H.pylori testing

Question 1

List the different types of tests available for H.pylori suspicious gastric ulcer.

Answer 1

1. Urea breath test (UBT)
2. Faecal and serology test
3. Biopsy urease test (endoscopy)
4. Tissue examination (endoscopy)
5. Microbiological culture and sensitivity test

Question 2

Describe the mechanism and how the urea breath test is carried out.

Answer 2

UBT is carried out by asking patient to drink ‘non-radioactive carbon 13C’ or ‘radioactive C14’. 13C is recommended for young children and pregnant women.

H. pylori will convert it to CO2 (eliminated by body) and urea. This is detected in the breath test.

Question 3

How is stool antigen assay used?

Answer 3

Bacterial antigen indicates ongoing H. pylori infection. This is quite cost efficient.

Question 4

How is serology test used to detect H. pylori?

Answer 4

You can run ELISA test to detect immunoglobulin (IgG), and it is inexpensive and noninvasive. But there are concerns over its accuracy.

Question 5

Is H. pylori easily cultured and responsive to Abx?

True
False

Answer 5

False.

H. pylori can be cultured from tissue sample from endoscopy, but they are very resistant to antibiotics. (Hence the dual therapy of 2 Abx + 1 PPI)

Question 6

How does H. Pylori cause gastric ulcers?

Answer 6

It increases the secretion of gastric which in turn increases the secretion of HCl from the parietal cells of the stomach lining. H. Pylori also contains enzymes that break down the mucin that forms the protective lining of the stomach whilst the bacteria itself is surrounded by a basic environment to neutralise the acid.