1495. An Update of the HIV-1 Subtypes and Drug Resistance-Associated Mutations Present in Singapore: A Retrospective Study from the National University Hospital, 2011-2012
Session: Poster Abstract Session: Global HIV
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
  • 1495_IDWPOSTER.pdf (290.5 kB)
  • Background:

    Since July 2011, an inexpensive and sensitive direct-sequencing-based in-house HIV-1 genotyping resistance test (GRT) has been in routine clinical service at the National University Hospital (NUH). We conducted a retrospective study of HIV-1 subtypes and drug-resistance mutations (DRMs) in a Singapore HIV-1-infected population.


    GRT data obtained from the Molecular Diagnosis Centre was reviewed and compiled for all HIV-1 patients presenting to NUH during July 2011-December 2012.


    A total of 114 patients were identified in this study, of whom 103 (90.4%) were male and 43 (37.7%) were known to be treatment-na´ve.

    Subtypes: Circulating Recombinant Form (CRF) strains were more prevalent (75.9%) than the pure subtypes (24.1%) and were distributed as follows: 80 (70.2%) CRF01_AE, 25 (21.9%) B, 6 (5.3%) CRF02_AG, 2 (1.8%) C, and 1 (0.88%) CRF06_cpx. Consistent with previous local studies, CRF01_AE and subtype B were the main circulating strains.

    Genotyping: Of the 114 samples, 60 (52.6%) were fully antiretroviral-susceptible. Among those with DRMs, 5 (4.4%) were PI-resistant, 39 (34.2%) RTI-resistant, and 10 (8.8%) were resistant to both. A total of 184 DRMs (57 PR and 127 RT) were isolated. The in-house assay detected 14/36 PR and 26/32 RT drug-resistance associated codons listed in the HIV-1 DRMs 2011 update. Furthermore, E35G (decreased NFV/TPV susceptibility), K238T and Y318F (decreased NVP/EFV susceptibility) were detected. The majority of the DRMs (63%) were found in RT positions 69, 101, 103, 138, 179, 184, 190 and 219, and PR position 10. Of the 43 treatment-na´ve patients, 14 (32.6%) harbored primary genotypic resistance in the following subtypes: CRF01_AE (7/28), B (4/11), CRF02_AG (1/2), C (1/1) and CRF06_cpx (1/1).


    The landscape of HIV epidemiology in Singapore has changed. Notably, CRF01_AE is more dominant (>70%) as compared to past findings and a significant number of treatment-na´ve patients have primary genotypic resistance.

    Sophia Archuleta, MD1, CW Ng2, CK Lee2, MJ Khoo2, Lily Chiu2, Jwt Tang2 and ESC Koay2,3, (1)Division of Infectious Diseases, University Medicine Cluster, National University Hospital Singapore, Singapore, Singapore, (2)Molecular Diagnosis Centre, Department of Laboratory Medicine, National University Hospital, Singapore, Singapore, Singapore, (3)Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore


    S. Archuleta, None

    C. Ng, None

    C. Lee, None

    M. Khoo, None

    L. Chiu, None

    J. Tang, None

    E. Koay, None

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