Development of phenotypic HIV-1 drug resistance after exposure to single-dose nevirapine.

Objectives: Single-dose nevirapine (sdNVP) used to prevent mother-to-child transmission of HIV-1 results in the selection of genotypic drug resistance mutations. To assess the levels of phenotypic resistance conferred by these mutations, we examined the ability of sample-derived HIV-1 reverse transcriptase to function in the presence of nevirapine (NVP).

Methods: Plasma samples from HIV-1 pregnant women before and after exposure to sdNVP were used to extract viral reverse transcriptase for the Cavidi ExaVir Drug susceptibility assay.