BackgroundTo evaluate the prevalence of more virulent H. pylori genotypes in relatives of gastric cancer patients and in patients without family histories of gastric cancer.MethodsWe 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.ResultsThe 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.ConclusionsWe 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.

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. Helicobacter pylori infection significantly increases the risk of development of peptic ulcer disease, distal gastric carcinoma, and gastric lymphoma (1). Infection of the general population with virulent strains, especially those carrying the cagA gene and vacAs1 genotype, is a predictor of increased risk for development of severe H. pylori-associated diseases. However, the majority of the methods used for genotyping H. pylori strains require an invasive procedure, endoscopy, for tissue sample collection and are not indicated in epidemiological studies evaluating asymptomatic individuals, especially children. The string test, a minimally invasive nonendoscopic procedure, seems to be an accurate method to obtain gastric specimens in order to investigate H. pylori virulence genes. It has been demonstrated that the genotypes of H. pylori strains in DNA from the gastric juice or tissue samples are identical (2).Previously we have shown a high prevalence of infection by H. pylori strains carrying the cagA gene and the vacAs1 allele in dyspeptic adult patients who underwent endoscopy in northeastern Brazil (3). Furthermore, we have demonstrated that in this population, the infection is acquired earlier in childhood (4), another predictor of gastric cancer. However, we are unaware of studies evaluating the profile of the circulating strains in children of the general population living in areas at increased risk of gastric cancer. Therefore, our aim was to investigate whether the most virulent strains of H. pylori circulate in asymptomatic children from the population, by obtaining H. pylori DNA in gastric juice or mucus by the string test. We also aimed to evaluate the accuracy of an H. pylori-specific nested PCR for the diagnosis of the infection in asymptomatic children.The study was approved by the Ethics and Research Committee of the Federal University of Ceará. All children and their parents signed the informed consent. Individuals who had participated in previous H. pylori epidemiological studies in Parque Universitário, a low-income urban community in Fortaleza, Brazil, were invited to participate (5). Children who had taken antibiotics potentially active against H. pylori were not included. Fifty children (24 females and 26 males) 8 to 18 years old with a mean age of 14.3 years were evaluated. After a 6-h fast, the children were submitted to the [ 13 C]urea breath test ( 13 C-UBT) (6) and immediately after to the string test. We used a homemade string test with a small capsule, which increased the adherence of the participants, following the protocol previously described, with minor modifications (7). A gelatin capsule containing a 90-cm-long absorbent cotton string was swallowed wit...

Helicobacter pylori infection is one of the most common infections worldwide and is associated with gastric diseases. Virulence factors such as VacA and CagA have been shown to increase the risk of these diseases. Studies have suggested a causal role of CagA EPIYA-C in gastric carcinogenesis and this factor has been shown to be geographically diverse. We investigated the number of CagA EPIYA motifs and the vacA i genotypes in H. pylori strains from asymptomatic children. We included samples from 40 infected children (18 females and 22 males), extracted DNA directly from the gastric mucus/juice (obtained using the string procedure) and analysed the DNA using polymerase chain reaction and DNA sequencing. The vacA i1 genotype was present in 30 (75%) samples, the i2 allele was present in nine (22.5%) samples and both alleles were present in one (2.5%) sample. The cagA-positive samples showed distinct patterns in the 3’ variable region of cagA and 18 of the 30 (60%) strains contained 1 EPIYA-C motif, whereas 12 (40%) strains contained two EPIYA-C motifs. We confirmed that the studied population was colonised early by the most virulent H. pylori strains, as demonstrated by the high frequency of the vacA i1 allele and the high number of EPIYA-C motifs. Therefore, asymptomatic children from an urban community in Fortaleza in northeastern Brazil are frequently colonised with the most virulent H. pylori strains.