7% (95% CI 19.9–37.5%). Our study reflects learn more the need to monitor the evolution of resistance on a regular basis and trends of transmitted resistance. The initiation of highly active antiretroviral therapy (HAART) in developing countries where HIV-1 non-B subtypes circulate has been associated with good clinical outcomes when combined with appropriate clinical follow-up [1]. However, as HAART is scaled up, it is essential to monitor the emergence

of primary resistance, as this may impact on the success of an already limited choice of first-line therapies in resource-limited settings [2]. Furthermore, studies have shown that polymorphisms in non-B subtype genomes can lead to different pathways to drug resistance from those found in subtype B HIV-1 [3–5]. We have studied the rate of primary resistance in Mali, a resource-limited country in West Africa. With a population of 11 million inhabitants, Mali has an estimated HIV prevalence of 1.3%, representing 146 000 persons infected with HIV [6]. The first antiretroviral drugs became available in 1997, followed by roll-out of HAART through a national treatment programme in 2004 with stavudine, lamivudine and nevirapine recommended as first-line treatment [7]. A study in 2006 estimated that the overall prevalence of primary resistance in Mali was 11.5% [7]. In the context of the scale-up of HAART, we therefore decided to evaluate the evolution of primary

resistance in this country. A total of 101 antiretroviral-naïve HIV-infected individuals from Mali were prospectively enrolled in this study. Primary resistance was evaluated during the period from July 2007 to October LDK378 PAK5 2008. Individuals were recruited from three different sites in Bamako, Mali’s capital: 42 patients were recruited from the Centre d’Écoute de Soins, d’Animation et de Conseil (CESAC), which offers diagnostic services and care to HIV-infected individuals of rural and urban origin, 43 from the Gabriel Touré Hospital (HGT), and

16 from the Point G Hospital (HPG). HGT and HPG are the two largest hospitals in Mali. Although their patient populations are mainly urban, they are reference centres and see referrals from the entire country. Samples obtained from the patients were stored at −80 °C until they were sent on dry ice for genotyping at the retrovirology laboratory at the Centre Hospitalier de l’Université de Montréal (CHUM), Montréal, Canada. This study was approved by the ethics committees of Mali and CHUM research centre. Viral RNA was extracted using the viral QIAamp Spin Mini Kit (Qiagen, Mississauga, Ontario, Canada) and according to the protocol provided by Virco (Mechelem, Belgium). It was then amplified using Superscript III HIFI (Invitrogen, Carlsbad, CA, USA) with primers 5′out and 3′RT (Virco) covering the protease and reverse transcriptase (RT-PR) genes. For the nested PCR, we used the expand HF PCR (Roche Applied Science, Quebec, Canada) as the PCR enzyme and primers 5′IN and 3′IN (Virco).