Prevalence of transmitted HIV-1 drug resistance among female sex workers and men who have sex with men in El Salvador, Central America.

Transmitted drug resistance has important implications for the successful use and management of therapy among persons infected with HIV. We estimated the prevalence of transmitted drug resistance in 145 samples from female sex workers (n = 47) and men who have sex with men (n = 98) in El Salvador. Samples were collected during March to September 2008, using a respondent driven sampling. The HIV-1 pol gene was sequenced to identify drug resistance mutations and transmitted drug resistance was scored as recommended by World Health Organization. Specimens were classified as recent or established infections using the Immunoglobulin G-Capture BED-Enzyme Immunoassay. The overall prevalence of transmitted drug resistance was 9.4% (95% CI: 4.7-16.1%), and was 5.9% for non-nucleoside reverse transcriptase inhibitors, 4.2% for nucleoside reverse transcriptase inhibitors, and 0.8% for protease inhibitors. Transmitted drug resistance prevalence was 10.3% (95% CI: 2.8-24.2%) among female sex workers, and 9.0% (95% CI: 3.6-17.6%) among men who have sex with men. Nineteen patients were classified as having recent infection (16.2%, 95% CI: 10.1-24.2%), while 98 patients (83.8%, 95% CI: 75.8-89.9%) were classified as having established infections. Transmitted drug resistance among recent and established infections was similar at 10.5% and 9.2%, respectively. This study shows that the prevalence of transmitted drug resistance is moderate among female sex workers and men who have sex with men in El Salvador. These results highlight the importance of transmitted drug resistance surveillance in a representative sample of recently infected patients following the World Health Organization guidelines.