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Genomic organization and diversity of Clostridium botulinum group III

the bug behind animal botulism

Skarin, Hanna (2015). Genomic organization and diversity of Clostridium botulinum group III. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2015:80
ISBN 978-91-576-8358-8
eISBN 978-91-576-8359-5
[Doctoral thesis]

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Abstract

Botulism is caused by botulinum neurotoxins (BoNTs) produced by the spore forming strictly anaerobic bacterium Clostridium botulinum. Seven different types of BoNTs (type A-F) have so far been established on the basis of neutralization with different antibodies. Botulism affects both humans and animals, and there are occasionally large-scale outbreaks of high mortality in animals. Especially large outbreaks of avian botulism have been reported from various countries, including Sweden. Other animals relatively commonly affected are cattle, horses, sheep and farmed fur animals. C. botulinum is a diverged species and can be organized into four groups, which reflect their genetic and physiological differences. C. botulinum group III strains producing BoNT types C, D and chimers C/D and D/C, are mainly connected to animal botulism. The gene encoding BoNT in C. botulinum group III strains is located on an unstable plasmid-like phage.

In this thesis, strains of the previously relatively uncharacterised C. botulinum group III were isolated and genotyped with pulsed-field gel electrophoresis. Several pulsotypes were formed, but the majority clustered closely together and represented most of the chimeric strains. Strains representing different pulsotypes and different animal and geographical origin, were selected for whole genome sequencing and the resulting genomes could be divided into four genomic lineages. Comparisons against genomes of Clostridium novyi and Clostridium haemolyticum revealed that they could be organized into the same genomic lineages (lineages II-IV), which resulted in the suggested collective term C. novyi sensu lato. The organization of all sequenced genomes was analysed. It revealed a relatively conserved chromosome and an abundance of highly dynamic plasmids. The plasmids, lineages and species were entwined because plasmids and toxin genes had moved across the lineage boundaries. Of the four lineages, only lineage I was C. botulinum specific, and this lineage includes strains of the most common pulsotype. One genome of lineage I was assembled into completion. It was smaller than C. botulinum group I and II genomes, but contained as much as five plasmids. Most of the identified putative toxin genes were found on these plasmids. Strains of lineage I may be more virulent than other C. botulinum group III strains, which is reflected by their domination in animal botulism cases today.

Authors/Creators:Skarin, Hanna
Title:Genomic organization and diversity of Clostridium botulinum group III
Subtitle:the bug behind animal botulism
Series/Journal:Acta Universitatis agriculturae Sueciae
Year of publishing :August 2015
Depositing date:18 August 2015
Volume:2015:80
Number of Pages:78
Papers/manuscripts:
NumberReferences
ISkarin, H., Lindberg, A., Blomqvist, G., Aspán, A. and Båverud, V. (2010). Molecular characterization and comparison of Clostridium botulinum type C avian strains. Avian Pathology, 39(6): 511–518.
IIAnza, I1., Skarin, H1., Vidal D., Lindberg, A., Båverud, V. and Mateo, R. (2014). The same clade of Clostridium botulinum strains is causing avian botulism in southern and northern Europe. Anaerobe, 26: 20-23. 1These authors contributed equally to this publication
IIISkarin, H., Håfström, T., Westerberg, J. and Segerman, B. (2011). Clostridium botulinum group III: a group with dual identity shaped by plasmids, phages and mobile elements. BMC Genomics, 12:185. doi:10.1186/1471-2154-12-185.
IVSkarin, H. and Segerman, B. (2014). Plasmidome interchange between Clostridium botulinum, Clostridium novyi and Clostridium haemolyticum converts strains of independent lineages into distinctly different pathogens. PLoS ONE, 9 (9): e107777. doi:10.1371/journal.pone.0107777.
Place of Publication:Uppsala
Publisher:Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences
Associated Programs and Other Stakeholders:SVA - National Veterinary Institute > A contributor is enlisted in SVA
ISBN for printed version:978-91-576-8358-8
ISBN for electronic version:978-91-576-8359-5
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:L Animal production > L73 Animal diseases
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Cell Biology
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Microbiology (Microbiology in the medical area to be 30109)
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 403 Veterinary Science > Pathobiology
Agrovoc terms:clostridium, botulism, neurotoxins, genomes, bacteriophages, plasmids, gel electrophoresis
Keywords:Clostridium botulinum, Clostridium haemolyticum, Clostridium novyi, botulinum neurotoxin, BoNT, botulism, PFGE, genome, plasmid, bacteriophage
URN:NBN:urn:nbn:se:slu:epsilon-e-2845
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-2845
ID Code:12514
Faculty:VH - Faculty of Veterinary Medicine and Animal Science
Department:(VH) > Dept. of Biomedical Sciences and Veterinary Public Health
Deposited By: Hanna Skarin
Deposited On:19 Aug 2015 07:15
Metadata Last Modified:07 Feb 2016 05:22

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