Background:  Transmission of HIV-1 mutations associated with drug resistance can limit antiretroviral treatment options. We adapted the World Health Organization (WHO) surveillance list of drug resistance mutations to estimate transmitted drug resistance-associated mutations (TDRM) for the predominantly subtype B epidemic in the United States.

Methods:  Using the adapted WHO mutation list, we analyzed TDRM in HIV genomic sequences reported to the national HIV surveillance system from 10 states and one county in the United States, which were funded for antiretroviral drug resistance surveillance. Cases included antiretroviral drug-naïve individuals who were newly diagnosed with HIV in 2007 and reported to the national HIV surveillance with genomic sequences through June 2008. We used the national HIV surveillance data to determine differences in TDRM by demography and transmission category.

Results:  In 2007, of the 10,496 new HIV-1 diagnoses in the funded areas, 2480 (24%) were reported with genomic sequences. Of these sequences, 1867 (75%) were from males, 2056 (83%) from persons aged 20 to 49 years, 1461 (59%) from non-Hispanic blacks, and 1163 (47%) were from persons who reported male-to-male sexual contact. Three hundred eighty-eight (16%) contained one or more TDRM, including 202 (8%) with non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations, 152 (6%) with nucleoside reverse transcriptase inhibitor (NRTI) mutations, and 103 (4%) with protease inhibitor (PI) mutations. Three hundred thirty-two (13%) of the sequences had TDRM for a single drug class, 43 (2%) for 2 drug classes, and 13 (<1%) for 3 drug classes. In sequences with TDRM, the most prevalent NNRTI mutation was K103N (104/202; 52%), NRTI was M41L (48/152; 32%), and PI was L90M (36/103; 35%). We observed no significant differences in TDRM presence by race, sex, age, or transmission category.

Conclusions:  One of every 6 newly diagnosed HIV-1 transmissions in antiretroviral drug resistance surveillance in 2007 contained one or more mutations associated with drug resistance that commonly affected men: persons aged 20 to 49 years, non-Hispanic blacks, and those who reported male-to-male sexual contact. Most TDRM was for a single drug class, NNRTI mutations were more common than NRTI and PI mutations, and K103N was the most common NNRTI mutation. Continued TDRM surveillance will help identify HIV drug resistance trends in the United States.