Molecular characterization of HIV type 1 strains from newly diagnosed patients in Cyprus (2007-2009) recovers multiple clades including unique recombinant strains and lack of transmitted drug resistance.

HIV-1 evolution generates substantial genetic diversity among isolates, the majority of which are represented in areas where multiple strains cocirculate. A heterogeneous genetic HIV-1 pool has been found in Cyprus, directing us to determine the dynamics of the local HIV-1 infection by characterizing strains isolated from 74 subjects during 2007-2009, representing 88% of the known-living HIV-1-infected population, of whom 53 are newly diagnosed therapy-naive patients and 21 are chronic patients, according to the European HIV Resistance guidelines. Near full-length genome sequences were amplified by RT-nested PCR using diluted RNA from all HIV-1 seropositives and sequenced using a newly designed assay. Resistant mutations were not found among the population of the newly diagnosed therapy-naive patients either to protease, reverse transcriptase, or integrase inhibitors. Phylogenetic analyses indicated subtype B as the main subtype (48.6%), followed by subtype A (18.9%), subtype C (10.8%), CRF02_AG (8.1%), CRF11_cpx (2.7%), and (sub)subtype F1 and CRF37_cpx (1.4% each). Six HIV-1 isolates (8.1%) were not classified in any pure (sub)subtype or circulating recombinant form (CRF). Complete phylogenetic and bootscanning analyses revealed that each isolate had a new, unique recombinant pattern and is distinct from all other CRFs or unique recombinant forms (URFs) reported so far. Two of the six isolates have the same mosaic pattern. Analogous to results of the earlier epidemiological studies, this study expands on the HIV-1 sequence database and reveals the high degree of diversity of HIV-1 infection in Cyprus.