HIV-1 genetic diversity in Galicia Spain: BG intersubtype recombinant viruses circulating among injecting drug users

Background: The HIV-1 epidemics in Western Europe are dominated by B subtyp e viruses. Non-B subtype is largely restricted to individuals infected outs ide of Europe and to their direct contacts and is generally acquired by the heterosexual route. Methods: Protease and a segment of reverse transcriptase were amplified and sequenced from plasma RNA in 451 individuals from seven cities of Galicia, northwestern Spain. Subtype sequence homologies were determined using the BLAST algorithm. Non-B sequences were examined by phylogenetic analysis and intersubtype recombination by bootscanning. The env V3 region was analysed in all non-B and in 38 B subtype viruses. Results: Ten different non-B genetic forms were identified in 20 (4.4%) ind ividuals. Subtypes were concordant between pol and V3 in five viruses; 14 ( 70%) infections were with intersubtype recombinant viruses, and one individ ual had a dual B+G infection. Seven recombinant viruses were phylogenetical ly related to five reported recombinant forms. Three non-recombinant G and six recombinant BG viruses formed a monophyletic cluster for pol. All but t hree individuals with non-B infections were native Spanish. Only 6 of 16 in dividuals referred to sexual contacts with sub-Saharan Africans. Twelve (60 %) non-B subtype infections, including all with G and BG viruses, were in i njecting drug users (IDU). Conclusions: Non-B subtype viruses were identified in 4.4%, with a high div ersity of genetic forms, including 70% infections with intersubtype recombi nant viruses. The majority of individuals with non-B infections were IDU, m ost of them without known contacts with non-European sources, and among who m BG recombinant viruses are circulating. (C) 2001 Lippincott Williams & Wi lkins.