Identification of non-B human immunodeficiency virus type 1 subtypes in rural Georgia

As part of an ongoing molecular epidemiological investigation of human immu nodeficiency virus type 1 (HIV-1) in rural Georgia, the 50 half of reverse transcriptase (RT) genotypes from 30 patients was sequenced and phylogeneti cally analyzed. Two patients, GA132 and GA169, were infected with pol seque nces of non-B subtype origin that were found to cluster phylogenetically wi th subtype A-E of Thai origin. Sliding window bootstrap analysis of GA169 s howed clear evidence of A/B recombination within the pol gene segment, wher eas in the other patient, GA132, no break point within RT could be identifi ed. Interestingly, pairwise comparisons between these 2 patients' C2-V3 env region revealed a 13.5% divergence. However, similar comparisons within th e non-B pol segments yielded a 1.23% nucleotide divergence, which suggests a complex phylogenetic and epidemiological history of the subtype A pol gen otype in this region. These data demonstrate an increasing diversity of HIV -1 subtypes and the potential emergence of previously unidentified HIV-1 A- E/B recombinants in the rural United States.