Short Communication: HIV Type 1 Tropism Determination in a Novel Dried Blood Spot Membrane and the Use of a Mixture of Outer Nested Polymerase Chain Reaction Primers

Abstract

Genotropism was determined in 608 Brazilian samples collected in dried blood spots using Polyethersulfone collection cards. Patients were infected by subtype B (88.8%), F (5.6%), C (3.3%), A (1.8%), and G (0.5%). All patients were exposed to three classes of antiretrovirals, and 59.8% of the samples harbored R5 viruses, 35% non-R5-tropic viruses, and 5.1% harbored mixtures of R5 and non-R5-tropic viruses, with non-R5 more prevalent among clade B-infected patients as compared to non-B (42.8% versus 19.1%; p<0.0003). A strategy using a mixture of outer nested polymerase chain reaction (PCR) primers reduced the number of negative PCR results from 39% to 19%.