Pneumonia (gram positive cocci)

Question 1

Characteristics - Pneumonia

Answer 1

Gram-positive bacteria which is found in the respiratory tract, it is asymptomatic in 20% of people and can be acquired either from the community or in a hospital.

Question 2

Diseases caused - Pneumonia

Answer 2

Pneumonia, meningitis, sinusitis, otitis media

Question 3

Adhesion virulence factors - Pneumonia

Answer 3

pneumolysin may help in binding to pneumocytes and endothelial cells. ChoP allows interaction with rPAF. PavA binds to fibrionectin. Enolase binds to plasminogen

Question 4

Invasion/Replication virulence factors - Pneumonia

Answer 4

Autolysin is responsible for cell wall degradation as well as cell death. Pneumolysin disrupts tight junctions and integrity of bronchial epithelial monolayer, also disrupts alveolar-capillary barriers

Question 5

Evasion virulence factors - Pneumonia

Answer 5

pneumolysin defends against mechanical defences such as ciliary in respiratory tract by slowing ciliary beating. Also inhibits phagocytes and immune cell function as well as decreate bactericidal activity of PMNs by suppressing oxidative burst. IgA protease. PspC binds to sIgA. PspA inhibits complement deposition. Capsule is vital, antiphagocytic, binds to factor H (stop C3b opsonization).

Question 6

Toxins - Pneumonia

Answer 6

Pneumolysin activates classic complement pathway which leads to inflammation and tissue damage. It will also kill host cells in a similar fashion to membrane attack complex’s. Autolysin is responsible for release of pneumolysin. Hyaluronidase breaks down cellular components. Hydrogen peroxide directly damages lungs

Question 7

Pathogenesis - Pneumonia

Answer 7

Colonization of nasopharynx – binds to disaccharide on oral epithelial cells

Colonization of lung – binds to pneumocytes in the lung

Nost and throat – Binds to fibrionectin, rPAF and plasminogen.

Will then damage the lung via activating inflammatory response and direct damage

Question 8

How is Pneumonia detected?

Answer 8

X-ray, sputum

Question 9

How is Pneumonia treated?

Answer 9

Vaccine