title: Comparative genome analysis identifies few traits unique to the Escherichia coli ST131 H30Rx clade and extensive mosaicism at the capsule locus.
abstract: BACKGROUND
  E.coli ST131 is a globally disseminated clone of multi-drug resistant E. coli responsible for that vast majority of global extra-intestinal E. coli infections. Recent global genomic epidemiological studies have highlighted the highly clonal nature of this group of bacteria, however there appears to be inconsistency in some phenotypes associated with the clone, in particular capsule types as determined by K-antigen testing both biochemically and by PCR.
  
  
  RESULTS
  We performed improved quality assemblies on ten ST131 genomes previously sequenced by our group and compared them to a new reference genome sequence JJ1886 to identify the capsule loci across the drug-resistant clone H30Rx. Our data shows considerable genetic diversity within the capsule locus of H30Rx clone strains which is mirrored by classical K antigen testing. The varying capsule locus types appear to be randomly distributed across the H30Rx phylogeny suggesting multiple recombination events at this locus, but that this capsule heterogeneity has little to no effect on virulence associated phenotypes in vitro.
  
  
  CONCLUSIONS
  Our data provides a framework for determining the capsular genetics of E. coli ST131 and further beyond to ExPEC strains, and highlights how capsular mosaicism may be an important strategy in becoming a successful globally disseminated human pathogen.
authors.forename: Abdulaziz
authors.initials: A
authors.lastname: Alqasim
authors.forename: Fleming
authors.initials: F
authors.lastname: Scheutz
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Zong
authors.affiliation: Pathogen Research Group, Nottingham Trent University, Nottingham NG11 8NS, UK. alan.mcnally@ntu.ac.uk.
authors.forename: Alan
authors.initials: A
authors.lastname: McNally
mesh_terms: D000942:Antigens, Bacterial / Q000145:classification / Q000235:genetics; D000954:Antigens, Surface / Q000145:classification / Q000235:genetics; D016667:Bacterial Capsules / Q000235:genetics; D055028:Comparative Genomic Hybridization; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D056426:Genetic Loci; D016680:Genome, Bacterial; D009030:Mosaicism; D010641:Phenotype; D010802:Phylogeny; D014774:Virulence / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D000954:Antigens, Surface; C030659:K antigens