The resistance rate of Helicobacter pylori to clarithromycin (CAM) is high among the infected children in Japan; therefore, a new method for detecting CAM-resistant H. pylori using a less invasive technique is strongly desired. We aimed to confirm the clinical usefulness of our newly developed Nested polymerase chain reaction-QProbe (quenching probe) (Nested PCR-QP) method using stool specimens. Methods The first was an evaluation of our method using the residual solution of the H. pylori stool

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... antigen test for adolescents, and the second was an evaluation of our method using culture testing for adults. Results Of the 57 middle school students with H. pylori , the Nested PCR-QP test results of 53 (90.3%) could be analyzed; 28 students were found to have CAM resistance mutations. The results indicating genetic mutation in 28 and no mutation in 23 students were consistent with those of PCR-direct sequencing. In the 23 adults who were diagnosed with H. pylori infection using the rapid urease test and culture testing, it was possible to use Nested PCR-QP for analyzing all 21 adults who tested positive in the stool H. pylori antigen test. The results obtained for all the 21 adults were consistent with those obtained via the drug susceptibility test. Conclusions Our novel method could be useful for non-invasively detecting CAM resistance mutations in H. pylori. This may help select an eradication drug to reduce eradication failure rates against H. pylori.