HIV-1 genetic diversity and resistance to antiretroviral drugs among pregnant women in Ribeirão Preto (SP), Brazil. Cross-sectional study

BACKGROUND: Increasing genetic diversity of HIV-1 and emergence of drug-resistant mutations may reduce the efficacy of antiretroviral therapy and prophylaxis that are used to prevent mother-to-child transmission. The aim of this study was to assess the genetic diversity and prevalence of drug-resistant mutations among HIV-infected pregnant women. DESIGN AND SETTING: Cross-sectional study at an outpatient clinic for infectious diseases within gynecology and obstetrics. METHODS: This study evaluated the dynamics of HIV-1 subtypes and the prevalence of transmitted and acquired drug-resistant mutations among 38 HIV-infected pregnant women (20 previously exposed to antiretroviral therapy and 18 naive), in Ribeirão Preto (SP), Brazil, between 2010 and 2011. Genotyping was performed by means of molecular sequencing of the protease and reverse transcriptase regions of the HIV-1 pol gene. RESULTS: Subtype B was identified in 84.2% of the samples, recombinant forms between B and F in 7.9%, subtype F1 in 5.3% and the recombinant form K/F in 2.6%. No mutation associated with transmitted drug resistance was detected in the samples from the naive pregnant women, whereas mutations associated with acquired drug resistance were found in 35.0% of the pregnant women previously exposed to antiretroviral therapy. CONCLUSION: The results showed that subtype B predominated, while there was low prevalence of sequences with transmitted drug resistance.