Microbial Pathogenesis & Infectious Diseases

Intracellular pathogenesis

Intracellular parasites are micro-parasites that are capable of growing and reproducing inside the cells of a host. Facultative intracellular parasites are capable of living and reproduce either inside or outside cells. Bacterial examples include: Francisella tularensis, listeria, monocytes, Salmonella Typhi, Mycobacterium. Obligate intracellular parasites cannot reproduce outside their host cell, means that the reproduction of the parasite is entirely dependent on intracellular resources. Examples include viruses, certain bacteria, includes Chlamydia, and closely related species, Coxiella, certain species of Mycobacterium such as Mycobacterium leprae and Mycobacterium tuberculosis.

The majority of intracellular parasites must keep its host cells alive as long as they are reproducing and growing. In order to grow, they need nutrients that might be less in their free form in the cell. People with T cell deficiencies are susceptible to intracellular pathogens.