Recombinant strains of HIV type 1 in the United Kingdom

Twenty-five recombinant (mosaic) HIV-1 genomes were detected among 151 samp les comprising 118 non-B subtype sequences and 33 samples containing subtyp e B sequences. Seven of the 25 mosaic patterns were similar to characterize d circulating recombinant forms (two A/E, four A/G, and one D/F) and one wa s a MAL-like A/D recombinant. Eighteen of the recombinants had evidence of subtype A sequences in at least one region of their genome. One sample was found to contain a novel recombinant form (pol F, env K). Two samples could not be characterized unambiguously as recombinant forms and a further one appeared to be a complex C/J/D/A genomic form, The majority of the mosaic g enomes were recombinants between gag, pol, or env, whereas the C/J/D/A mosa ic had cross-over breakpoints within pol. These findings suggest that almos t 20% of non-B subtype isolates of HIV-1 circulating in the United Kingdom have mosaic genomes. This shows the diverse origin of HIV-1 strains circula ting in the United Kingdom and may have implications for antiretroviral dru g resistance.