Which genotype kit should be used for detecting drug-resistant mutations in subtype C patients? We are particularly interested in performing tests for mutations conferring resistance to AZT, nevirapine and protease inhibitors.
Dr. David Katzenstein responds:
There are several competing kits for genotyping. The ones I am most familiar with are the Visible Genetics (True Gene) and the P.E./ ABI ViroSeq. Of course, if you have the capacity to do DNA sequencing in your own laboratory, then it is far less expensive to develop your own primers. There is a "rapid and simple" hybridization test that was developed by Innogenetics and is now marketed by Bayer Diagnostics, the "LIPA assay," which provides data on selected resistance mutations.
There have been a few comparisons of the VisGen and ABI kits using subtype C samples and both perform well, although experience is limited. For the Visible Genetics test, it is critical that you obtain their 1.5 primers with subtype C samples. I am not aware of extensive experience with the LIPA assay in subtype C samples, but many of the resistance mutations you are interested in can be found with their kit and are present following drug failure in subtype C.
The companies that provide these kits (ABI, Vis Gen and Innogenetics/Bayer) all have links on the HIVresistanceweb.com site, which can bring you to the company web sites that describe their products in more detail.
