[Development and clinical application of invader assay--detection of resistant mutation to clarithromycin in Helicobacter pylori].
Invader Assay is a novel technology used for the direct analysis of genomic DNA without PCR amplification, including the detection of single nucleotide polymorphisms (SNPs) in human genome. It has high accuracy and reproducibility. We have previously developed SNPs assays of cytochrome P450 (CYP) 2C19 and many other drug metabolized enzymes by Invader technology to realize personalized medicine. Here, we developed Invader assays to detect mutations with resistance to clarithromycin (CAM) in H. pylori which achieves resistance by A2143G or A2142G mutation of 23S rRNA. The sensitivity of this assay is 10(3) copies/ gastric tissue sample, and it can detect 5% existence of mutant bacteria in wild type-bacteria. We examined the A2143G genotypes of 6 colonies picked up from each culture dish of gastric tissue samples. These samples were categorized three groups; all colonies are wild-type (genotype A) or mutant-type (genotype G), and intermingled-type, including genotype A, genotype B and genotype A/G. The genotypes of each colony from the group of intermingled samples were compared with MIC values of the CAM susceptibility test. All colonies of genotype A and genotype B were consistent with the MIC value. Inconsistencies were observed for some colonies of genotype A/G. Proton pump inhibitor (PPI), CAM and amoxicillin were given to eradicate H. pylori. PPI is influenced by SNPs of CYP2C19, and mutations become resistant to CAM. It was shown that the determination of these two genotypes before setting doses was very important for to obtain a high cure rate.
Development of Clinical Genomics, BML Inc., Kawagoe 350-1101.
Toru
T
Egashira
D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics; D017291:Clarithromycin / Q000494:pharmacology* / Q000627:therapeutic use; D065731:Cytochrome P-450 CYP2C19; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005753:Gastric Mucosa / Q000382:microbiology; D005838:Genotype; D016481:Helicobacter Infections / Q000188:drug therapy; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics*; D006801:Humans; D006899:Mixed Function Oxygenases / Q000235:genetics; D009154:Mutation; D010597:Pharmacogenetics; D020641:Polymorphism, Single Nucleotide; D012329:RNA, Bacterial / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics
D012329:RNA, Bacterial; D012338:RNA, Ribosomal, 23S; D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19; D017291:Clarithromycin