In VitroActivities of Voriconazole and Five Licensed Antifungal Agents AgainstCandida dubliniensis:Comparison of CLSI M27-A2, Sensititre YeastOne, Disk Diffusion, and Etest Methods

Mechanisms of antifungal drug resistance in Candida dubliniensis

Candida dubliniensis was first described in 1995 and is the most closely related species to the predominant human fungal pathogen Candida albicans. C. dubliniensis is significantly less prevalent and less pathogenic than C. albicans and is primarily associated with infections in HIV-infected individuals and other immunocompromised cohorts. The population structure of C. dubliniensis consists of three well-defined major clades and is significantly less diverse than C. albicans. The majority of C. dubliniensis isolates are susceptible to antifungal drugs commonly used to treat Candida infections. To date only two major patterns of antifungal drug resistance have been identified and the molecular mechanisms of these are very similar to the resistance mechanisms that have been described previously in C. albicans. However, significant differences are evident in the predominant antifungal drug mechanisms employed by C. dubliniensis, differences that reflect its more clonal nature, its lower prevalence and characteristics of its genome, the complete sequence of which has only recently been determined.

Multifocal osteomyelitis caused by Candida dubliniensis

Candida dubliniensis is an emerging fungal pathogen, especially in immunodeficient patients. We report what is to the best of our knowledge the first case of multifocal osteomyelitis following disseminated infection in a patient after haematopoietic stem cell transplantation. PFGE for typing of C. dubliniensis was developed and the necessity of long-term antifungal therapy is discussed.

Isolation of Candida dubliniensis in denture stomatitis

OBJECTIVE

To describe the isolation of Candida dubliniensis from a patient with denture stomatitis and to compare with the presence of yeasts in the oral cavities of denture wearers.

DESIGN

One hundred and fifty-two Candida isolates were recovered through oral swabs from denture as well as the underlying mucosa from 100 patients wearing denture. For detection and identification of fungal isolates, standard phenotypic and genotypic methods were used.

RESULTS

Forty-five of 100 denture wearers suffered from denture stomatitis. Seventy-three Candida isolates were recovered from 38 denture wearers without denture stomatitis. In this group, Candida albicans was the predominant species (58.9%), followed by Candida tropicalis (15.1%), Candida guilliermondii (13.7%), Candida glabrata (9.6%), and Candida parapsilosis (2.7%). Seventy-nine isolates were yielded from 40 patients suffering from denture stomatitis. C. albicans was also the most frequently isolated species (58 isolates, 73.4%), followed by C. glabrata and C. tropicalis (7 isolates each, 8.9%), and Saccharomyces cerevisiae (2 isolates, 2.5%). One isolate was yielded of the following species: Candida famata, Candida krusei, C. parapsilosis and C. guilliermondii. Moreover 1 isolate was phenotypic and genotypic identified as C. dubliniensis genotype 1.

CONCLUSIONS

C. albicans is the predominant fungal species isolated from denture wearers. C. dubliniensis could be isolated from adults with denture stomatitis.

[In vitro antifungal activity of voriconazole: New data after the first years of clinical experience]

Voriconazole has been developed to meet the increasing need for new and useful antifungal agents for the treatment of invasive mycoses. This review describes the spectrum of voriconazole antifungal activity based on data from in vitro studies published during the last three years. This survey demonstrates that voriconazole has a broad antifungal spectrum against the most common fungal pathogens being its action fungistatic for Candida and fungicidal for Aspergillus and other filamentous fungi. Overall, more than 95% of all Candida isolates tested are susceptible to voriconazole and less than 3% are resistant. Similar or even better activity rates have been described for Aspergillus, Cryptococcus and most of yeasts and moulds of medical importance. We also discuss the limitations related to the azole cross-resistance observed in some Candida glabrata isolates, the poor activity of voriconazole against Scedosporium prolificans, its activity against fungal biofilms and the great potential usefulness of combination of voriconazole with other antifungal drugs.