title: Prevalence of HIV-1 drug resistance after failure of a first highly active antiretroviral therapy regimen in KwaZulu Natal, South Africa.
abstract: BACKGROUND
  Emergence of human immunodeficiency virus type 1 (HIV-1) drug resistance may limit the benefits of antiretroviral therapy in resource-limited settings. The prevalence of resistance was assessed among patients from KwaZulu Natal, South Africa, following failure of their first highly active antiretroviral therapy (HAART) regimen.
  
  
  METHODS
  Genotypic resistance testing was performed on plasma virus samples from patients who experienced virologic failure of their first HAART regimen at 2 clinics in KwaZulu Natal. Clinical and demographic data were obtained from medical records. Regression analysis was performed to determine factors associated with > or =1 significant drug resistance mutation.
  
  
  RESULTS
  From January 2005 through August 2006, a total of 124 antiretroviral-treated adults who experienced virologic failure were enrolled. The predominant subtype was HIV-1C. Virus samples from 83.5% of participants carried > or =1 significant drug resistance mutation. Dual-class drug-resistant virus was present in 64.3% of participants, and 2.6% had virus with triple-class drug resistance. The most common mutation was M184V/I (64.3% of patients); K103N was present in virus from 51.3%, and V106M was present in virus from 19.1%. Thymidine analog resistance mutations were found in virus from 32.2% of patients, and protease resistance mutations were found in virus from 4.4%.
  
  
  CONCLUSIONS
  Antiretroviral drug-resistant virus was detected in >80% of South African patients who experienced failure of a first HAART regimen. Patterns of drug resistance reflected drugs used in first-line regimens and viral subtype. Continued surveillance of resistance patterns is warranted to guide selection of second-line regimens.
authors.affiliation: Section of Retroviral Therapeutics, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02139, USA.
authors.forename: Vincent C
authors.initials: VC
authors.lastname: Marconi
authors.forename: Henry
authors.initials: H
authors.lastname: Sunpath
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Lu
authors.forename: Michelle
authors.initials: M
authors.lastname: Gordon
authors.forename: Kofi
authors.initials: K
authors.lastname: Koranteng-Apeagyei
authors.forename: Jane
authors.initials: J
authors.lastname: Hampton
authors.forename: Steve
authors.initials: S
authors.lastname: Carpenter
authors.forename: Janet
authors.initials: J
authors.lastname: Giddy
authors.forename: Douglas
authors.initials: D
authors.lastname: Ross
authors.forename: Helga
authors.initials: H
authors.lastname: Holst
authors.forename: Elena
authors.initials: E
authors.lastname: Losina
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Walker
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Kuritzkes
mesh_terms: D000328:Adult; D019943:Amino Acid Substitution / Q000235:genetics; D019380:Anti-HIV Agents / Q000494:pharmacology*; D023241:Antiretroviral Therapy, Highly Active; D024882:Drug Resistance, Viral; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology*; D015497:HIV-1 / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D012367:RNA, Viral / Q000097:blood / Q000235:genetics / Q000302:isolation & purification; D013019:South Africa
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral