RESUMO
Development of drug resistance is the inevitable consequence of incomplete suppression of virus plasma levels in HIV-1-infected patients treated with highly active antiretroviral therapy. Resistance mutations previously characterized have been found in B subtype viruses of developed countries. Moreover, mutation profiles for non-B and more divergent B subtype viruses found in developing countries shall be analyzed together with their ex vivo phenotyping in order to establish an exact correlation between the genotyping data and the clinical management counseling for those uncommon virus subtypes. In the present study, we evaluated the mutation profile for individuals infected with B subtype and non-B subtype viruses. Viral DNA fragments corresponding to the RT gene were amplified, sequenced, and subtyped. Phenotyping analysis for reverse transcriptase nucleoside (NRTI) and nonnucleoside inhibitor susceptibility was performed using the recombinant virus assay technology. Brazilian non-B subtypes (subtype F, n = 4, and subtype A, n = 1) isolates showed essentially the same B subtype mutation profile, presenting an NRTI drug resistance with similar MIC50% and MIC90% values for all drugs analyzed regardless of their subtypes. A strong cross-resistance phenotype among AZT, 3TC, and abacavir could be seen in all isolates analyzed. A novel result was that some RT sequences not only revealed the presence of G333D/E mutations but also correlated to the presence of mutation T386I that could abrogate the M184V-surpassing effect of L210W or L210W plus G333D/E. These findings suggest that Brazilian non-B subtype HIV-1 strains use an identical RT drug resistance mutation pattern when compared to B isolates and will contribute to the validation of the genotypic and phenotypic tests in these predominant worldwide-spread viral variants.
Assuntos
Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Fármacos Anti-HIV/uso terapêutico , Resistência a Múltiplos Medicamentos/genética , Transcriptase Reversa do HIV/genética , HIV-1/classificação , HIV-1/enzimologia , Inibidores da Transcriptase Reversa/uso terapêutico , Síndrome da Imunodeficiência Adquirida/epidemiologia , Síndrome da Imunodeficiência Adquirida/virologia , Sequência de Aminoácidos , Substituição de Aminoácidos/genética , Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/farmacologia , Brasil/epidemiologia , Análise Mutacional de DNA , Resistência Microbiana a Medicamentos , Quimioterapia Combinada , Feminino , Variação Genética/genética , Genótipo , Transcriptase Reversa do HIV/antagonistas & inibidores , Transcriptase Reversa do HIV/metabolismo , HIV-1/efeitos dos fármacos , HIV-1/genética , Humanos , Masculino , Dados de Sequência Molecular , Mutação/genética , Fenótipo , Filogenia , Inibidores da Transcriptase Reversa/administração & dosagem , Inibidores da Transcriptase Reversa/farmacologia , Fatores de Risco , Alinhamento de Sequência , Fatores de Tempo , Falha de TratamentoRESUMO
We have investigated the phenotypic and genotypic susceptibility of 14 HIV-1 strains isolated from individuals failing HAART therapy to protease inhibitors (PI). Proviral and plasma viral pol gene fragment were amplified, sequenced and subtyped. Nine samples clustered with protease subtype B reference strains and the remaining samples were classified as non-B subtype corresponding to subtype F (n = 4) and subtype A (n = 1). Although all patients were treated with similar P1 drug regimen, the non-B subtype isolates did not present the L90M and 184V mutations and used mainly G48V and V82A/F to achieve drug resistance. A strong cross-resistance phenotype among all four PI was associated with the mutation L90M in the subtype-B isolates, and with G48V and V82A/F in the non-B counterparts. This observation revealed that the non-B viruses tested had specific genotypic characteristics contrasting with the subtype-B isolates.