AEGiS-14IAC: HIV genotyping drug resistance virco vs visible genetics methods evaluation.

14th International AIDS Conference

Barcelona, Spain - July 7-12, 2002

HIV genotyping drug resistance virco vs visible genetics methods evaluation.

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. B10186)

Swantee C, Fearon M, Sandstrom P, Choi KW, Major C
Ontario Ministry of Health and Long-Term Care, Toronto, Canada

BACKGROUND: To compare the results of HIV genotyping drug resistance testing using the Virco Virtual Phenotype method and the Visible Genetics TRUGENE HIV-1 Genotyping Systems.

METHODS: Thirty-one plasma specimens were selected from naïve (17) and ART experienced(14) patients. HIV viral load ranged from 1000 - >500,000 copies/ml. The TRUGENE kit was run in our laboratory. "In-house" sequencing coupled to a Virco Virtual Phenotype report was carried out at the British Columbia Centre for Excellence in HIV. Results reported by each system were compared with respect to the resistance-associated mutations identified and drug resistance assessments.

RESULTS: Of 31 specimens tested, 4 produced invalid Virco results; 3 different samples produced invalid TRUGENE results leaving 24 samples in the analysis. 8/24 (33%) specimens had concordant mutations identified in the RT region and 5/24 (21%) were concordant in the PRO region. In the RT region, 4 mutations were reported by TRUGENE, but not by Virco and 26 mutations were reported by Virco and not by TRUGENE. In the PRO region, 17 mutations were reported by TRUGENE exclusively and 22 mutations by Virco only. The most common discrepant mutations were: in the RT region 211K (Virco only, 12 specimens), in the PRO region 63P (TRUGENE only, 10 specimens) and 77I (Virco only, 9 specimens). 4/24 (17%) specimens had discrepant drug interpretations. TRUGENE reported additional drug resistance for NVP, DLV, EFV (1 specimen), ddI, ddC, ABC (1 specimen), SQV, NFV (1 specimen), AZT (1 specimen) not reported by Virco.

CONCLUSIONS: Frequent differences in the reporting of individual drug resistance associated mutations (67% RT, 79% PRO) are likely due to differences in reporting secondary mutations. Of concern are the 17% of specimens with differences in drug resistance interpretations. Further investigation including phenotyping is planned to establish which interpretation is correct.

Keywords: AEGIS, HIV, HIV Infections, HIV-1, Drug Resistance, Viral, Genotype, Anti-HIV Agents, HIV Protease, HIV-1 Reverse Transcriptase, Mutation, HIV Protease Inhibitors, HIV Seropositivity, Phenotype, Drug Resistance, Drug Resistance, Microbial, British Columbia, Human, genetics, methods

020707
B10186