Colonization of Helicobacter pylori can be declared roughly as half of the world population.
They were discovered in 1982. The diseases caused by H. pylori are gastritis and peptic ulcers.
Having Helicobacter pylori is a risk factor for gastric carcinoma and mucosal-associated lymphoid tissue (MALT) lymphomas.
Formerly Helicobacter pylori was also called as Campylobacter pylori.
Children as well as adults are infected with this disease.
More than 90% of adults are infected with Helicobacter pylori in developing countries.
Transmission of this disease can be occurred by person to person contact as well as by contaminated food and water.
Most of the infections caused by Helicobacter pylori are asymptomatic.
Microscopy
When stained with Gram stain H. pylori are small, Gram-negative rods. They are spiral, curved or “S” shaped.
They are 2-6.5 µm long. H. pylori has a sheathed unipolar flagellum. They can also be stained using Giemsa stain other than Gram stain.
Culture
Isolation of H. pylori is required occasionally in the investigation of gastric disease.
For culture gastric mucosal biopsy is needed. H. pylori are strictly micro-aerophilic organisms and moist carbon dioxide is needed for the growth.
It is a slow grower. Colonies are grey color and translucent. Colonies resemble H. influenzae colonies.
Growth of colonies can be seen within 3-7 days. H. pylori grow well at 37 ºC.
Blood agar
Slightly beta-hemolytic colonies can be seen
Other than that, pieces of biopsy are inoculated into chocolate agar and Campylobacter medium. Moreover, Christensen’s urea broth is also inoculated with pieces of biopsy.
Biochemical Identification
- Catalase positive
- Oxidase positive
- Urease positive
Histology
To investigate gastric lesions, gastric biopsies can be sent for Histopathology Laboratory. Biopsy should be preserved in 10% formal saline.
Serology
Serology tests can be done for the identification of H. pylori. Enzyme based latex agglutination tests and ELIZA tests are used for the detection of antibodies.
They are expensive tests. However, they have less value in the investigation and follow up of the disease.
Antigen detection in stool samples can be done for the diagnosis and for the confirmation of the success of treatment done to eliminate the organisms.
Polymerase chain reaction (PCR)
PCR is a valuable test to detect H. pylori in gastric juice, feces, dental plaque and water supplies
Urease breath test
This test is also used for the diagnosis purposes in specialist gastroenterology centres. However, this is a non-microbiology test.
Treatment
Normally when treating these infections doctors use antibiotics to eliminate the bacteria and another drug to reduce the gastric acidity.
Antibiotic treatments are not always necessary to eliminate the H. pylori infection.
However, peptic ulcer disease and gastric MALT lymphoma are treated.
Moreover, it is necessary to treat the patients with non-ulcer dyspepsia refractory to conventional treatment and patients with a family history of gastric carcinoma to prevent future complications.
pylori is sensitive to most β-lactam antibiotic drugs, Macrolides, Tetracyclines and Nitroimidazoles.
However, they are sensitive to Trimethoprim.
Though above many antibiotics are sensitive in-vitro, choice of treatment depends on the stability against gastric acid, activity against very slow growing organisms and diffusion of antibiotic into the gastric mucus layer.
Usually Amoxicillin, Clarithromycin, Tetracycline and Metronidazole are used for the treatment.
To eradicate H. pylori, combination of two antibiotics are used.
As acid-lowering drugs Omeprazole and Lansoprazole are used. H. pylori has shown some resistance mechanisms against Metronidazole.
Prevention and Control
Vaccine in not available for the prevention of this infection. In western countries social advancement is done for the reduction of infection.
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