Drug resistance mutations are frequently detected in antiretroviral–naive HIV positive patients, however the data on transmitted resistance in non-B subtypes are limited. As HIV1 subtype F is prevalent in Romania, our goal is to analyze resistance mutations in the pol gene of HIV–1 isolates from drug–naive Romanian patients. HIV–1 pol gene from 12 untreated patients, newly diagnosed (n = 6) and chronically infected (n=6), with detectable HIV RNA viral load was genotyped and the viral subtype was determined by using the Stanford database algorithm. 8/12 strains belonged to the F subtype, 1/12 to the G subtype, and the rest of the studied strains appeared to be K/F, A/F and J/F inter–subtype recombinant forms. The prevalence of HIV–1 strains with at least one major drug resistance mutation in the studied group was unexpectedly high. Major mutations associated with NRTI, NNRTI and PI resistance were detected in 6/12 patients, 2/12 patients and 3/12 patients, respectively; in addition all viral strains had minor mutations in the protease gene. Newly diagnosed patients harbored resistant variants more often than chronically infected ones (4/6 vs. 2/6) did. These data support the use of genotypic resistance testing in treatment–naive HIV positive patients, in order to guide the selection of the first line of antiretrovirals, due to the fact that persons with transmitted drug resistance have a higher risk for both virologic failure and development of resistance at treatment initiation.

HIV–Human immunodeficiency virus; TDR–transmitted drug resistance; HAART–highly active antiretroviral therapy ; SDRM–surveillance list of drug resistance mutations ; NRTIs–nucleos(t)idic reverse–transcriptase inhibitors; NNRTIs– non–nucleosidic reverse transcriptase inhibitors; PIs–protease inhibitors; TAMs–thy–midine analogue mutations; 3TC –lamivudine ; FTC–emtricitabine ; ddI –didanosine ; ABC–abacavir ; ZDV–zidovudine ; d4T–stavudine ; TDF –tenofovir