II. Definitions
- Obligate Intracellular Organism
- Organisms unable to survive outside the host intracellular environment (e.g. all viruses)
- Facultative Intracellular Organism
- Organisms that are able to survive inside and outside host cells
- Many facultative Bacteria can survive and multiply within Macrophages after Phagocytosis
III. Mechanisms
- ATP-ADP Translocator
- Cell membrane transport system used by Obligate Intracellular Bacteria (e.g. Rickettsiae, Chlamydia)
- Imports ATP from the host cell into the Bacterial cell
- Exports ADP from the Bacterial cell into the host cell
- Resistance to Macrophage Phagocytosis
- Some Bacteria (e.g. Yersinia Pestis or Plague) secrete resistance factors that prevent lysis within Macrophages
- After Phagocytosis, these organisms multiply within Macrophages, via which they are distributed systemically
IV. Types: Bacterial Obligate Intracellular Parasites
V. Types: Bacterial Facultative Intracellular Parasites (Optional Intracellular)
- Other Mycobacterium species
- Brucella
- Bartonella Henselae
- Francisella Tularensis
- Listeria monocytogenes
- Salmonella typhi and other species
- Legionella
- Nocardia
- Rhodococcus equi
- Yersinia Pestis (Plague)
VI. Types: Intracellular Fungi
VII. Types: Intracellular Protozoa
- Trypanomsoma cruzi
- Leishmania donovani
- Toxplasma
VIII. Types: Intracellular Viruses
- All viruses are obligate intracellular Parasites
IX. References
- Davis (1990) Microbiology, 4th ed, Lippincott, Philadelphia, p. 446
- Intracellular Parasite (Wikipedia)
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Related Studies
| Concepts | Bacterium (T007) |
| SnomedCT | 414922005 |
| English | Obligate intracellular bacteria (organism), Obligate intracellular bacteria |
| Spanish | bacterias intracelulares obligadas (organismo), bacterias intracelulares obligadas |
