Sullivan, Westerneng, Haynes, Bennett & Coleman (1995)
Macroscopic morphology
Colonies on Sabouraud dextrose agar at 25°C are white to cream, soft, and smooth to wrinkled. This isolate has poor to no growth at 42°C. Colonies grown on Chromager are dark green as opposed to the light blue-green exhibited by C. albicans.
Microscopic morphology
On cornmeal following 72 hours incubation at 25°C, abundant branched pseudohyphae and true hyphae with blastoconidia are present. Many strains produce an abundance of chlamydoconidia resulting in excess of 25-30 being observed in each microscopic field. Chlamydoconidial arrangement includes single, pairs, chains, and clusters.
Special Notes
This isolate is germ tube positive which accounts for its historic miss-identification as C. albicans. Initially thought to be associated only with HIV disease, several reports have been published since its description implicating it in non-HIV associated infection as well [381], [704], [1543]. Molecular analysis show that C. dubliniensis is distinct from C. albicans by 13-15 nucleotides in the ribosomal RNA gene sequences [2191]. Early reports purported that C. dubliniensis was responsible for fluconazole-resistant thrush but susceptibility studies reveal that it’s categorical distribution is similar to C. albicans with isolates ranging from susceptible to resistant.
FTL* in vitro susceptibility data
| AMB | CAS | 5FC | FLU | ITRA | VORI | KETO |
|---|---|---|---|---|---|---|
| <0.03 µg/ml=1 | <0.03 µg/ml=11 | <0.125 µg/ml=3 | <0.125 µg/ml=9 | <0.015 µg/ml=9 | <0.015 µg/ml=9 | <0.03 µg/ml=4 |
| 0.06 µg/ml=4 | 0.06 µg/ml=5 | 0.25 µg/ml=9 | 0.03 µg/ml=3 | 0.03 µg/ml=1 | ||
| 0.125 µg/ml=6 | 0.125 µg/ml=2 | 0.5 µg/ml=2 | 0.06 µg/ml=1 | 1.0 µg/ml=1 | ||
| 0.25 µg/ml=1 | 0.25 µg/ml=2 | 2.0 µg/ml=1 | 0.5 µg/ml=1 | >8 µg/ml=1 | ||
| 1.0 µg/ml=1 | 4.0 µg/ml=1 | |||||
| >64 µg/ml=2 |
| Drug/N | AMB/13 | CAS/20 | 5FC/3 | FLU/24 | ITRA/14 | VORI/12 | KETO/4 |
|---|---|---|---|---|---|---|---|
| MIC Range | <0.03-1.0 | <0.03-0.25 | <0.125 | <0.125-64 | <0.015-0.5 | <0.015->8 | <0.03 |
| MIC50 | 0.125 | <0.03 | – | 0.25 | <0.015 | <0.015 | – |
| MIC90 | 0.25 | 0.125 | – | 4.0 | 0.06 | 1.0 | – |
* Fungus Testing Laboratory unpublished data (NCCLS M27-A2)