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Title: Understanding the pathobiology of Brachyspira pilosicoli in order to develop novel intervention strategies against avian intestinal spirochaetosis
Author: Mappley, Luke John
ISNI:       0000 0004 2741 6647
Awarding Body: Royal Holloway, University of London
Current Institution: Royal Holloway, University of London
Date of Award: 2012
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The anaerobic spirochaete Brachyspira pilosicoli causes enteric disease in avian, porcine and human hosts, amongst others. Avian intestinal spirochaetosis (AIS), the resulting disease from colonisation of the caeca and colon of poultry by Brachyspira leads to production losses, with an estimated annual cost of circa £18 million to the commercial layer industry in the United Kingdom. A lack of knowledge of the metabolic capabilities and little genomic information for Brachyspira has resulted in a limited understanding of the pathobiology of this genus. In addition, an emergence of antibiotic resistance in Brachyspira, together with bans on the prophylactic use of antimicrobials in animal feed, drive an urgent requirement for alternative treatment strategies for diseases such as AIS. In the first intra-species genome comparison within the genus Brachyspira, these studies report the whole genome sequence of an avian strain of B. pilosicoli, B2904, and the incomplete genome sequence of a human strain of B. pilosicoli, WesB. Comparisons are made between the de novo sequenced strains and those of B. pilosicoli 95/1000, a pig strain and other available Brachyspira genome sequences from public databases. Furthermore, this study reports the first application of the high-throughput Biolog phenotype screening tool to Brachyspira for detailed phenotypic analysis and confirmation of metabolic deductions made from the genotypic data. Probiotics have been reported as protecting against infection with common enteric pathogens in livestock and in this study investigations into which aspects of the biology of Brachyspira they antagonise were undertaken. Lactobacilli reduced the growth and motility of B. pilosicoli and its ability to adhere and invade epithelial cells in vitro. Following these encouraging results, an in vivo intervention study was performed using a B. pilosicoli challenge model in poultry to elucidate the potential for probiotic intervention against AIS. This study demonstrated that when administered in drinking water, L. reuteri LM1, isolated from a healthy chicken, reduced all aspects of the clinical presentation of AIS.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Brachyspira ; Avian intestinal spirochaetosis ; Poultry ; Probiotics ; Lactobacillus ; Biolog Phenotype MicroArray ; Genome sequencing ; Comparative genomics ; Three-dimensional cell culture ; In vitro organ culture ; Experimental challenge