Detection of Helicobacter pylori in Gastric Biopsy Samples by Polymerase Chain Reaction with a Simple DNA Extraction Method

We have established a PCR assay for the detection of Helicobacter pylori in gastric biopsy specimens with primers specific to adhesin subunit gene. The minimum amount of H. pylori DNA that could be detected was 0.4 pg. Seventy-two antral biopsy specimens were taken from patients with gastritis and/or duodenal ulcer. H. pylori was found in 58.3%, 44.4% and 54.2% of patients according to the results of histology, urease test and PCR assay respectively. The sensitivity and specificity of PCR assay, compared to histology technique were 66.7% and 63.3% respectively. Samples diagnosed to be positive for H. pylori by both histology and urease test were only 85% PCR positive. Specimens that were negative in both tests were also PCR negative (72%). DNA was extracted by two methods: the Chelex chelating resin method and the Qiagen DNA Mini Kit. The sensitivity and specificity of the PCR assay, using the Chelex-extracted DNA as templates were 85.7% and 85% respectively as compared to those extracted with the kit.