title: Subtype and genotypic resistance analysis of HIV-1 infected patients in Austria.
abstract: BACKGROUND
  Analysis of HIV-1 subtypes and genotypic resistance have been shown to be relevant for epidemiologic and therapeutic studies or for vaccine development. In Europe, the majority of HIV-1 isolates belong to subtype B. Due to migration an increasing incidence for additional subtypes and complex recombinant forms are expected.
  
  
  OBJECTIVE
  To evaluate the prevalence of HIV-1 subtypes in Austria, 188 plasma samples of treatment experienced patients were investigated. For phylogenetic analysis protease and reverse transcriptase genes were amplified and sequenced. Subtypes were determined by comparing reference sequences. For genotypic resistance determination, the Resistance-Algorithm-Comparison from Stanford University was used.
  
  
  RESULTS
  Non-B subtypes were found in 20.2% of all patients with a dominant prevalence (50%) in the Southern provinces of Austria. With 85% CRF01_AE and CRF02_AG are the predominant circulating recombinant forms in Austria. When resistance mutations were analyzed, 57.4% of all patients were susceptible to all three groups of antiretroviral drugs, whereas in 12.2% resistance against all three classes of antiretroviral drugs was found.
  
  
  CONCLUSIONS
  HIV-1 subtype B is still dominant in major parts of Austria. However, a significantly increasing percentage of non-B subtypes and recombinant forms are observed in the Southern provinces.
authors.affiliation: Department of Hygiene, Microbiology and Social Medicine, Innsbruck Medical University, Innsbruck, Austria. barbara.falkensammer@i-med.ac.at
authors.forename: Barbara
authors.initials: B
authors.lastname: Falkensammer
authors.forename: Martin
authors.initials: M
authors.lastname: Doerler
authors.forename: Harald H
authors.initials: HH
authors.lastname: Kessler
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Puchhammer-Stoeckl
authors.forename: Walter
authors.initials: W
authors.lastname: Parson
authors.forename: Christina
authors.initials: C
authors.lastname: Duftner
authors.forename: Manfred P
authors.initials: MP
authors.lastname: Dierich
authors.forename: Heribert
authors.initials: H
authors.lastname: Stoiber
mesh_terms: D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use*; D024882:Drug Resistance, Viral / Q000235:genetics*; D004641:Emigration and Immigration; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy / Q000635:transmission / Q000821:virology*; D016333:HIV Protease / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000145:classification / Q000235:genetics*; D006801:Humans; D008297:Male; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic / Q000235:genetics; D012189:Retrospective Studies; D019562:Viral Load
chemical_list: D000998:Antiviral Agents; D054303:HIV Reverse Transcriptase; D016333:HIV Protease