Clostridium botulinum group III: a group with dual identity shaped by plasmids, phages and mobile elements

BMC Genomics

Research Article

Josefina Westerberg¹  Therese Håfström¹  Bo Segerman¹  Hanna Skarin² 

[1] Department of Bacteriology, National Veterinary Institute (SVA), Uppsala, Sweden;Department of Bacteriology, National Veterinary Institute (SVA), Uppsala, Sweden;Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden;

关键词: Draft Genome;    Mobile Element;    Toxin Gene;    Botulism;    Clostridium Botulinum;   

DOI  :  10.1186/1471-2164-12-185

 received in 2011-01-19, accepted in 2011-04-12,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundClostridium botulinum strains can be divided into four physiological groups that are sufficiently diverged to be considered as separate species. Here we present the first complete genome of a C. botulinum strain from physiological group III, causing animal botulism. We also compare the sequence to three new draft genomes from the same physiological group.ResultsThe 2.77 Mb chromosome was highly conserved between the isolates and also closely related to that of C. novyi. However, the sequence was very different from the human C. botulinum group genomes. Replication-directed translocations were rare and conservation of synteny was high. The largest difference between C. botulinum group III isolates occurred within their surprisingly large plasmidomes and in the pattern of mobile elements insertions. Five plasmids, constituting 13.5% of the total genetic material, were present in the completed genome. Interestingly, the set of plasmids differed compared to other isolates. The largest plasmid, the botulinum-neurotoxin carrying prophage, was conserved at a level similar to that of the chromosome while the medium-sized plasmids seemed to be undergoing faster genetic drift. These plasmids also contained more mobile elements than other replicons. Several toxins and resistance genes were identified, many of which were located on the plasmids.ConclusionsThe completion of the genome of C. botulinum group III has revealed it to be a genome with dual identity. It belongs to the pathogenic species C. botulinum, but as a genotypic species it should also include C. novyi and C. haemolyticum. The genotypic species share a conserved chromosomal core that can be transformed into various pathogenic variants by modulation of the highly plastic plasmidome.

【 授权许可】

Unknown   
© Skarin et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.