Helicobacter pylori (H. pylori) are a type of bacteria infection. This infection can contribute to the development of diseases, such as heartburn, bloating, nausea, gastritis (inflammation of the stomach), and ulcers in the stomach and duodenum.
H. pylori infection is very common in the United States: About 20 percent of people under 40 years old and half of those over 60 years have it. In industrialized countries, the infection is rare in children, and only about 40% of adults are infected. Once you are infected, unless treated, the infection usually stays for the rest of your life.

Causes

It is believed that H. pylori's shape and characteristics cause the damage that leads to ulcers. Because of their shape and the way they move, the bacteria can penetrate the stomach's protective mucous lining where they produce the enzyme urease, which generates substances that neutralize the stomach's acids.
This weakens the stomach's protective mucus, makes the stomach cells more susceptible to the damaging effects of acid and pepsin, and leads to sores or ulcers in the stomach or duodenum (first part of the small intestine).

Symptoms

When symptoms are present, they may include :-

Dull, gnawing pain
Weight loss
Loss of appetite
Bloating
Burping
Nausea
Vomiting

Younger children with peptic ulcer disease may not have symptoms as clear-cut as those of older children, and their illness may be harder to diagnose.

Treatment

H. pylori is difficult to treat from the stomach because it is capable of developing resistance to commonly used antibiotics. Because a single antibiotic may not kill the bacteria, your child may be given a combination of antibiotics. To treat ulcers due to H. pylori infection, the organism must first be eradicated, followed by treatment of the ulcers so that the healing process can begin.

The combination of two or more antimicrobial agents increases rates of cure and reduces the risk of selecting for resistant H. pylori. The chief antimicrobial agents used in these regimens are amoxicillin, clarithromycin, metronidazole, tetracycline, and bismuth. Primary resistance to amoxicillin and tetracycline remains uncommon, but the frequency of clarithromycin resistance is now around 10 percent in most European countries and the United States and even higher in Japan.

Metronidazole resistance ranges between 20 percent and 30 percent and is more frequent among women and among both men and women in developing countries, because of the frequent use of nitroimidazoles to treat other diseases. Resistance of H. pylori to macrolides is caused by point mutations in the 23S ribosomal RNA genes.