Prevalence and incidence of Helicobacter pylori Infection in a healthy pediatric population in the Lisbon area.

BACKGROUND: Helicobacter pylori is mainly acquired in childhood. Although adult studies reported a high prevalence of H. pylori infection in Portugal, the actual rate in children remains unknown. This study aimed to determine the prevalence and the incidence of H. pylori infection in an asymptomatic pediatric population of the Lisbon area and to correlate prevalence with sociodemographic determinants. MATERIALS AND METHODS: Helicobacter pylori infection was determined by stool antigen test in 844 asymptomatic children (age 0-15 years; 49.4% boys). For the incidence study, H. pylori-negative children in the prevalence study were followed-up every 6 months over a 3-year period. RESULTS: The global prevalence of H. pylori infection was 31.6%, increasing with age (19.9, 37.0 and 51.5%, in age groups 0-5, 6-10, and 11-15, respectively), but was similar among genders (34.5% in boys and 28.4% in girls). Older age and attendance of nursery/kindergarten during preschool constituted independent risk factors. The overall estimated incidence was 11.6 per 100 child-years (CY). Although 47.5% of children acquired H. pylori infection before 5 years of age, the mean age of acquisition was 6.3. The incidence of infection was similar among the three age groups (11.5, 13.0, and 10.5 per 100 CY, in age groups 0-5, 6-10, and 11-15, respectively). CONCLUSIONS: The prevalence of H. pylori infection in the Portuguese pediatric population is still high. Although this study confirmed that the highest acquisition rate occurs at young age, it showed that in high-prevalence populations, older children can also acquire H. pylori infection at a rate similar to that of young children.

Primary antibiotic resistance of Helicobacter pylori strains isolated from Portuguese children: a prospective multicentre study over a 10 year period.

OBJECTIVES: The aim of this study was to prospectively assess the pattern of evolution of primary resistance to antibiotics in Helicobacter pylori strains isolated from Portuguese children over a 10 year period (2000-09). METHODS: A total of 1115 H. pylori strains were tested for antibiotic susceptibility to clarithromycin, metronidazole, amoxicillin, ciprofloxacin and tetracycline. RESULTS: H. pylori strains were isolated from children and adolescents [ages 4 months-18 years (mean age 10.17 ±â€Š4.03 years)], comprising 562 (50.4%) boys and 553 (49.6%) girls. Overall, the primary resistance rate was 34.7% to clarithromycin, 13.9% to metronidazole and 4.6% to ciprofloxacin, while 6.9% were resistant to two of these antibiotics simultaneously. Resistance to amoxicillin and to tetracycline was not detected. In general, the resistance rate was not associated with gender or the children's age. European ethnicity, when compared with an African background, was associated with clarithromycin resistance [P = 0.002; odds ratio (OR) = 0.30; 95% confidence interval (CI) 0.14-0.66], while the inverse situation was observed for metronidazole (P < 0.001; OR = 3.50; 95% CI 1.90-6.45). No significant temporal trend was noticed for resistance to clarithromycin and metronidazole, whereas ciprofloxacin and double-resistance rates have significantly increased over time (P = 0.004 and P = 0.05, respectively). CONCLUSIONS: The primary resistance rate of H. pylori strains isolated from Portuguese children to the commonly used anti-H. pylori antibiotics used is high. Additionally, the increasing trend of ciprofloxacin-resistant and double-resistant strains may compromise H. pylori eradication in a high-prevalence population.