Antiretroviral drug resistance in a respondent-driven sample of HIV-infected men who have sex with men in Brazil.

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.