[Prevalence of transmitted drug resistance in HIV-infected treatment-naive patients in Chile]

Transmitted drug resistance (TDR) occurs in patients with HIV infection who are not exposed to antiretroviral drugs but who are infected with a virus with mutations associated with resistance.

To determine the prevalence of TDR and characterize HIV reverse transcriptase and protease mutation patterns.

HIV infected antiretroviral treatment-naive patients treated in three centers between 2014 and 2018 were studied. A genotyping study was carried out. The HIVdb Program (Stanford University) and the World Health Organization (WHO) TDR surveillance mutation list were used to register resistance-associated mutations.

We enrolled 220 patients aged a median of 29 (interquartile range (IQR) 24-34) years, 99% men. Median CD4 count was 365 cells/μL (IQR 250-499 cells/μL) and median viral load was 39.150 copies/mL (IQR 9,270 -120,000). The overall prevalence of RTD was 10.45% (95% CI 6.7-15.2, N = 23/220). The higher frequency of TDR was against non-nucleoside reverse transcriptase inhibitors, reaching 9.0% (95% CI 5.6-13.6), followed by nucleoside reverse transcriptase inhibitors reaching 1.8% (95% CI 0.49-4.5) and protease inhibitors reaching 0.45% (95% CI 0.01-2.5). The mutations in reverse transcriptase were M41L, L210W, D67N, K70E, M184V, K103N (6.36%, 95% CI 3.5-10.4), G190A, E138A, K101E, and I84V in protease.

These results should prompt a change in recommendations for starting antiretoviral therapy, especially in first-line regimens that include non-nucleoside reverse transcriptase inhibitors.