The Library
Neutral genomic microevolution of a recently emerged pathogen, salmonella enterica serovar agona
Tools
Tools
Tools
Zhou, Zhemin, McCann, Angela, Litrup, Eva, Murphy, Ronan, Cormican, Martin, Fanning, Seamus, Brown, Derek, Guttman, David S., Brisse, Sylvain and Achtman, Mark (2013) Neutral genomic microevolution of a recently emerged pathogen, salmonella enterica serovar agona. PLoS Genetics, 9 (4). e1003471. doi:10.1371/journal.pgen.1003471
|
Text
WRAP_Zhou_journal.pgen.1003471.pdf - Published Version Available under License Creative Commons Attribution. Download (3633Kb) | Preview |
Official URL: http://dx.doi.org/10.1371/journal.pgen.1003471
Abstract
Salmonella enterica serovar Agona has caused multiple food-borne outbreaks of gastroenteritis since it was first isolated in
1952. We analyzed the genomes of 73 isolates from global sources, comparing five distinct outbreaks with sporadic
infections as well as food contamination and the environment. Agona consists of three lineages with minimal mutational
diversity: only 846 single nucleotide polymorphisms (SNPs) have accumulated in the non-repetitive, core genome since
Agona evolved in 1932 and subsequently underwent a major population expansion in the 1960s. Homologous
recombination with other serovars of S. enterica imported 42 recombinational tracts (360 kb) in 5/143 nodes within the
genealogy, which resulted in 3,164 additional SNPs. In contrast to this paucity of genetic diversity, Agona is highly diverse
according to pulsed-field gel electrophoresis (PFGE), which is used to assign isolates to outbreaks. PFGE diversity reflects a
highly dynamic accessory genome associated with the gain or loss (indels) of 51 bacteriophages, 10 plasmids, and 6
integrative conjugational elements (ICE/IMEs), but did not correlate uniquely with outbreaks. Unlike the core genome, indels
occurred repeatedly in independent nodes (homoplasies), resulting in inaccurate PFGE genealogies. The accessory genome
contained only few cargo genes relevant to infection, other than antibiotic resistance. Thus, most of the genetic diversity
within this recently emerged pathogen reflects changes in the accessory genome, or is due to recombination, but these
changes seemed to reflect neutral processes rather than Darwinian selection. Each outbreak was caused by an independent
clade, without universal, outbreak-associated genomic features, and none of the variable genes in the pan-genome seemed
to be associated with an ability to cause outbreaks.
Request changes or add full text files to a record
Repository staff actions (login required)
 |
View Item |
Downloads
Downloads per month over past year
