Diabetes mellitus (DM) is a systemic condition characterized by a deficient sugar metabolism, which affects the immune system and favors the development of yeasts. The aim of the present study was to perform biochemical, morphological, exoenzyme analyses of Candida species and the molecular identification (DNA) of C. albicans in patients with type II diabetes mellitus. The exoenzyme quantification was compared to non-diabetic patients as controls. Two hundred and seventy-four patients who make use of complete dentures were evaluated, 28 of whom had diabetes and erythematous oral candidiasis. Other thirty patients presented the same clinical feature but without diabetes. Samples were isolated for biochemical identification (auxonogram), morphological identification (production of germ tubes) and PCR molecular identification (DNA). The capability of the Candida samples in producing phospholipases and proteinases was also determined. The diabetic patients had a greater diversity of Candida species (Fischer's exact test, P = 0.04). The production of proteinases by C. albicans in patients with diabetes was greater than in the control group (unpaired "t" test P < 0.003). However, there was no difference between groups for phospholipase production (unpaired "t" test P > 0.05). It was concluded that patients with controlled DM exhibited systemic conditions predisposing C. albicans proteinase increased production.

Candida dubliniensis is a new, recently described species of yeast. This emerging oral pathogen shares many phenotypic and biochemical characteristics with C. albicans, making it hard to differentiate between them, although they are genotypically distinct. In this study, PCR (Polymerase Chain Reaction) was used to investigate the presence of C. dubliniensis in samples in a culture collection, which had been isolated from HIV-positive and HIV-negative patients with oral erythematous candidiasis. From a total of 37 samples previously identified as C. albicans by the classical method, two samples of C. dubliniensis (5.4%) were found through the use of PCR. This study underscores the presence of C. dubliniensis, whose geographical and epidemiological distribution should be more fully investigated.

This investigation was designed to evaluate the frequency of erythematous candidosis (EC) and Candida species, proteinase and phospholipase exoenzyme production, and to compare clinical features in patients with complete dentures and HIV+/Acquired Immunodeficiency Disease Syndrome (AIDS). Fifty-one patients were selected from a total of 285 with EC: denture wearers (n = 30) and HIV+/AIDS (n = 21). The yeast prevalence and the production of exoenzymes, such as proteinase and phospholipase by Candida species were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) electrophoresis. The frequency of Candida albicans was significantly higher (P < 0.05) in both groups although other yeast species (Candida glabrata, Candida krusei, Candida parapsilosis, Candida guilliermondi and Candida tropicalis) were also found. Candida albicans showed greater levels of proteinase production in the denture wearers, when compared with the HIV+/AIDS group. There was no difference between groups with regard to phospholipase production. The protein bands presented similar molecular weights, showing the presence of proteinases in both groups. It could be concluded that the clinical manifestation of EC may be related to its proteinase production capacity. Combination therapies using proteinase inhibitors play an important role in inhibiting exoenzyme production by Candida species, mainly C. albicans.

The antifungal minimal inhibitory concentrations (MIC) were determined to 35 samples of Candida albicans; 14 of them were isolated from HIV-positive patients, and 21 from HIV-negative patients with oral erythematous candidosis. The aim of this study was to evaluate the performance of agar dilution method in the determination of susceptibility of Candida albicans isolated from buccal lesions of HIV-positive and negative patients to some antifungals and compare the results with the plasmatic concentration reached by each one of these drugs. The samples were evaluated in vitro by the agar dilution method and showed higher MIC values to ketoconazole, fluconazole, itraconazole and amphotericin B than the concentrations achieved by these antifungals in plasma. 88.9% of the samples presented in vitro resistance to ketoconazole and the plasmatic levels of this antifungal varied from 1 to 8 µg/mL. Regarding fluconazole and itraconazole, most samples presented MIC larger than 128 µg/mL and plasmatic concentration varying from 0.4 to 8 µg/mL. Only 11.9% of the samples were susceptible in vitro to fluconazole and 2.7% of them to itraconazol. The usage concentrations prescribed for the topical antifungals nystatin, fenticonazole and miconazole are markedly higher than the values of MIC obtained. Related to nystatin, it was verified that its MIC values were between 1 and 4 µg /mL. The plasmatic levels to this drug are extremely low. Fenticonazole presented a MIC value larger than 128 µg/mL. Relating to miconazole, the plasmatic levels vary from 1 to 8 µg/mL and 11.9% of the samples presented in vitro susceptibility to this drug. No significant differences (p<0.05) were found in the susceptibility profiles of the samples obtained from HIVpositive and HIV-negative patients.