Detection of Helicobacter Pylori by Different Pcr Methods

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. SOUTHEAST ASIAN J TROP MED PUBLIC HEALTH 136 Vol 36 No. 1 January 2005 ent DNA loci were evaluated for the detection of H. pylori on gastric biopsy specimens. The sensitivities and specificities of the PCR methods were compared to those of other methods. In addition, we also looked at the potential use of the same pieces of tissue used for the urease test for assuring the presence of H. pylori by PCR. MATERIALS AND METHODS