Helicobacter Pylori

Question 1

Characteristics - H. Pylori

Answer 1

Extremophile, can live in stomach. Gram negative spiral.

Question 2

Diseases caused - H pylori

Answer 2

Duodenal and gastric ulcers

Question 3

Adhesion virulence factors - H. Pylori

Answer 3

BabA – binds to lewis antigen on human gastric epithelial cells. SabA – binds to siaylated carbohydrates on host cell surfaces

Question 4

Toxins - H. Pylori

Answer 4

cagA – induces inflammatory response and causes cytoskeletal rearrangement of host cells, affecting cell cycle and promoting cell mobility (elongation).
VacA – region of genes which induce apoptosis, induce vacuolization, form membrane channels, inhibit T cell activation and proliferation

Question 5

Invasion/Survival virulence factors - H. Pylori

Answer 5

Urease creates H+ from gastric juice, allowing for area around bacteria to be less acidic.

Question 6

Pathogenesis - H. Pylori

Answer 6

H pylori enters host and survives in gastric environments. Once there is uses chemotaxis to arrive at the mucus layer close to epithelial cells guided by bicarbonate-dependent mucus pH gradients. Colonization will then occur in gastric mucus with some bacteria attaching to epithelial cells.

Receptors on epithelial cells will detect bacteria and produce proinflammatory cytokines which causes ulceration in stomach, it is unable to eliminate bacteria due to intracellular replication leading to prolonged inflammation and promotion of cancer.

Question 7

How is H. Pylori treated?

Answer 7

Antibiotics