Frequency Of Primary Resistance Research Articles

Low Frequency of Protease Inhibitor Resistance Mutations and Insertions in HIV-1 Subtype C Protease Inhibitor-Naïve Sequences.

Human immunodeficiency virus-1 (HIV-1) protease sequences from 2,225 protease inhibitor (PI)-naïve HIV-1 subtype C-infected individuals collected over a 14-year period were analyzed for polymorphisms. Over 50% of sequences differed from an HIV-1 subtype B consensus sequence at 8 of the 99 amino acids at residues 12, 15, 19, 36, 41, 69, 89, and 93, but not in the functionally important regions. The frequency of primary resistance and accessory mutations occurred in <1% of the sequences. Of note, 11 sequences (0.5%) harbored amino acid insertions between residues 36 and 39, located in the elbow of the flap region. The insertions were found throughout the 13-year period. Occurrence of insertions in subtype C viruses is rare and viruses remain sensitive to currently used PIs (lopinavir/r, atazanavir/r, and darunavir/r). However, ongoing characterization of isolates is required to identify changes that may impact PI treatment since PIs are part of standard SA regimens.

Prevalence of Primary Antiretroviral Resistance: Trends in Korea

Primary drug resistance is an emerging problem in HIV infections. We have investigated the current prevalence of primary resistance in Korea and compared it with previous data. Drug-naive HIV patients attending the outpatient clinic of Seoul National University Hospital between April and August 2006 were enrolled. A medical interview and a genotypic resistance test were performed for each patient. The International AIDS Society-USA Panel consensus statement issued in 2006 was used to define resistance mutations. Eighty-one drug-naive HIV patients were enrolled. Two (2.5%) were infected with primary drug-resistant virus: M41L and K103N, respectively. In our previous study, conducted between 1998 and 2002, three (6%) of 50 subjects harbored resistant viruses. Thus the frequency of primary resistance was lower in the present sample than in the earlier one, though the difference is not statistically significant (p = 0.37). In view of our findings, routine antiretroviral resistance tests for drug-naive HIV patients are not obligatory in Korea.

Resistencias primarias a los fármacos antirretrovirales en los pacientes diagnosticados de infección por el VIH en Gran Canaria entre los años 2002-2005

This study examines the prevalence of primary resistance to antiretroviral drugs in patients diagnosed with HIV infection during 2002 to 2005 and determines the clinical and epidemiological characteristics of this population. A prospective analysis of genotypic resistance was carried out in 125 patients by gene sequencing (88.0% diagnosed in 2002, 28.9% in 2003-2004, and 87.9% in 2005). Thirteen patients had a diagnosis of recent primary infection. Sixteen patients (12.8%) carried viruses with at least one drug-resistance mutation; among them, 4 had recent infection (30.8%) and 12 chronic infection or infection of unknown duration (10.7%). Six patients (4.8%) presented at least one resistance mutation to nucleoside/tide reverse transcriptase inhibitors, 9 patients (7.2%) to non-nucleoside/ tide reverse transcriptase inhibitors inhibitors and 2 patients (1.6%) to protease inhibitors. One patient (0.8%) harbored a multidrug-resistant variant. The frequency of primary resistance was higher in patients with HIV subtype B (15.5%), in the homosexual/bisexual population (17.9%), and in patients diagnosed in 2005 (17.9%). Prevalence increased from 9.3% in 2002 to 16.3% in 2005 in chronically infected patients or those with unknown duration of the infection. Primary resistance to antiretroviral drugs is high in both recent and chronic HIV infection and has increased in recent years. Genotype resistance testing in patients with a diagnosis of HIV infection is recommended before beginning antiretroviral therapy.