title: Rapid detection of point mutations conferring resistance to fluoroquinolone in gyrA of Helicobacter pylori by allele-specific PCR.
abstract: Helicobacter pylori strains with reduced susceptibility to fluoroquinolones have a mutation at either codon 87 Asn or 91 Asp of the gyrA gene. A rapid test based on an allele-specific PCR (AS-PCR) was designed to detect the gyrA mutations. Clinical H. pylori isolates were obtained from the stomachs of 51 patients with H. pylori infections who showed treatment failure. The MICs of gatifloxacin (GAT) were determined by the agar dilution method. Identical genotyping results were obtained with AS-PCR and conventional PCR. The gyrA mutations of H. pylori causing reduced susceptibility to fluoroquinolones could be detected successfully by this method. A significant association was observed between the presence of mutations, as detected by AS-PCR, and the resistance of the strains to GAT. Moreover, genotyping by AS-PCR took less than 3 to 4 h. The AS-PCR method for the detection of gyrA mutations in H. pylori is useful for easy identification of fluoroquinolone-resistant strains of H. pylori.
authors.affiliation: Department of Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nishizawa
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Suzuki
authors.forename: Ayako
authors.initials: A
authors.lastname: Umezawa
authors.forename: Hiroe
authors.initials: H
authors.lastname: Muraoka
authors.forename: Eisuke
authors.initials: E
authors.lastname: Iwasaki
authors.forename: Tatsuhiro
authors.initials: T
authors.lastname: Masaoka
authors.forename: Intetsu
authors.initials: I
authors.lastname: Kobayashi
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Hibi
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D000890:Anti-Infective Agents / Q000494:pharmacology*; D027081:DNA Gyrase / Q000235:genetics*; D024881:Drug Resistance, Bacterial; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology*; D000077734:Gatifloxacin; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests / Q000379:methods; D008875:Middle Aged; D017354:Point Mutation; D016133:Polymerase Chain Reaction / Q000379:methods*; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D027081:DNA Gyrase; D000077734:Gatifloxacin