14th ICID - Poster Abstracts - International Society for Infectious ...

When citing these abstracts please use the following reference:
Author(s) of abstract. Title of abstract [abstract]. Int J Infect Dis 2010;14S1: Abstract number.
Please note that the official publication of the International Journal of Infectious Diseases 2010, Volume 14, Supplement 1
is available electronically on http://www.sciencedirect.com
Final Abstract Number: 27.032
Session: HIV: Epidemiology and Prevention
Date: Wednesday, March 10, 2010
Time: 12:30-13:30
Room: Poster & Exhibition Area/Ground Level
Type: Poster Presentation
Molecular epidemiology of HIV-1 in newly-diagnosed treatment-naïve patients in Singapore
Y.-J. Sun 1 , P. Kaur 1 , Y. S. Leo 2
1 Tan Tock Seng Hospital, Singapore, Singapore, 2 Communicable Disease Centre, Tan Tock
Seng Hospital, Singapore, Singapore
Background: The molecular epidemiology of HIV-1 has not been well studied in Singapore.
Information on HIV-1 molecular epidemiology obtained from previous studies was either based on
a small sample size or on a specific HIV-1 population (seroconverters). In this study we aimed to
have a better understanding to HIV-1 molecular epidemiology in newly-diagnosed treatmentnaïve
patients on the basis of a larger sample size.
Methods: Newly-diagnosed treatment-naïve HIV-1 patients were prospectively, consecutively
recruited from the Communicable Disease Centre, Tan Tock Seng Hospital, Singapore. PCR
products of pol gene that encompass the entire protease gene and two-third of the reverse
transcriptase (RT) gene were amplified based on PBMC-associated viruses using an in-house
method. Direct sequencing was used to sequence the pol gene PCR products. The pol
sequences were used for phylogenetic analysis and for genotypic analysis of drug resistance.
Results: One hundred fifty-one patients were analyzed in this study. Of whom 92% (n=139) were
men, 49.7% (n=75) were men who have sex with men (MSM), and 49% (n=74) were
heterosexuals. Five HIV-1 subtype/CRF were identified, including CRF01_AE (n=94, 62.3%),
subtype B (n=53, 35.1%), CRF33_01B (n=3, 2%), and one each of CRF34_01B and CRF07_BC.
MSM accounted for 35.1% (n=33) of the CRF01_AE infections and 77.4% (n=41) of the subtype
B infections. Phylogenetic analysis showed that 55.3% (n=52) of 01_AE sequences were
clustered in each of 8 clusters and 73.6% (n=39) of subtype B sequences were clustered in each
of 5 clusters; in addition, MSM was more common in one of the clusters compared to
heterosexuals in both 01_AE clusters (55.7% vs. 37.7%, OR 11.9, 95% CI 3.9-36.7) and subtype
B clusters (87.8% vs. 25%, OR 21.6, 95% CI 4.6-101.5). There was no any known drug-resistant
mutation was detected by direct sequencing.
Conclusion: CRF01_AE and subtype B remain the primary etiology for HIV-1 infections in
Singapore. The high extent of clustering of MSM suggests active transmission of HIV-1 in this
specific population, and therefore, more effective prevention intervention measures for HIV-1
transmission are needed for this group of individuals.