Helicobacter pylori (H. pylori)

What is H. pylori?

Helicobacter pylori (H. pylori) is an infamous member of Helicobacter genus, a family of gram-negative bacteria possessing a characteristic helix shape. This family is susceptible to antibiotics and is aerophilic, meaning that they can survive on small amounts of oxygen.

In the human body, H. pylori can be found in the stomach, in the junction of the stomach and duodenum. It uses a long whip-like tail (flagellum) for locomotion. H. pylori can survive in the harshest stomach environment by colonizing the mucus lining, which is the main defense of stomach walls against erosion. The H. pylori digs deep into the mucus, while it neutralizes stomach acids by releasing an enzyme called urease. Urease breaks down urea, which is naturally present in the stomach, into bicarbonates and ammonia which are very effective substances in neutralizing acids. The neutralization process protects H. pylori against acids and releases chemicals that are detected by the well known urea breath tests for identifying the presence of this bacterium.

H. pylori infection continues to be a significant factor in the development of peptic ulcer disease, gastric malignancies and dyspeptic symptoms. It is more prevalent in developing countries, with an estimated 30%-40% incidence in the United States.

What Causes H. pylori?

H. pylori related stomach damage and ulceration is caused by a cycle that starts with opportunistic infection and inflammation, which affects the surrounding mucus-producing cells. In turn, this will result in a reduced secretion of stomach acids which contributes to further colonization of adjacent stomachal areas. If not stopped, this cycle will lead to chronic gastritis.

There are also pathological factors related to the genetic constitution of different H. pylori strains. Certain strains have a set of genes that confer them the ability to enhance the inflammatory response and use that property to produce more aggressive infections.

Symptoms of H. pylori

About 80% of the people infected with H. pylori may be asymptomatic. Some patients may develop the following symptoms:

• Nausea and vomiting are the first signs of acute infection of H. pylori
• Bloating and fullness
• Abdominal pain that lasts from more than a few to weeks
• Dyspepsia
• Presence of stomach ulcers in pylorus and duodenum
• Hunger within 1 to 3 hours after eating

Diagnosis of H. pylori

Simple breath, blood and stool tests can conclude the existence of infection by H. pylori. The most conclusive and informative test is endoscopy. This test consists in the insertion of a small flexible tube, called an endoscope, into the esophagus, stomach and duodenum. It enables direct visualization of potential ulcers, polyps and fissures that may arise due to H. pylori infection. The endoscope can also be equipped with instruments to collect stomach tissues which will be microscopically examined for H. pylori. Identification of H. pylori by examining biopsy samples is the most accurate method for diagnosis.

A urea breath test can determine the presence of H. pylori. Urea with a small amount of radioactive carbon is given to the patient and the expelled breath is examined. The urea will be metabolized by H. pylori and releases the radioactive carbon as labeled carbon dioxide, that can be easily detected.

Treatment of H. pylori

Once it is established that H. pylori is causing infection and ulceration in the stomach, the usual procedure is to allow the ulcer to heal. First-line drug treatment consists of a proton-pump inhibitor such as omeprazole, esomeprazole and lansoprazole to decrease the stomach acid production along with an antibiotic such as clarithromycin, amoxicillin and metronidazole.

There is increasing number of cases of antibiotic-resistant H. pylori strains. They are treated with second-line antibiotics such as tetracycline and levoflozacin. Usual proton-pump inhibitors are given with added bismuth subsalicylate.

Care is given to prevent further bleeding of the stomach, such as eliminating the use of non-steroidal anti-inflammatory drugs and aspirin. Milk and soft drinks are restricted because they aggravate bleeding.

Alternative Treatment

Certain foods such as broccoli, yogurt products, kimchi and green tea can help reduce H pylori infection and help to heal ulcers.

Prognosis of H. pylori

After treatment, the recurrence of symptoms is very unlikely. But a doctor will never tell you that you are free from H. pylori. Common medical knowledge tells them that once you are infected with H. pylori, it is likely that it will persist there throughout your life, especially if you have chronic gastritis or delayed H. pylori treatment for a long time. However, a patient may never experience clinical symptoms and the prognosis is usually good.

Infection by H. pylori is associated with an increased lifetime risk of having stomach cancer and  mucosa-associated lymphoid tissue (MALT) lymphoma.

Preventing H. pylori

Because the probable route of transmission is via oral-fecal and exchange of mouth fluids, the best preventive method is good personal hygiene and a clean environment, especially in food preparation. There is no vaccine against H. pylori yet.

Living with H. pylori

People with H. pylori may or may not have symptoms. If you had gastric ulcers and bleeding, avoid foods and drugs that can aggravate bleeding. Because it is transmitted via the oral-fecal route, it is advisable to have exclusive eating utensils and dispose body wastes carefully to avoid transmitting the bacterium. It is important to follow treatment guidelines in order to reduce the numbers of H. pylori to negligible levels.

Current Research of H. pylori

Currently, researchers are developing a vaccine against H. pylori, but its effectiveness still requires further studies. Research efforts continue to focus also on the complex pathological mechanisms of H. pylori.