Subversion of host recognition and defense systems by Francisella spp

Microbiol Mol Biol Rev. 2012 Jun;76(2):383-404. doi: 10.1128/MMBR.05027-11.

Abstract

Francisella tularensis is a gram-negative intracellular pathogen and the causative agent of the disease tularemia. Inhalation of as few as 10 bacteria is sufficient to cause severe disease, making F. tularensis one of the most highly virulent bacterial pathogens. The initial stage of infection is characterized by the "silent" replication of bacteria in the absence of a significant inflammatory response. Francisella achieves this difficult task using several strategies: (i) strong integrity of the bacterial surface to resist host killing mechanisms and the release of inflammatory bacterial components (pathogen-associated molecular patterns [PAMPs]), (ii) modification of PAMPs to prevent activation of inflammatory pathways, and (iii) active modulation of the host response by escaping the phagosome and directly suppressing inflammatory pathways. We review the specific mechanisms by which Francisella achieves these goals to subvert host defenses and promote pathogenesis, highlighting as-yet-unanswered questions and important areas for future study.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Animals
  • Francisella tularensis / growth & development
  • Francisella tularensis / pathogenicity*
  • Genome, Bacterial
  • Host-Pathogen Interactions
  • Humans
  • Inflammation Mediators / metabolism
  • Microbial Viability
  • Phagosomes / microbiology
  • Tularemia / microbiology*

Substances

  • Inflammation Mediators