Journal: Antimicrobial Agents and Chemotherapy

Article Title: Discordance between Etravirine Phenotype and Genotype-Based Predicted Phenotype for Subtype C HIV-1 from First-Line Antiretroviral Therapy Failures in South Africa

doi: 10.1128/AAC.02101-19

Figure Lengend Snippet: ETR resistance of 100 first-line antiretroviral treatment failures. (A) ETR fold change (FC) values were determined by dividing the EC50 generated for each plasma-derived virus by a composite EC50 from 12 treatment-naive plasma-derived viruses collected form the same geographical region. The bar color and pattern indicate the ETR phenotypic clinical cutoffs of <2.9 FC as susceptible (diagonal stripes), ≥2.9 FC (gray) as intermediate resistance, and >10 FC as high-level resistance (black). The EC50 values of samples 91 through 100 exceeded the highest concentration of ETR that could be tested in TZM-bl cells without cytotoxicity and are reported as >272 nM. (B) The GRT-IS scores were determined using the HIVdb resistance interpretation algorithm version 8.4 (13). The five HIVdb classifications were collapsed into three by merging susceptible and/potential low-level into “susceptible” and low-level and/intermediate into a “low-intermediate” for comparison.

Article Snippet: To assess if the discordances observed for ETR were specific to the HIVdb v8.4, the data set was reanalyzed with the Tibotec resistance algorithm for ETR and a significant correlation (ρ = 0.92; P < 0.0001) between the HIVdb v8.4 and Tibotec ETR scores (Fig. S2) ( 29 ) was observed.

Techniques: Generated, Clinical Proteomics, Derivative Assay, Virus, Concentration Assay, Comparison

Journal: Antimicrobial Agents and Chemotherapy

Article Title: Discordance between Etravirine Phenotype and Genotype-Based Predicted Phenotype for Subtype C HIV-1 from First-Line Antiretroviral Therapy Failures in South Africa

doi: 10.1128/AAC.02101-19

Figure Lengend Snippet: Comparison of ETR phenotype to genotype-based predicted phenotype. (A) ETR phenotype (fold change in EC50) does not strongly correlate with HIVdb score (r = 0.47) for HIV-1 subtype C isolates. Results show 52% of genotype scores were concordant (●, classifications matching), 44% were partially discordant (■, HIVdb predicted 1 classification different), and 4% were completely discordant (▲, HIVdb predicted 2 classifications different) relative to the phenotype clinical cutoffs. (B) Error matrixes of actual fold phenotypic resistance versus predicted resistance for ETR. More samples (26/100) with high phenotypic ETR resistance (FC >10) were misclassified as having low or intermediate resistance. GTR-IS scores were determined using the HIVdb v8.4.

Article Snippet: To assess if the discordances observed for ETR were specific to the HIVdb v8.4, the data set was reanalyzed with the Tibotec resistance algorithm for ETR and a significant correlation (ρ = 0.92; P < 0.0001) between the HIVdb v8.4 and Tibotec ETR scores (Fig. S2) ( 29 ) was observed.

Techniques: Comparison