In a retrospective multicenter study, 102
formalin-fixed
paraffin-embedded (FFPE) tissue specimens with histopathology results were tested. Two 4- to 5-μm FFPE tissue sections from each specimen were digested with
proteinase K, followed by automated
nucleic acid extraction. Multiple real-time quantitative PCR (qPCR) assays targeting the internal transcribed spacer 2 (ITS2) region of
ribosomal DNA, using fluorescently labeled primers, was performed to identify clinically important genera and species of Aspergillus, Fusarium, Scedosporium, and the Mucormycetes The molecular identification was correlated with results from histological examination. One of the main findings of our study was the high sensitivity of the automated
DNA extraction method, which was estimated to be 94%. The qPCR procedure that was evaluated identified a range of fungal genera/species, including Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus, Aspergillus niger, Fusarium oxysporum, Fusarium solani, Scedosporium apiospermum, Rhizopus oryzae, Rhizopus microsporus, Mucor spp., and Syncephalastrum Fusarium oxysporum and F. solani
DNA was amplified from five specimens from patients initially diagnosed by histopathology as having
aspergillosis. Aspergillus flavus, S. apiospermum, and Syncephalastrum were detected from histopathological
mucormycosis samples. In addition, examination of four samples from patients suspected of having concomitant
aspergillosis and
mucormycosis infections resulted in the identification of two A. flavus isolates, one Mucor isolate, and only one sample having both R. oryzae and A. flavus Our results indicate that histopathological features of molds may be easily confused in tissue sections. The qPCR assay used in this study is a reliable tool for the rapid and accurate identification of fungal pathogens to the genus and species levels directly from FFPE tissues.