldwide. They can colonize the intestinal mucosa of poultry, to high levels leading to contamination of meat, at slaughter. Their numbers can be reduced in different ways including chicken treatment with bacteriophages. For such treatments to be successful, in depth understanding of the bacteriophage that infects and kills campylobacters is vital. The work in this thesis describes: isolation and comprehensive characterisation of bacteriophage candidates for future therapy applications.

In order to increase the available stocks of characterized candidate bacteriophage, a number of attempts were made to isolate bacteriophages from poultry excreta. The new isolates together with some uncharacterized phages from our laboratory stocks were characterized with respect to their host range and genomic size. Some bacteriophages preparations in previous studies showed genomes of different sizes and a number of attempts were done for their separation. This raised questions about the relationship between the two different sized genomes. Prior to this work, a co isolate pair had been successfully separated and the sequence of the larger genome, CP220, was determined. Part of the work here, was performed to extend this study by obtaining the sequence of the smaller co isolate, CPX and compare it to CP220. They did not appear to have any identifiable relationship at the genetic level, but the availability of the CPX sequence will further extend our knowledge of bacteriophage genetics and this phage has clear therapeutic potential. Attempts were also made to separate and characterize a second co-isolate pair but these were unsuccessful.

The availability of the DNA sequence of CP220 allowed a much closer molecular characterisation and comparison of Campylobacter phage genomes, than had previously been possible. One area that was investigated in this study was the presence of repeat regions identified in the CP220 genome, which were amplified by PCR, but could not be cloned in E. coli. Furthermore, genes encoding potential lysins were identified in the CP220 genome and they were amplified, cloned and attempts were made to express the proteins, which may have potential therapeutic value. One gene product was successfully expressed and showed evidence of lytic activity on Campylobacter and other bacterial genera.

In summary, this thesis describes a much closer examination of molecular biology of Campylobacter bacteriophage than had previously been possible, including the determination of the sequence CPX phage.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Connerton, I.F.
Keywords: Campylobacter reduction in poultry, Bacteriophage therapy, Bacteriophage genetics, Campylobacter phage genomes
Subjects: Q Science > QR Microbiology
Faculties/Schools: UK Campuses > Faculty of Science > School of Biosciences
Item ID: 14529
Depositing User: EP, Services
Date Deposited: 10 Sep 2014 08:31
Last Modified: 14 Sep 2016 16:17

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