HIV-1 pol phylogenetic diversity and antiretroviral resistance mutations in treatment naïve patients from Central West Brazil

Abstract

Background: Primary resistance represents a challenge for the control of HIV-1 because it can reduce the efficacy of first line antiretroviral therapy and may impact clinical outcomes.

Objectives: To describe the prevalence of primary HIV-1 drug resistance and subtypes circulating in Central West Brazil.

Study design: 103 antiretroviral naïve patients were recruited in Goiânia city, Central West Brazil during 2007-2008. Protease and partial reverse transcriptase regions were retrotranscribed from plasma HIV-1 RNA and 97 were sequenced after direct nested PCR. HIV-1 subtype was assigned by phylogenetic analysis. Primary drug resistance was analyzed by the Calibrated Population Resistance (CPR) tool using Stanford Surveillance Drug Resistance Mutation (SDRM) and International AIDS Society-USA (IAS-USA) major mutation list.

Results: Primary drug resistance mutations ranged from 8% (IAS) to 10% (SDRM). High level resistance to at least one antiretroviral drug was observed. T215D/S revertant mutations were identified in 4/97 patients. HIV-1 subtype B represented 82.5%, subtype F1 6.2%, subtype C 3.1%, B/F1 7.2% and one sample was a F1/C/B mosaic. HIV-1 subtype C sequences formed a monophyletic cluster with other Brazilian subtype C sequences.

Conclusions: Our HIV-1 pol sequences from Central West region include the first inland HIV-1 subtype C sequences and help compose the molecular epidemiology map of HIV-1 in Brazil. This data also show that a significant proportion of the naïve patients presented important drug resistance mutations. Therefore naive patients from this setting may benefit from pre-treatment genotypic testing to optimize the choice of antiretroviral drugs and to help control HIV-1 transmission.