Review of the Food-borne Zoonoses Research ... - ARCHIVE: Defra

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to elucidate the antigenic repertoire of this bacterium at one antigen locus, will provide an accurate, comprehensive, and portable typing system for C. jejuni and related organisms, with a firm theoretical basis in bacterial population biology. OZ0611 Campylobacter is the most common cause of bacterial infectious intestinal disease in the UK. Although various risk factors for infection, including consumption of undercooked poultry or unpasteurised milk have been identified, the epidemiology of this disease remains poorly understood. This is because (i) outbreaks are rarely detected, hence valuable information on sources and transmission routes which is obtained from outbreak investigations is generally lacking, and (ii) Campylobacter genomes are genetically diverse, and unstable, with frequent inter and intragenomic recombination, together with phase variation, which complicates the interpretation of data from many typing methods. However, a suitable typing techniqe is multilocus sequence typing (MLST). MLST for Campylobacter jejuni, together with a comprehensive internet accessible MLST database (http://pubmlst.org/campylobacter/) was developed with DEFRA support (contract number: OZ0604). MLST offers advantages over previous typing techniques including 100% typeability, reproducibility, and the straightforward sharing of data via the internet. The Campylobacter MLST database now contains 4434 isolates (29 th May 2007) and provides a resource for the scientific, public health, and veterinary communities as well as the food industry. Database submissions are received from laboratories internationally. The database is curated to ensure quality control, and additional MLST schemes and databases have been set up for other Campylobacter species including C. coli, C. fetus and C. lari. If it is to continue, and undergo further expansion, this program of work will require continued support. Review Summary The work performed in OZ0604 and OZ0611 has been of fundamental importance in developing and applying a robust molecular typing method to Campylobacter. Adoption of MLST for Campylobacter at an international level demonstrates the strength of the work performed. As OZ0611 comes to an end and further work is considered, it is important that the MLST database is populated with campylobacters of public health importance. In addition, when selecting environmental isolates, quantity, source, geographical, and temporal factors must all be taken into account to ensure the database is not biased. The database must then be interrogated to identify sources of human infection and therefore where interventions will have the greatest impact. 72
Project code: OZ0605 Project title: Genotypic and Phenotypic Instability of Campylobacters from Environmental, Animal and Human Sources Start date (dd/mm/yy): 01/08/1999 End date (dd/mm/yy): 31/07/2002 £298,279 Total cost: Affiliation: Veterinary Laboratories Agency Sub-contractor(s): Scottish Reference Laboratory for Campylobacters, Aberdeen Department of Food Science, Queens University, Belfast Campylobacter Reference Unit, Laboratory of Enteric Pathogens, Central Public Health Laboratory (now Health Protection Agency), London Institute for Animal Science and Health, The Netherlands Abstract of research Campylobacters can only grow in a host, usually in the gut, and are considered very fragile organisms. However, they are ubiquitous in the general environment, where they survive a wide range of stresses, which may be potentially lethal. This conundrum is confounding for the investigation of the epidemiology of campylobacters in the poultry farm and meat production environments, particularly given the absence of known mechanisms of stress adaptation in campylobacters. Genetic instability is a wellrecognised property of Campylobacters and has been proposed as a survival mechanism. In this project the role of genetic instability as a mechanism for stress survival and adaptation during exposure to the host gut was investigated. Genotypic and phenotypic instability occurred in about 20% of outbreak-related strains investigated and was most readily observed using the typing technique of PFGE. Such instability was detected as a change in banding patterns consistent with point mutations. However, the apparent loss or gain of DNA fragments, including fragments of up to 50kb, was also detected, suggesting DNA insertion/deletion events. Nevertheless, some genotypically stable clones were also detectable. The mechanisms and role of genetic instability were investigated in a clonally-derived set of strains previously recovered from a single batch of poultry meat. Instability was induced by in vitro exposure to heat and cold stresses as well as frozen storage. Using a competition model of chick colonisation following oral challenge with multiple variants, evidence was obtained for a selective benefit in vivo for some variants. These results demonstrate that genetic instability is an important ecological property of campylobacters and that understanding of this property will be essential to the detection and control of this foodborne pathogen. Review Summary OZ0605 commenced at a time when little was known about the genetic variability of Campylobacter spp. The researchers looked at a wide range of typing methodologies 73
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Contents Section A - Introduction..
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Review of the Food-borne Zoonoses (
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Plans for taking forward these prio
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Policy Objectives The key policy ob
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Figure 2. Laboratory reports of Sal
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Figure 4. Laboratory reports of Cam
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6. Aims of the FBZ research review
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Section B - Review Summaries 16
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epidemiology of Salmonella and anti
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There is a need to objectively asse
Page 22 and 23: 2. Campylobacter review summary 2.1
Page 24 and 25: for this organism. Research within
Page 26 and 27: 3. E. coli review summary 3.1 Succe
Page 28 and 29: 4. Other zoonotic pathogens of inte
Page 30 and 31: Annex 1 - Projects Reviewed 30
Page 32 and 33: OZ0311 Conventional versus capillar
Page 34 and 35: OZ0402 OZ0404 OZ0405 OZ0407 OZ0604
Page 36 and 37: OZ0704 OZ0705 OZ0706 OZ0707 Quantif
Page 38 and 39: Annex 2 - Project Abstracts and Pro
Page 40 and 41: To test the suitability of the AFLP
Page 42 and 43: Project code: OZ0324 Project title:
Page 46 and 47: Review Summary The knowledge that t
Page 48 and 49: Review Summary The project was felt
Page 52 and 53: It is clear that the EC legislative
Page 54 and 55: if the vaccines currently available
Page 56 and 57: Four published papers have come out
Page 58 and 59: Review Summary This epidemiological
Page 60 and 61: Project code: OZO316 Project title:
Page 64 and 65: agricultural industry/public health
Page 66 and 67: testing laboratories. In addition,
Page 68 and 69: animal pathogen but is a human path
Page 70 and 71: esearch has also substantially impr
Page 74 and 75: and have contributed to our underst
Page 76 and 77: Fundamental issues concerning the f
Page 78 and 79: Review summary Project OZ0606 focus
Page 80 and 81: Abstract of research OZ0608 The ado
Page 82 and 83: thinning process for molecular trac
Page 84 and 85: Project code: LK0665 Project title:
Page 86 and 87: Review summary While poultry meat i
Page 88 and 89: Review summary A key aim of this pr
Page 90 and 91: Review summary This project aimed t
Page 96 and 97: Project code: OZ0138C Project title
Page 102 and 103: Abstract of research Projects OZ070
Page 104 and 105: produced were both relevant and imp
Page 106 and 107: List of External Reviewers. Mr. Pau
Page 108 and 109: Review of Defra’s FBZ Research Pr
Page 110 and 111: Review of Defra’s FBZ Research Pr
Page 112 and 113: Annex 5 - Review Timetable 112
Page 114 and 115: 11.45 - 12.00 Bovine and Porcine Fo
Page 116: Campylobacter Other 11.50 - 12.05 P
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