title: Microevolution of Monophasic Salmonella Typhimurium during Epidemic, United Kingdom, 2005-2010.
abstract: Microevolution associated with emergence and expansion of new epidemic clones of bacterial pathogens holds the key to epidemiologic success. To determine microevolution associated with monophasic Salmonella Typhimurium during an epidemic, we performed comparative whole-genome sequencing and phylogenomic analysis of isolates from the United Kingdom and Italy during 2005-2012. These isolates formed a single clade distinct from recent monophasic epidemic clones previously described from North America and Spain. The UK monophasic epidemic clones showed a novel genomic island encoding resistance to heavy metals and a composite transposon encoding antimicrobial drug resistance genes not present in other Salmonella Typhimurium isolates, which may have contributed to epidemiologic success. A remarkable amount of genotypic variation accumulated during clonal expansion that occurred during the epidemic, including multiple independent acquisitions of a novel prophage carrying the sopE gene and multiple deletion events affecting the phase II flagellin locus. This high level of microevolution may affect antigenicity, pathogenicity, and transmission.
authors.forename: Liljana
authors.initials: L
authors.lastname: Petrovska
authors.forename: Alison E
authors.initials: AE
authors.lastname: Mather
authors.forename: Manal
authors.initials: M
authors.lastname: AbuOun
authors.forename: Priscilla
authors.initials: P
authors.lastname: Branchu
authors.forename: Simon R
authors.initials: SR
authors.lastname: Harris
authors.forename: Thomas
authors.initials: T
authors.lastname: Connor
authors.forename: K L
authors.initials: KL
authors.lastname: Hopkins
authors.forename: A
authors.initials: A
authors.lastname: Underwood
authors.forename: Antonia A
authors.initials: AA
authors.lastname: Lettini
authors.forename: Andrew
authors.initials: A
authors.lastname: Page
authors.forename: Mary
authors.initials: M
authors.lastname: Bagnall
authors.forename: John
authors.initials: J
authors.lastname: Wain
authors.forename: Julian
authors.initials: J
authors.lastname: Parkhill
authors.forename: Gordon
authors.initials: G
authors.lastname: Dougan
authors.forename: Robert
authors.initials: R
authors.lastname: Davies
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kingsley
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015373:Bacterial Typing Techniques; D060965:Clonal Evolution / Q000235:genetics*; D002999:Clone Cells; D004251:DNA Transposable Elements; D004196:Disease Outbreaks; D024901:Drug Resistance, Multiple, Bacterial; D062665:Epidemiological Monitoring; D005408:Flagellin / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D014644:Genetic Variation; D044404:Genomic Islands; D006801:Humans; D007558:Italy / Q000453:epidemiology; D010802:Phylogeny; D039002:Prophages / Q000235:genetics / Q000302:isolation & purification; D012480:Salmonella Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D012486:Salmonella typhimurium / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000821:virology; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; C103987:SopE protein, Salmonella; D005408:Flagellin
keywords: MDR; Salmonella; Salmonella Typhimurium; United Kingdom; antimicrobial resistance; bacteria; heavy metal resistance; microevolution; molecular epidemiology; monophasic