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Session 100 Poster Session Molecular Epidemiology Session Time: 4:30-6:30 pm Room 4E-F

759-W. Increasing Prevalence and Heterogeneous Nature of HIV-1 Subtype-G Recombinants Spreading in Southern Europe Á. Holguín*, A. Álvarez, and V. Soriano Inst. de Salud Carlos III, Madrid, Spain Background: Several major genetic variants can be recognized within HIV-1 group M, including 9 subtypes (A, B, C, D, F, G, H, J, K) and 12 major circulating recombinant forms (CRFs). An increasing prevalence of HIV-1 non-B variants has been noticed recently in Spain and Portugal. The close contact with former colonies in West Africa (i.e., Equatorial Guinea) may account for this finding. Subtype G as well as CRF02-AG strains have been among the most frequently found among both native intravenous drug users (IDUs) and African immigrants. Their co-circulation with other HIV variants may give rise to different HIV-1 subtype G recombinants with a mosaic genome comprising fragments of different subtypes. Methods: The RT (600-pb) and env (300-bp) genes were examined in HIV-1 obtained from 26 individuals living in Spain, in whom a previous analysis at the protease gene (297-bp) revealed that they belonged to subtype-G. Phylogenetic analyses were performed using the Neighbor-Joining program. Results: Genetic characterization at the protease, RT, and env genes revealed that 22 (65.4%) of 26 clinical samples were recombinant G variants: 17 were G/G/A, 3 G/G/B, 1 G/B/B, and 1 was a triple G/B/A recombinant. Only 4 (15.4%) samples carried subtype G sequences at all 3 genomic regions. Of note, only a small fraction of G/A variants clustered with the well-characterized reference CRF-02AG IbNg isolate. All sequences have been sent to the Los Alamos database. Therefore, G/A variants are the most frequent recombinants in our sample set, mainly represented by immigrants who acquired the infection through heterosexual contact. In contrast, recombinant B/G variants predominate in Portugal and northwestern Spain, mainly among native IDUs. Conclusion: Subtype-G recombinants circulating in southern Europe have a highly heterogeneous nature, being G/A variants the most frequently found among immigrants and G/B among native IDUs. The spread of subtype-G variants coupled with inter-subtype recombination must be taken into account, since it may influence the results of viral load determinations. Moreover, the susceptibility to antiretroviral drugs may differ in subtype G in respect to subtype-B viruses.

©2002 9th Conference on Retroviruses and Opportunistic Infections