title: Comparison of ruminant and human attaching and effacing Escherichia coli (AEEC) strains.
abstract: The presence of 12 genes associated with virulence in human attaching and effacing Escherichia coli (AEEC) was studied within a collection of 20 enterohemorrhagic E. coli (EHEC) and 206 atypical enteropathogenic E. coli (EPEC) isolated from ruminants. In addition, virulence genes and the clonal relationship of 49 atypical EPEC O26 strains isolated from humans and ruminants were compared to clarify whether ruminants serve as a reservoir of atypical EPEC for humans. A great diversity in the content of virulence gene was found. Thus, the espH, espG and map genes were detected in more than 85% of ruminant AEEC strains; the tccP2, espI, efa1/lifA, ehxA and paa genes were present in 50-70% of strains; and other genes such as tccP, espP, katP and toxB were detected in <25% of strains. EHEC strains contained more virulence genes than atypical EPEC strains. Our results suggest for the first time that the efa1/lifA gene is associated with diarrhea in newborn ruminants and that the AEEC strains with the H11 flagellar antigen are potentially more virulent than the non-H11 AEEC strains. Importantly, we identified a new intimin variant gene, eaeρ, in three ruminant atypical EPEC strains. The comparison of ruminant and human EPEC O26 strains showed that some ruminant strains possess virulence gene profiles and pulse-field gel electrophoresis pulsotypes similar to those of human strains. In conclusion, our data suggest that atypical EPEC is a heterogeneous group with different pathogenic potential and that ruminants could serve as a reservoir of atypical EPEC for humans.
authors.affiliation: Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Horcajo
authors.forename: Gustavo
authors.initials: G
authors.lastname: Domínguez-Bernal
authors.forename: Ricardo
authors.initials: R
authors.lastname: de la Fuente
authors.forename: José A
authors.initials: JA
authors.lastname: Ruiz-Santa-Quiteria
authors.forename: Jesús E
authors.initials: JE
authors.lastname: Blanco
authors.forename: Miguel
authors.initials: M
authors.lastname: Blanco
authors.forename: Azucena
authors.initials: A
authors.lastname: Mora
authors.forename: Ghizlane
authors.initials: G
authors.lastname: Dahbi
authors.forename: Cecilia
authors.initials: C
authors.lastname: López
authors.forename: Beatriz
authors.initials: B
authors.lastname: Puentes
authors.forename: María Pilar
authors.initials: MP
authors.lastname: Alonso
authors.forename: Jorge
authors.initials: J
authors.lastname: Blanco
authors.forename: José A
authors.initials: JA
authors.lastname: Orden
mesh_terms: D000818:Animals; D003967:Diarrhea / Q000382:microbiology; D054324:Enterohemorrhagic Escherichia coli / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D054308:Enteropathogenic Escherichia coli / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D004926:Escherichia coli / Q000145:classification* / Q000302:isolation & purification / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics; D006801:Humans; D012418:Ruminants / Q000382:microbiology*; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D029968:Escherichia coli Proteins; D037521:Virulence Factors