Transmitted drug-resistance in human immunodeficiency virus-infected adult population in El Salvador, Central America.

El Salvador harbours one of the largest Central American human immunodeficiency virus (HIV) epidemics, but few studies have analysed it in depth. Here, we describe the presence of transmitted drug resistance (TDR) and HIV variants in the HIV-infected adult population in El Salvador. Dried blood spots from 119 HIV-infected antiretroviral-naive adults attended in El Salvador were collected in 2011. The TDR was assessed according to the list recommended by the WHO. HIV-1 variants were described using phylogeny. Pol sequences could be amplified in 88 patients (50.6% men), with a mean age of 35 years. Almost all (96.7%) were infected with HIV through sexual practice and 58.7% were recently diagnosed. The mean CD4(+) count was 474 cells/mm(3) and 43.1% and 15.5% of patients showed moderate (<500 CD4 cells) or severe (<200) immune suppression, respectively. HIV-1 viral load was >100 000 copies/mL in 24.7% of patients and <2000 copies/mL in 9.1%. Five samples (5.7%) harboured any TDR mutation: 2.3% for nucleoside reverse transcriptase inhibitor (NRTI) and non-nucleoside reverse transcriptase inhibitor (NNRTI), and 1.4% for protease inhibitor (PI). All showed only one TDR single-class resistance mutation: M184I (two cases) for NRTI, K101E and K103N for NNRTI and L23I for PI. All viruses excepting one (URF_BG) belonged to subtype B. No phylogenetic TDR networks were found. In conclusion, we report a TDR prevalence of 5.7% in El Salvador, lower than in other Central American studies. Periodical studies are essential to monitor and prevent TDR emergence in low-income and middle-income regions. Also, more efforts are needed to promote early diagnosis and prevention of infection in El Salvador.

HIV-1 non-B subtypes: High transmitted NNRTI-resistance in Spain and impaired genotypic resistance interpretation due to variability.

Genotypic resistance algorithms interpret drug-resistance mutations, but are mainly developed for HIV-1 subtype B, meanwhile non-B subtypes cause 90% of worldwide infections. They include clade-specific amino acid at drug-resistance positions different than subtype B. This study explores: (i) the variability at resistance-related positions in 128 non-B and 226 B sequences from 354 treatment-naïve patients diagnosed in Spain (1999-2007); (ii) the discordances between five resistance interpretation algorithms (ANRS, Stanford, Rega, Geno2pheno, RIS); and (iii) the reliability of five subtyping tools (Stanford, Geno2pheno, Rega, NCBI, EuResist) for each HIV-1 variant. Primary drug-resistance prevalence was 13.6%, although higher in non-B vs. B subtypes (18.7% vs. 10.6%), due to a twofold higher NNRTI-resistance prevalence (15.7% vs. 7.6%). Most secondary PI-resistances, more frequent in non-B, were in fact clade-specific residues. Most sequences were interpreted as susceptible to all antiretrovirals by the five resistance algorithms, except for tipranavir by ANRS in non-B clades. Interalgorithm discordances were significantly higher in non-B variants for specific drugs. The agreement with phylogenetic analysis differed among subtyping tools testing non-B variants. We found a higher prevalence of NNRTI-resistance mutations in non-B subtypes. Certain algorithms overestimate the resistance in non-B subtypes due to natural patterns of mutations. Subtyping tools should be optimised for non-B variants.