Differences in extracellular enzymatic activity between Candida dubliniensis and Candida albicans isolates

Area of Science:

• Mycology
• Medical Microbiology
• Immunocompromised Host Research

Background:

• Candida species are opportunistic fungal pathogens, frequently causing oral infections in individuals with human immunodeficiency virus (HIV).
• Accurate differentiation of Candida species, particularly Candida dubliniensis and Candida albicans, is crucial for appropriate clinical management.
• Extracellular enzymatic activities are important virulence factors and potential targets for species identification.

Purpose of the Study:

• To compare the extracellular enzymatic profiles of oral Candida dubliniensis and Candida albicans strains isolated from HIV-infected patients.
• To evaluate the utility of specific enzymatic activities, assessed via the API-ZYM system, in differentiating these two closely related species.
• To investigate the relationship between enzymatic activities and filamentation in these Candida strains.

Main Methods:

• Twenty-six Candida dubliniensis and 27 Candida albicans oral isolates from HIV patients were analyzed.
• Germ tube production and 21 extracellular enzymatic activities were assessed.
• The API-ZYM commercial kit system was employed to evaluate 19 different enzymes, including protease and phospholipase.

Main Results:

• All tested strains exhibited protease activity, with higher levels than phospholipase activity in both species.
• Significant differences in API-ZYM profiles were observed between C. dubliniensis and C. albicans, particularly in cystine-arylamidase, naphtol-AS-BI-phosphohydrolase, and alpha-glucosidase activities.
• No correlation was found between protease, phospholipase, and other enzymatic activities in C. dubliniensis; average filamentation ranged from 32-42%.

Conclusions:

• The enzymatic profiles, especially the activities of cystine-arylamidase, naphtol-AS-BI-phosphohydrolase, and alpha-glucosidase, can effectively differentiate C. dubliniensis from C. albicans in oral isolates from HIV patients.
• These enzymatic markers, combined with other phenotypic characteristics, offer valuable tools for distinguishing between these two important fungal species.
• Further research may elucidate the role of these enzymatic differences in the pathogenesis and clinical presentation of oral candidiasis in immunocompromised individuals.