Chapter 8 - Infectious Diseases Flashcards
Is Epstein-Barr virus (EBV) found in circulating T lymphocytes?
No. EBV infects B lymphocytes, in which it resides in a latent state for the remainder of the patient’s life.
How is response to therapy assessed in AIDS patients?
RT-PCR amplification of HIV-1 RNA
What are 3 mechanisms by which pathogens may establish symptomatic gastrointestinal disease?
- Toxin production - without necessarily establishing infection in host (eg. Staph aureus)
- Bacterial colonisation and toxin production (e.g V. choleraie and enterotoxigenic E. coi)
- Adhesion and mucosal invasion (Shigella, Salmonella, Camylobacter jejuni, Entamoeba histolytica)
the predilection for viruses to infect certain cells and not others
tropism
the persistence of viral genomes in cells that do not produce infectious virus
Latency
Cells latently infected by CMV
Monocytes
Bacteria that expresses surface receptors for fibrinogen, fibronectin and vitronectin and uses these molecules to bind to host endothelial cells
S. aureus
Expresses surface protein A which binds the Fc portion of immunoglobulins, allowing the organism to escape antibody-mediated killing
S. aureus
Causes polyclonal T cell proliferation by binding to conserved portions of MHC molecules and to relatively conserved portions of T cell receptor beta chains
May stimulate up to 20% of T lymphocytes leading to large cytokine release
Can trigger SIRS response
Bacterial superantigens
Bacteria that can cause Ritter disease
Staph aureus can cause Staphylococcal scaled-skin syndrome (Ritter disease)
Most important virulence factor of S. pneumoniae
Antiphagocytic capsule
Bacteria that is a major source of dental caries
Streptococcus mutans
Slender gram positive rod with clubbed ends. Spreads from person to person in respiratory droplets or skin exudate.
Causes pharyngeal or less often nasal/laryngeal infection
Damage to heart, nerves and other organs may be present
Corynebacterium diphtheriae
Bacteria that catalyses the covalent transfer of ADP-ribose to elongation factor 2 (EF-2), inhibiting E2 function which is required for the translation of mRNA into protein
C. diphtheriae
Gram positive bacillus (intracellular pathogen) that causes gastroenteritis in most individuals who ingest it in sufficient quantity, and severe food borne infections in vulnerable hosts
Listeria monocytogenes
Bacterial infection characterised by necrotising inflammatory lesions in the skin or GI tract or systemically
Large spore-forming gram positive rod-shaped bacteria found in environmental sources
Anthrax (Bacillus anthracis)
Bacteria that has 2 A subunits (Edema Factor and Lethal Factor) and 1 B subunit (Protective Antigen, serves to deliver the EF and LF into cells)
B. anthracis
Aerobic gram positive bacteria found in soil that cause opportunistic infections.
Grows in distinctive branched chains
Nocardia spp.
Bacteria that causes whooping cough
Bordetella pertussis
acute, ulcerative STI caused by Haemophilus ducreyi
Chancroid (soft chancre)
chronic inflammatory STI caused by Klebsiella granulomatis
Granuloma inguinale (or donovanosis)
Receptors used by M. tuberculosis to enter macrophages
Mannose-binding lectin and type 3 complement receptor (CR3)
are expressed on the phagocyte
Cytokines that promote differentiation of Th1 cells about 3 weeks after infection with M. tuberculosis
IL-12 and IL-18
Cytokine that is a critical mediator of Th1-mediated macrophage activation and killing of bacteria in TB infection
IFN-gamma
when vertebrae are affected by TB
Pott disease
most frequent presentation of extrapulmonary tuberculosis
Lymphadenitis
Spirochete that causes syphillis
Treponema pallidum
protein on outer membrane of T. pallidum which accumulates structural diversity during the course of infection through gene conversion (recombination)
TprK
spirochetes that cause Lyme disease
Borrelia
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Clostridium species that can cause spontaneous gas gangrene and highly associated with underlying malignancy
Clostridium septicum