title: [Phylogenetic and molecular analysis of A/H1N1pdm influenza viruses isolated in the epidemic season 2012/2013 from hospitalised patients with -symptoms of influenza-like illness].
abstract: OBJECTIVE
  To perform phylogenetic and molecular analysis of A/H1N1pdm influenza viruses isolated in the epidemic season 2012/2013 from hospitalised patients with symptoms of influenza-like illness (ILI).
  
  
  METHODS
  The study set included 34 strains of the A/H1N1pdm influenza virus isolated in the Czech Republic in the epidemic season 2012/2013. The strains were analysed by partial or whole-genome sequencing. The genome segments were compared at the nucleotide and amino acid levels, absolute and percentage sequence identity were determined, and phylogenetic relations were identified. The last steps were the comparison of the H1 molecule with that of the most recent vaccine strain and identification of the genotypic structure and molecular markers linked to the pathogenicity and antiviral resistance.
  
  
  RESULTS
  Phylogenetic analysis of the H1 molecule suggested that all 34 A/H1N1pdm isolates from the 2012/2013 season in the Czech Republic should be assigned to H1 group 6 divided into sublineages 6A and 6B. The comparison of the known antigenic regions of the H1 molecule with those in the most recent vaccine strain revealed two stable changes in antigenic regions Sb and Ca1. Furthermore, sporadic mutations were identified in antigenic regions Ca2, Cb, and Sb. Genotyping revealed co-circulation of two related but clearly distiguishable genotypes of A/H1N1pdm. All isolates showed sensitivity to oseltamivir. One strain consisted of two N1 sub-populations, one oseltamivir sensitive and the other oseltamivir resistant, in nearly equimolar proportions.
  
  
  CONCLUSIONS
  All A/H1N1pdm isolates from the epidemic season 2012/2013 in the Czech Republic formed a phenotypically uniform group. At the nucleotide level, the divergence was relatively more pronounced and H1 sublineages and discrete genotypes were possible to identify. H1 molecules were highly identical to those of the vaccine strain A/California/7/2009 (H1N1) which showed that the current vaccine was protective enough. All strains were sensitive to oseltamivir; however, the selection of oseltamivir resistant N1 subpopulations was observed.
authors.forename: A
authors.initials: A
authors.lastname: Nagy
authors.forename: H
authors.initials: H
authors.lastname: Jiřincová
authors.forename: M
authors.initials: M
authors.lastname: Havlíčková
authors.forename: O
authors.initials: O
authors.lastname: Džupová
authors.forename: K
authors.initials: K
authors.lastname: Herrmannová
authors.forename: M
authors.initials: M
authors.lastname: Trojánek
authors.forename: J
authors.initials: J
authors.lastname: Kynčl
authors.forename: Z
authors.initials: Z
authors.lastname: Blechová
authors.forename: V
authors.initials: V
authors.lastname: Marešová
mesh_terms: D018153:Czech Republic / Q000453:epidemiology; D024882:Drug Resistance, Viral; D058872:Epidemics; D005260:Female; D006760:Hospitalization; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000187:drug effects / Q000235:genetics*; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology; D008297:Male; D053139:Oseltamivir / Q000494:pharmacology; D010802:Phylogeny; D013997:Time Factors
chemical_list: D053139:Oseltamivir