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 relationships between vacA, cagA and iceA genotypes and gastric diseases in Portuguese patients. Methods: A total of 319 patients were endoscoped and gastric biopsy specimens were studied by PCR and reverse hybridization (LiPA(TM)). 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 the presence of vacA s1 (P=0.008 and P < 0.001, respectively) and vacA m1 genotype (P = 0.007 and P <. 0.001, respectively). Duodenal ulcers were associated 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 ulcer (P < 0.001), gastric ulcer (P = 0.009) and gastric carcinoma (P < 0.001). iceAI was found in 27.3% and iceA2 in 32.3% of the cases. In 36.7% of the isolates both iceA alleles were found. and 3.8% were negative for iceA. The iceA genotype was not associated with clinical outcome. Conclusions: vacA s1 and cagA H. pylori strains are associated with duodenal ulcer, gastric ulcer or gastric carcinoma. vacA m1 is associated with gastric ulcer or carcinoma but not with duodenal ulcer. infection with multiple H. pylori strains is remarkably high in Portugal and is more frequent in duodenal ulcer patients.