H. pylori: When It Won't Quit

Helicobacter pylori is one of the most common bacterial infections on the planet. It colonises the stomach lining of approximately half the world's population, and in many people it causes no symptoms at all. But in those it does affect, the consequences can be serious: peptic ulcers, chronic gastritis, gastric lymphoma, and — most significantly — gastric cancer, one of the leading causes of cancer death worldwide.

The World Health Organisation classifies H. pylori as a Group 1 carcinogen. Eradicating it is not optional when there is an indication to treat — it is a medical imperative. And yet, in 2026, eradication is becoming increasingly difficult.

The Resistance Crisis

Standard first-line treatment for H. pylori — typically a proton pump inhibitor combined with two antibiotics such as amoxicillin and clarithromycin — was once highly effective, with eradication rates above 90 percent. Those days are over. In Australia, clarithromycin resistance rates now approach 30 to 40 percent in some populations, and global resistance is rising steadily.

This means that a substantial proportion of patients who complete a full course of triple therapy will still have H. pylori at the end of treatment. They will have endured two weeks of antibiotics, experienced the associated side effects, and potentially developed further antibiotic resistance — all without clearing the infection.

Metronidazole resistance is even more widespread globally, and dual resistance to both clarithromycin and metronidazole renders many standard regimens essentially ineffective. This is not a failure of the patient. It is a predictable consequence of antibiotic resistance evolution, and it demands a fundamentally different approach.

The rise of resistance is driven by the inexorable logic of natural selection. Every time we expose H. pylori to an antibiotic, we select for any organisms that happen to carry resistance mutations. In populations with high antibiotic use, this selective pressure accumulates, and resistance becomes increasingly prevalent. Combined with poor adherence to treatment regimens (which amplifies resistance), inadequate acid suppression (which impairs antibiotic activity), and the organism's own ability to acquire and share resistance genes horizontally, we find ourselves in a situation where empiric triple therapy is increasingly unreliable.

Why Does Eradication Matter So Much?

Some patients understandably ask whether they really need to keep trying to eradicate H. pylori, particularly after one or two failed treatment courses. The answer, in most cases, is emphatically yes. Persistent H. pylori infection drives ongoing inflammation of the stomach lining, which over decades can progress through a well-characterised sequence: chronic gastritis, atrophic gastritis, intestinal metaplasia, dysplasia, and ultimately gastric adenocarcinoma.

This progression is not inevitable, and not every infected person will develop cancer. But the risk is real and cumulative, and eradication at any point in the cascade reduces that risk. For patients with a family history of gastric cancer, the imperative is even greater.

Beyond cancer risk, persistent H. pylori can cause ongoing dyspepsia, bloating, nausea, and epigastric pain that significantly impacts quality of life. It is also associated with iron deficiency anaemia and idiopathic thrombocytopenic purpura, among other extra-gastric conditions.

The presence of chronic gastritis also impairs gastric acid production — H. pylori-driven atrophic gastritis can severely reduce parietal cell function and stomach acid secretion. This creates a vicious cycle: reduced acid impairs antibiotic activity, making eradication harder. But it also impairs nutrient absorption, worsens bacterial overgrowth in the stomach and small intestine, and perpetuates malabsorption of iron, vitamin B12, and calcium. Successful eradication can reverse much of this damage if caught before the atrophic changes become permanent.

The Diagnostic Approach

Accurate diagnosis is the foundation of effective treatment. We use a combination of methods depending on the clinical context. The urea breath test is our standard non-invasive diagnostic tool — it is highly accurate and allows us to confirm both initial infection and post-treatment eradication.

For patients who have failed previous treatment, we strongly recommend endoscopy with gastric biopsy. This serves two purposes: it allows direct visualisation of the stomach to assess for complications such as ulceration or metaplasia, and it provides tissue for culture and sensitivity testing. Knowing exactly which antibiotics the organism is resistant to allows us to design a targeted salvage regimen rather than guessing.

The biopsy also allows us to assess the degree of gastric atrophy, the presence and extent of intestinal metaplasia, and whether dysplastic changes have begun — all of which have implications for prognosis and follow-up surveillance. Patients with extensive atrophic gastritis or intestinal metaplasia require vigilant endoscopic surveillance, even after successful H. pylori eradication, to detect dysplasia at the earliest opportunity.

Advanced Therapy: The Vonoprazan Revolution

One of the most significant advances in H. pylori treatment in recent years is the introduction of vonoprazan, a potassium-competitive acid blocker (P-CAB) that represents a fundamentally different mechanism of acid suppression compared to traditional proton pump inhibitors.

Unlike PPIs, which require acid activation and have a slow onset, vonoprazan inhibits gastric acid secretion rapidly, potently, and independently of meal timing. This results in more profound and sustained acid suppression, which is critical for H. pylori eradication because the antibiotics used work best in a less acidic environment. When stomach pH is consistently elevated, antibiotic efficacy is dramatically enhanced.

Critically, vonoprazan's efficacy is not affected by CYP2C19 genetic polymorphisms — the enzymes that break down proton pump inhibitors. This means that rapid metabolisers (who typically fail PPI-based therapy because they break down the drug too quickly) respond just as well to vonoprazan as slow metabolisers. For a patient population struggling with resistance and treatment failures, this is a substantial advantage.

Our advanced salvage regimen combines vonoprazan with rifabutin, amoxicillin, and bismuth. This four-drug combination has achieved a 92 percent eradication rate in our practice for patients with refractory H. pylori — meaning patients who have already failed two or more standard treatment courses. This is a remarkable success rate in a population that, by definition, has the most resistant organisms.

Rifabutin is a key component of this regimen because H. pylori resistance to rifabutin remains exceedingly rare worldwide. Rifabutin works through inhibition of bacterial RNA polymerase, a completely different mechanism from beta-lactams and nitroimidazoles, so cross-resistance is minimal. Combined with the superior acid suppression of vonoprazan and the mucosal-protective effects of bismuth (which also has antimicrobial properties), this regimen attacks the infection from multiple angles simultaneously, overwhelming the organism's capacity to escape.

The Next Frontier: Gastric Microbiome Transplant

Beyond pharmacological therapy, we are exploring an entirely novel approach: gastric microbiome transplantation. Just as faecal microbiota transplantation restores the colonic ecosystem, gastric microbiome transplantation aims to restore the microbial environment of the stomach itself.

The stomach was once thought to be essentially sterile, but we now know it harbours a diverse microbial community that plays important roles in mucosal defence, immune regulation, and resistance to pathogenic colonisation. Chronic H. pylori infection disrupts this community, and even after successful eradication, the gastric microbiome may remain altered. Gastric microbiome transplantation is a frontier we are actively investigating as a way to optimise the post-eradication gastric environment and reduce the risk of reinfection.

The rationale is compelling: successful H. pylori eradication eliminates the pathogenic organism, but it may leave the gastric mucosal environment in a depleted or dysbiotic state, making it potentially vulnerable to recolonisation. By transplanting a healthy gastric microbiome from a screened donor after successful eradication, we aim to create an environment so resistant to pathogenic colonisation that H. pylori simply cannot re-establish itself. This represents a genuine paradigm shift — from eradication alone to eradication-plus-restoration.

A Smarter Approach to a Stubborn Bug

If you have been told you have H. pylori and your first treatment did not work, you are not alone — and you are not out of options. The key is to move beyond empiric therapy and toward a precision approach: culture-guided antibiotic selection, vonoprazan-based regimens, and close follow-up to confirm eradication.

Failing H. pylori treatment is not the end of the road. It is the beginning of a smarter, more targeted approach — and the results speak for themselves.

We encourage anyone with refractory H. pylori to seek specialist input. With the right combination of advanced diagnostics and evidence-based therapy, eradication is achievable in the vast majority of cases.