Human immunodeficiency virus 1
27 subtype C HIV-1 isolates from treated patients at failure of a regimen with d4T/AZT-3TC-EFV/NVP and which had been sequenced by Sanger, were investigated by UDPS at codon 65 of the reverse transcriptase (RT). 19 isolates from naive patients and dilutions of a control K65R plasmid were analysed by Sanger plus UDPS and UDPS respectively.