No abstract

Brazil has a low prevalence of drug-resistant strains circulating among recently diagnosed individuals. However, there was an increase in these rates compared with similar studies performed with samples collected in Brazil from 1996 to 1998. Continued surveys are required to detect trends in these rates, but routine genotypic testing in the drug-naive population prior to antiretroviral initiation is not required in Brazil.

Introduction of subtype C of HIV-1 in Brazil was likely a single event of one or a mixture of similarly related strains. Recombination between subtype C and B viruses is an ongoing process in the country. Primary and secondary drug resistance mutations were observed, although some of the secondary mutations could be associated with subtype C molecular signatures. Subtype-specific polymorphisms of PR and RT sequences found in this subtype C Brazilian variant might influence this emergence and have an impact on HIV treatment and on vaccine development in the country.

The subtype C epidemic in the southern Brazilian region was initiated by the introduction of a single founder strain closely related to subtype C strains from Burundi. Our results suggest that this founder event probably took place around the early 1980s, roughly a decade before the previous estimates.

BACKGROUND Sexually transmitted infections (STIs) such as Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) can lead to adverse pregnancy and neonatal outcomes. STI prevalence and its association with HIV mother-to-child transmission (MTCT) were evaluated in a sub-study analysis from a randomized, multi-center clinical trial. METHODOLOGY Urine samples from HIV-infected pregnant women collected at the time of labor and delivery were tested using polymerase chain reaction (PCR) testing for the detection of CT and NG (Xpert® CT/NG, Cepheid, Sunnyvale, CA). Infant HIV infection was determined by HIV DNA PCR at 3 months. RESULTS Of the 1373 urine specimens, 249 (18.1%) were positive for CT and 63 (4.6%) for NG; 35 (2.5%) had both CT and NG detected. Among 117 cases of HIV MTCT (8.5% transmission) the lowest transmission rate occurred among infants born to CT and NG uninfected mothers (8.1%) as compared to those infected with only CT (10.7%) and both CT and NG (14.3%), (p = 0.04). Infants born to CT-infected mothers had almost a 1.5-fold increased risk for HIV acquisition (OR 1.47, 95% CI 0.9–2.3, p=0.09). CONCLUSION This cohort of HIV-infected pregnant women are at high risk for infection with CT and NG. Analysis suggests that STIs may predispose to an increased HIV MTCT risk in this high risk cohort of HIV-infected women.