title: Rapid and specific detection of amantadine-resistant influenza A viruses with a Ser31Asn mutation by the cycling probe method.
abstract: Amantadine is one of the antiviral agents used to treat influenza A virus infections, but resistant strains have widely emerged worldwide. In the present study, we developed a novel method to detect amantadine-resistant strains harboring the Ser31Asn mutation in the M2 gene based on the cycling probe method and real-time PCR. We also studied the rate of amantadine resistance in the 2007-2008 influenza season in Japan. Two different primer and cycling probe sets were designed for A/H1N1 and A/H3N2 each to detect a single nucleotide polymorphism corresponding to Ser/Asn at residue 31 of the M2 protein. By using nasopharyngeal swabs from patients with influenza-like and other respiratory illnesses and virus isolates, the specificity and the sensitivity of the cycling probe method were evaluated. High frequencies of amantadine resistance were detected among the A/H1N1 (411/663, 62%) and A/H3N2 (56/56, 100%) virus isolates collected from six prefectures in Japan in the 2007-2008 influenza season. We confirmed that the cycling probe method is suitable for the screening of both nasopharyngeal swabs and influenza virus isolates for amantadine-resistant strains and showed that the incidence of amantadine resistance among both A/H1N1 and A/H3N2 viruses remained high in Japan during the 2007-2008 season.
authors.affiliation: Department of Public Health, Niigata University, Graduate School of Medical and Dental Sciences, 1-757, Asahimachi-Dori, Niigata City, Niigata Prefecture 951-8510, Japan. yasshi@med.niigata-u.ac.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Reiko
authors.initials: R
authors.lastname: Saito
authors.forename: Hassan
authors.initials: H
authors.lastname: Zaraket
authors.forename: Clyde
authors.initials: C
authors.lastname: Dapat
authors.forename: Isolde
authors.initials: I
authors.lastname: Caperig-Dapat
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D000547:Amantadine / Q000494:pharmacology*; D019943:Amino Acid Substitution / Q000235:genetics; D000998:Antiviral Agents / Q000494:pharmacology*; D024882:Drug Resistance, Viral; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D053122:Influenza A Virus, H3N2 Subtype / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D007251:Influenza, Human / Q000821:virology; D007564:Japan; D008826:Microbial Sensitivity Tests / Q000379:methods; D025202:Molecular Diagnostic Techniques / Q000379:methods; D020125:Mutation, Missense; D009305:Nasopharynx / Q000821:virology; D020641:Polymorphism, Single Nucleotide; D012680:Sensitivity and Specificity; D014763:Viral Matrix Proteins / Q000235:genetics*; D000086082:Viroporin Proteins
chemical_list: D000547:Amantadine; D000998:Antiviral Agents; D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins