Efficient identification of clinically relevant Candida yeast species by use of an assay combining panfungal loop-mediated isothermal DNA amplification with hybridization to species-specific oligonucleotide probes.

Abstract

The occurrence of invasive mycoses has progressively increased in recent years. Yeasts of the genus Candida remain the leading etiologic agents of those infections. Early identification of opportunistic yeasts may contribute significantly to improved disease management and the selection of appropriate antifungal therapy. We developed a rapid and reliable molecular identification system for clinically relevant yeasts that makes use of nonspecific primers to amplify a region of the 26S rRNA gene, followed by reverse hybridization of the digoxigenin-labeled products to a panel of species-specific oligonucleotide probes arranged on a nylon membrane macroarray format. DNA amplification was achieved by the recently developed loop-mediated isothermal DNA amplification technology, a promising option for the development of improved laboratory diagnostic kits. The newly developed method was successful in distinguishing among the major clinically relevant yeasts associated with bloodstream infections by using simple, rapid, and cost-effective procedures and equipment.