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Helicobacter pylori bacterium

Helicobacter pylori (previously known as Campylobacter pylori) is a bacterium that is usually found in the stomach and is one of the major causes of gastritis and gastric ulcers.


Helicobacter pylori infection is widely spread all over the world as about 50% of the population globally is estimated to be infected. However, not all of the infected individuals become symptomatic and hence many people may have no idea that they carry bacteria in the stomach. If it causes symptoms the disease usually manifests with gastritis (inflammation of the stomach lining) or peptic ulcer (hole in the lining of the stomach or duodenum). In some cases, it can also give rise to stomach cancer.  

As H. pylori require only low concentrations of oxygen to thrive it can live and reproduce in the stomach. High urease production by the bacterium neutralizes stomach acid and thus protects bacteria. The urease production is especially relevant for physicians, as some diagnostic tools used to detect H. pylori are based on the presence of urease. The infection spreads via mouth-to-mouth contact, through contaminated food and water.

Risk factors

Young girl suffering from abdominal pain

A person is more likely to get infected in childhood in case of living in the following conditions:
– crowded homes (a lot of people live in a home together);
– water supply issues;
– lives in a developing country (crowded and unsanitary living conditions);
– lives with someone who has an H. pylori infection.
– Intake of nonsteroidal anti-inflammatory drugs (NSAIDs) for a long period of time increases the risk of developing a peptic ulcer.


Signs and symptoms of H. pylori infection may include:
– Aching or burning pain in the abdomen;
– Abdominal discomfort or pain that worsens when the stomach is empty;
– Heartburn;
– Nausea;
– Foul breath (halitosis) and belching;
– Diarrhea;
– Loss of appetite (anorexia);
– Bloating;
– Unexplained weight loss;
– Bloody or black-colored feces (so-called tar-like stools) or vomit due to the bleeding of the ulcer;


Helicobacter pylori infection can lead to some complications including:
– internal bleeding characterized by tar-like stool or throwing up with black vomit;
– obstruction caused by an ulcer blocking the food passage;
– perforation when an ulcer breaks through the stomach wall;
peritonitis when the abdominal cavity or its lining is infected;


To detect H. pylori in the stomach several tests may be performed:

  • H. pylori fecal antigen test is used to detect bacterium in the stool;
  • Carbon 13 urea breath test – a person is drinking urea (usually with a beverage) that has a carbon isotope (carbon 13 or carbon 14). Later the concentration of the carbon is measured in the breath;
  • H. pylori serology – detection of immunoglobulin G antibodies against H. pylori;
  • Esophagogastroduodenoscopy with biopsy of the stomach lining helps visualise the stomach lining and bacterium can be found in the tissue samples;


There are several antibiotic regimens that may be used to eradicate Helicobacter pylori infection:
Triple therapy
Triple therapy is a first-line therapy that includes the following medications:
Proton pump inhibitor (PPI) (omeprazole 20 mg twice a day (BID), lansoprazole 30 mg BID, esomeprazole 40 mg four times per day (QD) etc.) plus
Clarithromycin 500 mg BID or metronidazole 500 mg BID (in case of clarithromycin resistance) plus
Amoxicillin 1000 mg BID or metronidazole;
Nonbismuth quadruple therapy
Nonbismuth quadruple therapy may be given as a sequential or concomitant therapy.

1) Sequential therapy
Sequential therapy requires a 14-day intake of the following medications:
PPI plus amoxicillin for 5-7 days (pantoprazole 40 mg BID and amoxicillin 1 g BID for 7 days), then
PPI plus 2 other antibiotics (usually clarithromycin and metronidazole) for the next 5-7 days;

2) Concomitant therapy
Concomitant therapy includes:
PPI in a standart dose
Clarithromycin (1 g QD)
The therapy requires 10-14 days of treatment.

Bismuth-based therapy. Helicobacter pylori
Bismuth-based therapy is an option to treat those who live in areas with high clarithromycin and metronidazole resistance.  It lasts for 10-14 days and consists of:
PPI or H2 receptor antagonist (lansoprazole 30 mg BID or ranitidine 150 mg BID)
Bismuth subsalicylate 525 mg QID (or bismuth tripotassium dicitrate 300 mg QID)
Metronidazole 250 mg QID or 500 mg TID (levofloxacin may be used instead)
Tetracycline 500 mg QID

Levofloxacin-containing therapy
This regimen includes of a PPI + amoxicillin 1 g BID + levofloxacin 500 mg QD for 7-10 days.
Second-line therapy should avoid repeating previously used treatment regimens and include at least one antibiotic.

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