Correlation between enzyme production, germ tube formation and susceptibility to fluconazole in Candida species isolated from patients with denture-related stomatitis and control individuals

Introduction: Phospholipase and proteinase secretion in yeasts of the genus Candida has been described as a relevant virulence factor. Also, germ tube formation by Candida albicans is associated with its invasive capacity and is considered an important pathogenic mechanism. Methods: To link the production of hydrolytic enzymes with the capacity to produce infection, 232 clinical isolates of yeasts from the oral cavity of 140 individuals wearing removable maxillary protheses were studied. The sample was composed of 70 patients with denture-related stomatitis (DRS) and 70 individuals with normal palatal mucosa. For strains identified as C. albicans, the correlation between germ tube formation and their capacity to cause infection was studied and the presence of Candida dubliniensis was investigated. Susceptibility to fluconazole was evaluated. Results: Candida albicans was the only species producing phospholipase and germ tube. We observed a higher level of production of phospholipase in cases of infection compared with commensals. Significant differences between the two groups of C. albicans isolates were observed as to germ tube production. Only, Candida glabrata showed lower susceptibility to fluconazole. Conclusion: The results reinforced the idea that C. albicans is the most frequent and can be the most pathogenic yeast in oral candidosis. However, the strains isolated from DRS patients and healthy individuals showed the same virulence factors. It seems that several virulence attributes are involved in the infective process but no single factor contributes to Candida virulence. Candida dubliniensis was absent in the oral cavity of individuals with and without DRS.