Helicobacter Pylori Virulence Factors (and how to test)

Helicobacter pylori virulence factors are not tested as part of a standard H.pylori test, but they are very important when considering whether you need to treat the infection or not

Helicobacter pylori (H.pylori) is a common infection that can affect up to 50% of the population. For some people, it can cause a wide range of symptoms, yet other people can have no symptoms.

H.pylori is the number one cause of gastric ulcers and can also cause gastric cancer, yet why does this occur in some people and not others?

Helicobacter pylori can cause reflux, gastritis, diarrhea, constipation and other symptoms of Irritable Bowel Syndrome in many people. Nevertheless, there are many people who have an H.pylori infection who are completely asymptomatic.

The answer to why some people get affected and other people do not is in the virulence factors that H.pylori can produce. Basically, there are different types of H.pylori virulence factors that lead to inflammation.

Helicobacter Pylori Testing


The commonly used tests to diagnose an H.pylori infection don't detect different virulence factors that H.pylori produces. They will just give you a positive or negative test result.

The G.I Map test is a DNA stool test that will give you an accurate level of bacteria present, and more importantly will show you if you are positive for the H.pylori virulence factors.

In case virulence factors were detected, it means you are at high risk for ulcers, gastric cancer or other health conditions caused by H.pylori.

Let’s look at the pros and cons of the common methods for diagnosing Helicobacter pylori.

Blood Testing

Blood Test is commonly used but it is less accurate and cannot distinguish between past or current infection.

Urea Breath Test

Urea Breath Test is another common way of diagnosing an H.pylori infection. It is convenient and quite accurate but you can get false positives from other urea producing bacteria. In addition, the breath test doesn't test for the H.pylori virulence factors.


Biopsy is the most invasive method as it is done during a gastroscopy. It is quite accurate but it may miss a low level of infection. A biopsy also doesn't test for the H.pylori virulence factors.

G.I Map Stool Test

G.I Map Stool Test is a highly accurate test to assess for H.pylori infection plus the presence of the H.pylori virulence factors. This test has the advantage of being able to assess for other gut bacteria, parasite and yeast infections, as well as other intestinal health markers.

Helicobacter Pylori Virulence Factors

Once you get an H.pylori infection 4 steps are required before infection will cause symptoms, or lead to gastritis or an ulcer.

1. Survival in the acidic stomach - H.pylori utilizes its urease activity to neutralize the acidic conditions of the stomach.

2. The movement towards the epithelial cells by flagella-mediated motility - this ensures a more alkaline environment so the H.pylori can survive.

3. Attachment to host cells by adhesion receptor interaction.

4. Causing tissue damage by toxin release.

We are going to focus on step number 4, without which you will not get the pathogenic effect of a positive H.pylori infection. This is why some people will have no symptoms yet many other people can have a wide range of symptoms.

H.pylori Virulence Factors Cause Toxin Release


The H. pylori virulence factors that are most well recognized are vacA and cagA.

Virulence Factors & Deseases


BabA (Blood group antigen binding adhesin) is an outer membrane adhesin protein that facilitates binding of H. pylori to the gastric mucosa. BabA is thought to play a significant role in inducing inflammation in the gastric mucosa and in promoting long-term infection. Higher expression levels of BabA are associated with severity of inflammation and the development of the clinical disease.


CagA (Cytotoxin-associated protein A) presence in H.pylori strains has been significantly associated with gastric cancer and peptic ulcer. The gene codes for a type IV secretion system which allows the bacterium to inject the cagA protein into the host cell. Once inside the host’s gastric epithelial cells, cagA can disrupt cell signaling, leading to abnormal proliferation, motility, and changes in the cytoskeleton. These changes to normal cell signaling can initiate cancer.


Cag PAI (Cag pathogenicity island). This “island” includes two genes: virB and virD. Cag PAI is a section of the H. pylori genome that encodes CagA and a Type IV Secretion System, a multiprotein complex that mediates the transfer of H. pylori virulence factors – including CagA - into gastric epithelial cells. 

The presence of Cag PAI is associated with highly virulent strains of H. pylori. 


DupA (Duodenal ulcer-promoting gene A) is strongly linked to an increased risk for developing duodenal ulcers, but not gastric cancer. DupA is thought to be involved in inducing the inflammatory cytokine IL-8, as well as secretion of urease and inhibition of mitochondria-mediated apoptosis. 


IceA (Induced by Contact with Epithelium A) has been linked to increased expression of the inflammatory cytokine IL-8, and the development of gastric inflammation, peptic ulcer disease, and gastric cancer, in some studies.


OipA (Outer Inflammatory Protein A) is an adhesion protein found in the outer cell membrane of H. pylori, and functions in adherence of H. pylori to the gastrointestinal mucosa. OipA contributes to the activity of the CagA virulence factor, and to H. pylori’s ability to induce inflammation via IL-8. It is associated with gastric cancer and peptic ulcers.


VacA (Vacuolating toxin A) has been associated with gastric cancer, peptic ulcer, and duodenal ulcer. The vacA gene is present in all strains of H.pylori but is polymorphic, which leads to different levels of vacuolating toxin. VacA toxins interact with certain receptors on host cells, setting off a chain of events including mitochondrial damage, inhibition of T-lymphocytes, and interference of antigen presentation.

H.pylori - Antibiotic-Resistant Genes


If you have tested positive for Helicobacter pylori with your doctor, most likely you have been given a course of triple therapy. This is two different antibiotics and an acid-lowering drug to eliminate H.pylori.

While this antibiotic treatment can be successful, for many people it is not.

The reason why antibiotics may not be successful is that you may have a genetic resistance to specific antibiotics, and the G.I Map can test for this.

The antibiotic-resistant genes section on the G.I Map test will show you what types of antibiotics would be effective or ineffective for you. Knowing this information can help to determine if antibiotics would be beneficial or possibly make your situation worse.

Note: Antibiotic treatment can be beneficial as it can eliminate H.pylori. However, it can also create other imbalances in your microbiome which will lead to a worsening of your digestive symptoms.

H.Pylori Treatment


Fifty percent of the world’s population is believed to be infected with H. pylori but only 2% of those develop gastric cancer. H. pylori may be asymptomatic and require no treatment or only supportive care to improve the intestinal mucosa and gastrointestinal lining.

A person’s immune status and acid secretion seem to be other important factors contributing to H. pylori’s colonization and pathogenesis, another reason why one person can develop symptoms while others can be symptom-free.

The first step is to get proper testing done to assess if you have an H.pylori infection and to see if any of the H.pylori virulence factors are present.

The results combined with your signs and symptoms will help to guide on the best treatment options for you.

The G.I Map test will assess H.pylori, the H.pylori virulence factor plus if you are resistant to the antibiotics that are commonly prescribed to treat H.pylori.

At Planet Naturopath we use a natural treatment plan to eliminate an H.pylori infection and improve your digestive health.

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