Low prevalence of transmitted drug resistance among newly diagnosed HIV‐1 patients in Latvia

Abstract

Transmitted drug resistance (TDR) is a concern because it may reduce the efficacy of antiretroviral treatment. Plasma samples of 119 HIV-1-infected patients who were newly diagnosed at the Infectology Center of Latvia in 2005 and 2006 were analyzed by an in-house genotypic resistance assay to determine the prevalence of TDR in Latvia. TDR was identified using the WHO 2009 list of mutations for surveillance of TDR as implemented in the Stanford Calibrated Population Resistance tool. Neighbor-joining phylogenetic analyses were used to determine genetic subtype and investigate the relatedness of the sequences. Resistance testing was successful in 117 of 119 patients. The study population represented ∼20% of all patients that were diagnosed in Latvia in 2005 and 2006 and was well distributed between gender, transmission routes, and areas of residence. Four patients showed evidence of TDR, which represents a prevalence of TDR of 3.4% (95% CI: 0.9-8.5%). All four patients displayed single, but different resistance mutations (M46I, F53L, M41L, and G190A). All patients, except one, were predicted to respond well to standard first-line therapy in Latvia. The prevalence of TDR in Latvia was low, which partly may be due to the low proportion of HIV-1 patients who receive antiretroviral therapy. The results indicate that routine resistance testing in Latvia currently should be focused on patients who display treatment failure, rather than treatment naive patients.

Stable level of HIV transmitted drug resistance in Estonia despite significant scale-up of antiretroviral therapy

“…Importantly, the use of cART in Eastern Europe has increased considerably in the 2000s, mainly within the format of potent drug regimens rather than suboptimal mono-or dual therapy (12). The reported data of TDR from FSU countries vary but are generally below 10% [0% in Lithuania (13), 2.1% in Ukraine (10), 3-7% in Latvia (14,15), 0-13% in Russia (depending on the study) (16)].…”

Transmission Dynamics of HIV-1 Drug Resistance among Treatment-Naïve Individuals in Greece: The Added Value of Molecular Epidemiology to Public Health

“…However, an increasing trend was found for NNRTI resistance in the Americas/Caribbean, Europe and upper-income Asia. These estimates were modeled by sample year or by year due to antiretroviral treatment scale-up in different regions [ 5 , 6 , 7 , 8 ], suggesting that the incidence of resistance is unknown. Estimates of primary resistance have been based mostly on the proportions of newly diagnosed individuals carrying resistance strains [ 5 , 6 , 9 ], and in a few studies on proportions of resistant strains among newly or acutely infected subjects [ 10 , 11 , 12 , 13 , 14 , 15 ].…”

Mutations in HIV-1gagandpolCompensate for the Loss of Viral Fitness Caused by a Highly Mutated Protease

“…In the past, the transmission of drug-resistant viruses, which can sometimes persist even without the selective pressure of HAART, was becoming increasingly frequent (9,20). Nowadays, several studies show a decline in the transmission of drug-resistant variants in the western world to approximately 10% (2,14), whereas other studies still report stable transmission rates for certain resistance-associated mutations (RAMs) (5,45). The key to an effective treatment regimen relies on both the genetic barrier to resistance to a specific drug and on the ability of antiviral drugs to decrease viral load.…”