A study in the June 15 edition of The Journal of Infectious Diseases shows that 8% of new HIV cases diagnosed in the United States are caused by virus already resistant to at least one anti-HIV medication. The study also shows that gay men diagnosed with HIV infection were among those most likely to be infected with drug-resistant virus; whites and partners of HIV-positive adults taking antiretroviral drugs also were at a high risk for infection with drug-resistant HIV. Nearly 1,100 newly diagnosed patients were tested with genotypic and phenotypic HIV resistance tests. Ninety of the study subjects--8.3%--were infected with HIV with genetic mutations conveying resistance to at least one anti-HIV medication or drug class. Among gay HIV-positive men newly infected, 12% carried drug-resistant virus. About 14% of those newly diagnosed who had an HIV-positive partner taking antiretroviral medications were infected with drug-resistant HIV. The lowest rate of infection with drug-resistant virus was among African-Americans, at 5.4%.