Use of SCW4 gene primers in PCR methods for the identification of six medically important Aspergillus species.

Aspergillus species are the cause of invasive mold infections in immunocompromised patients: Aspergillus fumigatus, A. flavus and A. terreus account for most cases of invasive aspergillosis (IA). As certain species are associated with higher mortality and vary in their resistance to antifungal therapy, diagnosis requires increasingly rapid molecular methods that enable sensitive detection and species discrimination. We have developed PCR and Multiplex PCR assays for the detection of six medically important Aspergillus spp. species DNA in bronchoalveolar lavage (BAL) specimens from hematology and intensive care unit (ICU) patients at risk of IA, using different species and genus-specific PCR primers, selected within the SCW4 gene, encoding a cell wall glucanase of A. fumigatus, similar to mannoprotein Mp65 of Candida albicans. The genus-specific PCR primers were able to amplify only Aspergillus DNAs but not that belonging to other fungal genera tested. The species-specific PCR primers allowed differentiation of each Aspergillus species by the amplicon length produced. The methods described in this study are rapid (less than 4 h), reproducible, simple and specific and demonstrate potential application in the clinical laboratory.