Genotyping of Helicobacter pylori strains in formalin-fixed or formaldehyde-sublimate-fixed paraffin-embedded gastric biopsy specimens

Different genotypes of Helicobacter pylori can play a role in the developme nt of atrophic gastritis, peptic ulcer disease, and gastric carcinomas. In this study the authors developed polymerase chain reaction assays for the d etection and identification of vacA (s- and m-regions), cagA, and iceA geno types of H. pylori in formalin-fixed or formaldehyde-sublimate-fixed paraff in-embedded gastric biopsy specimens. Polymerase chain reaction products we re analyzed by reverse hybridization on a line-probe assay. Complete genoty ping was achieved in 26 of 28 samples (93%), and multiple genotypes, indica ting the presence of multiple strains, were detected in nine samples (32%). This genotyping method offers the possibility for long-term retrospective studies on H. pylori genotypes and gastric pathology in the same archival g astric tissue specimens.