title: Transmitted drug resistance of HIV-1 strains among individuals attending voluntary counselling and testing in Taiwan.
abstract: BACKGROUND
  Genotypic drug resistance testing for HIV-1 has been integrated into voluntary counselling and testing (VCT) programmes to investigate the trends of transmitted drug resistance (TDR), including integrase mutations, among individuals with recent or chronic HIV infections in Taiwan.
  
  
  METHODS
  Between 2006 and 2014, 745 of 21 886 subjects (3.4%) tested HIV positive in the VCT service. The BED assay was used to identify recent HIV infections. Genotypic resistance mutations were interpreted using the WHO 2009 list. Integrase resistance mutations were analysed using the Stanford HIV Drug Resistance Database.
  
  
  RESULTS
  Three-hundred-and-sixty (48.3%) patients were recently infected with HIV-1. Of 440 patients linked to HIV care with analysable reverse transcriptase and protease genes, 49 (11.1%) were infected with HIV-1 harbouring at least one resistance-associated mutation (RAM). The prevalence of TDR to NRTIs, NNRTIs and PIs was 4.1%, 6.4% and 2.3%, respectively. TDR prevalence did not change significantly during the study period. CD4 counts ≤500 cells/mm(3) and hepatitis B surface antigen positivity were independent factors associated with acquiring drug-resistant HIV. The prevalence of integrase mutations was 3.2%. Among the seven major integrase mutations (T66I, E92Q, G140S, Y143C/H/R, S147G, Q148H/K/R and N155H), only one strain harbouring the Q148R mutation was detected. We found no statistically significant difference between patients with chronic infection and those with recent infection in the prevalence of drug-resistant mutations to any of the four classes of antiretroviral agents.
  
  
  CONCLUSIONS
  The prevalence of TDR of HIV-1 strains to available antiretroviral agents is moderately high, but transmission of HIV-1 with drug-resistant mutations remains stable in Taiwan.
authors.affiliation: Department of Internal Medicine, Kaohsiung Medical University Hospital and College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Chung-Chih
authors.initials: CC
authors.lastname: Lai
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Wen-Chun
authors.initials: WC
authors.lastname: Liu
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan Institute of Epidemiology and Preventive Medicine, National Taiwan University College of Public Health, Taipei, Taiwan.
authors.forename: Chi-Tai
authors.initials: CT
authors.lastname: Fang
authors.affiliation: Center for Research, Diagnostics, and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan.
authors.forename: Jyh-Yuan
authors.initials: JY
authors.lastname: Yang
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Lan-Hsin
authors.initials: LH
authors.lastname: Chang
authors.affiliation: Center of Infection Control, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Pei-Ying
authors.initials: PY
authors.lastname: Wu
authors.affiliation: Center of Infection Control, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Yu-Zhen
authors.initials: YZ
authors.lastname: Luo
authors.affiliation: Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Shu-Fang
authors.initials: SF
authors.lastname: Chang
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Yi-Ching
authors.initials: YC
authors.lastname: Su
authors.affiliation: Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan Department of Laboratory Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Sui-Yuan
authors.initials: SY
authors.lastname: Chang
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan Department of Medical Research, China Medical University Hospital, Taichung, Taiwan Department of Medical Research, China Medical University Hospital and China Medical University, Taichung, Taiwan hcc0401@ntu.edu.tw.
authors.forename: Chien-Ching
authors.initials: CC
authors.lastname: Hung
mesh_terms: D000328:Adult; D018562:Disease Transmission, Infectious; D024882:Drug Resistance, Viral; D005260:Female; D005838:Genotype; D060005:Genotyping Techniques; D015658:HIV Infections / Q000175:diagnosis* / Q000453:epidemiology / Q000635:transmission / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D015995:Prevalence; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult