Thermophilic helicase-dependent isothermal DNA amplification for molecular detection of Helicobacter pylori

Abstract number: 1733_87

Gill P., Abdul-Tehrani H., Ghaemi A., Hashempour T., Alvandi A., Noori-Daloii M.

Objectives:Helicobacter pylori is a Gram-negative, pathogenic bacterium, which specifically colonises in the human gastric mucosa. The infection with this microorganism is one of the most prevalent infections in humans and about 50% of the adults in the industry and more than 90% of the population in developing countries are infected. Several PCR-based methods have been described for molecular diagnosis of this bacterium in biological specimens. However, in this study, we designed and developed a novel procedure for detection of ureC gene of Helicobacter pylori, so called thermophilic helicase-dependent isothermal DNA amplification, (tHDA).

Methods: Like PCR, the tHDA reaction selectively amplifies a target sequence defined by two primers. However, unlike PCR, tHDA uses an additional enzyme called thermophilic helicase to separate DNA rather than heat. Since, this DNA amplification is an isothermal technique, as an advantage it does not need any thermocycler. The accuracy of the technique was checked on DNA extracted from pure culture of Helicobacter pylori.

Results: We obtained same results when several experiments were performed on specimens prepared from infected gastric biopsies. All the results were shown the equal specificity and sensitivity for this technique in comparison to PCR.

Conclusion: THDA can be used for molecular detection of Helicobacter pylori more cost-effectively than PCR in developing countries. Further studies are under taken to develop this technique using ELISA and real-time formats.