Author(s): Bradley Connor

Infectious Agent

Helicobacter pylori is a small, curved, microaerophilic, gram-negative, rod-shaped bacterium.

Transmission

H. pylori is believed to be transmitted mainly by fecal–oral route, but also possibly by oral–oral.

Epidemiology

H. pylori is recognized as one of the most common chronic bacterial infections worldwide, and about two-thirds of the world’s population is infected; it is more common in developing countries. Short-term travelers appear to be at low risk of acquiring H. pylori through travel, but expatriates and long-stay travelers could be at greater risk.

Clinical Presentation

Although usually asymptomatic, H. pylori infection is the major cause of peptic ulcer disease and gastritis worldwide, which often present as gnawing or burning epigastric pain. Less commonly, symptoms include loss of appetite, nausea, or vomiting. Designated as a carcinogen by the World Health Organization, H. pylori infection is the strongest known risk factor for non-cardia gastric adenocarcinoma. Infected people have a 2–6-fold increased risk of developing gastric cancer and mucosal associated-lymphoid-type (MALT) lymphoma compared with their uninfected counterparts.

Diagnosis

H. pylori diagnosis can be made through fecal antigen assay, urea breath test, rapid urease test, or histology of a biopsy specimen. A positive serology indicates present or past infection.

Treatment

Asymptomatic infections generally do not need to be treated. Determine treatment on an individual basis, and treat patients with active duodenal or gastric ulcers if they are infected. Standard treatment is bismuth quadruple therapy: proton pump inhibitor (PPI) or H2-blocker + bismuth + metronidazole + tetracycline. Clarithromycin triple therapy (PPI + clarithromycin + amoxicillin or metronidazole) is an option in regions where H. pylori clarithromycin resistance is known to be <15% and in patients with no previous history of macrolide exposure.

Recently, combination therapies using rifabutin have become available, especially for refractory cases. Longer treatment durations (14 days vs. 7 days) provide higher eradication success rates.

Prevention

No specific recommendations.