HIV-1 subtyping in Salvador, Bahia, Brazil: A city with African sociodemographic characteristics

To investigate the prevalence of the HIV-1 subtypes in different population s from Salvador, Bahia, Brazil, blood samples from 72 HIV-1-seropositive in jecting drug users (IDUs) and 62 individuals infected sexually were analyze d using the heteroduplex mobility assay (HMA). In the IDU group, 89.5% were classified as subtype B, 3% as subtype F, and 7.5% showed a B/F HMA profil e. In the sexual transmission (ST) group, 95% were identified as B subtype, 3.4% showed a B/F profile, and 1.6% a B/C/E HMA profile. All Brazilian sam ples that showed multiple reactivities in the HMA analysis clustered on seq uencing with B North American/European HIV-1 isolates in the phylogenetic a nalysis, whereas the F subtypes clustered with F Brazilian HIV-1 isolates. Serologic reactivities of IDU's sera were examined using a panel of synthet ic V3 loop peptides representative of the different HIV-1 subtypes. No diff erence in serologic reactivity between F and B subtype plasma could be obse rved. Predominance of HIV-1 subtype B was identified in both study groups, whereas subtype F was detected only among IDUs in a frequency lower than de scribed for other Brazilian regions.