Fate of germinated Bacillus anthracis spores in primary murine macrophages

Mol Microbiol. 2001 Nov;42(4):931-8. doi: 10.1046/j.1365-2958.2001.02695.x.


We investigated the fate of germinated Bacillus anthracis spores after their germination in Swiss murine peritoneal macrophages and in the cell line RAW264.7. We found that the lethal toxin and the oedema toxin are germ-associated factors that are essential for the survival of the vegetative form in host cells. We also found that pX02 is not involved in this complex pathogenic process. By transmission electron microscopy, we showed the tight interaction between the exosporium of the spore and the phagosomal membrane of the macrophage. Our data strongly suggest that the B. anthracis toxinogenic, unencapsulated Sterne strain (7702) does not multiply within macrophages. These results contributed to reveal the strategies used by B. anthracis to survive within the host and to reach the external medium where they proliferate.

MeSH terms

  • Adenylyl Cyclases / metabolism*
  • Animals
  • Anthrax / microbiology
  • Antigens, Bacterial*
  • Bacillus anthracis / growth & development
  • Bacillus anthracis / pathogenicity
  • Bacillus anthracis / physiology*
  • Bacterial Toxins / metabolism*
  • Cell Line
  • Cell Survival
  • Exotoxins / metabolism
  • Female
  • Immunohistochemistry
  • Macrophages, Peritoneal / cytology
  • Macrophages, Peritoneal / metabolism
  • Macrophages, Peritoneal / microbiology*
  • Mice
  • Microscopy, Confocal
  • Spores, Bacterial / physiology*
  • Spores, Bacterial / ultrastructure


  • Antigens, Bacterial
  • Bacterial Toxins
  • Exotoxins
  • anthrax toxin
  • Adenylyl Cyclases