Antiretroviral drug-resistant HIV-2 infection--a new therapeutic dilemma.

HIV-2 drug resistance in a case of dual HIV infection presents a formidable challenge to the treating physician. We report a patient with dual infection on highly active antiretroviral therapy (HAART) since March 2001 presented with clinical failure. Laboratory assays showed undetectable HIV-1 viral RNA copies, but with low CD4 count. Suspecting HIV-2 resistance, specific genotype assays were performed. Mutations at codons M184V and Q151M conferring resistance to nucleoside reverse transcriptase inhibitors (NRTIs) in HIV-1 infection were detected, as were mutations at codons V71I and L90M implying indinavir and nelfinavir resistance as well. Salvage therapy was initiated with good clinical response.