title: Genomic characterization of enteroaggregative Escherichia coli from children in Mali.
abstract: BACKGROUND
  Enteroaggregative Escherichia coli (EAEC) is a cause of epidemic and sporadic diarrhea, yet its role as an enteric pathogen is not fully understood.
  
  
  METHODS
  We characterized 121 EAEC strains isolated in 2008 as part of a case-control study of moderate to severe acute diarrhea among children 0-59 months of age in Bamako, Mali. We applied multiplex polymerase chain reaction and comparative genome hybridization to identify potential virulence factors among the EAEC strains, coupled with classification and regression tree modeling to reveal combinations of factors most strongly associated with illness.
  
  
  RESULTS
  The gene encoding the autotransporter protease SepA, originally described in Shigella species, was most strongly associated with diarrhea among the EAEC strains tested (odds ratio, 5.6 [95% confidence interval, 1.92-16.17]; P = .0006). In addition, we identified 3 gene combinations correlated with diarrhea: (1) a clonal group positive for sepA and a putative hemolysin; (2) a group harboring the EAST-1 enterotoxin and the flagellar type H33 but no other previously identified EAEC virulence factor; and (3) a group carrying several of the typical EAEC virulence genes.
  
  
  CONCLUSIONS
  Our data suggest that only a subset of EAEC strains are pathogenic in Mali and suggest that sepA may serve as a valuable marker for the most virulent isolates.
authors.affiliation: Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Nadia
authors.initials: N
authors.lastname: Boisen
authors.forename: Flemming
authors.initials: F
authors.lastname: Scheutz
authors.forename: David A
authors.initials: DA
authors.lastname: Rasko
authors.forename: Julia C
authors.initials: JC
authors.lastname: Redman
authors.forename: Søren
authors.initials: S
authors.lastname: Persson
authors.forename: Jakub
authors.initials: J
authors.lastname: Simon
authors.forename: Karen L
authors.initials: KL
authors.lastname: Kotloff
authors.forename: Myron M
authors.initials: MM
authors.lastname: Levine
authors.forename: Samba
authors.initials: S
authors.lastname: Sow
authors.forename: Boubou
authors.initials: B
authors.lastname: Tamboura
authors.forename: Aliou
authors.initials: A
authors.lastname: Toure
authors.forename: Dramane
authors.initials: D
authors.lastname: Malle
authors.forename: Sandra
authors.initials: S
authors.lastname: Panchalingam
authors.forename: Karen A
authors.initials: KA
authors.lastname: Krogfelt
authors.forename: James P
authors.initials: JP
authors.lastname: Nataro
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D016022:Case-Control Studies; D002675:Child, Preschool; D055028:Comparative Genomic Hybridization; D004269:DNA, Bacterial / Q000235:genetics; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D016680:Genome, Bacterial; D005838:Genotype; D006460:Hemolysin Proteins / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008302:Mali / Q000453:epidemiology; D017720:Molecular Epidemiology; D060885:Multiplex Polymerase Chain Reaction; D010447:Peptide Hydrolases / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D006460:Hemolysin Proteins; C096725:SepA protein, Shigella; D037521:Virulence Factors; D010447:Peptide Hydrolases; C570452:SepA protein, E coli