Atypical enteropathogenic Escherichia coli genomic background allows the acquisition of non-EPEC virulence factors

• Published in: FEMS microbiology letters Vol. 299; no. 1; pp. 22 - 30
• Main Authors: Bando, Silvia Y, Andrade, Fernanda B, Guth, Beatriz E.C, Elias, Waldir P, Moreira-Filho, Carlos A, Pestana de Castro, Antônio F
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01-10-2009; Blackwell Publishing Ltd; Wiley-Blackwell; Oxford University Press
• Subjects: Antigens; atypical enteropathogenic Escherichia coli; Bacteria; Bacterial Typing Techniques; Bacteriology; Biological and medical sciences; Clusters; Diarrhea; diarrheagenic Escherichia coli; E coli; Electrophoresis; Enteropathogenic Escherichia coli - classification; Enteropathogenic Escherichia coli - genetics; Enteropathogenic Escherichia coli - isolation & purification; Enteropathogenic Escherichia coli - metabolism; Escherichia coli; Escherichia coli Infections - microbiology; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Evaluation; Fundamental and applied biological sciences. Psychology; Gel electrophoresis; Genetic diversity; Genetic relationship; Genomics; Humans; Microbiology; Miscellaneous; Molecular Sequence Data; Multilocus Sequence Typing; Phylogenetics; Phylogeny; Pulsed-field gel electrophoresis; Virulence; Virulence factors; Virulence Factors - genetics; Virulence Factors - metabolism; multilocus sequence typing; pulsed-field gel electrophoresis; diarrheagenic; atypical enteropathogenic; Pulsed field electrophoresis; diarrheagenic Escherichia coli; Escherichia coli; Virulence; Bacteria; Genotype; Atypical; Enterobacteriaceae; atypical enteropathogenic Escherichia coli
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2009.01735.x

Atypical enteropathogenic Escherichia coli (aEPEC) has been associated with infantile diarrhea in many countries. The clonal structure of aEPEC is the object of active investigation but few works have dealt with its genetic relationship with other diarrheagenic E. coli (DEC). This study aimed to evaluate the genetic relationship of aEPEC with other DEC pathotypes. The phylogenetic relationships of DEC strains were evaluated by multilocus sequence typing. Genetic diversity was assessed by pulsed-field gel electrophoresis (PFGE). The phylogram showed that aEPEC strains were distributed in four major phylogenetic groups (A, B1, B2 and D). Cluster I (group B1) contains the majority of the strains and other pathotypes [enteroaggregative, enterotoxigenic and enterohemorrhagic E. coli (EHEC)]; cluster II (group A) also contains enteroaggregative and diffusely adherent E. coli; cluster III (group B2) has atypical and typical EPEC possessing H6 or H34 antigen; and cluster IV (group D) contains aEPEC O55:H7 strains and EHEC O157:H7 strains. PFGE analysis confirmed that these strains encompass a great genetic diversity. These results indicate that aEPEC clonal groups have a particular genomic background - especially the strains of phylogenetic group B1 - that probably made possible the acquisition and expression of virulence factors derived from non-EPEC pathotypes.