title: Uropathogenic Escherichia coli pathogenicity islands and other ExPEC virulence genes may contribute to the genome variability of enteroinvasive E. coli.
abstract: Enteroinvasive Escherichia coli (EIEC) may be the causative agent of part of those million cases of diarrhea illness reported worldwide every year and attributable to Shigella. That is because both enteropathogens have many common characteristics that difficult their identification either by traditional microbiological methods or by molecular tools used in the clinical laboratory settings. While Shigella has been extensively studied, EIEC remains barely characterized at the molecular level. Recent EIEC important outbreaks, apparently generating more life-threatening cases, have prompted us to screen EIEC for virulence traits usually related to extraintestinal pathogenic E. coli (ExPEC). That could explain the appearance of EIEC strains presenting higher virulence potential.
  
  
  
  EIEC strains were distributed mainly in three phylogroups in a serogroup-dependent manner. Serogroups O124, O136, O144, and O152 were exclusively classified in phylogroup A; O143 in group E; and O28ac and O29 in group B1. Only two serogroups showed diverse phylogenetic origin as follows: O164 was assigned to groups A, B1, C, and B2 (one strain each), and O167 in groups E (five strains), and A (one strain) (Table 1). Eleven of 20 virulence genes (VGs) searched were detected, and the majority of the 19 different VGs combinations found were serogroup-specific. Uropathogenic E. coli (UPEC) PAI genetic markers were detected in all EIEC strains. PAIs IJ96and IICFT073were the most frequent (92.1 and 80.4%, respectively). PAI IV536was restricted to some serogroups from phylogroups A, B1 and E. PAI ICFT073was uniquely detected in phylogroups B2 and E. A total of 45 (88%) strains presented multiple PAI markers (two to four). PAIs IJ96and IICFT073were found together in 80% of strains.
  
  
  
  EIEC is a DEC pathovar that presents VGs and pathogenicity island genetic markers typically associated with ExPEC, especially UPEC. These features are distributed in a phylogenetic and serogroup-dependent manner suggesting the existence of stable EIEC subclones. The presence of phylogroups B2 and E strains allied to the presence of UPEC virulence-associated genes may underscore the ongoing evolution of EIEC towards a hypervirulent pathotype.
authors.affiliation: Department of Microbiology, Immunology, and Parasitology, Federal University of São Paulo, Rua Botucatu 862, CEP 04023-062, São Paulo, SP, Brazil.
authors.forename: Laís Cristina
authors.initials: LC
authors.lastname: da Silva
authors.affiliation: Department of Microbiology, Immunology, and Parasitology, Federal University of São Paulo, Rua Botucatu 862, CEP 04023-062, São Paulo, SP, Brazil.
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: de Mello Santos
authors.affiliation: Department of Microbiology, Immunology, and Parasitology, Federal University of São Paulo, Rua Botucatu 862, CEP 04023-062, São Paulo, SP, Brazil. rosa.unifesp@gmail.com.
authors.forename: Rosa Maria
authors.initials: RM
authors.lastname: Silva
mesh_terms: D004269:DNA, Bacterial; D004926:Escherichia coli / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D004927:Escherichia coli Infections / Q000382:microbiology; D019143:Evolution, Molecular; D000072282:Extraintestinal Pathogenic Escherichia coli / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D005819:Genetic Markers / Q000235:genetics; D016680:Genome, Bacterial; D044404:Genomic Islands / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D010802:Phylogeny; D065288:Serogroup; D012760:Shigella / Q000235:genetics / Q000472:pathogenicity; D056689:Uropathogenic Escherichia coli / Q000235:genetics* / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D005819:Genetic Markers
keywords: Enteroinvasive E. coli; ExPEC virulence genes; Pathogenicity-associated islands; Phylogenetic origin; Uropathogenic E. coli