Drug-Resistant Reverse Transcriptase Genotyping and Phenotyping of B and Non-B Subtypes (F and A) of Human Immunodeficiency Virus Type I Found in Brazilian Patients Failing HAART

Abstract

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.

Re-mapping the molecular features of the human immunodeficiency virus type 1 and human T-cell lymphotropic virus type 1 Brazilian sequences using a bioinformatics unit established in Salvador, Bahia, Brazil, to give support to the viral epidemiology studies

“…A more recent heterosexual epidemic, characterized by the presence of subtype C viruses, was identified in South Brazil , Soares et al 2003. Other reports have also demonstrated that distinct HIV-1 subtypes (A, B, C, D, F1) and recombinant forms (B/C, B/ F1) are actively participating in the Brazilian Aids epidemic (Morgado et al 1998, Caride et al 2001, Soares et al 2005, Couto-Fernandez et al 2005, Barreto et al 2006, De Sa Filho et al 2006).Financial support: Fapesp, PN-DST/AIDS +Corresponding author: lalcan@cpqgm.fiocruz.br ATLQ and ACAM-M contribute equally to this paper. …”

Amino Acid Mutation N348I in the Connection Subdomain of Human Immunodeficiency Virus Type 1 Reverse Transcriptase Confers Multiclass Resistance to Nucleoside and Nonnucleoside Reverse Transcriptase Inhibitors

“…This complex can emerge during combination treatment that includes NRTIs (10,41) and confers resistance to multiple drugs by enhancing the excision reaction that causes resistance by unblocking NRTI-terminated primers (40). G333E or G333D polymorphisms with thymidine analogue-associated mutations (TAMs) and M184V have also been reported to facilitate moderate resistance to at least two NRTIs, AZT and lamivudine (3TC) (7,22). RT mutations K103N, V106M, and Y188L are associated with resistance to multiple NNRTIs (1,5).…”

Autochthonous horizontal transmission of a CRF02_AG strain revealed by a human immunodeficiency virus type 1 diversity survey in a small city in inner state of Rio de Janeiro, Southeast Brazil

“…In Brazil, molecular analyses of HIV-1 nucleotide sequences have shown an epidemic driven mainly by three group M subtypes: B, C, and subsubtype F1 (heretofore designated subtype F1), as well as a myriad of unique BF1 intersubtype recombinants (Morgado et al 1998, Tanuri et al 1999, Vicente et al 2000, Soares et al 2003. Isolated cases of other subtypes, such as subtype D (Morgado et al 1998, CoutoFernandez et al 2006, subtype A (Caride et al 2000), CRF02_AG (Pires et al 2004, Couto-Fernandez et al 2005, CRF28_BF and CRF29_BF (De Sa Filho et al 2006) have also been reported.…”