Helicobacter Pylori

Sample for Helicobacter Pylori

1. It is done on the patient’s serum by various methods, like ELISA.
2. H. pylori can be diagnosed with a duodenal biopsy.
3. H. pylori sample can be cultured.
4. Various samples available are :
5. Serum, for specific antibodies. This is a non-invasive method and easy to perform. This antibody appears after 2 months of infection and remains elevated for more than a year after the treatment.
   1. Initially, IgM is formed, followed by IgG and IgA. These are found in the blood and the mucosa and are high titer in chronic cases.
   2. Types of antibodies:
      1. IgG – anti-H. pylori
      2. IgA – anti- H. pylori.
      3. IgM – anti-H. pylori
6. Biopsy. These bacteria can be seen in the gastric mucosal biopsy. (Giemsa stain shows these bacteria). This is a more specific and confirmatory test.
7. Culture. A sample of mucus can be obtained through a gastroscope for culture.
8. Rapid urease test. For this test, the sample can be gastric mucosa or gastric mucus.
9. Breath test. This detects gastric urease and measures CO2 in the breath. The patient needs to be at rest for this test.
10. The stool is examined for the H. Pylori antigen. Try to do the test on the fresh sample.

Precautions for Helicobacter Pylori

• For culture, stop antibiotics, antacids, and bismuth therapy 5 to 14 days before the procedure.

Purpose of the test (Indications) for Helicobacter Pylori

1. These tests are used to diagnose H. Pylori infection.
2. In the patient with chronic gastric or duodenal ulcers.

Definition of the Helicobacter Pylori 

1. Helicobacter Pylori was formerly called Campylobacter pylori or pyloridis.
2. It is S-shaled, curved, “gull-winged” like Campylobacter.
3. It is a gram-negative bacillus found in the mucus covering the gastric mucosa.
4. It lies next to gastric lining epithelial cells and gastric pits.

 Helicobacter Pylori Bacteriology:

1. This is a small gram-negative, spiral rod bacillus discovered in 1982.
2. Helicobacter pylori (H.pylori) was known as Campylobacter pylori.
3. These are strongly urease positive.
4. Gram-negative spiral-shaped rods.
5. It has a common feature with Campylobacter.
6. It has multiple flagella at one pole and is actively motile.
7. H. Pylori growth takes 3 to 6 days when grown at 37 °C in a microaerophilic atmosphere.
8. Culture media used are:
   1. Skirrow medium.
   2.  Can add vancomycin, polymyxin B, and trimethoprim.
   3. Chocolate medium and selective media with antibiotics.
9. The colonies are translucent and measure 1 to 2 mm in diameter.
   1. These colonies have characteristic morphology.
   2. H. pylori is oxidase-positive and catalase-positive.
   3. Bacteria are motile and strong producers of urease.

Association of Helicobacter Pylori:

1. This bacteria causes gastritis and gastric and duodenal ulcers.
   1. This may even cause an oesophageal ulcer.
2. This bacteria is also associated with gastric carcinoma.
3. H. pylori is lying in the mucous of the gastric mucosa.
4. This bacteria is seen in various conditions:
   1.  It is found in acute and chronic gastritis in the stomach antrum and is positive in 90% of patients with duodenal ulcers.
      1. 95% to 98 % of the patient with a duodenal ulcer (another reference say 100%).
   2. 70%  (70% to 75%) positive in gastric ulcers.
   3. This is also seen in gastric ulcers in 60% to 70% of patients.
   4. 20% to 25 % of patients with gastric cancer are positive for H.Pylori.
   5. 10% of healthy people in the younger age group, around 30 years, are positive for H.pylori.
   6. It is positive in 50% of the cases with non-ulcer dyspepsia.
   7. The positivity of H. pylori increases with increasing age.
5. Gastric colonization by H. pylori increases with age.
6. Most of the people with H. Pylori colonization are asymptomatic.
7. Helicobacter pylori antibodies are found in 20% to 25% of healthy US citizens.
8. It shows that Helicobacter Pylori infection is subclinical.

Pathophysiology of Helicobacter Pylori infection:

1. H. Pylori growth has optimum pH of 6.0 to 7.0 and would be killed, or it can not grow at the pH within the gastric lumen.
2. Gastric mucus is impermeable to acid and acts as a buffer system.

Helicobacter pylori role in gastric ulcer formation

3. H. Pylori produces a protease enzyme that will modify gastric mucus and reduce the ability of the acid to diffuse through the mucus.
4. H. Pylori produces urease activity, leading to NH3 production and further buffering of the acid.
5. H. Pylori was given to volunteers; later on, it was found that those people developed gastritis and hypochlorhydria.
6. When antibiotics were given to these patients, they found improvement in gastritis and duodenal ulcers.
7. Toxins and lipopolysaccharide may damage the mucosal cells, while NH3 can cause direct damage to the epithelial cells.
8. Microscopic findings are:
   1. Gastritis is characterized by the infiltration of chronic and acute inflammatory cells.
   2. Neutrophils and mononuclear phagocytic cells are seen within the epithelium and lamina propria.
   3. There are vacuoles in the epithelial cells.
   4. The epithelium is damaged.
   5. There is glandular atrophy.

Pathogenesis of Ulcer due to Helicobacter Pylori:

1. These bacteria enter the body and damage the lining of the stomach mucosa.
2. The stomach mucus protects the mucosa from acid (HCl).
3. When these bacteria cause damage to the mucosa, then acid can get through the lining, leading to ulcer formation.
4. These bacteria may be dormant, and the patient may be asymptomatic.

H. Pylori mechanism for gastric ulcer

Mode of the spread of Helicobacter Pylori:

1. Its transmission is from person to person.
2. These bacteria can enter the body from:
   1. Food.
   2. Water.
   3. Utensils.
   4. Saliva and body fluids through close contact.

Clinical presentation of Helicobacter Pylori infection:

1. The incidence of H. pylori is age-related.
   

   Age of the group	Positive antibodies
   25 to 45 years	5% or less
   45 to 55 years	20%
   55 to 65 years	50%
   >65 years	75%

2. H. pylori is associated to a lesser degree with focal areas of gastritis in the body of the stomach.
3. In the case of acute infection:
   1. There may be nausea and abdominal pain.
   2. These S/S may be lost for many days.
   3. Histologically there is gastritis with infiltration by neutrophils.
4. The above stage may go into a chronic stage.
   1. There is diffuse mucosal involvement (chronic gastritis).
   2. There is the infiltration of neutrophils and lymphocytes.
   3. Chronic H. pylori infection with gastritis may be seen in 30 to 50% of the patients, and these may be asymptomatic.
5. Chronic or recurrent duodenal ulcer is associated with excessive acid production and Helicobacter Pylori presence.
   1. In the case of Zollinger-Ellison syndrome duodenal ulcers, H. pylori infection is almost negative.

The pattern of H.pylori infection:

Helicobacter Pylori: Helicobacter Pylori infection pattern

Chronic H. Pylori infection outcome is:

1. 10% develop a duodenal or gastric ulcer.
2. 0.1 to 3% develop gastric cancer.
3. 0.01% develop B-lymphocytes lymphoma called MALT, mucosa-associated lymphoid tissue lymphoma.

Normal Helicobacter Pylori

H. pylori antibody

• The negative antibody by Eliza indicates that there is no infection.
• The positive antibody test indicates the IgG-H-Pylori antibody in serum.

Lab Diagnosis of Helicobacter Pylori:

1. The gold standard for diagnosis is the endoscopic gastric mucosa biopsy for culture.
   1. This biopsy is placed in the isotonic saline of 2 to 3 mL.
   2. It is plated on enriched media (chocolate agar or selective media Skirrow’s).
   3. It is then incubated for 5 to 7 days at 37 °C.
   4. 75% of cases are positive for culture.
   5. If you do Giemsa stain on the biopsy, will detect 90% of the cases.
   6. Warthin-Starry silver stain has better results than Grams and Giemsa stain.
2. Culture takes several weeks before the final result comes.
3. Rapid Urease test. This bacteria produces a urease enzyme that acts on urea. This makes the bases for other tests. This can be done on:
   1. Gastric mucosa tissue.
   2. The gastric mucosa is placed on the paper, and its color will change.
   3. The special tablet is placed in the test tube, and gastric mucosa is added.
4. The breath test is noninvasive because H. pylori can produce CO2 by the urease enzyme acting on urea.
   1. The patient is given radiolabel Carbon-13 or carbon-14. It is given orally.
   2. Then expired air is tested for radioactivity 20 to 120 minutes later.
   3. This test sensitivity is >95%, and specificity is also >95%.
   4. This test is considered the gold standard test than the culture.
5. Serology of the Helicobacter Pylori (antibody test):
   1. The anti-IgG H. pylori are most commonly used.
      1. Its level rises after two months of infection and remains raised for a year after the treatment.
   2. The anti-IgM rises first in about 3 to 4 weeks after the infection.
      1. It disappears in 2 to 3 months after the treatment.
   3. IgM and IgA antibody levels fall after the complete treatment in about 4 weeks.
      1. While IgG level is not affected by the treatment.

Helicobacter Pylori: Helicobacter pylori serology

1. 1. By ELIZA: Antibodies are positive in almost 100% of the duodenal ulcer.
      1. 80% in gastric ulcers.
      2. Positivity increases with increasing age.
      3. Positive results do not confirm the diagnosis, but negative results rule out H. pylori infection.
2. H. pylori antigen is done on fresh stool.

Raised level of a breath test for H. pylori:

1. Acute and chronic gastritis.
2. Gastric ulcer.
3. Recurrent duodenal ulcer.
4. Carcinoma of the stomach.

Table showing the outcome of H. Pylori infection

The common tests used to diagnose H. Pylori infection:

Treatment of Helicobacter Pylori:

1. Usually, a gastroenterologist advises the tripple regime.
   1. Most clinicians advised Amoxicillin, clarithromycin, and PPI.
   2. Some advised clarithromycin, metronidazole, and tinidazole.
      1. In addition, proton pump inhibitors and H2 blockers are advised.
2. Avoid non-steroidal anti-inflammatory drugs.

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