Lack of High-Level Resistance Mutations in HIV Type 1 BF Recombinant Strains Circulating in Northeast Brazil Joana Paixao Monteiro-Cunha, 1 Adriano Fernando Araujo, 1 Edson Santos, 2 Bernardo Galvao-Castro, 1,2 and Luiz Carlos Junior Alcantara 1,2,3 Abstract The genetic variability and the prevalence of drug resistance-associated mutations (DRAM) of HIV-1 isolates from 50 women and 8 children from Feira de Santana, Bahia, Brazil were investigated. DNA samples were obtained and pol sequences were generated by PCR and direct sequencing. Phylogenetic analysis showed that 39 (67.2%) samples were subtype B, four (6.9%) F, one (1.7%) C, and 14 (24.1%) BF recombinants. Four different BF recombination patterns were detected. Twelve (20.7%) samples shared the same breakpoint within the reverse transcriptase (RT) sequence. Fifty-five (94.8%) isolates showed several resistance-associated mutations in the RT and the protease (PR) genes. Ten (17.2%) isolates presented mutations associated with a high level of resistance: nine (15.5%) to nucleoside RT inhibitors (NRTI), four (6.9%) to nonnucleoside RT inhibitors (NNRTI), and three (5.2%) to PR inhibitors (PIs). Subtype B-infected patients had, on average, 0.5 high-level DRAM per sequence while no mutations were observed in BF recombinants, although the two groups were under ARV for a similar period of time. Our data indicate the predominance of the subtype B, followed by BF recombinants in this population, and the dissemination of a recombinant strain in Bahia, which could be related to adaptive ad- vantages of these variants over the predominant subtype B. Introduction I t is estimated that 33.2 million people are living with the human immunodeficiency virus-1 (HIV-1) worldwide, of which 15.4 million are women and 2.5 million are children under 13 years. Every year, approximately 2.5 million people are infected with HIV, 18% of whom are children. 1 The ma- jority of HIV infections result from heterosexual transmission, while mother-to-child transmission (MTCT) represents the main form of HIV infection among children. MTCT can occur during pregnancy, labor, delivery, or breastfeeding and is related to multiple factors. This includes viral, maternal, be- havioral, obstetric, and newborn factors. 2 In Brazil, more than 544,000 AIDS cases have been documented, of which nearly 12,500 cases were associated with MTCT. 3 The HIV is highly diverse and has been classified into two main types: HIV-1 and HIV-2. The HIV-1 is largely dissemi- nated throughout the globe and is divided into three groups: M, O, and N. The group M is further divided into nine sub- types (A, B, C, D, F, G, H, J, and K), 43 circulating recombinant forms (CRF), and several unique recombinant forms (URF). 4–7 These various genotypes present differential geographic dis- tribution worldwide. The subtype B is more disperse while the subtype C is more prevalent. 8 In Brazil, subtype B is the predominant genotype followed by B/F recombinants and subtypes F and C. 7,9–12 However, due to the vast territory and to an intense social and cultural heterogeneity, the Bra- zilian geographic regions have been characterized by striking differences concerning subtype distribution. The extreme variability of HIV-1 is related to the high error rate of the reverse transcriptase enzyme and to the occurrence of homologous recombination of the viral RNA during rep- lication. 13 The accumulation of mutations favors the emer- gence of virus mutants that escape the immune response and ARV therapy. In Brazil, HIV-infected patients have been provided with full and free access to all Brazilian Health Surveillance Agency (Anvisa)-approved ARVs since 1996. Although it has contributed to an increase in survival and quality of life, the sequential use of ARVs has also contributed to the emergence of viral resistance, which has consequences 1 Laborato ´ rio Avanc ¸ado de Sau ´de Pu ´ blica (LASP), Centro de Pesquisa Gonc ¸alo Moniz (CPqGM), Fundac ¸a ˜ o Oswaldo Cruz (FIOCRUZ), Salvador, Bahia, Brazil. 2 Fundac ¸a ˜ o Bahiana para o Desenvolvimento das Cie ˆncias (FBDC), Escola Bahiana de Medicina e Sau ´ de Pu ´ blica (EBMSP), Salvador, Bahia, Brazil. 3 Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland. AIDS RESEARCH AND HUMAN RETROVIRUSES Volume 27, Number XX, 2011 ª Mary Ann Liebert, Inc. DOI: 10.1089/aid.2010.0126 1