Molecular typing and in-vitro activity of azoles against clinical isolates of Aspergillus fumigatus and A. niger in Japan

Twenty-three isolates of Aspergillus from Japanese transplant recipients were identified by phenotyping and subjected to detailed sequence analyses using the ITS regions and β-tubulin (benA). Gene sequences derived from the ITS regions and benA of all Aspergillus isolates were compared with sequences in the GenBank database for species identification. Nineteen isolates were identified as A. fumigatus and 4 isolates as A. niger. The antifungal susceptibility of the isolates to itraconazole (ITZ), voriconazole (VCZ), and posaconazole (POS) was assessed using the E-test with a 48-h incubation. Almost all the clinical isolates of the Aspergillus species seemed to be more susceptible to VCZ and POS than to ITZ, whereas 1 clinical isolate of A. fumigatus was resistant to ITZ. Sequencing of the 14α-demethylase gene (cyp51A) of this isolate revealed a novel mutation (F332K) in the gene.