title: Antiretroviral drug resistance in a respondent-driven sample of HIV-infected men who have sex with men in Brazil.
abstract: BACKGROUND
  : There are few studies on HIV subtypes and primary and secondary antiretroviral drug resistance (ADR) in community-recruited samples in Brazil. We analyzed HIV clade diversity and prevalence of mutations associated with ADR in men who have sex with men in all five regions of Brazil.
  
  
  METHODS
  : Using respondent-driven sampling, we recruited 3515 men who have sex with men in nine cities: 299 (9.5%) were HIV-positive; 143 subjects had adequate genotyping and epidemiologic data. Forty-four (30.8%) subjects were antiretroviral therapy-experienced (AE) and 99 (69.2%) antiretroviral therapy-naïve (AN). We sequenced the reverse transcriptase and protease regions of the virus and analyzed them for drug resistant mutations using World Health Organization guidelines.
  
  
  RESULTS
  : The most common subtypes were B (81.8%), C (7.7%), and recombinant forms (6.9%). The overall prevalence of primary ADR resistance was 21.4% (i.e. among the AN) and secondary ADR was 35.8% (i.e. among the AE). The prevalence of resistance to protease inhibitors was 3.9% (AN) and 4.4% (AE); to nucleoside reverse transcriptase inhibitors 15.0% (AN) and 31.0% (AE) and to nonnucleoside reverse transcriptase inhibitors 5.5% (AN) and 13.2% (AE). The most common resistance mutation for nucleoside reverse transcriptase inhibitors was 184V (17 cases) and for nonnucleoside reverse transcriptase inhibitors 103N (16 cases).
  
  
  CONCLUSIONS
  : Our data suggest a high level of both primary and secondary ADR in men who have sex with men in Brazil. Additional studies are needed to identify the correlates and causes of antiretroviral therapy resistance to limit the development of resistance among those in care and the transmission of resistant strains in the wider epidemic.
authors.affiliation: Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Elkin Hernan
authors.initials: EH
authors.lastname: Bermúdez-Aza
authors.forename: Ligia Regina Franco Sansigolo
authors.initials: LR
authors.lastname: Kerr
authors.forename: Carl
authors.initials: C
authors.lastname: Kendall
authors.forename: Adriana Araujo
authors.initials: AA
authors.lastname: Pinho
authors.forename: Maeve Brito
authors.initials: MB
authors.lastname: de Mello
authors.forename: Rosa Salani
authors.initials: RS
authors.lastname: Mota
authors.forename: Mark Drew Crosland
authors.initials: MD
authors.lastname: Guimarães
authors.forename: Cecilia Salete
authors.initials: CS
authors.lastname: Alencar
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: de Brito
authors.forename: Ines Costa
authors.initials: IC
authors.lastname: Dourado
authors.forename: Sonia Maria Batista
authors.initials: SM
authors.lastname: da Batista
authors.forename: Fabiano
authors.initials: F
authors.lastname: Abreu
authors.forename: Lisangela Cristina
authors.initials: LC
authors.lastname: de Oliveira
authors.forename: Adão
authors.initials: A
authors.lastname: de Souza Moraes
authors.forename: Adele Schwartz
authors.initials: AS
authors.lastname: Benzaken
authors.forename: Edgar
authors.initials: E
authors.lastname: Merchan-Hamann
authors.forename: Gisele Maria Brandão
authors.initials: GM
authors.lastname: de Freitas
authors.forename: Willi
authors.initials: W
authors.lastname: McFarland
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Albuquerque
authors.forename: George W
authors.initials: GW
authors.lastname: Rutherford
authors.forename: Ester
authors.initials: E
authors.lastname: Sabino
mesh_terms: D000328:Adult; D019943:Amino Acid Substitution; D044966:Anti-Retroviral Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001938:Brazil; D016000:Cluster Analysis; D003625:Data Collection; D024882:Drug Resistance, Viral; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy / Q000821:virology*; D016333:HIV Protease / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D017422:Sequence Analysis, DNA; D014505:Urban Population
chemical_list: D044966:Anti-Retroviral Agents; C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase; D016333:HIV Protease