The Research Capacity ProgramAs in many areas of Brazil, the AIDS epidemic in Curitiba is relatively stable, but surveillance is important to support public policy. The molecular characteristics of HIV may be instrumental for monitoring epidemic trends. We evaluated plasma HIV-1 RNA (n = 37) from 38 cases presenting with positive serology, who were among 820 consenting volunteers visiting the downtown counselling and serology testing centre. Seroprevalence was 4.6% 3) and the estimated HIV incidence, as defined by the BED assay, was 2.86 persons/years ). An additional set of contemporaneous, anonymous samples from a local laboratory was also analysed (n = 20) . Regions of the HIV-1 polymerase (n = 57) and envelope (n = 34) were evaluated for subtyping, determination of mosaic structure, primary drug resistance mutations (pDRM), envelope V3 loop motifs and amino acid signatures related to viral tropism. HIV-1 clade B was observed in 53% of cases; HIV-1C in 30% and BC mosaics in 14%, with one F genome and one CF mosaic. Clade C infection was associated with recent infections among males (p < 0.03). Stanford surveillance pDRM was observed in 8.8% of sequences, with 7% showing high level resistance to at least one antiretroviral drug. Tropism for CXCR4 co-receptor was predicted in 18% of envelope sequences, which were exclusively among clade B genomes and cases with serological reactivity to chronic infection.Key words: epidemiology -antiretroviral resistance -genetic diversity -HIV-1 -tropism -BrazilUnderstanding the local HIV-1 epidemic will not only support the regional response, but it may also provide information to nationwide efforts in the fight against AIDS. The variability of HIV-1 has been an obstacle to treatment and to the development of prevention innovations such as vaccines. HIV-1 clusters phylogenetically into distinct clades (subtypes), a fact that has helped to unravel the molecular characteristics of the epidemic. In some regions, differential distribution of HIV-1 clades has been documented (Van Harmelen et al. 1997, Tovanabutra 2001, Rios et al. 2005, Ryan et al. 2007) and phylogeny may indicate the source(s) of incoming variants (Sarker 2008). Worldwide, clade C is responsible for about half of the epidemic, whereas clade B is the major variant in industrialised nations (Hemelaar et al. 2006). HIV variability may influence the performance of laboratory tools for diagnostic, monitoring and surveillance (Koch et al. 2001 (Baeten et al. 2007, Kaleebu 2007 and transmission potential (Yang et al. 2003, John-Stewart et al. 2005 have been associated to distinct HIV clades, but the actual impact of genetic diversity in HIV disease still remains uncertain (Stebbing & Moyle 2003, Hemelaar et al. 2006, Tebit et al. 2007). However, some characteristics of HIV, such as tropism to either CCR5 or CXCR4 coreceptors, seem to be associated with a distinct pattern of disease progression (Shepherd et al. 2008). Another relevant issue is the identification of primary drug resistance mutations (pDRM) among untreate...

BackgroundHTLV-1 is endemic in Brazil (0.07-15.9%) and HIV/ HTLV-1-coinfection has been detected, mostly in the North and Northeast regions. This study characterized HTLV-1 isolates from HIV-coinfected patients from Southern and Southeastern Brazil. Material and methodsDNA from 17 HIV/HTLV-1-co-infected patients; 5 from the South and 12 from Southeast were amplified by nested-PCR (env and LTR) and sequenced. HTLV subtyping was performed by NCBI-Genotyping and REGASubtyping tools websites and by phylogenetic methods using Paup4 and MEGA4. ResultsEnv sequences (705-bp) from 15 isolates and LTR sequences (731-bp) from 17 isolates were obtained. Molecular analysis of env and LTR sequences disclosed respectively, nucleotide similarities of 99.5% and 98.8% within sequences, 99% and 97.4% with ATK, and 91.6% and 90.3% with Mel5. Four sequences that showed the highest similarities with ATK clustered separately in the trees (p≤0.001 for env and LTR, bootstrap=96% for LTR); they had C386T and T594C nucleotide substitutions in LTR sequences. All except these four sequences had mutations T5637G, T5730C, A6120G in env and T500A, A549G, G676A, T766C, T767G in LTR sequences. Six sequences presented the amino acid change V1981I and clustered together in the env tree.All isolates belonged to Cosmopolitan HTLV-1a subtype. ConclusionsThese data show that Cosmopolitan HTLV-1a subtype is also frequent in HIV-coinfected patients from Southern and Southeastern Brazil, suggesting spreading of HTLV-1 in the country. The mutations observed should be monitored in the context of molecular epidemiology.

Southern Brazil has the highest prevalence rate of AIDS in the country and is the only region in the Americas where HIV-1 C prevails. Metropolitan areas and harbor cities have been evaluated, but limited information is available for small towns and specific populations. We studied women attending the obstetric outpatient clinic of Criciuma, State of Santa Catarina in 2007 to evaluate the molecular epidemiology of HIV-1 among pregnant women living with HIV/AIDS. Forty-two cases had partial pol gene sequenced and additional partial gag and/or env genes from nine women. HIV subtyping was evaluated by phylogenetic methods and antiretroviral (ARV) drug resistance mutations (DRMs) at the Stanford Database. DRMs to one or more ARV class was observed in 20/42, 48% of cases, with 15/41, 37% with viral load <500 copies/ml. Subtype C at pol was identified in 33/42, 78.6% (95% CI: 64-89%), C mosaics (CB, CF) in 2, 4.8% (95% CI: 0.8-19%), F in 4, 9.5% (95% CI: 3-21%), and B in 3, 7.1% (95% CI: 1.8-18%). Discordance in concatenated gag/pol/env or intraregion mosaic was observed in 1/9, 11% of HIV-1 C genomes. The proportion of HIV-1 C in this study is the highest rate described in the Americas. Molecular surveillance in specific populations is instrumental for a better understanding of the Brazilian HIV epidemic.

Raltegravir is an integrase inhibitor (INI) licensed for clinical use and other INI are in advanced stage of development. Different resistance mutations in HIV integrase from patients using these antiretroviral drugs have been described and G148H/R/K, N155H and less frequently Y143C/H/R are considered major resistant mutations to raltegravir. Both Stanford Database and Geno2Pheno list F121Y as conferring intermediate resistance "in vitro" both to raltegravir and elvitegravir. We report for the first time the "in vivo" selection F121Y and evolution to Y143R in a 31years old male clade B HIV-1 infected patient failing a raltegravir-containing salvage regimen. Plasma samples nine months prior to raltegravir (RAL-Naïve) and at weeks 32, 40 and 88 after RAL-containing regimen were analyzed. Antiretroviral susceptibility was evaluated at Stanford and Geno2Pheno from sequences obtained with RT-PCR. After a Viral load at week 12 below 50 copies/mL, viremia raised at week 20 to 4.5log10. The emergence of F121Y was observed at week 32 and 40, alongside with L74I, T97A, Q137H and V151I. At week 88 F121Y was no longer detected, L74I and T97A were maintained and Y143R emerged. F121Y might be an alternative pathway to Y143R. Changing of RAL-containing regimen upon the identification of F121Y might avoid the evolution of raltegravir resistance.

The presence of X4-tropic variants in more than 80% of our cohort of antiretroviral-experienced children and adolescents with vertical HIV-1 infection indicates a very limited role for CCR5 antagonists as part of salvage regimens for highly treatment-experienced vertically HIV-1-infected patients with extensive antiretroviral drug resistance and limited treatment options.