Helicobacter Pylori

Question 1

What is helicobacter pylori?

Answer 1

A gram negative, spiral-shaped bacterium colonizing gastric mucosa

Question 2

What kind of conditions does helicobacter pylori lead to?

Answer 2

Chronic gastritis

Peptic ulcer disease

Gastric cancer (WHO Group I Carcinogen)

Question 3

What are the symptoms of helicobacter pylori infection?

Answer 3

Upper abdominal discomfort

Nausea

Loss of appetite and weight loss

Question 4

What is the prevalence of helicobacter pylori infection?

Answer 4

It is seen worldwide in approximately 50% of people.

Higher in developing countries and indigenous communities. (70 - 80%)

Question 5

What condition do all H. Pylori cause?

Answer 5

Gastritis (inflammation of the stomach)

Either this gastritis causes high acidity leading to peptic ulcers, normal acid with very few symptoms and 5% chance of non-ulcerative dyspepsia, and low acid which increases cancer risk but besides that very few symptoms.

Question 6

Why does gastritis lead to different symptoms in different people?

Answer 6

Helicobacter pylori lives under the mucous the stomach produces. It extracts nutrients from gastric cells exerting immune response. H. pylori masks itself from the immune cells. This results in the immune response attacking stomach cells and releasing inflammation factors causing “mass destruction” killing glandular cells (goblet cells, parietal cells, and atrophic gastritis)

Body repairs stomach with intestinal stem cells leading to intestinal metaplasia

Question 7

What happens when goblet cells are lost?

Answer 7

Mucous secretion decreases

Question 8

What happens when parietal cells are lost?

Answer 8

Reduction of stomach acid

Question 9

How can Helicobacter pylori get diagnosed?

Answer 9

Non-invasive:

Serology

Urea breath test

Faeces antigen

Invasive:

Urease test

Culture main lab

Histology

Question 10

Can serology be used to confirm that treatment has been successful for HP?

Answer 10

No, due to immune memory of HP

Question 11

Which tests are sensitive to PPIs?

Answer 11

All the test results are confounded by PPIs except for serology.

Question 12

Why does HP produce urease?

Answer 12

It breaks down urea into ammonia and CO2 to neutralize the acid of the stomach.

To survive when there is no acid (due to alkalinity) it has porin channels on its outer membrane. When there is no acid they close and so urea no longer brought in and broken down.

Question 13

What is the name of the gene that activates in acidic conditions to allow urea into the cell?

Answer 13

Ure1

Question 14

How does the urea breath test work?

Answer 14

Utilizes the urease gene.

Radiolabelled (C13/C14) urea is put into a pill and swallowed and used by the bacteria to produce CO2 and NH3 which results in the labelled CO2 to appear in the breath (after entering bloodstream and going to lungs)

Question 15

What is the CLO test?

Answer 15

Gel with pH indicator is put into stomach and when helicobacter is activated by acidity it changes colour.

Question 16

What causes stomach cancer?

Answer 16

Bacteria (H.pylori)

Salt (high salt diet associated with cancer)

Other?

Question 17

What must be used in addition to antibiotics when eradicating HP?

Answer 17

Acid must be blocked by PPIs

Question 18

What drugs are used for acid suppression?

Answer 18

Antacids (neutralize acids directly)

Coating agents (Thickening gastric content)

H2 receptor blockers (Suppress meal-stimulation)

PPIs

Question 19

What is the first line treatment of HP?

Answer 19

Nexium HP7 triple therapy:

PPI

Amoxicillin

Metronidazole (In South East Asian countries) / Clarithromycin (In Australia)

Question 20

What is the second line treatment?

Answer 20

Quadruple therapy:

Amoxicillin

Bismuth

Furazolidone

Tetracycline

Question 21

What guides antibiotic use for HP?

Answer 21

Antibiotic sensitivity testing (Europeans go straight to quadruple therapy)

Question 22

What is the cure rate for dual therapy treatment of HP?

Answer 22

PPI + amoxicillin:

50%

Question 23

What is the cure rate for triple therapy?

Answer 23

80%

Question 24

What is the cure rate for quadruple therapy?

Answer 24

90%

Question 25

Why do quadruple therapies get discontinued?

Answer 25

They cause nausea and vomiting and causes trouble in a lot of patients (31%)

Question 26

Why is it so hard to treat HP?

Answer 26

Easily gain resistance

Complicated treatment plan (sequential vs concomitant vs hybrid)

Many tablets

Whole treatment process is too long (2 - 4 weeks treatment)

Question 27

How can HP transmission be prevented?

Answer 27

Personal hygiene

Avoid sharing food/drink

Make sure everyone under the same roof isn’t infected

Maintain good oral hygiene (reflux at night theory seems to explain HP in saliva)

Question 28

Do natural products heal HP?

Answer 28

No (Tests have only shown effectiveness in vitro which is not an ideal environment for HP survival)

Question 29

What is the most common way for HP to be transferred?

Answer 29

Mother to child (60% from parents to children)

40% from spouse to spouse

Question 30

Why does HP survive poorly outside the body?

Answer 30

HP is sensitive to oxygen

Slow growing and less competitive for nutrients

Require moist environments

Un-culturable after 1 day incubation in saline at room temperature