Evolving patterns of HIV-1 resistance to antiretroviral agents in newly infected individuals.
OBJECTIVE
To assess temporal changes in prevalence of transmitted HIV-1 drug resistance in a homogeneous cohort of newly infected individuals.


METHODS
Pretreatment genotypic and phenotypic drug resistance was tested in 154 subjects with primary HIV-1 infection identified between 1995 and 2001 (group A; n = 76) and 1999 and 2001 (group B; n = 78). Sequence analysis was assessed by population-based sequencing. Virus susceptibility to antiretroviral agents was determined by the PhenoSense assay (ViroLogic).


RESULTS
The frequency of resistance-associated mutations in protease (PR) and reverse transcriptase (RT) genes increased from 13.2% (1995-1998) to 19.7% (1999-2001). Although the overall prevalence of viruses with phenotypic resistance did not vary (1995-1998, 10.0%; 1999-2001, 10.8%), the distribution of drug classes changed [nucleoside RT inhibitor (NRTI): 8.3% to 2.7%; non-NRTI: 5.0% to 8.1%; protease inhibitors (PI): 1.7% to 5.4%]. The decrease of phenotypic resistance to NRTI in 1999-2001 was caused by the absence of transmitted lamivudine-resistant variants. Phenotypically susceptible variants with aspartic acid or serine residues at position 215 of RT (5.3%; P = 0.04) instead emerged. Hypersusceptibility to PI decreased from 18.3% to 5.4% (P = 0.02) while the amino acid substitutions in PR increased over time: M36I (6.6% to 19.7%) and A71V/T (3.9% to 15.8%).


CONCLUSIONS
There was an increase in the number of HIV-1 variants with both genotypic and phenotypic resistance to non-NRTI and PI over time. Furthermore, viruses with altered genotypes compatible with thymidine analogue or PI exposure but susceptible phenotypes were seen in 1999-2001. The latter findings suggest transmission of viruses from subjects who have either changed or discontinued therapy.
Simon
Viviana
V
Aaron Diamond AIDS Research Center, The Rockefeller University, New York 1016, USA.
Vanderhoeven
Jeroen
J
Hurley
Arlene
A
Ramratnam
Bharat
B
Louie
Michael
M
Dawson
Keith
K
Parkin
Neil
N
Boden
Daniel
D
Markowitz
Martin
M
D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology* / Q000627:therapeutic use; D024921:Drug Resistance, Multiple, Viral / Q000235:genetics*; D004359:Drug Therapy, Combination; D005006:Ethnicity; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy / Q000635:transmission* / Q000821:virology*; D016333:HIV Protease / Q000235:genetics; D017320:HIV Protease Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D017421:Sequence Analysis
D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors; D054303:HIV Reverse Transcriptase; D016333:HIV Protease