H. Pylori

Question 1

Is H.pylori Gram positive or negative?

Answer 1

Gm negative

Question 2

What mechanisms does H Pylori use to survive the acidic gastric environment?

Answer 2

1. using its flagella to burrow into the mucous lining (pH not as acidic here)
2. secretes urease
   => urea converted to NH3
   => alkalises acidic environment

Question 3

How does H.Pylori cause disease? (pathogenesis)

Answer 3

releases bacterial cytotoxins (e.g. CagA toxin)
=> causes disruption of gastric mucosa

Question 4

Gastric conditions associated with H Pylori

Answer 4

• peptic ulcer disease
• gastric cancer
• MALT lymphoma
• atrophic gastritis

Question 5

H Pylori eradication therapy

Answer 5

amoxicillin + clarithromycin OR metronidazole + PPI

if penicillin-allergic:
clarithromycin + metronidazole + PPI

Question 5

H Pylori eradication therapy

Answer 5

a proton pump inhibitor + amoxicillin + (clarithromycin OR metronidazole)
if penicillin-allergic: a proton pump inhibitor + metronidazole + clarithromycin

Question 6

Investigations for H Pylori

Answer 6

Urea breath test
- checks for eradication
- at least 4 weeks after tx

Tests on gastric biopsy
- Rapid urease test (CLO)
- histology
- culture

Stool antigen test