Comparative study of the GenePath group 4 reagent system and other CHEF systems for karyotype analysis of Candida spp.

The commercial GenePath Group 4 Reagent Candida kit (BioRad), designed to simplify the electrophoretic karyotyping of Candida spp. was evaluated against several other established contour-clamped homogeneous electric field (CHEF) systems for Candida. This comparison allowed assessment of both the GenePath system and the other CHEF systems regarding the sources of technical variability of the assays and variation in karyotypic analysis. The GenePath system appeared to be a simple, rapid and reliable tool for karyotyping of Candida spp. with a discriminatory power comparable with established CHEF systems. The evaluation showed that the variability of the CHEF systems for subtyping of Candida is largely a function of technical variabilities in the assay system (reagents, sample preparation, running conditions, and test performance), and of analytical variabilities due to imprecision or observers bias. Lack of standardization of these factors may contribute to variability among investigators and have an impact on the ultimate conclusions of an epidemiological study using CHEF methods.