Helicobacter pylori is a highly mobile, spiral-shaped Gram negative bacillus surrounded by flagella. It was first isolated in 1983 by Warren and Marshall, relating this bacterium with gastric ulcers.

In people infected with the bacterium, it lives in the layer of mucous in the stomach where it produces ammonia due to its urease activity and it can therefore partially neutralize hydrochloric acid. This bacterium segregates certain proteins which attract macrophages and neutrophils, causing inflammation in the affected area. It also produces large amounts of urease, which neutralizes surrounding stomach acid during urea hydrolysis and it is through this mechanism that it is even further protected from the external medium.

Helicobacter pylori infection is very common. The prevalence of Helicobacter pylori varies between different groups of the population and within the same group. The risk of infection in people from developed countries throughout their entire lifetime is between 40% and 60%, while it is more than 90% in developing countries where approximately 50% of the population is infected by the age of 10 years.

Helicobacter pylori has been associated with different diseases, most of which concern the digestive tract.

The involvement of these bacteria in active chronic gastritis, their association with gastroduodenal ulcers and their inclusion by the IARC (World Health Organization cancer study group) among Group 1 carcinogens in 1994, have made it one of the microorganisms of greater interest in human pathology.

The bacterium causes infection in over half the population and can bring about complications such as:

• Chronic gastritis: most common inflammatory process in humans and closely related to Helicobacter pylori infection.
• Duodenal ulcer and Gastric ulcer: Perforations in the intestinal or stomach mucous.
• MALT lymphoma: A lymphoma occurring predominantly in adult age, most common in women and it makes up 5-10 % of all gastric neoplasias.
• Non-ulcer dyspepsia: chronic recurrent pain or discomfort in the upper abdomen.
• Gastric cancer: Helicobacter pylori infection is considered a risk factor in the development of stomach cancer.

The recommended guidelines are: treatment must be well-tolerated, easy to comply with and have an eradication rate of at least 85%. The risk-benefit ratio must always be assessed.

Treatment must always be that indicated by the prescribing physician.

There are different techniques for diagnosing Helicobacter pylori:

• Invasive techniques (urease test, histological exam or PCR)
• and other non-invasive techniques, especially the BREATH TEST..

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