Candida dubliniensis
Scientific classification
Kingdom:	Fungi
Phylum:	Ascomycota
Subphylum:	Saccharomycotina
Class:	Saccharomycetes
Order:	Saccharomycetales
Family:	Saccharomycetaceae
Genus:	Candida
Species:	C. dubliniensis
Binomial name
Candida dubliniensis Sullivan et al.

Candida dubliniensis is a fungal opportunistic pathogen originally isolated from AIDS patients. It is also occasionally isolated from immunocompetent individuals. It is a dimorphic yeast of the genus Candida, very closely related to Candida albicans but forming a distinct phylogenetic cluster in DNA fingerprinting. It is most commonly isolated from oral cavities, ^[1] and is also occasionally found in other anatomical sites.

Contents 1 Prevalence and epidemiology 2 Antifungal susceptibility 2.1 Fluconazole 3 References 4 External links

[edit] Prevalence and epidemiology

Candida dubliniensis is cosmopolitan (found around the world), and has been described as a separate species in 1995.^[2] Retrospective studies have shown that previously it had been commonly identified as Candida albicans, with which C. dubliniensis is closely related and shares a number of characteristics.

One test for distinguishing C. dubliniensis from C. albicans, is laboratory culture of the organism at 42°C. Most C. albicans strains grow at this temperature,^[3] whereas most C. dubliniensis isolates do not.^[2] There are also significant differences in the conditions that lead to the formation of chlamydospores between C. albicans and C. dubliniensis, although they are otherwise phenotypically very similar.^[2]

A European study of 2,589 isolates, that had originally been identified as C. albicans, revealed that 52 of them (2.0%) were C. dubliniensis. Most of these isolates were from oral or faecal specimens from HIV-positive patients, though one vaginal and two oral isolates were from healthy individuals.^{[citation needed]} Another study in the United States surveyed 1,251 yeasts previously identified as C. albicans, and identified 15 isolates (1.2%) as C. dubliniensis. Most of these isolates were from immunocompromised individuals, such as AIDS, chemotherapy, or organ transplant patients.^{[citation needed]} The majority of C. dubliniensis strains were recovered from respiratory, urine and stool specimens.^{[citation needed]} The Memorial Sloan-Kettering Cancer Center also conducted several studies, both retrospective and prospective. In 974 germ-tube positive yeasts, 22 isolates (2.3%) from 16 patients were C. dubliniesis. All individuals were immunologically compromised with either malignancy or AIDS, and the isolates came from a variety of different sites. C. dubliniensis was also isolated from the mouths of 18% of patients with diabetes and who use insulin.^[4]

[edit] Antifungal susceptibility

In one study, all 20 C. dubliniensis' isolates tested were susceptible to itraconazole, ketoconazole and amphotericin B.^[5]

[edit] Fluconazole

Many isolates of C. dubliniensis are sensitive to fluconazole. In one study, 16 of 20 isolates were sensitive to fluconazole, while four were resistant.^[5] It has been hypothesized that C. dubliniensis has the ability to rapidly develop resistance to fluconazole, especially in patients who are on long-term therapy.^[5]

Stable fluconazole resistance could be induced in vitro by subjecting sensitive strains to increasing concentrations of this antifungal. This resistance is mediated by a multidrug transporter that can be mobilized rapidly in vitro, on exposure to fluconazole.^{[citation needed]}

Cases in America have also shown the emergence of fluconazole-resistant C. dubliniensis. Three isolates were discovered in Texas, two of which were resistant (MIC, 64 µg/mL), and one had dose-dependent susceptibility (MIC, 16 µg/mL). Among C. dubliniensis isolates in HIV+ patients in Maryland, most isolates were highly susceptible to fluconazole. A study of 71 isolates in Ireland, showed that both the fluconazole-resistant and susceptible strains were susceptible to itraconazole, amphotericin B, and 5-fluorocytosine (microdilution). They were also susceptible to experimental triazoles and voriconazole and echinocandin.^{[citation needed]}

[edit] References

[edit] External links

• Doctor Fungus page about Candida dubliniensis