[The emergence of viruses resistant to antiviral agents: a new challenge].

Recent use of antiviral drugs and the increase in the number of viral infections in immunocompromised hosts have led to the development of viral resistance. In this paper, the author reviews the antiviral drugs on the market, the antiviral susceptibility tests and presents a review of the literature concerning infections with resistant viruses. Acyclovir-resistant herpes simplex and varicella-zoster virus, ganciclovir-resistant cytomegalovirus and zidovudine-resistant human immunodeficiency virus will be discussed.