title: Transmission of HIV-1 drug resistance in Switzerland: a 10-year molecular epidemiology survey.
abstract: OBJECTIVE
  Representative prevalence data of transmitted drug-resistant HIV-1 are essential to establish accurate guidelines addressing resistance testing and first-line treatments.
  
  
  METHODS
  Systematic resistance testing was carried out in individuals in Switzerland with documented HIV-1 seroconversion during 1996-2005 and available samples with RNA > 1000 copies/ml obtained within 1 year of estimated seroconversion. Resistance interpretation used the Stanford list of mutations for surveillance of transmitted drug resistance and the French National Agency for AIDS Research algorithm.
  
  
  RESULTS
  Viral sequences from 822 individuals were available. Risk groups were men having sex with men (42%), heterosexual contacts (32%) and intravenous drug users (20%); 30% were infected with non-B subtype viruses. Overall, prevalence of transmitted resistance was 7.7% [95% confidence interval (CI), 5.9-9.5] for any drug, 5.5% (95% CI, 3.9-7.1) for nucleoside reverse transcriptase inhibitors, 1.9% (95% CI, 1.0-2.8) for non-nucleoside reverse transcriptase inhibitors and 2.7% (95% CI, 1.6-3.8) for protease inhibitors. Dual- or triple-class resistance was observed in 2% (95% CI, 0.8-2.5). No significant trend in prevalence of transmitted resistance was observed over years. There were no differences according to ethnicity, risk groups or gender, but prevalence of transmitted resistance was highest among individuals infected with subtype B virus.
  
  
  CONCLUSIONS
  The transmission rate of drug-resistant HIV-1 has been stable since 1996, with very rare transmission of dual- or triple-class resistance. These data suggest that transmission of drug resistance in the setting of easy access to antiretroviral treatment can remain stable and be kept at a low level.
authors: Laboratory of Virology, University of Geneva Hospitals, Geneva, Switzerland. sabine.yerly@hcuge.ch
authors: Sabine
authors: S
authors: Yerly
authors: Viktor
authors: V
authors: von Wyl
authors: Bruno
authors: B
authors: Ledergerber
authors: Jürg
authors: J
authors: Böni
authors: Jörg
authors: J
authors: Schüpbach
authors: Philippe
authors: P
authors: Bürgisser
authors: Thomas
authors: T
authors: Klimkait
authors: Martin
authors: M
authors: Rickenbach
authors: Laurent
authors: L
authors: Kaiser
authors: Huldrych F
authors: HF
authors: Günthard
authors: Luc
authors: L
authors: Perrin
mesh_terms: D019380:Anti-HIV Agents / Q000627:therapeutic use; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D019450:Genes, MDR; D015658:HIV Infections / Q000188:drug therapy / Q000635:transmission* / Q000821:virology; D017320:HIV Protease Inhibitors / Q000627:therapeutic use; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D016015:Logistic Models; D008297:Male; D009154:Mutation; D015995:Prevalence; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use; D012307:Risk Factors; D017422:Sequence Analysis, DNA; D013557:Switzerland / Q000453:epidemiology
chemical_list: D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors