Table 3.
Cross-resistance between isavuconazole (MICs of ≥4 μg/ml) and three licensed triazoles among 26 Aspergillus isolates, as determined by the CLSI M38-A2 microdilution method at 48 ha
| Species complex (no. of isolates) | Range (mode)b (μg/ml) withd: |
|||
|---|---|---|---|---|
| Itraconazole | Posaconazole | Voriconazole | Isavuconazole | |
| A. fumigatus (15)c | 1–≥16 (≥16) | 0.5–8 (2) | 0.5–8 (8) | 4–8 (8) |
| A. flavus (1) | 1 (NA) | 1 (NA) | 1 (NA) | 4 (NA) |
| A. niger (9) | 1–16 (2, 8) | 0.5–1 (1) | 1–≥16 (2) | 4–≥16 (4) |
| A. versicolor (1) | 8 (NA) | 1 (NA) | 4 (NA) | >8 (NA) |
Isavuconazole MICs of ≥4 μg/ml were not reported for the other species evaluated. Itraconazole, posaconazole, and voriconazole ECVs for the A. fumigatus species complex and the A. flavus species complex were 1, 0.25, and 1 μg/ml, respectively; those for the A. niger species complex were 2, 0.5, and 2 μg/ml, respectively; and those for the A. versicolor species complex were 2, 1, and 2 μg/ml, respectively (27).
Most frequent MIC.
Twelve of the 15 isolates contained a TR34 promoter duplication and an L98H mutation in the cyp51A gene (14, 17).
NA, not applicable, because modes were not determined for single isolates.