Transmission of HIV-1 drug resistance

Background: The use of highly-active anti-retroviral therapy (HAART) for treating HIV infections is increasing. Recent studies have demonstrated that HAART is improving both the length and quality of life in HIV-infected patients. Resistant strains of HIV arise when drug adherence is poor. This can lead to the transmission of drug-resistant strains of HIV to susceptible individuals. This can lead to suboptimal first-line therapy, if the resistance profile of the transmitted virus is unknown. Objectives: To review the mechanisms of how drug resistance arises; the methods used to characterise drug resistance; the problems arising with compliance leading to the development of drug-resistant HIV strains; the evidence for the incidence, prevalence and trends in the transmission of resistant HIV strains in different risk groups; and the evidence of suboptimal response to first-line therapy where transmission of a resistant HIV strain has occurred. On the basis of this, a case is presented for the routine resistance testing of all newly diagnosed HIV-infected individuals. Study design: Literature review. Results and conclusions: There is evidence, though limited at present, that transmission of drug-resistant HIV strains can lead to suboptimal response to first-line therapy in newly diagnosed HIV-infected individuals. As the use of HAART can only increase in the future, and compliance will always be a problem in such HAART-treated patients, baseline resistance testing should become a routine part of their management.