title: Protease Inhibitor Resistance Is Uncommon in HIV-1 Subtype C Infected Patients on Failing Second-Line Lopinavir/r-Containing Antiretroviral Therapy in South Africa.
abstract: Limited data exist on HIV-1 drug resistance patterns in South Africa following second-line protease-inhibitor containing regimen failure. This study examined drug resistance patterns emerging in 75 HIV-1 infected adults experiencing virologic failure on a second-line regimen containing 2 NRTI and lopinavir/ritonavir. Ninety six percent of patients (n = 72) were infected with HIV-1 subtype C, two patients were infected with HIV-1 subtype D and one with HIV-1 subtype A1. Thirty nine percent (n = 29) of patients had no resistance mutations in protease or reverse transcriptase suggesting that medication non-adherence was a major factor contributing to failure. Major lopinavir resistance mutations were infrequent (5 of 75; 7%), indicating that drug resistance is not the main barrier to future viral suppression.
authors.affiliation: Department of Molecular Medicine & Hematology, University of the Witwatersrand, Wits Medical School, 3B22, 3rd Floor, 7 York Road, Parktown 2193, South Africa.
authors.forename: Carole L
authors.initials: CL
authors.lastname: Wallis
authors.forename: John W
authors.initials: JW
authors.lastname: Mellors
authors.forename: Willem D F
authors.initials: WD
authors.lastname: Venter
authors.forename: Ian
authors.initials: I
authors.lastname: Sanne
authors.forename: Wendy
authors.initials: W
authors.lastname: Stevens