Evolution of < i > Salmonella enterica < /i > serotype Typhimurium driven by anthropogenic selection and niche adaptation

by Matt Bawn, Nabil-Fareed Alikhan, Ga ëtan Thilliez, Mark Kirkwood, Nicole E. Wheeler, Liljana Petrovska, Timothy J. Dallman, Evelien M. Adriaenssens, Neil Hall, Robert A. KingsleySalmonella enterica serotype Typhimurium (S. Typhimurium) is a leading cause of gastroenteritis and bacteraemia worldwide, and a model organism for the study of host-pathogen interactions. TwoS. Typhimurium strains (SL1344 and ATCC14028) are widely used to study host-pathogen interactions, yet genotypic variation results in strains with diverse host range, pathogenicity and risk to food safety. The population structure of diverse strains ofS. Typhimurium revealed a major phylogroup of predominantly sequence type 19 (ST19) and minor of ST36. The major phylogroup had a population structure with two high order clades ( α and β) and multiple subclades on extended internal branches, that exhibited distinct signatures of host adaptation and anthropogenic selection. Clade α contained a number of subclades composed of strains from well characterized epidemics in domesticated animals, while clade β contained multipl e subclades associated with wild avian species. The contrasting epidemiology of strains in clade α and β was reflected by the distinct distribution of antimicrobial resistance (AMR) genes, accumulation of hypothetically disrupted coding sequences (HDCS), and signatures of functional diversificatio n. These observations were consistent with elevated anthropogenic selection of clade α line...
Source: PLoS Genetics - Category: Genetics & Stem Cells Authors: Source Type: research