Helicobacter Pylori

Infectious Agent

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


Believed to be mainly fecal–oral or possibly oral–oral.


About two-thirds of the world’s population is infected, but it is more common in developing countries. Short-term travelers do not appear to be at significant risk of acquiring H. pylori through travel, but expatriates and long-stay travelers may be at higher risk.

Clinical Presentation

Usually asymptomatic, but H. pylori is the major cause of peptic ulcer disease and gastritis worldwide, which often present as gnawing or burning epigastric pain. Less commonly, symptoms include nausea, vomiting, or loss of appetite. Infected people have a 2-fold to 6-fold increased risk of developing gastric cancer and mucosal associated-lymphoid-type (MALT) lymphoma compared with their uninfected counterparts.


Fecal antigen assay, urea breath test, rapid urease test, or histology of biopsy specimen. A positive serology indicates present or past infection.


Asymptomatic infections do not need to be treated. Patients with active duodenal or gastric ulcers should be treated if they are infected. Treatment should be determined on an individual basis. Standard treatment is bismuth quadruple therapy (PPI or H2-blocker + bismuth + metronidazole + tetracycline). Clarithromycin triple therapy (proton pump inhibitor [PPI] + clarithromycin + amoxicillin or metronidazole) can be used in regions where H. pylori clarithromycin resistance is known to be <15% and in patients with no previous history of macrolide exposure. See http://gi.org/guideline/treatment-of-helicobacter-pylori-infection.


No specific recommendations.


  1. Chey WD, Leontiadis GI, Howden CW, Moss SF. ACG clinical guideline: treatment of Helicobacter pylori infection. Am J Gastroenterol. 2017;112:212–38.  [PMID:28071659]
  2. Lindkvist P, Wadstrom T, Giesecke J. Helicobacter pylori infection and foreign travel. J Infect Dis. 1995 Oct;172(4):1135–6.  [PMID:7561197]
  3. Potasman, I, Yitzhak A. Helicobacter pylori serostatus in backpackers following travel to tropical countries. Am J Trop Med Hyg. 1998;58(3):305–8.  [PMID:9546407]


Bradley A. Connor