Helicobacter pylori genotypes are associated with clinical outcome in Portuguese patients and show a high prevalence of infections with multiple strains

Background: Clinical outcome of Helicobacter pylori infection is associated with virulence-associated bacterial genotypes. This study assessed the rel ationships between vacA, cagA and iceA genotypes and gastric diseases in Po rtuguese patients. Methods: A total of 319 patients were endoscoped and gas tric biopsy specimens were studied by PCR and reverse hybridization (LiPA(T M)). Results: vacA gcnotypes s1/ mi, s1/m2 and s2/m2 were observed in 53%, 14.5% and 32.5% of the cases, respectively. The majority (93.4%) of the s1 cases were s1b and 6.6% were s1a. Multiple vacA genotypes were found in 37. 3% of the cases. Gastric ulcer and gastric carcinoma were associated with t he presence of vacA s1 (P=0.008 and P < 0.001, respectively) and vacA m1 ge notype (P = 0.007 and P <. 0.001, respectively). Duodenal ulcers were assoc iated with vacA s1 (P < 0.001) but not with the vacA m genotype (P = 0.221) . cagA was present in 71.2% of the cases and was associated with duodenal u lcer (P < 0.001), gastric ulcer (P = 0.009) and gastric carcinoma (P < 0.00 1). iceAI was found in 27.3% and iceA2 in 32.3% of the cases. In 36.7% of t he isolates both iceA alleles were found. and 3.8% were negative for iceA. The iceA genotype was not associated with clinical outcome. Conclusions: va cA s1 and cagA H. pylori strains are associated with duodenal ulcer, gastri c ulcer or gastric carcinoma. vacA m1 is associated with gastric ulcer or c arcinoma but not with duodenal ulcer. infection with multiple H. pylori str ains is remarkably high in Portugal and is more frequent in duodenal ulcer patients.