Human immunodeficiency virus type 1 (HIV-1) transmitted drug resistance (TDR) is an important public health issue. In Brazil, low to intermediate resistance levels have been described. We assessed 225 HIV-1 infected, antiretroviral naïve individuals, from HIV Reference Centers at two major metropolitan areas of Sao Paulo (Sao Paulo and Campinas), the state that concentrates most of the Brazilian Aids cases. TDR was analyzed by Stanford Calibrated Population Resistance criteria (CPR), and mutations were observed in 17 individuals (7.6%, 95% CI: 4.5%–11.9%). Seventy-six percent of genomes (13/17) with TDR carried a nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance mutation, mostly K103N/S (9/13, 69%), potentially compromising the preferential first-line therapy suggested by the Brazilian HIV Treatment Guideline that recommends efavirenz-based combinations. Moreover, 6/17 (35%) had multiple mutations associated with resistance to one or more classes. HIV-1 B was the prevalent subtype (80%); other subtypes include HIV-1 F and C, mosaics BC, BF, and single cases of subtype A1 and CRF02_AG. The HIV Reference Center of Campinas presented more cases with TDR, with a significant association of TDR with clade B infection (P < 0.05).

The presence of X4-tropic variants in more than 80% of our cohort of antiretroviral-experienced children and adolescents with vertical HIV-1 infection indicates a very limited role for CCR5 antagonists as part of salvage regimens for highly treatment-experienced vertically HIV-1-infected patients with extensive antiretroviral drug resistance and limited treatment options.

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The objective of this study is to identify subtypes of Human Immunodeficiency Virus type 1 (HIV-1) and to analyze the presence of mutations associated to antiretroviral resistance in the protease (PR) and reverse transcriptase (RT) regions from 48 HIV-1 positive treatment naïve patients from an outpatient clinic in Maringá, Paraná, Brazil. Sequencing was conducted using PR, partial RT and group-specific antigen gene (gag) nested PCR products from retrotranscribed RNA. Transmitted resistance was determined according to the Surveillance Drug Resistance Mutation List (SDRM) algorithm. Phylogenetic and SimPlot analysis of concatenated genetic segments classified sequences as subtype B 19/48 (39.6%), subtype C 12/48 (25%), subtype F 4/48 (8.3%), with 13/48 (27.1%) recombinant forms. Most recombinant forms were B mosaics (B/F 12.5%, B/C 10.4%), with one C/F (2.1%) and one complex B/C/F mosaic (2.1%). Low levels of transmitted resistance were found in this study, 2/48 (2.1% to NRTIs and 2.1% for PI). This preliminary data may subsidize the monitoring of the HIV evolution in the region.

Raltegravir is an integrase inhibitor (INI) licensed for clinical use and other INI are in advanced stage of development. Different resistance mutations in HIV integrase from patients using these antiretroviral drugs have been described and G148H/R/K, N155H and less frequently Y143C/H/R are considered major resistant mutations to raltegravir. Both Stanford Database and Geno2Pheno list F121Y as conferring intermediate resistance "in vitro" both to raltegravir and elvitegravir. We report for the first time the "in vivo" selection F121Y and evolution to Y143R in a 31years old male clade B HIV-1 infected patient failing a raltegravir-containing salvage regimen. Plasma samples nine months prior to raltegravir (RAL-Naïve) and at weeks 32, 40 and 88 after RAL-containing regimen were analyzed. Antiretroviral susceptibility was evaluated at Stanford and Geno2Pheno from sequences obtained with RT-PCR. After a Viral load at week 12 below 50 copies/mL, viremia raised at week 20 to 4.5log10. The emergence of F121Y was observed at week 32 and 40, alongside with L74I, T97A, Q137H and V151I. At week 88 F121Y was no longer detected, L74I and T97A were maintained and Y143R emerged. F121Y might be an alternative pathway to Y143R. Changing of RAL-containing regimen upon the identification of F121Y might avoid the evolution of raltegravir resistance.

Background: Bioinformatics algorithms have been developed for the interpretation of resistance from sequence submission, which supports clinical decision making. This study evaluated divergences of the interpretation of the genotyping in two commonly used algorithms, using sequences with indels of reverse transcriptase genes. Methods: Sequences were obtained from virus RNA of patients failing highly active antiretroviral therapy from 2004 to 2011. Alignments were obtained using Clustal W including subtype B consensus and HXB2. Sequences with evidence of indels were submitted to the Stanford Resistance Database and to the Geno2Pheno to locate indel positioning and determine the resistance profile. Results: A total of 1,959 partial reverse transcriptase sequences were assessed, mostly subtype B (74%). Insertions and deletions were observed in 0.9 and 0.6% of sequences, respectively. Discordant insert positioning was assigned for most (90%) insertion sequences, with 27% discordances for deletions. Susceptibility differed for some antiretroviral drugs, predominantly for TDF, d4T and ETV, when sequences with deletions were evaluated. Conclusion: Both indel positioning and its impact on drug susceptibility varies depending on the algorithm, a fact that might influence the clinical decision. Critical analysis of indel sequences with manual alignments is important, and its use alongside different algorithms may be important to better understand the outcomes of genotypic resistance prediction.

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