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

ABSTRACT 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.

【背景】人类免疫缺陷病毒1型（HIV-1）遗传多样性不断增加以及耐药突变的出现，可能会降低用于预防母婴传播的抗逆转录病毒治疗（antiretroviral therapy）与预防用药的疗效。本研究旨在评估HIV感染孕妇群体中的遗传多样性与耐药突变流行率。
【研究设计与研究场景】本研究为一项横断面研究（cross-sectional study），开展于巴西圣保罗州里贝朗普雷图的一所妇产科传染病门诊。
【研究方法】本研究于2010年至2011年间，在巴西圣保罗州里贝朗普雷图纳入38名HIV感染孕妇（其中20名曾接受抗逆转录病毒治疗，18名为初治患者），评估了HIV-1亚型的分布动态以及传播性耐药（transmitted drug resistance）与获得性耐药（acquired drug resistance）突变的流行率。研究通过对HIV-1 pol基因（HIV-1 pol gene）的蛋白酶（protease）与逆转录酶（reverse transcriptase）区域进行分子测序来完成基因分型。
【研究结果】84.2%的样本被鉴定为B亚型，7.9%为B与F的重组形式，5.3%为F1亚型，2.6%为K/F重组形式。初治孕妇的样本中未检测到与传播性耐药相关的突变，而在曾接受抗逆转录病毒治疗的孕妇中，有35.0%检出了与获得性耐药相关的突变。
【结论】本研究结果显示，B亚型为主要流行亚型，且携带传播性耐药的序列流行率较低。