title: A novel putative enterococcal pathogenicity island linked to the esp virulence gene of Enterococcus faecium and associated with epidemicity.
abstract: Enterococcus faecalis harbors a virulence-associated surface protein encoded by the esp gene. This gene has been shown to be part of a 150-kb putative pathogenicity island. A gene similar to esp has recently been found in Enterococcus faecium isolates recovered from hospitalized patients. In the present study we analyzed the polymorphism in the esp gene of E. faecium, and we investigated the association of esp with neighboring chromosomal genes. The esp gene showed considerable sequence heterogeneity in the regions encoding the nonrepeat N- and C-terminal domains of the Esp protein as well as differences in the number of repeats. DNA sequencing of chromosomal regions flanking the esp gene of E. faecium revealed seven open reading frames, representing putative genes implicated in virulence, regulation of transcription, and antibiotic resistance. These flanking regions were invariably associated with the presence or absence of the esp gene in E. faecium, indicating that esp in E. faecium is part of a distinct genetic element. Because of the presence of virulence genes in this gene cluster, the lower G+C content relative to that of the genome, and the presence of esp in E. faecium isolates associated with nosocomial outbreaks and clinically documented infections, we conclude that this genetic element constitutes a putative pathogenicity island, the first one described in E. faecium. Except for the presence of esp and araC, this pathogenicity island is completely different from the esp-containing pathogenicity island previously disclosed in E. faecalis.
authors.affiliation: Diagnostic Laboratory for Infectious Diseases, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
authors.forename: Helen
authors.initials: H
authors.lastname: Leavis
authors.forename: Janetta
authors.initials: J
authors.lastname: Top
authors.forename: Nathan
authors.initials: N
authors.lastname: Shankar
authors.forename: Katrine
authors.initials: K
authors.lastname: Borgen
authors.forename: Marc
authors.initials: M
authors.lastname: Bonten
authors.forename: Jan
authors.initials: J
authors.lastname: van Embden
authors.forename: Rob J L
authors.initials: RJ
authors.lastname: Willems
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D016984:Enterococcus faecium / Q000235:genetics* / Q000472:pathogenicity*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D009113:Muramidase / Q000235:genetics; D016366:Open Reading Frames; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; C116707:enterococcal surface protein, esp; D009113:Muramidase