”Nested” PCR test for diagnostics of Helicobacter pylori infection

According to the European Helicobacter Study Group the main obstacle in the treatment of H. pylori infection is reliable diagnostics. We elaborated “nested“ PCR test, based on the primers designed to the variable regions of 16S rRNA gene, to identify H. pylori in 63 gastric biopsy, 39 saliva and 20 stool samples. The test is 100 times more sensitive than widely used stool antigen test. The reliability was verified by sequencing of 44 PCR products, providing exclusively H. pylori specific DNA sequence. H. pylori was identified in 30% gastric biopsies, in 30% of stool and in 25,6% of saliva samples. The detection limits for individual method was determined by spiking the negative samples with known number of H. pylori cells. In the case of “nested“ PCR it was ≥5x10³/g or ml of the sample. The main drawback in non-invasive diagnostic is associated with the low prevalence of H. pylori in stool and saliva (5x10³/ml or 5x10³/g) in comparison with the gastric biopsies (1x10⁵/g – 2,5x10⁶/g).