Helicobacter pylori

The gross specimen shows a typical peptic ulcer of the first portion of the duodenum. The great majority of these ulcers are associated with chronic H. pylori infection, which plays a pathogenetic role.

Eradication of H. pylori is necessary not only for rapid healing of active ulcers, but also to prevent future recurrence. Therefore, drugs that eradicate this gram-negative bacillus are used for treatment of active peptic ulcer disease. Proton pump inhibitors (omeprazole or lansoprazole) also have activity against H. pylori, but alone are not sufficient to achieve eradication.

This treatment must be combined with at least one of the antibiotics (usually two) that are effective against H. pylori. Clarithromycin is usually used in combination with either metronidazole or amoxicillin.

The urea breath test, the stool antigen test, and biopsy-based tests can all be used to assess the success of treatment

Ans. is ‘d’ i.e., It provides life long immunity 

. There is no effective immunity against H. pylori infection. The immune response to H. pylon includes both the production of antibody (local and systemic) and a cell-mediated response but is ineffective in clearing the bacterium.

. H. Pylori has a protective role against gastroesophageal reflux disease (GERD) and adenocarcinoma of the esophagus and gastric cardia.

.  Antral predominant gastritis is most closely linked with duodenal ulceration, whereas pangastritis is linked with gastric ulceration and adenocarcinoma.

Antral gastritis       —> duodenal ulcer

Pangastritis           —> Gastric ulcer

Gastric adenocarcinoma

.  IL – 1 fi is the major proinflammatory cytokine in peptic ulcer disease.

About other options

.   Urea breath test is the most consistently accurate test.

.   H. pylori is a gram negative, flagellate bacillus which is motile by lophotrichous flagella.

Ans. is ‘c’ i.e., All children in developing counteries have immunity by five years of age

.   “Today, helicobacters colonise the stomach of half the human population of the world”.

Developed countries                                 30%

Developing countries                               > 80%

.   H. pylori is usually acquired in childhood but immunity does not develop.

.  Low socioeconomic status is a risk factor for H. pylori positivity.

Ans. is ‘d’ i.e., Urease activity provides protective environment to the bacilli

.  H. pylori produces an exceptionally powerful urease, almost 100 times more active than that of proteus vulgaris, which is vital to its survival in the stomach.

.  Urease acts on urea to generate ammonia, which neutralizes acid around bacteria.

Remember

.  H pylori is easily cultured from vomitus and gastroesophageal refluxate and is less easily cultured from stool.

About other options

Option A

–       Microbial culture is most specific but may be insensitive because of difficulty with H. pylori isolation. (How can an insensitive procedure be gold standard investigation).

Option B

–   Urea breath test is the most consistently accurate test. It will be positive with massive infection.

Option C

– Antiurease antibodies are not produced. The only antibody produced by the infection of H. pylori is anti `CagA’

antibody.

Ans. is ‘a’ i.e., Low grade malt lymphoma 

Answer is C (Gastric leiomyoma)

Gastric leiomyomas are not associated with H. pylori infections

Answer is B (Urea breath test) :

The test of choice for documenting eradication is urea breath test.

Assessing success of Treatment / Eradicatiion of H. Pyrlori  :

• Assessment should be done atleast 4 weeks after completin of anti H. Pylori therapy.
• In the assessment of treatment success non invasive tests are normally preferred.

Assessment of success of treatment

Answer is A (Less prevalent in developing countries)

H. pylori infection are inane prevalent in developing countries.

• The prevalence of H. pylori is approx. 30% in U.S. and other developed countries as against > 80% in most developing countries – Harrison
• H. Pylori is a gram negative, spiral, flagellated bacillus – Harrison
• Strains producing toxins (strains possessing cag pathogenicity DNA island) are more likely to give rise to severe gastritis, peptic ulceration and gastric cancer than strains without it.
• DNA island or cag pathogenicity island is a large region of DNA which has genes that control production of toxins.
• Urea breath test is a simple, inexpensive and consistently accurate test for H.pylori detection.

Answer is B (The incidence of complications has remained unchanged)

• H. pylori eradication decreases the likelihood of occurrence of complications.
• The incidence of H.pylori is > 80% in most developing countries, and so the chances of reinfection are also high.
• H. pylori eradication reduced the chances of recurrence
• ‘After successful eradication of H.pylori with antibiotics, ulcer recurrence rates are reduced dramatically to 5-20% at 1 year – CMDT 2003/571
• Option ‘b’ ‘The incidence of complications has remained unchanged’ is thus the answer of exclusion !!

Ans. D i.e. H. pylori

Peptic ulcer/Peptic ulcer disease

• It is defined as mucosal erosions equal to or greater than 0.5 cm.
• As many as 70-90% of such ulcers are associated with Helicobacter pylori, a helical-shaped bacterium that lives in the acidic environment of the stomach.
• Four times as many peptic ulcers arise in the duodenum—the first part of the small intestine, just after the stomach—as in the stomach itself.
• About 4% of gastric ulcers are caused by a malignant tumor, so multiple biopsies are needed to exclude cancer.
• Duodenal ulcers are generally benign.

Ans. D: Cimetidine

A proton pump inhibitor combined with two antibiotics has been shown to be very effective in clearing H pylori from the stomach.

The current recommendation is treatment with amoxicillin, clarithromycin, and a proton pump inhibitor (lansoprazole) for 2 weeks.

Ans. D: Tetracycline

Ans. C. H.pylori

Helicobacter pylori is a Gram-negative, microaerophilic bacterium that can inhabit various areas of the stomach and duodenum.

It causes a chronic low-level inflammation of the stomach lining and is strongly linked to the development of duodenal and gastric ulcers and stomach cancer.

Over 80% of individuals infected with the bacterium are asymptomatic.

The most reliable method for detecting H. pylori infection is a biopsy check during endoscopy with a rapid urease test, histological examination, and microbial culture.

The standard first-line therapy is a one week “triple therapy”

Ans. is `d’ i.e., Helicobacter pylori

Microaerophiles are those groups of bacteria that can grow under reduced oxygen (5% to 10%) and increased carbon dioxide (8% to 10%).

Higher oxygen tensions may be inhibitory to them. This environment can be obtained in specially designed jars or bags.

Examples of Microaerophiles are: Campylobacter jejuni, Helicobacter pylori etc.

H. pylori has five to seven sheathed polar flagella as shown in the photograph above.

Vibrio cholerae and Pseudomonas aeruginosa have single polar flagellum. Occasional strains of pseudomonas may contain 2 or 3 flagella.

Spirochetes (Treponema) is motile by endoflagella.