Helicobacter pylori

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H.Pylori electronic micrograph

Helicobacter pylori (H. pylori) is a gram-negative, microaerophilic, spiral-shaped bacterium that colonizes the human stomach mucosa. It was first discovered by Australian scientists Barry Marshall and Robin Warren in 1982.

Pathophysiology

H. pylori infection leads to a chronic inflammatory response in the gastric mucosa, known as chronic gastritis. The bacterium has developed several strategies to survive and persist in the acidic environment of the stomach. Some of these strategies include:

• Producing urease enzyme, which breaks down urea in the stomach into ammonia and carbon dioxide, thus neutralizing stomach acid
• Motility, facilitated by its spiral shape and flagella, allowing the bacterium to penetrate the mucus layer and attach to the gastric epithelium
• Inducing a local immune response, which further damages the gastric mucosa and contributes to the pathogenesis of gastritis and peptic ulcer disease

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H. Pylori

File:Immunohistochemical detection of Helicobacter pylori histopathology.jpg

Immunohistochemical detection of Helicobacter pylori

Transmission

• H. pylori is primarily transmitted through the oral-oral or fecal-oral routes.
• Transmission can occur through ingestion of contaminated food, water, or utensils, as well as through direct contact with infected individuals. The prevalence of H. pylori infection is higher in developing countries due to overcrowded living conditions and poor sanitation.

Clinical Manifestations

Most individuals infected with H. pylori are asymptomatic. However, in some cases, the infection can lead to the development of various gastrointestinal disorders, including:

• Chronic gastritis
• Peptic ulcer disease (gastric and duodenal ulcers)
• Gastric adenocarcinoma
• Gastric mucosa-associated lymphoid tissue (MALT) lymphoma
• Symptoms associated with these conditions may include abdominal pain, nausea, vomiting, bloating, loss of appetite, weight loss, and gastrointestinal bleeding.

Diagnosis

H. pylori infection can be diagnosed using several methods, such as:

• Non-invasive tests:
• Urea breath test (UBT)
• Stool antigen test (SAT)
• Invasive tests (require endoscopy and biopsy):
• Histology
• Rapid urease test (RUT)
• Culture

Treatment

The treatment of H. pylori infection typically involves a combination of antibiotics and acid-suppressing medications, such as proton pump inhibitors (PPIs) or H2-receptor antagonists. The most common treatment regimen is triple therapy, which consists of:

• A PPI (e.g., omeprazole, lansoprazole, or pantoprazole)
• Clarithromycin
• Amoxicillin or metronidazole
• The duration of treatment is usually 10-14 days. Quadruple therapy, which includes the addition of bismuth subsalicylate, may be used in cases of treatment failure or antibiotic resistance.

Prevention

Preventing H. pylori infection involves maintaining good hygiene practices, such as:

• Washing hands thoroughly with soap and water before preparing or eating food
• Consuming food and water from safe sources
• Avoiding sharing utensils or personal items with infected individuals
• Although a vaccine for H. pylori is not currently available, research is ongoing to develop an effective and safe immunization strategy.

See also

• Peptic ulcer
• Stomach cancer
• Gastroenterology

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