Helicobacter pylori gastritis

Helicobacter pylori: survives acidic environment of the stomach (5)

1. H. pyroli is able to survive the acidic environment of the stomach. 2. It produces urease which converts urea to ammonia and CO2 to create an alkaline environment that neutralizes stomach acid 3. It burrows within the mucus layer that coats the stomach lining. 4. Bacterial cells use their flagella to penetrate the mucus layer. 5. Then, they attach to the mucus-secreting epithelium or multiply adjacent to it.

Helicobacter pylori gastritis: causative agent (5)

1. Helicobacter pylori 2. short, curved 3. Gram negative 4. microaerophile 5. multiple sheathed polar flagella

Helicobacter pylori: virulence factors (2)

1. Vac A: vacuolating cytotoxin 2. Cag A: cytotoxin-associated gene

Cag A/cytotoxin-associated gene

1. alters host cytoskeleton 2. interferes with host cell signaling 3. in strains with higher risk of cancer

Helicobacter pylori: treatment

1. antibiotics + medication to inhibit acid production

Helicobacter pylori: stomach ulcers

1. as the local epithelial cells are damaged due to the combined effects of the H. pylori products, stomach acid, and chronic inflammation, mucus production decreases 2. stomach juices damage the exposed tissue to cause a peptic ulcer

Helicobacter pylori: vulnerable population (3)

1. incidence increases with age 2. infection rates are highest in low socioeconomic groups--bacteria are found in well water 3. fecal oral route

Helicobacter pylori gastritis: signs and symptoms (6)

1. most infections are asymptomatic 2. gastritis with belching and vomiting may occur 3. chronic gastritis can lead to stomach cancer 4. localized abdominal pain 5. tenderness 6. bleeding

Helicobacter pylori: prevention

1. no proven preventive

Vac A/vacuolating cytotoxin

1. promotes the flow of urea 2. induces apoptosis in epithelial cells 3. interferes with T cell function

Helicobacter pylori: pathogenesis overview (5)

1. survives the acidic environment of the stomach by urease production and burrowing within the mucus layer coating the stomach lining 2. avoids recognition by immune system receptors 3. 2 virulence factors: Vac A and Cag A 4. mucus production decreases 5. stomach juices damage the exposed tissue to cause a peptic ulcer

Helicobacter pylori gastritis: incubation period and infection length (2)

1. undetermined incubation period 2. infections persist for years, often for life.