Development of a loop-mediated isothermal amplification assay for rapid Helicobacter pylori detection.

Infection with cagA-positive Helicobacter pylori is associated with gastric cancer. Molecular techniques are vital for accurate H. pylori diagnosis. We developed a loop-mediated isothermal amplification (LAMP) for detecting the H. pylori cagA gene and evaluated its use for clinical diagnosis. A LAMP primer set was designed to recognize the homologous regions of cagA gene sequences of 6 H. pylori strains. LAMP sensitivity was evaluated with serial dilutions of H. pylori ATCC 43504 and fecal specimens; specificity was evaluated with H. pylori ATCC 49396 and CIP 104086. The LAMP sensitivity for H. pylori specimens was 10-1 cfu/tube (reaction time, 37 min), which was 10-fold more sensitive than polymerase chain reaction. LAMP was also highly sensitive and rapid for fecal specimens. It detected cagA gene from ATCC 49396 and CIP 104086. The findings suggest LAMP can be used for diagnosing and screening of H. pylori infections to decrease gastric cancer incidence.