T. Svidzinski

Propolis: a potential natural product to fight Candida species infections.

AIM To evaluate the effect of propolis against Candida species planktonic cells and its counterparts biofilms. MATERIALS & METHODS The MIC values, time-kill curves and filamentation form inhibition were determined in Candida planktonic cells. The effect of propolis on Candida biofilms was assessed through quantification of CFUs. RESULTS MIC values, ranging from 220 to 880 µg/ml, demonstrated higher efficiency on C. albicans and C. parapsilosis than on C. tropicalis cells. In addition, propolis was able to prevent Candida species biofilms formation and eradicate their mature biofilms, coupled with a significant reduction on C. tropicalis and C. albicans filamentation. CONCLUSION Propolis is an inhibitor of Candida virulence factors and represents an innovative alternative to fight candidiasis.

Adhesion and biofilm formation in artificial saliva and susceptibility of yeasts isolated from chronic kidney patients undergoing haemodialysis.

Yeasts of the genera Candida and Saccharomyces are opportunist pathogens and cause oral lesions, especially in immunocompromised patients. This study assessed yeasts isolated from chronic kidney patients undergoing haemodialysis for their adhesion capacity, biofilm formation and susceptibility to antifungal agents. Ten isolates of Candida spp. and one isolate of Saccharomyces cerevisiae were tested for adhesion to buccal epithelial cells (BECs), adhesion and formation of biofilm in artificial saliva and their susceptibility profile to antifungal agents. Adhesion and biofilm formation were undertaken in polystyrene plates with artificial saliva, whilst susceptibility to antifungal agents was evaluated by broth microdilution. Candida parapsilosis had the highest adhesion index in BECs (154.55 ± 22.13) and Candida rugosa was the species with the highest adhesion capacity (18 398  Abs cm(-2)) in abiotic surface with artificial saliva. Candida albicans provided the greatest biofilm formation (2035  Abs cm(-2) ± 0.09) but was revealed to be susceptible to the five antifungal agents under analysis. However, some non-albicans Candida isolates showed a lower susceptibility for the antifungal agents itraconazole, fluconazole and voriconazole. All of the species were sensitive to amphotericin B and nystatin. The current analysis showed that yeasts isolated from the mouth of chronic kidney patients undergoing haemodialysis varied significantly with regard to their capacity for adherence, biofilm formation and susceptibility to antifungal agents, underscoring the high virulence of non-albicans Candida species.

γ-irradiation from radiotherapy improves the virulence potential of Candida tropicalis

AIM To evaluate if radiation used in radiotherapy can cause changes in the virulence potential of Candida tropicalis ATCC 750. MATERIALS & METHODS C. tropicalis was exposed in vitro to identical dose and scheme of irradiation would be used in patients with head and neck cancer. Some virulence parameters were analyzed before and after irradiation. RESULTS Colony morphologies were irreversibly affected by irradiation. Increase in growth rate, filamentation, adhesion on cell lines and phagocytosis process were also observed. Overall the irradiated C. tropicalis cells became more efficient at causing systemic infection in mice. CONCLUSION γ-radiation induced important changes in C. tropicalis increasing its virulence profile, which could directly affect the relationship between yeasts and hosts.