HIV resistance testing: an update.

In recent years, resistance testing has become an important tool in optimizing the combination therapy for treating HIV infected individuals. The identification of resistance mutations has allowed physicians to select the antiviral agents with maximum therapeutic benefic and minimum toxic side effects. The current therapeutic agents approved by the Food and Drug Administration (FDA), their mechanisms of actions, and the mutations of the HIV viral genome that lead to resistance to antiviral agents are discussed. In addition, methods of resistance testing, both genotypic and phenotypic, are evaluated with consideration of their inherent advantages and disadvantages.