Genotyping of Helicobacter pylori in paraffin-embedded gastric biopsy specimens: relation to histological parameters and effects on therapy.

Abstract OBJECTIVES: Colonization with Helicobacter pylori can lead to GI disease. Bacterial genotypes and host factors, such as acid production, can influence the progress of disease. We investigated H. pylori genotypes and histological parameters in the same paraffin-embedded gastric biopsy specimens. METHODS: Paraffin-embedded antrum and corpus biopsy samples from 75 gastroesophageal reflux disease patients were histologically examined and tested for H. pylori vac A (s and m regions), cag A, and ice A genotypes. Patients were investigated at baseline (58 H. pylori positive and 17 H. pylori negative) and after treatment with omeprazole with or without additional antibiotic therapy. RESULTS: Genotyping at baseline was complete in 52 (90%) of the 58 H. pylori positive patients. Multiple genotypes were detected in eight (14%) of these. Genotypes were highly consistent between antrum and corpus biopsy specimens at baseline and in follow-up samples. Genotypes from paraffin sections matched those from corresponding cultured strains in 10 selected cases. In the antrum, the degree of inflammation was associated with vac A s1 and cag A+ genotypes, and the degree of neutrophil activity was associated with the cag A+ genotype. In the corpus, the degree of inflammation was significantly associated with vac A s1, cag A+, and ice A1 genotypes and the degree of atrophy was associated with vac A s1, m1, and cag A+ genotypes, whereas the degree of neutrophil activity was associated with vac A s1 and cag A+ genotypes. vac A s2 and cag A− strains appeared more resistant to antibiotic therapy, irrespective of resistance to clarithromycin. CONCLUSIONS: Our findings confirm the relevance of the H. pylori genotypes for the severity of gastric disease and the efficacy of antibiotic therapy.