Intracellular Organisms

Obligate intracellular parasites

• Intracellular existence protects bug from B-cell defenses
• Cannot be cultured on inert media
• Bacteria
  • Chlamydia spp.
    • cannot make any ATP
  • Rickettsia spp.
    • cannot make enough ATP
  • Mycobacterium leprae
• Viruses
  • all viruses are obligate intracellular parasites
• Protozoa
  • Plasmodium spp.
  • Toxoplasma gondii
  • Babesia spp.
  • Leishmania donovani
  • Trypanosoma cruzi
• Fungi
• none

Facultative intracellular parasites

• Able to live and reproduce either inside or outside of cells
• Bacteria
  • Mycobacterium tuberculosis
  • Salmonella typhi
  • Francisella tularensis
  • Listeria monocytogenes
  • Legionella pneumophila
  • MOTTS
  • Brucella spp.
  • Neisseria spp.
  • Yersinia pestis
  • Nocardia spp.
• Fungi
  • Histoplasma capsulatum
• Helminths
• Enterobius vermicularis  

Other obligate parasites

• Cannot be cultured on inert media
• Found outside cells
• Bacteria
  • Treponema pallidum
• Fungus (yeast-like)
  • Pneumocystis jiroveci