HIV-1 Resistance to Antiretroviral Agents: Relevance to Mothers and Infants in the Breastfeeding Setting

HIV is a retrovirus whose genetic material is comprised of RNA. It is a decidedly adaptable virus with properties of high replication rates in association with an RNA copying enzyme-reverse transcriptase-which possesses a relatively high copying error rate, in the order of 1 error or mutation for every 10,000 nucleotides copied. This translates to a single mutation for every viral replication event on average in the setting of a billion viral copies produced daily in an infected individual. As such, the viral quasispecies (the pool of viral variants present at a given time) can and does adapt rapidly to environmental pressures such as the immune response or antiretroviral agents. It should not be surprising, therefore, that as antiretroviral agents have been developed and deployed, mutations in HIV genes associated with ARV resistance have rapidly been detected, underscoring the strategy of multiple agent and multiple class ARV therapy known as highly active antiretroviral therapy (HAART). © 2012 Springer Science+Business Media New York.