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Helicobacter Pylori Infection: What You Need to Know

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What Is Helicobacter pylori?

Helicobacter pylori (HP) is a flagellated, gram-negative bacterium which is microaerophilic (this means it needs lower levels of oxygen to survive) and thrives in the acid environment of the stomach. It can cause inflammation by dialling up the acid production. This damages the lining of the stomach and leads to gastritis and/or ulcers. Acid reflux, epigastric pains, nausea or coughing are all possible symptoms.

However, in some people, the bacteria can live in the stomach for a long time without causing any symptoms. Approximately 50% of people are infected with a higher incidence in developing countries.

Linking HP to Stomach Ulcers

HP was first isolated in 1982. At the time, it was known as campylobacter pylori. In 1983, two Australian scientists, Barry Marshall and Robin Warren which had discovered the bacterium, performed an important experiment.

This proved to the world that HP is associated with stomach ulcers. In order to demonstrate this, Marshall drank a broth in which HP had been cultivated after a baseline gastroduodenoscopy (to prove that he was not infected from the beginning).

After a couple of hours, he started experiencing stomach pains and a second gastroduodenoscopy showed an ulcer from which HP was cultured. Marshall and Warren also conducted a study on 58 symptomatic patients from whom they were able to Isolate HP (from the gastric biopsies).

Despite Marshall's impressive self-experiment and the published results from their study, it took more than 10 years for the medical community to accept this, although there are several facts that support this hypothesis:

  • Most patients with stomach ulcers (without documented use of NSAIDs) have an HP infection
  • HP has been isolated from the stomach before ulcers/gastritis occurs
  • After eradication, the symptoms improve

Transmission of HP

The method of transmission of HP still remains unknown. There are several theories to how it infects humans. HP has been detected in drinking water, seawater, vegetables, animals such as cat saliva, primates and sheep. However, humans seem to be the only reservoir (with 50% of the world population infected) and human-to-human transmission is very likely, since HP infections often occur in clusters within families for example. Fecal/oral transmission through contaminated water is also possible. Some scientists believe the transmission to be foodborne because of the ability of HP to survive in milk, vegetables and other foods. Additional studies will hopefully shed more light on how people contract HP.

EM of Helicobacter pylori

EM of Helicobacter pylori

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Diagnosis of Helicobacter pylori Infection

If you suffer from nausea, heartburn, epigastric pains (especially after eating), you should speak to your treating physician about getting tested for HP infection. For this, I would recommend scheduling a gastroduodenoscopy. This is a procedure during which a physician can look into your stomach and take samples that can be tested for HP.

The procedure allows the inspection of the stomach as well as the diagnosis of other pathologies which can cause the same unspecific symptoms as HP infection. This has been explained in detail in my article Dealing with Gastritis.

Antibiotics for Treatment

I will not go into the "when to treat and when to not treat" discussion. But most will agree that when a patient is having symptoms or has developed an ulcer even, HP eradication is necessary.

A combination of antibiotic agents (at least two) is required to eliminate HP. There are different regimes for the first-line therapy and when possible, the treatment should be adapted according to an antibiogram or local data on resistances.

Some resistances, especially against clarithromycin have been reported. Since this bacterium loves acid, a proton pump inhibitor is additionally prescribed in order to inhibit acid production in the stomach. This gives the antibiotics a better chance to fight it.

HP and Gastric Cancer

Whatever the reason, constant inflammation of a certain tissue in the body can always cause it to change (this is called dysplasia), and this in return can lead to uncontrolled proliferation and carcinogenic processes. Several studies have shown that HP infection is involved in the development of certain types of gastric cancer. A wide variability has been observed from person to person. This suggests that there are other factors involved such as environment, lifestyle as well as genetic factors. Of course, this is a process which probably takes decades. Since the infection does not necessarily cause symptoms, and very few people will develop cancer it is difficult to decide whether eradication is necessary in healthy patients as a preventive measure. This is a very controversial subject which would go beyond the scope of our discussion.

Does Helicobacter pylori protect us from allergies?

Many studies have found an inverse correlation between HP infection and allergies. This has been especially observed in early onset allergic asthma in children and youths. Moreover, it can protect against airway hyper-reactivity and in a mouse model, it was shown that an infection with HP can help prevent allergic asthma. However, when the bacterium is eradicated through antibiotic treatment, this positive effect is reversed. The latter is consistent with this hypothesis. HP infection has also been associated with several other diseases. More studies are needed to understand the full impact of this infection on our health.


  • Med J Aust.1985 Apr 15;142(8):439-44.Pyloric Campylobacter infection and gastroduodenal disease.Marshall BJ, McGechie DB, Rogers PA, Glancy RJ.
  • Ann Intern Med.1994 Jun 15;120(12):977-81.Helicobacter pylori infection and the risk for duodenal and gastric ulceration.Nomura A, Stemmermann GN, Chyou PH, Perez-Perez GI, Blaser MJ.
  • Gastroenterology.1996 Apr;110(4):1244-52.Relationship between Helicobacter pylori eradication and reduced duodenal and gastric ulcer recurrence: a review. Hopkins RJ, Girardi LS, Turney EA.
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  • N Engl J Med.2018 Mar 22;378(12):1085-1095. doi: 10.1056/NEJMoa1708423. Helicobacter pylori Therapy for the Prevention of Metachronous Gastric Cancer.
    Choi IJ, Kook MC, Kim YI, Cho SJ, Lee JY, Kim CG, Park B, Nam BH.

This content is for informational purposes only and does not substitute for formal and individualized diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed medical professional. Do not stop or alter your current course of treatment. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

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