Helicobacter pylori is a spiral-shaped bacterium that colonizes the lining of the stomach. It is a widespread bacterium, with estimates suggesting that it is present in about half of the world’s population. The discovery of H. pylori in 1982 was a significant development in gastroenterology, as it revealed a bacterial cause for conditions like peptic ulcers and gastritis, which were previously thought to be caused by stress and lifestyle factors.
How Helicobacter Pylori Spreads
The precise mechanisms of Helicobacter pylori transmission are not entirely understood, but person-to-person contact is the most common mode. The primary pathways are the oral-oral route, through contact with the saliva or vomit of an infected individual, and the fecal-oral route, which involves the ingestion of water or food contaminated with fecal matter. The bacteria can be found in saliva, dental plaque, and feces, facilitating its spread through close contact.
Infection is most often acquired during childhood, frequently spreading among family members. Risk factors include living in crowded or high-density conditions, which can facilitate transmission.
Another risk factor is a lack of access to clean water sources, as consuming water from contaminated sources has been linked to H. pylori infection. Inadequate sanitation and poor hygiene practices also contribute to a higher prevalence of the bacteria.
Symptoms and Associated Health Conditions
A significant number of people with a Helicobacter pylori infection remain asymptomatic throughout their lives. When symptoms do arise, they are related to the inflammation of the stomach lining, a condition known as gastritis. Common symptoms may include a dull or burning ache in the abdomen, bloating, frequent burping, nausea, and unintended weight loss.
H. pylori is a primary cause of peptic ulcers, which are open sores that develop on the inside lining of the stomach (gastric ulcers) or the upper portion of the small intestine (duodenal ulcers). The bacteria disrupt the protective mucous layer of the stomach, allowing stomach acid to damage the underlying tissue. It is estimated that about 10% to 15% of those with H. pylori will develop an ulcer.
Chronic inflammation caused by H. pylori is also a major risk factor for certain types of stomach cancer. The bacteria’s long-term presence can lead to a sequence of changes in the stomach lining that can develop into gastric adenocarcinoma, leading to H. pylori’s classification as a carcinogen.
Diagnostic Procedures
Among the most common non-invasive tests is the urea breath test. During this test, the patient ingests a substance containing urea with tagged carbon molecules; if H. pylori is present, the bacteria will break down the urea and release the tagged carbon, which can then be detected in the patient’s breath. Another widely used non-invasive option is the stool antigen test, which identifies H. pylori proteins in a stool sample.
Blood antibody tests are also available, which check for antibodies that the immune system produces in response to the bacteria. However, a limitation of the blood test is that it cannot distinguish between a current, active infection and a past one, as antibodies can remain in the blood for years.
For a more direct examination, an upper endoscopy may be performed. This is an invasive procedure where a thin, flexible tube with a camera is passed down the throat into the stomach and small intestine. This allows the physician to visually inspect the lining for signs of inflammation or ulcers. During the endoscopy, a small tissue sample, or biopsy, can be taken from the stomach lining for analysis to confirm the presence of H. pylori.
Eradication and Treatment Protocols
The primary goal of treating a Helicobacter pylori infection is the complete eradication of the bacteria to heal conditions like gastritis and peptic ulcers, and to reduce the long-term risk of stomach cancer. Treatment almost always involves a combination of medications taken for a specific duration, typically 14 days. This multi-drug approach is necessary to effectively kill the bacteria and prevent the development of antibiotic resistance.
The standard treatment regimens are often referred to as “triple therapy” or “quadruple therapy.” A common triple therapy approach includes a proton pump inhibitor (PPI), which is a medication that reduces the production of stomach acid, combined with at least two different antibiotics, such as clarithromycin and amoxicillin or metronidazole. The PPI helps the antibiotics work more effectively and allows the stomach lining to heal.
In areas with high rates of antibiotic resistance to clarithromycin, a quadruple therapy is often recommended as the first-line treatment. This typically involves a PPI, bismuth subsalicylate (an agent that helps protect the stomach lining), and two antibiotics like metronidazole and tetracycline.
Patients must take all medications as prescribed and complete the entire course of treatment, even if symptoms improve, to ensure the infection is fully cleared. After treatment is completed, follow-up testing, often using a breath test or stool test, is usually recommended to confirm that the H. pylori bacteria have been successfully eradicated. This step confirms the infection has been resolved.