Helicobacter pylori infection
Helicobacter pylori infection is caused by a gram-negative bacterium that primarily affects the inner mucus lining of the stomach, leading to conditions such as gastric ulcers. It is estimated that over 50% of the global population is infected, with notably higher prevalence in developing countries due to unsanitary conditions. Infection typically occurs through the consumption of contaminated food or water, or through contact with the bodily fluids of infected individuals. While many infected people may not show symptoms, those who do might experience abdominal pain, nausea, bloating, and weight loss, with more severe cases requiring immediate medical attention. Diagnosis can be achieved through methods such as endoscopy, breath tests, blood tests, and stool antigen tests. Treatment usually involves a combination of antibiotics and proton pump inhibitors to effectively combat the infection and reduce stomach acid. Preventive measures focus on improving sanitation and personal hygiene, as a comprehensive understanding of transmission is still evolving. Currently, there is a vaccine in development aimed at reducing the incidence of this widespread infection.
Helicobacter pylori infection
- ANATOMY OR SYSTEM AFFECTED: Gastrointestinal system, intestines, stomach
Definition
Helicobacter pylori is a gram-negative bacillus that causes an infection of the inner mucus lining of the stomach. It is the primary cause of gastric ulcers. The prevalence of H. pylori infection worldwide is more than 50 percent of the population and is much higher in developing countries.
Causes
H. pylori infections can result from the ingestion of food or liquids contaminated with the bacterium H. pylori, a spiral-shaped organism with multiple flagella that allow the organism to readily attach to the stomach mucosa. The organism survives using the enzyme urease to break urea down to ammonia and bicarbonate, neutralizing the strong gastric acidity. The bacterial secretions stimulate the formation of inflammatory cytokines, leading to chronic gastritis. The mucus layer is damaged and thinned by H. pylori secretions of cytokines and by enzymes such as proteases and phospholipases. With the loss of the protective mucus layer, the strong acids of the stomach attack and damage the stomach lining, resulting in peptic ulcers. Most peptic ulcer cases in the United States are associated with H. pylori infections.
Risk Factors
There is a much greater risk of contracting H. pylori infection in developing countries because of unsanitary conditions. Contaminated food and water are primary sources, but other sources include contact with the stool, vomit, or saliva of an infected person.
Symptoms
The majority of H. pylori infections do not cause symptoms. When the infection causes inflammation and ulcers, symptoms can include abdominal pain, nausea, frequent burping, bloating, and weight loss. Immediate medical help is needed if severe abdominal pain, difficulty swallowing, or bloody stools or vomit are experienced.
Screening and Diagnosis
There are three primary ways to diagnose H. pylori infection. In endoscopy, a physician threads a flexible tube into the stomach to remove and examine a tissue sample for the presence of the bacterium. A breath test involves a patient ingesting a test meal containing radioactively labeled urea. H. pylori breaks down the urea, forming radioactive carbon dioxide, which is detected. Finally, a blood test detects the presence of antibodies against H. pylori, which could indicate a current or prior infection. A stool antigen test that can detect the presence of H. pylori antigens in a stool sample may also be used.
Treatment and Therapy
Treatment usually consists of the administration of three drugs simultaneously for seven to fourteen days. One of the drugs, omeprazole (Prilosec), is a proton pump inhibitor (PPI). The other two drugs are antibiotics, typically clarithromycin and amoxicillin. The PPIs are necessary to suppress gastric acid production, which improves the effectiveness of the antibiotics. In 2022, a new treatment for H. pylori was approved by the Federal Drug Administration in the United States. The drug, Vonoprazen, an acid-suppressing medication, had proved more effective than traditional PPIs in the treatment of H. pylori.
Prevention and Outcomes
Although the mode of transmission of H. pylori is not fully understood, what is known is that improved sanitation and personal hygiene are essential preventive measures. A vaccine against the bacillus is under development.
Bibliography
Chey, William D., and Benjamin C. Y. Wong. "American College of Gastroenterology Guidelines on the Management of Helicobacter pylori Infection." American Journal of Gastroenterology, vol. 102, 2007, pp. 1808-1825.
"Helicobacter Pylori Infections." MedlinePlus, 5 May 2021, medlineplus.gov/helicobacterpyloriinfections.html. Accessed 1 Nov. 2024.
"Helicobacter Pylori (H. Pylori) Tests." MedlinePlus, 19 Sept. 2023, medlineplus.gov/lab-tests/helicobacter-pylori-h-pylori-tests. Accessed 1 Nov. 2024.
Hooi, James K. Y., et al. "Global Prevalence of Helicobacter pylori Infection: Systematic Review and Meta-Analysis." Gastroenterology, vol. 153, no. 2, 2017, pp. 420-429, doi:10.1053/j.gastro.2017.04.022. Accessed 1 Nov. 2024.
Maixner, Frank, et al. "The 5300-year-old Helicobacter pylori Genome of the Iceman." Science, 8 Jan. 2016, pp. 162–5.
McCarthy, Shane, et al. "A Guide to the Best Treatments for H. Pylori: Antibiotics, PPI Medications, and More." GoodRx, 4 Oct. 2022, www.goodrx.com/conditions/peptic-ulcer-disease/h-pylori-treatment. Accessed 1 Nov. 2024.
McColl, Kenneth E. L. "Helicobacter pylori Infection." New England Journal of Medicine, vol. 362, 2010, pp. 1597-1604.
Payão, S. L., and L. T. Rasmussen. "Helicobacter pylori and Its Reservoirs: A Correlation with the Gastric Infection." World Journal of Gastrointestinal Pharmacology and Therapeutics, vol. 7, no. 1, 2016, pp. 126–32.
Rosenberg, J. J. "Helicobacter pylori." Pediatrics in Review, vol. 31, no. 2, Feb. 2010, pp. 85-86.
Shirani, M., Pakzad, R., Haddadi, M. H., et al. "The Global Prevalence of Gastric Cancer in Helicobacter pylori-Infected Individuals: A Systematic Review and Meta-Analysis." BMC Infectious Diseases, vol. 23, no. 543, 2023, doi.org/10.1186/s12879-023-08504-5. Accessed 1 Nov. 2024.
Zamani, M., et al. "Systematic Review with Meta-analysis: The Worldwide Prevalence of Helicobacter Pylori Infection." Alimentary Pharmacology & Therapeutics, vol. 47, no. 7, 2018, pp. 868-876, doi.org/10.1111/apt.14561. Accessed 1 Nov. 2024.