CagA phosphorylation EPIYA-C motifs and the vacA i genotype in Helicobacter pylori strains of asymptomatic children from a high-risk gastric cancer area in northeastern Brazil

Abstract

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.

Determination of CagA EPIYA motif in Helicobacter pylori strains isolated from patients with digestive disorder

“…We did not observe any clinical association between the motifs and gastritis and peptic ulcer which is consistent with some studies [ 26 , 32 ] conducted in Iran but in disagreement with a study in Iran [ 1 ]and two studies in Mexico [ 14 ]and Brazil [ 36 ]. Our study showed that increased C fragments cannot increase pathogenicity; however, the number of motifs with two and more C fragments was very low and the prevalence rates and distributions of gastritis and peptic ulcer very high in our study, which is consistent with Ogordnik and Hossein & and Shekarzadeh [ 35 ] studies, but Vianna [ 36 ], Salih [ 34 ], Gonzalo [ 43 ], Basso [ 42 ] and Kalaf [ 44 ] have reported that increased C fragment was associated with clinical symptoms.…”

Helicobacter pylori virulence genes

“…Children: In children, the frequency of the oipA “on” status tends to be somewhat lower than in adults (49.6%, 67.6% and 68.8% in children from Portugal, United States and Brazil, respectively)[22,30,41], with higher frequencies among pediatric strains from high risk populations in which the incidence of H. pylori infection and related disease is significant. Moreover, the OR for PUD risk was shown to be higher in children (OR= 7.03, 95%CI: 3.71-13.34) compared to that in adults, suggesting increased risk for PUD in children with oipA “on” status[40,42].…”

Risk factors of Helicobacter pylori infection in an urban community in Northeast Brazil and the relationship between the infection and gastric diseases

“…Brazil has a population of over 200 million individuals with varying ethnic and geographic backgrounds. The country is heterogeneous with respect to sanitary coverage, and a large proportion of its population still do not have access to highquality water 9,10 . Access to high-quality water is not evenly distributed across Brazil and is highly dependent on sanitary facilities and infrastructure.…”