Helicobacter pylori and cagA and vacA gene status in children from Brazil with chronic gastritis

Abstract. Helicobacter pylori hasbeen shown to be strongly associated with chronic gastritis,gastric and duodenal ulceration, and is a risk factor forgastric carcinoma. Histology, urease, culture, and polymerasechain reaction have been employed as for H. pylori diagnostic methods, pre andpost treatment or during follow-up of dyspeptic adultindividuals referred for endoscopy. In order to obtain amore-sensitive and specific method for H. pylori detection, we evaluatedgastric body and antrum biopsies of 134 consecutive Brazilianconsecutive dyspeptic children aged 1–16 years by rapid ureasetest, histology and polymerase chain reaction using two pairs ofoligonucleotides. Our results indicated that polymerase chainreaction with Southern blotting and hybridization with specificchemiluminescent probes increased the number of positiveH. pylori patients by 35%.The genotyping of H. pyloristrains directly from gastric biopsy using the same nucleic acidmethodology revealed that there is no association of chronicgastritis in our infant patients with vacA s1 and the presence of thecagA gene. These data suggestan initial infection of children with normal mucosa and probablyothers factors than vacA s1genotype or the presence of the cagA gene are associated with the onsetof gastric disease. Altogether, our results reinforce the needfor using more sensitive diagnostic methods in order tounderstand the role of H.pylori in the genesis of gastric disease in childrenand its progression in adults.