The role of baseline HIV-1 resistance testing in patients with established infection

Effective long-term treatment of HIV-I infection is challenging because of several factors, including antiretroviral drug resistance. Antiretroviral resistance testing has short-term benefit for optimizing the choice of a rescue regimen after treatment failure. Resistance testing also is recommended before therapy in pregnancy and acute infection or recent seroconversion. The benefit of routine resistance testing before starting treatment for established infection is less clear. This report summarizes the accumulating evidence of persistence of resistant mutants after initial infection, detectability of resistant virus with standard assays before treatment of established infection, the potential adverse impact of this baseline resistance on effectiveness of therapy, and the increasing prevalence of resistance in treatment-naïve patients. Taken together, these data suggest that pretreatment genotypic resistance testing also may be useful in patients with established infection. Although further study is needed, clinicians are now encouraged to routinely obtain pretreatment resistance testing.