Sheldon, Ewart Jonathan (2018) Exploring the molecular mechanisms of antimicrobial resistance in Brachyspira hyodysenteriae using whole genome sequencing. PhD thesis, University of Warwick.

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Abstract

Brachyspira hyodysenteriae is the causative agent of swine dysentery, a disease characterised by bloody diarrhoea. It is endemic to the UK, and if untreated it can cause severe economic cost to farmers. Currently, it is treated with antibiotics including the pleuromutilin antibiotics tiamulin and valnemulin. B. hyodysenteriae has become more resistant to the antibiotics used to treat infections , and increasing levels of pleuromutilin resistance has been observed in some countries.
In this study, 84 clinical isolates, from 2004 to 2015, were sequenced on an Illumina MiSeq. From this, the population structure of B. hyodysenteriae in the UK was constructed. In addition, the phenotypic resistance of 47 sequenced isolates was obtained using a commercial broth dilution assay. The use of sequenced isolates enabled detection of a recently identified pleuromutilin resistance gene and enabled prediction of the resistance phenotype of all sequenced isolates. The use of whole-genome sequencing has increased our knowledge of B. hyodysenteriae in the UK, highlighting potential regional differences and has created a reference database of all B. hyodysenteriae isolates from 2004 to 2015. This will improve surveillance and increase the power of outbreak analysis.
Direct sequencing from clinical samples could further strengthen outbreak analysis and surveillance. This would improve the speed of identification and could provide useful information. To explore swine dysentery, positive samples were sequenced on an Illumina MiSeq and B. hyodysenteriae reads were extracted. From this, it was possible to identify the closest sequenced strains. This study highlights the potential uses of whole genome sequencing to analyse B. hyodysenteriae.

Item Type:	Thesis (PhD)
Subjects:	S Agriculture > SF Animal culture
Library of Congress Subject Headings (LCSH):	Swine dysentery, Swine -- Diseases, Swine -- Virus diseases, Veterinary medicine -- Research, Gene mapping, Genomes -- Analysis, Drug resistance in microorganisms, Antibiotics
Official Date:	May 2018
Dates:	Date Event May 2018 Submitted
Institution:	University of Warwick
Theses Department:	Warwick Medical School
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Anjum, Muna ; Pallen, Mark J.
Sponsors:	Veterinary Medicines Directorate ; Warwick Medical School
Extent:	xiii, 171 pages : illustrations
Language:	eng

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