Background: HIV screening during antenatal care is being expanded in Brazil for early diagnosis of HIV-1 infection during pregnancy and prevention of vertical transmission. HIV genotyping in pregnant women is crucial to reduce the risk of vertical transmission in those carrying resistant strains and may also be used for Transmitted Drug Resistance (TDR) surveillance purpose. We evaluated prevalence and patterns of HIV-1 TDR and HIV subtype distribution in recently diagnosed ARV naïve pregnant women from Rio de Janeiro, Brazil.

Methods: 299 blood samples of recently diagnosed HIV-1-infected pregnant women from four reference antenatal care public health units in Rio de Janeiro were consecutively collected and analyzed from 2005 to 2015.ViroseqTM (Abbott) and TrugeneTM HIV-1 Genotyping Systems (Siemens) were used for genotyping and the Standford Algorithm for Interpretation of HIV-1 Resistance for TDR and subtype identification.

Results: The most prevalent HIV-1 subtype was the subtype B (77%), followed by subtype F (15%), BF recombinant forms (4%), subtype C (2%) and the recombinant forms: CRF02_AG, CRF31_BC and DF identified in one subject each. Overall, the TDR mutations was 11.7%, 2.7% associated to the Nucleoside Reverse Transcriptase Inhibitors (NRTIs) of the samples, 2.7% to Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) and 1% to Protease Inhibitors (PIs). Mutations associated with NRTI resistance were TAMs, F77L, M184V; associated with NNRTI resistance were K103N, Y188H and L100I and. mutations associated to PIs were D30N, M46I, and V82L.

Conclusions: HIV-1 subtype B was the most prevalent subtype observed in our study. For the first time infections with the circulating recombinant forms CRF02_AG and CRF31_BC were described in a pregnant woman, suggesting the spread of African derived virus in Brazil and the introduction in Rio de Janeiro of the CRF31_BC coming from South Brazil. Our results strongly suggest the need of establishing a regular surveillance system for transmitted HIV-1 drug resistance in pregnant women in Brazil and its integration in antenatal care management policies for HIV-1 infected women should be considered.