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The surreptitious survival of the emerging pathogen Staphylococcus lugdunensis within macrophages as an immune

Ronald S Flannagan1, David W Watson1, Bas G J Surewaard2,3,4

  • 1Department of Microbiology and Immunology, The University of Western Ontario, London, Ontario, Canada.

Cellular Microbiology
|June 16, 2018
PubMed

Insights

Staphylococcus lugdunensis evades macrophage killing by persisting in phagolysosomes, requiring O-acetylated peptidoglycan for survival. This intracellular niche protects the bacteria and may act as a reservoir for dissemination.

Area of Science:

  • Microbiology
  • Immunology
  • Bacterial Pathogenesis

Background:

  • Staphylococcus lugdunensis is a commensal bacterium with pathogenic potential.
  • Macrophages are key immune cells involved in bacterial clearance.
  • Understanding bacterial evasion mechanisms is crucial for treating infections.

Purpose of the Study:

  • To investigate the intracellular survival mechanisms of Staphylococcus lugdunensis within macrophages.
  • To determine the role of O-acetylated peptidoglycan in S. lugdunensis survival.
  • To compare the intracellular behavior of S. lugdunensis with Staphylococcus aureus.

Main Methods:

  • In vitro macrophage infection models.
  • Analysis of bacterial survival and replication within phagolysosomes (LAMP-1 positive).
  • Assessment of the role of O-acetylated peptidoglycan (oatA mutant) and host cell intoxication.

Main Results:

  • Macrophages fail to kill ingested S. lugdunensis, which persist in LAMP-1-positive phagolysosomes without replicating.
  • Optimal survival requires O-acetylated peptidoglycan; oatA mutants show reduced survival.
  • Replicating S. lugdunensis escapes phagolysosomal and endomembrane constraints, unlike S. aureus.
  • In vivo, S. lugdunensis persists in murine Kupffer cells, requiring oatA for resistance.

Conclusions:

  • The macrophage intracellular environment serves as a protective niche for S. lugdunensis.
  • O-acetylated peptidoglycan is essential for S. lugdunensis resistance to host immunity.
  • S. lugdunensis intracellular persistence may act as a reservoir for dissemination.

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