Your stomach is generally a hostile environment for bacteria but a few species, such as Helicobacter pylori (H. pylori) can thrive there. It's a common inhabitant of the human stomach, although it usually doesn't cause any problems. H. pylori can cause symptoms such as stomach ulcers in some cases, however. H. pylori infections are more common in people who live in crowded conditions and developing countries. They're also more likely when a hot water supply is unavailable.
Frequency
H. pylori is found in approximately 20 percent of the U.S. population under age 40. This rate increases with age and half the population over the age of 60 have H. pylori. An infection of H. pylori becomes symptomatic in less than 20 percent of these cases. According to the National Digestive Diseases Information Clearinghouse, the reasons that H. pylori causes peptic ulcers in some people and not in others is not well understood. The most likely risk factors include the strain of H. pylori and the specific conditions of the infected stomach.
Transmission
H. pylori is primarily transmitted indirectly through fecal matter, usually by ingesting contaminated food or water. It's also found in saliva and may be transmitted directly from person to person through kissing. Once H. pylori enters the body by ingestion, it passes through the esophagus and into the stomach.
Infection
H. pylori secretes an enzyme that neutralizes stomach acid long enough for the bacteria to travel to the mucous lining of the stomach. It then burrows into the lining where it can be protected from stomach acid. This can weaken the mucous lining and allow the stomach acid to create an ulcer.
Symptoms
The symptoms of a peptic ulcer due to H. pylori typically include a dull stomach ache that occurs intermittently over several days. This is most likely after a meal but it can also happen with an empty stomach. H. pylori can also cause a poor appetite, weight loss, nausea and vomiting. The more severe symptoms of an H. pylori infection include sharp stomach pain, bloody stools or bloody vomit. These symptoms can indicate that the ulcer has penetrated the stomach wall and requires immediate medical attention.
Treatment
Medication that treats ulcers from H. pylori ulcers include antibiotics that kill the bacteria, acid suppressors that reduce the amount of stomach acid and stomach protectors that prevent the stomach acid from dissolving the lining of the stomach. Peptic ulcers are typically treated with all three types of medication.
