Use of different PCR primers and gastric biopsy tissue from CLO test for the detection of Helicobacter pylori.

Four different DNA loci were assessed for the detection of H. pylori by PCR on gastric biopsy specimens. PCR, with a primer specific 860 bp DNA fragment, was the most sensitive, with a detection limit of 0.02 pg H. pylori DNA, corresponding to approximately 10 organisms. Nested-PCR of the 860-bp DNA fragment was 10-fold more sensitive than single-step PCR. The sensitivity and specificity of the four PCR methods, in comparison to the results obtained from histology and the urease test, are as follows: 80.7% and 76% for the hpaA gene; 100% and 76% for the 16S rRNA gene; 84.6% and 80.0% for the 860-bp DNA fragment; 61.5% and 84.0% for the ureC (glmM) gene, respectively. The sensitivity of nested-PCR for the 860-bp DNA fragment was 100%. This nested-PCR gave positive results for eight specimens which were negative by conventional methods. PCR can be performed on gastric biopsy specimens obtained from the CLO test.