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1. Helicobacter pylori
Peptic Ulcer Disease
Dr. Marwa Tariq Ahmed
Dr. Dheyaa Saleh Mahdi
Department of medical microbiology
T.U.C.O.M
Lec. 5

2. General characteristics
• Gram-negative spiral or
curved bacillus
• Non-spore-forming
• Has multiple flagella on one
pole
• Fastidious in terms of
growth requirements
 Strictly micro-aerophilic
 Require C02 for growth on
charcoal medium

3. • Hallmark of the species is production of
urease enzyme
 Urease breaks urea down to C02+NH3.
 Amonia is a strong base. The process helps H.
pylori survive strongly acidic stomach
conditions.
• Very fragile (a point of importance when
referring samples to the lab)

4. Epidemiology
• - H. pylori infection occurs worldwide
• - Prevalence varies greatly among countries and
population groups
• - 20 – 50% prevalence in middle age adults in
industrialised countries
• - >80% prevalence in middle age adults in developing
countries, and may reflect poorer living conditions

5. Transmission
• - Oral ingestion of bacterium
• - Within families (esp children)
• - Person-person contact
• - Faecal-oral transmission
• - Role of water borne transmission
• - Usually contracted in the first 2 years
of life

6. Site of infection
• Highly adapted organism
that lives only on gastric
mucosa
• Gastric antrum is the most
favoured site
• Present in the mucus that
overlies the mucosa

7. Gastric-biopsy specimen showing Helicobacter pylori adhering to gastric epithelium and
underlying inflammation
McColl K. N Engl J Med 2010;362:1597-1604

8. Clinical signs
• After several days incubation period, patients suffer mild
attack of acute gastritis
 Abdominal pain
 Nausea
 Flatulence
 Bad breath
• Symptoms last about a month but hypochlorhydria can
last up to one year

9. H. pylori infection directly
associated with
• Peptic Ulcer Disease (PUD)
-Lifetime risk 3% in US, 25% Japan
-Eradication provides long-term cure
• Gastric carcinoma
-Strong evidence of increased risk 0.1-3%
-Unclear whether eradication reduces the risk of gastric cancer
• Mucosa-associated lymphoid tissue lymphoma (MALT
lymphoma)
-72%→ 98% of MALT lymphoma infected with H. pylori

10. Diagnosis
• Specimens: Stool samples and gastric biopsy
• Culture:
 Non selective media : Chocolate agar or Brucella agar (with 5%
horse blood)
 Selective media: Skirrow’s agar.
• Colony morphology: moist, runny looking and spreading
• Biochemical tests:
 Catalase +
 Oxidase +
 Urease +
 H2S +

11. Laboratory diagnosis:
non-invasive tests
• Serology : detect an immune response by examining a blood
sample for abs to the organism (ELISA)
• Urea breath test : a urea solution labelled with C14 isotope is
given to orally. Urea degraded by the urease activity in the
stomach releases 14CO2, which is absorbed into the
bloodstream and detected in the exhaled breath by a
scintillation counter. This test is highly specific and sensitive for
H. pylori

12. • Faecal antigen test :
detect H. pylori antigens
in faecal specimens
• Polymerase chain
reaction (PCR) : can
detect HP within a few
hours. Not routine in
clinical use.

13. Invasive testing
1. Histological examination of biopsy
specimens of gastric/duodenal
mucosa take at endoscopy
2. CLO-test ® : based again on urease-
production by the organism->NH3
production->rise in pH=>change in
the colour indicator of the kit
-High sensitivity and specificity
-Prompt result

14. Treatment
• Macrolids, amoxicillin and protein pump
inhibitors.
• Alternative regimen consisting of
metronidazole,tetracycline and bismuth
salt.
• Treatment should be administered for 7- 14
days to eradicate the infection.

15. Thank you