Brazilian Network for HIV Drug Resistance Surveillance (HIV-BResNet): a survey of chronically infected individuals.
OBJECTIVE
To study the prevalence of HIV drug resistance mutations and subtype distribution in a Brazilian drug-naive population. Asymptomatic, drug-naive HIV-1-infected individuals were targeted in 13 voluntary counseling and testing centers spread around the country.


METHODS
Plasma viral RNA was extracted from 535 HIV-1-positive subjects. Protease (PR) and reverse transcriptase (RT) genomic regions were sequenced for subtype determination and analysis of drug resistance mutations.


RESULTS
Eight samples (2.24 %) showed primary mutations related to protease inhibitor (PI) resistance, eight (2.36%) to nucleoside reverse transcriptase inhibitors (NRTI) and seven (2.06%) to non-nucleoside reverse transcriptase inhibitors (NNRTI). Accessory mutations were found in the PR gene at the following positions: L63P/V/T/A/I [153/345 (44.3%)], M36I/L [149/345 (43.2%)], L10I/F/V [82/345 (23.8%)], V77I [60/345 (17.4%)], A71V/T [11/345 (3.2%)], K20M/R [10/345 (2.9%)], and V82I [4/345 (1.2%)]. Mutations known to be associated with reduced sensitivity to NRTI or NNRTI (V118I, E44D, K219R, T69A, and V75L) were found in a low prevalence (0.6-2.4%). A high proportion of the isolates from subtype C was found in the southern states. Subtype F-related viruses were the main non-B variant in the rest of the country.


CONCLUSIONS
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.
Brindeiro
Rodrigo M
RM
Laboratory of Molecular Virology, Department of Genetics, Federal University of Rio de Janeiro, Brazil.
Diaz
Ricardo S
RS
Sabino
Ester C
EC
Morgado
Mariza G
MG
Pires
Ivone L
IL
Brigido
Luís
L
Dantas
Maria C
MC
Barreira
Draurio
D
Teixeira
Paulo R
PR
Tanuri
Amilcar
A
D000328:Adult; D001938:Brazil / Q000453:epidemiology; D002908:Chronic Disease; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D015995:Prevalence; D012307:Risk Factors