Abstract
The emergence of resistance-associated mutations to the antiretroviral agents and the genetic variability of HIV-1 impose challenges to therapeutic success. We report the results of genotype testing assays performed between 2002 and 2006 in 240 antiretroviral-experienced patients followed up in an HIV reference center in Brazil. Drug resistance mutations and viral subtypes were assessed through the algorithms from the Brazilian Genotyping Network (RENAGENO—Brazil) and from Stanford University. Mutation 184VI was the most prevalent (70%) and the thymidine analogue mutations that appeared most frequently were 215FY, 41L, 67N, and 210W, in this order. Among nonnucleoside reverse transcriptase inhibitor mutations, 103NS (32.5%) stood out. HIV subtype B was identified in 184 patients (76.7%). A significant increasing trend in the prevalence of non-B subtypes was observed during the study period (p=0.004). The main differences in prevalence of mutations among HIV-1 subtypes were related to viral protease, with 20MRI, 36I, and 89IMT more prevalent among non-B subtypes, and 84V, 10FR, 63P, 71LTV, and 77I more common in subtype B (p<0.05). Most mutations to etravirine had a prevalence lower than 10%, but at least one mutation to this drug was observed in 45% of the patients. In only 11 patients (4.6%) three mutations to etravirine were verified. Regional surveillance of the resistance profile and HIV-1 subtypes is crucial in the context of public health, to prevent the transmission of resistant strains and to guide the introduction of new drugs in a specific population.
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