Detection of Helicobacter pylori gene by means of immunomagnetic separation-based polymerase chain reaction in feces

Background: Detection of Helicobacter pylori is usually performed by culture, polymerase chain reaction (PCR), histology, or urease test on gastric biopsy samples. Although methods based on feces are noninvasive, their sensitivity has been relatively low. In this study, to improve its sensitivity, immunomagnetic separation (LMS) was used as a pre-PCR step for direct detection of H. pylori in feces. Methods: Fresh fecal samples were taken from 72 patients attending for endoscopy. Of these, 57 patients had a positive H. pylori status according to the results of culture, histology, and PCR on gastric biopsy samples. Anti-H. pylori antibody-sensitized immunomagnetic beads were used to concentrate the bacteria. PCR was then performed to detect the H. pylori urease A-encoding gene. Results: Of the 57 H. pylori-positive patients, 35 (61.4%) had positive fecal samples by IMS-based PCR method. None of the 15 H. pylori-negative patients had positive fecal samples. The sensitivity of this method was 61.4%, and the specificity 100.0%. Conclusions: This study confirms that non-invasive diagnosis of H. pylori infection could be made from feces by using IMS-based PCR.