A DNA microarray based on Arrayed-Primer Extension (APEX) technique for identification of pathogenic fungi responsible for invasive and superficial mycoses

Dipartimento di Biologia, Sezione di Genetica, Via Derna, 1, and Sezione di Microbiologia, Via San Zeno, 35-39, Università di Pisa, 56126 Pisa, Italy

^* To whom correspondence should be addressed. Email: ssenesi{at}biologia.unipi.it.

	Abstract

An oligonucleotide microarray, based on the arrayed primer extension (APEX) technique, has been developed to simultaneously identify pathogenic fungi frequently isolated from invasive and superficial infections. Species-specific oligonuceotide probes complementary to the internal transcribed spacer (ITS1 and ITS2) region were designed for 24 species belonging to 10 genera, including Candida (albicans, dubliniensis, famata, glabrata, tropicalis, kefyr; krusei, guilliermondii, lusitaniae, metapsilosis, orthopsilosis, parapsilosis, and pulcherrima), Cryptococcus neoformans, Aspergillus (fumigatus and terreus), Trichophyton (rubrum and tonsurans), Trichosporon cutaneum, Epidermophyton floccosum, Fusarium solani, Microsporum canis, Penicillium marneffei, and Saccharomyces cerevisiae. The microarray was tested for its specificity with a panel of reference and blinded clinical isolates. The APEX technique was proven to be highly discriminative, leading to unequivocal identification of each species including the highly related ones C. parapsilosis, C. orthopsilosis and C. metapsilosis. Because of the satisfactory basic performance traits obtained, such as reproducibility, specificity and unambiguous interpretation of the results, this new system represents a reliable method of potential use in clinical laboratories for parallel one-shot detection and identification of the most common pathogenic fungi.