pylori

Pylori commonly refers to Helicobacter pylori, a curved, Gram-negative, microaerophilic bacterium that colonizes the human stomach. It is best known for its ability to persist in the acidic gastric environment, a feat enabled by urease production that converts urea to ammonia, raising local pH and protecting the bacteria from acidity. H. pylori typically resides in the gastric mucosa and can also be found in the duodenum.

Epidemiology and transmission vary by region and socioeconomic factors. Infection is often acquired in childhood and can persist for life if not treated. Transmission pathways are not fully understood but are thought to include oral-oral and fecal-oral routes, as well as person-to-person contact or contaminated water.

Clinical significance varies. Many infections are asymptomatic, but H. pylori is a major cause of chronic gastritis and peptic ulcer disease and is associated with an increased risk of gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. The bacterium’s virulence factors, including cagA and vacA, contribute to inflammatory and carcinogenic processes.

Diagnosis relies on noninvasive and invasive methods. Noninvasive tests include the urea breath test and stool antigen tests. Invasive diagnosis uses endoscopic biopsy with histology, rapid urease testing, or culture.

Treatment typically involves a combination of antibiotics and a proton pump inhibitor for 10 to 14 days. Common regimens include clarithromycin-based triple therapy or bismuth-containing quadruple therapy, with selection influenced by local antibiotic resistance patterns. Resistance to clarithromycin and metronidazole can reduce effectiveness. No widely used vaccine exists; prevention emphasizes hygiene and sanitation to reduce transmission.