PCR-based restriction pattern typing of the vacA gene provides evidence for a homogeneous group among Helicobacter pylori strains associated with peptic ulcer disease

Detection of Helicobacter pylori in gastric mucosa of patients with gastroduodenal diseases by PCR-restriction analysis using the RNA polymerase gene (rpoB)

A novel PCR restriction analysis method using the RNA polymerase beta-subunit- coding gene (rpoB) was employed to both detect and identify Helicobacter pylori in biopsy specimens and culture isolates. The rpoB DNAs (458 bp) were specifically amplified by PCR with the Helicobacter-specific primers (HF and HR). Based on the determined rpoB sequences of the culture isolates, an H. pylori-specific restriction site, Tru9I, was found. H. pylori can be identified by observing two discernible DNA fragments (288 and 138 bp) after Tru9I digestion and agarose gel electrophoresis. The rpoB PCR and subsequent restriction analysis (PRA) enabled the specific detection and identification of H. pylori in biopsy specimens from patients with gastroduodenal diseases. The rpoB PRA conferred a compatible or a slightly higher positive rate (53.7%) than did the Campylobacter-like organism (CLO) test (50.4%) and glmM PCR (48.8%), suggesting that it is useful for diagnosing an H. pylori infection without culture in the clinical laboratory.

Detection of Helicobacter pylori virulence-associated genes

Helicobacter pylori is an important human pathogen and persistent colonization of the human gastric mucosa can cause severe gastrointestinal diseases. The bacterium should not be considered as a uniform organism, but as a population of closely related and yet genetically diverse bacteria. Several genes of H. pylori (such as vacA and cagA) have been identified as being virulence-associated and may have important clinical and epidemiological implications. Assessment of virulence-associated genes of H. pylori should be included in clinical and epidemiological studies as well as therapeutic trials, in order to stratify between patient groups, harboring H. pylori strains with particular virulence genotypes. Molecular determination of antibiotic resistance will be especially useful for treatment studies. Together with our increasing knowledge about the human genome, typing of H. pylori will facilitate the management of gastroenterological pathologies.