Objective To determine the frequency of highly active antiretroviraltherapy resistance mutations in the viral pol gene of humanimmunodeficiency virus–1 (HIV-1) genotypes that circulate inHong Kong, by means of an in-house HIV-1 genotyping system.Design Retrospective study.Setting Two HIV clinics in Hong Kong.Patients A modified in-house genotyping resistance test was used tosequence the partial pol gene in 1165 plasma samples from 965patients. The performance of our test was cross-compared withthe US Food and Drug Administration–approved ViroSeq HIV-1genotyping system. The results of genotyping were submitted tothe Stanford HIV-1 drug resistance database for analysis.Results The cost-effective in-house genotypic resistance test (US$40)demonstrated comparable performance to the US Food andDrug Administration–approved ViroSeq system. The detectionlimit of this in-house genotypic resistance test could reach 400copies/mL for both HIV-1 subtype B and CRF01_AE, which werethe predominant genotypes in Hong Kong. Drug resistancemutations were detected only in post-treatment samples fromtreatment-failure patients. However, there was no significantdifference in the frequency of drug resistance mutations betweensubtype B and CRF01_AE.Conclusion Our cost-effective in-house genotypic resistance test detectedno significant difference in drug resistance–related mutationsfrequencies between HIV-1 subtype B and CRF01_AE in HongKong. A drug resistance–related mutations database for differentHIV-1 genotypes should be established in Hong Kong to augmentguidance for HIV treatment.
