title: Transmission of HIV-1 drug resistance.
abstract: BACKGROUND
  The use of highly-active anti-retroviral therapy (HAART) for treating HIV infections is increasing. Recent studies have demonstrated that HAART is improving both the length and quality of life in HIV-infected patients. Resistant strains of HIV arise when drug adherence is poor. This can lead to the transmission of drug-resistant strains of HIV to susceptible individuals. This can lead to suboptimal first-line therapy, if the resistance profile of the transmitted virus is unknown.
  
  
  OBJECTIVE
  To review the mechanisms of how drug resistance arises; the methods used to characterise drug resistance; the problems arising with compliance leading to the development of drug-resistant HIV strains; the evidence for the incidence, prevalence and trends in the transmission of resistant HIV strains in different risk groups; and the evidence of suboptimal response to first-line therapy where transmission of a resistant HIV strain has occurred. On the basis of this, a case is presented for the routine resistance testing of all newly diagnosed HIV-infected individuals.
  
  
  METHODS
  Literature review.
  
  
  CONCLUSIONS
  There is evidence, though limited at present, that transmission of drug-resistant HIV strains can lead to suboptimal response to first-line therapy in newly diagnosed HIV-infected individuals. As the use of HAART can only increase in the future, and compliance will always be a problem in such HAART-treated patients, baseline resistance testing should become a routine part of their management.
authors.affiliation: Department of Virology, Windeyer Institute of Medical Sciences, Royal Free and University College Medical Schools, 46 Cleveland Street, London W1T 4JF, UK.
authors.forename: Julian W
authors.initials: JW
authors.lastname: Tang
authors.forename: Deenan
authors.initials: D
authors.lastname: Pillay
mesh_terms: D024882:Drug Resistance, Viral / Q000235:genetics*; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy* / Q000635:transmission / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D010349:Patient Compliance