Unusual insertion and deletion at codon 67 and 69 of HIV type 1 subtype C reverse transcriptase among first-line highly active antiretroviral treatment-failing South Indian patients: association with other resistance mutations

We report a high frequency of drug resistance mutations among patients with unusual insertions or deletions at the β(3)-β(4) hairpin-loop-coding region of HIV-1 subtype C reverse transcriptase, during failure of first-line antiretroviral therapy containing only reverse transcriptase inhibitors in Chennai, India.