Introduction: The use of highly active antiretroviral therapy has dramatically reduced morbidity and mortality among patients infected with HIV-1 (1,2). But the success of antiretroviral treatment is frequently limited by the emergence of HIV drug resistance (3-5). Importantly, drug resistant viruses can be transmitted to newly infected individuals (6-8). Transmission of drug resistant HIV is a major public health concern, as it could lead to a situation in which no effective drugs are available for the treatment of HIV. (...)