Helicobacter pylori virulence genes detected by string PCR in children from an urban community in northeastern Brazil.

The accuracy of a nested PCR in gastric DNA obtained by a string test for the diagnosis of Helicobacter pylori infection in asymptomatic children was 94.0%. The cagA-positive toxigenic vacAs1m1 strains were the most prevalent strains, indicating that this population is colonized early by the strains associated with gastric cancer.

Higher frequency of cagA EPIYA-C phosphorylation sites in H. pylori strains from first-degree relatives of gastric cancer patients.

BACKGROUND: To evaluate the prevalence of more virulent H. pylori genotypes in relatives of gastric cancer patients and in patients without family histories of gastric cancer. METHODS: We evaluated prospectively the prevalence of the infection by more virulent H. pylori strains in 60 relatives of gastric cancer patients comparing the results with those obtained from 49 patients without family histories of gastric cancer. H. pylori status was determined by the urease test, histology and presence of H. pylori ureA. The cytotoxin associated gene (cagA), the cagA-EPIYA and vacuolating cytotoxin gene (vacA) were typed by PCR and the cagA EPIYA typing was confirmed by sequencing. RESULTS: The gastric cancer relatives were significant and independently more frequently colonized by H. pylori strains with higher numbers of CagA-EPIYA-C segments (OR = 4.23, 95%CI = 1.53-11.69) and with the most virulent s1m1 vacA genotype (OR = 2.80, 95%CI = 1.04-7.51). Higher numbers of EPIYA-C segments were associated with increased gastric corpus inflammation, foveolar hyperplasia and atrophy. Infection by s1m1 vacA genotype was associated with increased antral and corpus gastritis. CONCLUSIONS: We demonstrated that relatives of gastric cancer patients are more frequently colonized by the most virulent H. pylori cagA and vacA genotypes, which may contribute to increase the risk of gastric cancer.

Low prevalence of H. pylori infection in HIV-positive patients in the northeast of Brazil.

BACKGROUND: This study conducted in Northeastern Brazil, evaluated the prevalence of H. pylori infection and the presence of gastritis in HIV-infected patients. METHODS: There were included 113 HIV-positive and 141 age-matched HIV-negative patients, who underwent upper gastrointestinal endoscopy for dyspeptic symptoms. H. pylori status was evaluated by urease test and histology. RESULTS: The prevalence of H. pylori infection was significantly lower (p < 0.001) in HIV-infected (37.2%) than in uninfected (75.2%) patients. There were no significant differences between H. pylori status and gender, age, HIV viral load, antiretroviral therapy and the use of antibiotics. A lower prevalence of H. pylori was observed among patients with T CD4 cell count below 200/mm3; however, it was not significant. Chronic active antral gastritis was observed in 87.6% of the HIV-infected patients and in 780.4% of the control group (p = 0.11). H. pylori infection was significantly associated with chronic active gastritis in the antrum in both groups, but it was not associated with corpus chronic active gastritis in the HIV-infected patients. CONCLUSION: We demonstrated that the prevalence of H. pylori was significantly lower in HIV-positive patients compared with HIV-negative ones. However, corpus gastritis was frequently observed in the HIV-positive patients, pointing to different mechanisms than H. pylori infection in the genesis of the lesion.

Younger siblings play a major role in Helicobacter pylori transmission among children from a low-income community in the Northeast of Brazil.

BACKGROUND AND AIMS: To further evaluate intrafamilial transmission of H. pylori infection during childhood, we investigated the prevalence of H. pylori in family members from a poor H. pylori high-prevalence urban community in the Northeast of Brazil. METHODS: H. pylori infection was investigated in 570 members of 128 households, by (13) C-urea breath test in children and by ELISA in mothers and other adult relatives. RESULTS: The overall prevalence of H. pylori infection (376/570) increased with age (p < .001) and ranged from 28.9%, in children aged 6 months to 5 years, to 82% in adults over 40 years. An H. pylori positive mother and the number of infected siblings are independent risk factors for childhood H. pylori infection (OR = 2.2, 95% CI = 1.0-4.6 and OR = 4.3, 95% CI = 2.3-8.1, respectively) The number of siblings, number of younger siblings, and number of infected younger siblings were also associated with the infection in the univariate analysis. The number of infected younger siblings remained independently associated with the infection (p = .000), even after controlling for all the above cited variables, in addition to the H. pylori status of siblings and mothers, age, number of people per room, and number of children in the household. CONCLUSION: The transmission of H. pylori occurs from infected mothers to their offspring and among siblings, notably from younger siblings to the older ones.

The association between Helicobacter pylori infection and height in children from an urban community in north-east Brazil.

BACKGROUND: An association between Helicobacter pylori infection and short stature in children has been described recently. AIM: To describe differences in stature between H. pylori-infected and non-infected children in a low-income community in north-east Brazil. METHODS: H. pylori status was evaluated by 13C-urea-breath test; centile values for weight and height were calculated for each child. RESULTS: The prevalence of H. pyloni was 55.8% (197/353) and increased with age. Of 197 H. pylori-positive children, 62% were below the 25th centile for height compared with 48% of H. pylori-negative children (75/156) [AOR (adjusted odds ratio) 1.61, 95% CI 1.04-2.49, p=0.03] after adjustment for variables with p < 0.25 in univariate analysis (gender, number of residents, of children per household and of persons per bed). These results were significant only when older children were included. Thus, in children aged 8-14 years, 80% (89/111) of H. pylori-positive were <25th centile for height compared with 63% (35/56) of H. pylori-negative children (p=0.01). Compared with children with a height >25th centile, the AOR for H. pylori infection increased from 2.42 in the crude analysis to 6.62 after adjustment (p=0.006). CONCLUSIONS: H. pylori is associated with short stature in older children living in a poor urban community in Brazil.

Helicobacter pylori colonization among children up to 6 years: results of a community-based study from Northeastern Brazil.

AIM: To determine the prevalence and risk factors associated with Helicobacter pylori infection among children up to 6 years. METHODS: Cross-sectional study carried out in a poor urban community in Fortaleza Northeast Brazil. A standardized questionnaire was applied. Helicobacter pylori status was evaluated by (13)C-urea breath test ((13)C-UBT) in children up to 48 months and by ELISA in the mothers. Sera were assayed by the Cobas Core anti-H. pylori IgG EIA. RESULTS: The overall prevalence of H. pylori infection was 40% (88/217), 41% (46/112) boys and 40% (42/105) girls were infected. The prevalence rate of infection by H. pylori increased significantly with age, from 29% (27/93) in the youngest group (3 months to 2 years) to 59% (35/59) in the oldest group (6 years), (p < 0.001). There was no significant difference in the prevalence of infection between gender, height and weight adjusted for age, history of breastfeeding, mother's education, number of people per room, number of people per bed, smoking habit of the mother and children's history of antibiotic intake. A significant difference was found in the prevalence of H. pylori infection and H. pylori status of mother (p = 0.02; odds ratio (OR) 2.98; 95% confidence interval (CI): 1.19-7.46) that remained significant after adjustment for covariates in multivariate analysis (p = 0.012; OR 4.65; 95%CI: 1.39-15.58). CONCLUSIONS: This study shows that children living in low socioeconomic status and poor hygienic conditions are infected very early in childhood. It identifies age and H. pylori positive mother as independent risk factors for infection.