Helicobacter pylori Infection

What is Helicobacter pylori?

Helicobacter pylori (H. pylori) is a bacterium that can settle in the stomach and live there for a long time.

The infection is most often acquired in childhood and, if untreated, may continue for years or even for life. In many people it causes no symptoms at all. In some, however, it may lead to chronic gastritis or to ulcers of the stomach or duodenum.

The importance of H. pylori does not lie only in its causing ulcers. Long-standing infection may in some people contribute to changes in the stomach lining such as atrophy and intestinal metaplasia, and may increase the risk of stomach cancer.

H. pylori is therefore now regarded not merely as “the ulcer bug” but as an important chronic infection that should be treated.

How common is H. pylori?

H. pylori is one of the commonest chronic bacterial infections in the world.

Large recent studies show its frequency worldwide falling compared with earlier years. A wide-ranging study covering the period 2015–2022 calculated that about 44% of adults had H. pylori infection.

The proportion varies greatly between countries. Socio-economic conditions, living conditions in childhood, crowded living, hygiene and access to clean water can all affect how often the infection is seen.

H. pylori is common in Turkey too. But because studies differ in period, region, age group and diagnostic method used, it is not correct to give a single percentage representing the whole of present-day Turkey.

What is the difference between prevalence and incidence?

Prevalence means the proportion of people in a population carrying H. pylori.

Incidence means the new infections arising within a given period.

Because H. pylori is mostly acquired in childhood, the rate at which new infection develops in adults is far lower than the overall frequency of the infection in the population.

As hygiene and living conditions improve, the frequency of infection is expected to fall steadily, particularly in younger generations.

How is H. pylori transmitted?

Not all the details of transmission have been established with certainty. But the bacterium is thought to pass mainly from person to person.

The possible routes of transmission are accepted as:

• Mouth to mouth,
• The faecal-oral route,
• Contact with vomit or stomach contents,
• Contaminated water or food where hygiene is poor.

That infection is seen more often among people living in the same household also supports the importance of transmission within the family.

For this reason the 2024 ACG guideline includes testing the adult household members of H. pylori positive people among the groups that should be considered.

The idea that H. pylori will inevitably be caught by eating from the same plate or being in the same room is not, however, correct.

How can H. pylori live in the stomach?

The stomach is a highly acidic environment. Despite this, H. pylori has special features that let it survive there.

The bacterium settles in the protective mucus layer on the stomach surface.

It produces an enzyme called urease. Through this enzyme the acid environment around the bacterium is partly neutralised and H. pylori creates a small area for itself in which life is easier.

The bacterium’s attachment to the stomach lining and the inflammation it produces may over time cause damage to the stomach surface.

This process is not the same in everyone. The features of the bacterium, the person’s genetic make-up, immune response, environmental factors and the duration of the infection all affect how the disease will run.

What diseases can H. pylori cause?

No serious disease develops in the great majority of people who have H. pylori.

Nonetheless the infection is associated with the following:

• Chronic gastritis
• Duodenal ulcer
• Gastric ulcer
• Iron deficiency anaemia in some patients
• Gastric atrophy and intestinal metaplasia
• MALT lymphoma
• Stomach cancer

H. pylori is one of the most important modifiable risk factors in the development of stomach cancer.

But being H. pylori positive does not mean that a person will get stomach cancer. Cancer develops in only a small proportion of infected people.

Even so, clearing the bacterium may contribute to reducing the long-term risk of stomach cancer.

Does H. pylori cause symptoms?

Most people may have no symptoms at all.

When there are symptoms, they may include:

• Pain or burning in the upper part of the stomach,
• Indigestion,
• Bloating,
• Nausea,
• Feeling full early.

But none of these symptoms is peculiar to H. pylori. The same complaints can occur in people who do not have the bacterium.

For this reason H. pylori cannot be diagnosed from the symptoms alone.

How is the diagnosis made?

There are methods for diagnosing H. pylori both without endoscopy and during endoscopy.

Urea breath test

A breath sample given after the patient drinks a special substance is analysed.

It is one of the more reliable methods for showing active infection and may also be used to confirm that the bacterium has been cleared after treatment.

H. pylori stool antigen test

Antigens belonging to the bacterium are sought in a stool sample.

It may be used to detect active infection and to check eradication after treatment.

Gastroscopy and biopsy

Small biopsies may be taken from the stomach in patients who need an endoscopy.

H. pylori can be sought in these samples by various methods. Gastritis, atrophy, intestinal metaplasia, ulcer or other stomach diseases can be assessed at the same time.

Blood test

Antibodies formed against H. pylori can be measured in the blood.

But because antibodies may remain positive for a long time after the bacterium has been cleared, a blood test cannot reliably distinguish active infection from past infection.

Breath and stool tests are therefore generally more valuable for assessing active infection or the success of treatment.

Should every H. pylori positive person be treated?

The approach here has changed markedly in recent years.

On the current ACG approach, eradication treatment should be offered to a person found to have active H. pylori infection.

One of the main reasons is that H. pylori is a chronic infection and is associated with important diseases such as peptic ulcer, MALT lymphoma and stomach cancer.

But there is an important distinction here:

Testing everyone indiscriminately for H. pylori and treating a person found to have active infection are not the same thing.

Who should be tested must be decided by weighing the person’s age, symptoms, family history, ulcer history, stomach cancer risk and other features.

How is it treated?

The aim is to clear the bacterium from the stomach completely. This is called eradication.

Treatment uses drugs that reduce stomach acid together with more than one antibiotic, and bismuth in some regimens.

Because antibiotic resistance is increasing, not every treatment widely used in the past now has the same success rate.

Clarithromycin resistance in particular is an important problem.

A meta-analysis of studies from Turkey reported clarithromycin resistance at about 27%, metronidazole resistance at 28% and levofloxacin resistance at about 20%.

The choice of treatment should therefore be made according to the antibiotics the patient has taken before, any antibiotic sensitivity results, allergies and local resistance patterns.

In current guidelines, one of the important options for suitable patients not previously treated and whose antibiotic sensitivity is unknown is 14 days of bismuth quadruple therapy.

Different treatment options may be used in some patients.

For this reason it is not right to start H. pylori treatment oneself from standard antibiotic lists found on the internet.

Is a check needed after treatment ends?

Yes. This is a very important point.

Symptoms settling does not necessarily mean that the bacterium has been cleared.

Whether eradication has succeeded should be confirmed in every patient treated for H. pylori.

For the check:

• The urea breath test,
• The H. pylori stool antigen test, or
• Biopsy-based tests where suitable

may be used.

The check test should be done at least four weeks after the antibiotic treatment is completed.

To avoid false negative results, PPI stomach medications generally need to have been stopped two weeks before the test, and antibiotics and bismuth four weeks before. Stopping the drugs should be planned by the doctor according to the patient’s condition.

Does H. pylori come back after treatment?

Re-infection can occur after successful eradication, but this is not thought to be common in adults.

If the test becomes positive again shortly after treatment, it should be considered that rather than a new infection, the first treatment may not have cleared the bacterium completely.

Is it possible to avoid H. pylori?

There is not yet a widely used vaccine that prevents the infection entirely.

General hygiene measures such as clean drinking water, proper food hygiene, and washing the hands after using the lavatory and before preparing food may help reduce the risk of transmission.

But because H. pylori is mostly acquired in childhood, hygiene measures taken in adult life do not clear an existing infection.

What is the outlook?

H. pylori infection can be treated successfully in most patients with suitable antibiotic combinations.

The most important points in the success of treatment are choosing the right drug combination, taking the drugs in full for the period advised, and confirming after treatment that the bacterium has gone.

Eradicating H. pylori substantially reduces the risk of ulcers recurring and also matters for long-term protection against stomach cancer.

Currency: This information was prepared taking account of the 2024 American College of Gastroenterology (ACG) H. pylori guideline and current international scientific evidence.

This content is for general information. The decision to test and treat for H. pylori should be made by a doctor according to the patient’s own circumstances.