title: Trends of antiretroviral drug resistance in treatment-naive patients with human immunodeficiency virus type 1 infection in Taiwan.
abstract: OBJECTIVE
  To determine the prevalence and trends of antiretroviral drug resistance among HIV-1-infected Taiwanese patients who have been provided with free-of-charge antiretroviral therapy (ART) since 1990.
  
  
  METHODS
  Blood samples collected from 786 HIV-1-infected patients from 1999 to 2006 were subjected to genotypic resistance assay. Antiretroviral resistance mutations were identified in accordance with the antiretroviral resistance mutation list of the International AIDS Society-USA Consensus Guidelines. Trends of resistance were studied in patients enrolled in two periods: before (period 1, January 1999 to December 2003) and after (period 2, January 2004 to December 2006) the CRF07_BC outbreak among injection drug users (IDUs).
  
  
  RESULTS
  The frequency of HIV-1 isolates harbouring one or more primary mutations associated with antiretroviral resistance to reverse transcriptase inhibitors or protease inhibitors increased significantly from 6.6% in period 1 to 12.7% in period 2 (P = 0.003). A significant increase in prevalence of antiretroviral drug resistance was observed among men who have sex with men and patients infected with HIV subtype B. In multivariate analysis, hepatitis C virus (HCV) exposure, which exhibited collinearity with injection drug use and infection with CRF07_BC, represented a lower risk for infection with resistant viruses.
  
  
  CONCLUSIONS
  Our findings suggest that the prevalence of antiretroviral resistance has increased in Taiwan over the past 8 years after the introduction of combination ART. IDUs who were HCV-seropositive and infected with CRF07_BC were at lower risk for infection with antiretroviral-resistant viruses.
authors.affiliation: Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Sui-Yuan
authors.initials: SY
authors.lastname: Chang
authors.forename: Mao-Yuan
authors.initials: MY
authors.lastname: Chen
authors.forename: Chun-Nan
authors.initials: CN
authors.lastname: Lee
authors.forename: Hsin-Yun
authors.initials: HY
authors.lastname: Sun
authors.forename: Wilson
authors.initials: W
authors.lastname: Ko
authors.forename: Shu-Fang
authors.initials: SF
authors.lastname: Chang
authors.forename: Kei-Lung
authors.initials: KL
authors.lastname: Chang
authors.forename: Szu-Min
authors.initials: SM
authors.lastname: Hsieh
authors.forename: Wang-Huei
authors.initials: WH
authors.lastname: Sheng
authors.forename: Wen-Chun
authors.initials: WC
authors.lastname: Liu
authors.forename: Cheng-Hsin
authors.initials: CH
authors.lastname: Wu
authors.forename: Chuan-Liang
authors.initials: CL
authors.lastname: Kao
authors.forename: Chien-Ching
authors.initials: CC
authors.lastname: Hung
authors.forename: Shan-Chwen
authors.initials: SC
authors.lastname: Chang
mesh_terms: D000328:Adult; D044966:Anti-Retroviral Agents / Q000494:pharmacology / Q000627:therapeutic use*; D024882:Drug Resistance, Viral / Q000187:drug effects / Q000235:genetics*; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000235:genetics; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008297:Male; D013624:Taiwan / Q000453:epidemiology
chemical_list: D044966:Anti-Retroviral Agents