Brazilian Network for HIV Drug Resistance Surveillance: a survey of individuals recently diagnosed with HIV

Abstract

Use of antiretrovirals is widespread in Brazil, where more than 200,000 individuals are under treatment. Although general prevalence of primary antiretroviral resistance in Brazil is low, systematic sampling in large metropolitan areas has not being performed.The HIV Threshold Survey methodology (HIV-THS, WHO) was utilized, targeting Brazil's four major regions and selecting the six most populated state capitals: Sao Paulo, Rio de Janeiro, Salvador, Porto Alegre, Brasilia and Belem. We were able to sequence samples from 210 individuals with recent HIV diagnosis, 17 of them (8.1%) carrying HIV isolates with primary antiretroviral resistance mutations. Five, nine and four isolates showed mutations related to resistance to nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs), respectively. Using HIV-THS, we could find an intermediate level of transmitted resistance (5% to 15%) in Belem/Brasilia, Sao Paulo and Rio de Janeiro. Lower level of transmitted resistance (<5%) were observed in the other areas. Despite the extensive antiretroviral exposure and high rates of virologic antiretroviral failure in Brazil, the general prevalence of primary resistance is still low. However, an intermediate level of primary resistance was found in the four major Brazilian cities, confirming the critical need to start larger sampling surveys to better define the risk factors associated with transmission of resistant HIV.

Association between KIR genotypes and HLA-B alleles on viral load in Southern Brazilian individuals infected by HIV-1 subtypes B and C

“…We hypothesized that HIV-1 subtype C was in some way more fit for the HLA/KIR genetic background of the local population than HIV-1 subtype B. However, although the subtype frequency distribution in our study (C = 63%; B = 31%; F = 4%; and CRF02 = 3%) was consistent with previous data [41,42], we did not find viral load or T-CD4 decay differences between subtype B and C in relation to KIR genotype or HLA-B alleles. It is still possible that differences in the incidence rate of the two subtypes in southern Brazil are due to some as yet unrecognized epidemiological nuance, a multifactorial process of the dissemination including human mobility, accessibility, and local founder events [43]or perhaps an intrinsic biological characteristic of subtype C viruses, similar to that found in a study that suggested a greater mucosal transmission [44] of subtype C as well as faster accumulation of drug resistance mutations in subtype C isolates [45].…”

Heterosexual transmission of human immunodeficiency virus type 1 subtype C in southern Brazil

“…1). [2][3][4][5] However in the Southern region, a distinct profile is observed. Currently, depending on the state, 27-79% of HIV infections are caused by HIV-1C, 23-45% by HIV-1B, 3-29% by CRF31 BC and other BC recombinants, and HIV-1F and its recombinants account for up to 10% of infections.…”

The HIV-1 Epidemic: Low- to Middle-Income Countries

“…Individuals infected with viruses carrying multiple drug resistance mutations may have reduced survival prospects, and for this reason, estimates of the rate at which drug resistance mutations are transmitted are a key target metric of the World Health Organization (WHO) HIVDR threshold survey . This survey has revealed that fewer than 5% of HIV transmissions in lowerincome countries such as Malawi (Kamoto et al 2008), Tanzania, Ethiopia, Swaziland, South Africa, Thailand, and Vietnam involve the transmission of viruses carrying known drug resistance mutations, whereas specific areas of Brazil and China have transmitted drug resistance mutation rates between 5% and 15% (Booth et al 2007;Inocencio et al 2009;Liao et al 2010). The prevalence of transmitted HIV drug resistance (TDR) in developing countries is lower than that in developed countries, where in some countries, such as the United States, rates of transmitted drug resistance within newly diagnosed antiretroviral naïve HIV-1-infected individuals are in the range of 15% (Wheeler et al 2010).…”