Helicobacter pylori (H. pylori) infection is widespread all over the world. The greatest number of infected people are in developing countries, whereas in developed countries the rate of infection is the smallest. Among risk factors of infection, the socioeconomic environment is regarded as one of the most important. In developed countries, the incidence of H. pylori infection in children is smaller than 12% and shows a tendency to decrease, while in developing countries it may exceed 40% (1). Multicenter studies conducted in Poland in the years [2002][2003] have demonstrated a high rate of H. pylori seroprevalence in both children and adults. In children aged 6 month to 18 years H. pylori seroprevalence rate was 32% and in adults aged 19 to 89 years 84% and varied depending on the region of the country (2). An influence of poor sanitary and hygiene conditions, economical status and parents education on the infection rate was demonstrated. In the last years a tendency to the decrease of infection rate has been shown, which could be linked to the improvement of social condition (3). H. pylori infection is a principal cause of chronic gastritis and peptic ulcer disease in children. In adulthood it leads to many diseases of the gastrointestinal tract including in particular JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY 2014, 65, 6, 801-807 www. Helicobacter pylori (H. pylori) plays an important role in the pathogenesis of the upper gastrointestinal tract diseases in both children and adults. The aim of this paper was to assess the differences between the clinical course of the disease in children and adults. This paper also presents an analysis of clinical symptoms, endoscopic and histopathological findings, H. pylori cagA and vacA genotypes rates and analysis of the sensitivity of these strains to antibiotics in the Polish population, with possible practical and therapeutic implications. The multicenter study on the frequency of H. pylori infections assessed by the presence of antibodies in IgG class against H. pylori in serum was conducted in the years 2002 and 2003. The study group included 6565 children and adults, in 3827 of whom antibodies levels were above 24 U/mL. The authors analyzed clinical and endoscopic symptoms and in some patients with H. pylori seropositivity also histopathological changes, and cagA and vacA genes. Sensitivity of H. pylori strains to antibiotics were also analyzed. Differences between the frequency of infection between children and adults were determined. Endoscopic examination in adults revealed more frequent cases of gastropathy (P=0.003) and erosive gastritis (P=0.001), and in children-thick mucosal folds (P<0.0001). Histopathological examinations carried out in adults have revealed atrophic gastritis and intestinal metaplasia. In children, cagA(+)s1m1 was observed more frequently than in adults (34.0% versus 23.1%; P=0.02) contrary to cagA(-)s2m2 which occurred more frequently in adults (27.1% versus 14.0%; P=0.003). No effect of the infection on nausea, regurgitation, vomiting, heartburn, and abdominal pain in children was detected. However, adults infected with H. pylori suffered from more frequent episodes of heartburn and abdominal pain. The H. pylori strain exhibited a high resistance to metronidazole (higher in adults: 41.7% versus 27.4%; P=0.002), and to clarithromycin (higher in children: 20.2% versus 15.4%; P>0.05), and dual resistance to metronidazole and clarithromycin (higher in children: 9.9% versus 8.4%; P>0.05). Resistance of the H. pylori to amoxicillin and tetracycline was not detected. The conducted study indicated clinical differences in the H. pylori infection in children and adults. Among the differences in children, especially the more frequent infections by the cagA(+)s1m1/m2 strain could have an influence on further consequences of the infection. The obtained results could be useful in therapeutic decisions
