Candida dubliniensis Species

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.

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.

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.

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* Fungus Testing Laboratory unpublished data (NCCLS M27-A2)

PubMed

GenBank

Double and triple chlamydospores of C. dubliniensis

References

381. Carr, M. J., S. Clarke, F. O'Connell, D. J. Sullivan, D. C. Coleman, and B. O'Connell. 2005. First reported case of endocarditis caused by Candida dubliniensis. J Clin Microbiol. 43:3023-3026.

704. Faggi, E., G. Pini, E. Campisi, C. Martinelli, and E. Difonzo. 2005. Detection of Candida dubliniensis in oropharyngeal samples from human immunodeficiency virus infected and non-infected patients and in a yeast culture collection. Mycoses. 48:211-215.

1543. Miron, D., Y. Horowitz, D. Lumelsky, S. Hanania, and R. Colodner. 2005. Dual pulmonary infection with Candida dubliniensis and Aspergillus fumigatus in a child with chronic granulomatous disease. J Infect. 50:72-5.

2191. Sullivan, D. J., T. J. Westerneng, K. A. Haynes, D. E. Bennett, and D. C. Coleman. 1995. Candida dubliniensis sp. nov.: phenotypic and molecular characterization of a novel species associated with oral candidosis in HIV-infected individuals. Microbiology. 141:1507-1521.