Enterococcal leucine-rich repeat-containing protein involved in virulence and host inflammatory response

Infect Immun. 2007 Sep;75(9):4463-71. doi: 10.1128/IAI.00279-07. Epub 2007 Jul 9.

Abstract

Enterococcus faecalis is an important nosocomial pathogen associated with high morbidity and mortality for patients who are immunocompromised or who have severe underlying diseases. The E. faecalis genome encodes numerous surface-exposed proteins that may be involved in virulence. This work describes the characterization of the first internalin-like protein in E. faecalis, ElrA, belonging to the recently identified WxL family of surface proteins. ElrA contains an N-terminal signal peptide for export, a leucine-rich repeat domain that may interact with host cells, and a C-terminal WxL domain that interacts with the peptidoglycan. Disruption of the elrA gene significantly attenuates bacterial virulence in a mouse peritonitis model. The elrA deletion mutant also displays a defect in infection of host macrophages and a decreased interleukin-6 response in vivo. Finally, elrA expression is induced in vivo. Altogether, these results demonstrate a role for ElrA in the E. faecalis infectious process in vivo and suggest that this surface protein may contribute to E. faecalis virulence by stimulating the host inflammatory response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Bacterial Proteins / genetics
  • Bacterial Proteins / physiology*
  • Disease Models, Animal
  • Enterococcus faecalis / genetics
  • Enterococcus faecalis / immunology
  • Enterococcus faecalis / pathogenicity*
  • Female
  • Gram-Positive Bacterial Infections / immunology*
  • Gram-Positive Bacterial Infections / microbiology
  • Gram-Positive Bacterial Infections / pathology
  • Interleukin-6 / biosynthesis
  • Leucine / genetics
  • Leucine / physiology*
  • Mice
  • Mice, Inbred ICR
  • Molecular Sequence Data
  • Peritonitis / immunology*
  • Peritonitis / microbiology
  • Peritonitis / pathology
  • Virulence

Substances

  • Bacterial Proteins
  • Interleukin-6
  • Leucine