HIV-1 genetic diversity and transmitted drug resistance to integrase strand transfer inhibitors among recently diagnosed adults in Porto Alegre, South Brazil

OBJECTIVES

The HIV-1 genetic diversity and the presence of transmitted drug resistance mutations (TDRMs) against integrase strand transfer inhibitors (INSTIs) were assessed sequencing samples of antiretroviral (ARV)-naive HIV-1-infected individuals from South Brazil.

METHODS

Viral RNA from 42 ART-naive individuals was submitted to complete HIV-1 integrase gene amplification by RT-PCR and sequencing.

RESULTS

Viral strains carrying TDRMs against INSTIs were not detected in the present study. However, the polymorphisms L74M and L74I were each observed in 4.8% of the individuals. These accessory mutations have been reported as putative causes of TDRMs in ART with raltegravir, but only when associated with additional major mutations. When submitted to HIV-1 subtyping, 50% were classified as subtype C, 21% as recombinant BC, 19% as subtype B, 4.8% as subtype F1 and 4.8% as recombinant CF1.

CONCLUSIONS

All 42 ARV-naive individuals were apparently susceptible to INSTIs, included in the Brazilian therapeutic guideline since 2009. To the best of our knowledge, this is the first study to evaluate TDRMs against INSTIs in Brazil. The most prevalent HIV-1 subtypes were subtype C, followed by the recombinant BC and subtype B, which is in agreement with previous studies. However, the presence of subtype F1 and recombinant CF1 reported herein was not observed in previous studies.