Intersubtype BF recombinants of HIV-1 in a population of injecting drug users in Argentina.

The presence of recombinant intersubtypes of HIV-1 in Argentina has been reported since the mid-1990s. In this study, sequences of a region of the gag, pol, and vpu genes of HIV-1 were analyzed in samples of 21 injection drug users (IDUs) residing in the suburbs of the city of Buenos Aires. Genomic characterization and identification of recombination sites were made comparing the 3 regions with reference isolation sequences of subtypes B, F, C, A, and B/F recombinants: CRF12_BF and non-CRF12_BF sequences. Subtype assignment of the analyzed segments was phylogenetically confirmed. All the samples turned out to be BF recombinants in at least 1 of the 3 studied genes. Twelve samples (57%) had the same pattern as the Argentinean CRF12_BF, whereas in the rest, the pattern differed in at least 1 of the 3 genes. The relation of these fragments to the CRF12_BF was phylogenetically verified. These results indicate the predominance of BF recombinants and the presence of a high percentage of sequences closely related to the CRF12_BF in the IDU population in Argentina and suggest a possible association between viral variants and the transmission route.