Evaluation of Candida albicans adhesion and biofilm formation on a denture base acrylic resin containing silver nanoparticles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Atividade antifúngica de óleos essenciais frente a amostras clínicas de Candida albicans isoladas de pacientes HIV positivos

Objetivou-se avaliar a atividade antifúngica dos óleos essenciais de Ocimum basilicum L. (manjericão), Cymbopogon martinii L. (palmarosa), Thymus vulgaris L. (tomilho) e Cinnamomum cassia Blume (canela da china) sobre cepas de Candida albicans isoladas de pacientes HIV positivos e cepa padrão (ATCC 76845). Quinze amostras clínicas de C. albicans (C1-C15) foram repicadas em ágar Sabouraud Dextrose, para confecção de suspensões em solução salina estéril (0,9%) contendo 1,5 x 10(6) UFC mL-1. As emulsões dos óleos essenciais foram preparadas em água destilada estéril e tween 80, com concentrações variando entre 1024 µg mL-1 e 4 µg mL-1. A ação antifúngica foi determinada por meio da Concentração Inibitória Mínima (CIM) utilizando-se a técnica da microdiluição. Foram utilizados como controles positivos a nistatina e o miconazol (50 µg mL-1). Os testes foram realizados em triplicata, sendo a CIM, a menor concentração capaz de inibir o crescimento das leveduras, observada por método visual de acordo com a turvação do meio de cultura. Para C. albicans (ATCC 76845), a CIM do óleo essencial de C. cassia foi 64 µg mL-1, enquanto para óleo de C. martinii foi 1024 µg mL-1. Para as cepas clínicas, verificou-se que a CIM de C. cassia para 80% das cepas foi 64 µg mL-1, sendo a variação dos valores da CIM entre 128 µg mL-1 e 64 µg mL-1. Observou-se que para 66,6% das amostras clínicas, a CIM de C. martinii foi 612 µg mL-1. Constatou-se que a nistatina não apresentou atividade frente às cepas clínicas (C1-C15), enquanto a atividade antifúngica do miconazol foi verificada em 100% das amostras. Não se constatou atividade antimicrobiana dos óleos essenciais de O. basilicum e T. vulgaris, nas concentrações avaliadas. Concluiu-se que os óleos essenciais de C. cassia e C. martinii, em diferentes concentrações, apresentam atividade antifúngica sobre cepas de C. albicans isoladas de pacientes HIV positivos e cepa padrão (ATCC 76845). Entretanto não foi observada inibição antimicrobiana para os óleos de O. basilicum e T. vulgaris.

Decolorization of textile dye by Candida albicans isolated from industrial effluents

The aim of the present work was to observe microbial decolorization and biodegradation of the Direct Violet 51 azo dye by Candida albicans isolated from industrial effluents and study the metabolites formed after degradation. C. albicans was used in the removal of the dye in order to further biosorption and biodegradation at different pH values in aqueous solutions. A comparative study of biodegradation analysis was carried out using UV-vis and FTIR spectroscopy, which revealed significant changes in peak positions when compared to the dye spectrum. Theses changes in dye structure appeared after 72 h at pH 2.50; after 240 h at pH 4.50; and after 280 h at pH 6.50, indicating the different by-products formed during the biodegradation process. Hence, the yeast C. albicans was able to remove the color substance, demonstrating a potential enzymatic capacity to modify the chemical structure of pigments found in industrial effluents.

Caries risk tests and salivary levels of immunoglobulins to Streptococcus mutans and Candida albicans in mouthbreathing syndrome patients

The aim of this study was to compare microbiological and salivary variables possibly related to caries risk in treated and untreated mouthbreathing syndrome (MBS) children and control children. Thirty control children, 30 mouthbreathers and 25 treated mouthbreathers were studied for the numbers of lactobacilli, mutans streptococci and yeasts in their saliva. Snyder's test, salivary flow and buffering capacity were also evaluated. Levels of immunoglobulins to Candida albicans and Streptococcus mutans in the saliva were quantified using ELISA. Considering the results obtained for the microbiological and salivary caries risk tests, no significant differences were observed among the proportions of patients with small/negative and high/moderate caries risk in the studied groups. The level of IgG to S. mutans was significantly higher in the treated MBS group in relation to MBS patients. on the other hand, the median anti-S. mutans IgM level was lower in the treated MBS patients than in the other groups. For the studied anti-Candida immunoglobulins, IgM level was significantly lower in the treated MBS group than in the other groups. No differences were observed for anti-S. mutans and anti-Candida IgA levels among the groups. The findings suggest that mouthbreathing cannot be considered a risk factor for dental caries. Copyright (C) 2003 S. KargerAG, Basel.

Effectiveness of ozonated water on Candida albicans, Enterococcus faecalis, and endotoxins in root canals

The aim of this study was to evaluate the effectiveness of ozonated water in the elimination of Candida albicans, Enterococcus faecalis, and endotoxins from root canals. Twenty-four single-rooted human teeth were inoculated with C. albicans and E. faecalis, and 24 specimens were inoculated with Escherichia coli endotoxin. Ozonated water (experimental group) or physiologic solution (control group) was used as irrigant agent. Antimicrobial effectiveness was evaluated by the reduction of microbial counts. Lipopolissacharide complex presence was assessed by limulus amebocyte lysate test and B-lymphocyte stimulation. Data were analyzed by Wilcoxon and Mann-Whitney tests (5%). Ozonated water significantly reduced the number of C. albicans and E. faecalis at the immediate sampling, but increased values were detected after 7 days. Ozonated water did not neutralize endotoxin. It could be concluded that ozonated water was effective against C. albicans and E. faecalis but showed no residual effect. No activity on endotoxin was observed.

Experimental systemic virulence of oral Candida dubliniensis isolates in comparison with Candida albicans, Candida tropicalis and Candida krusei

There are no previous studies on the comparative virulence of Candida dubliniensis with other non-albicans species. The aim of this study was to compare the virulence and infection kinetics of C. dubliniensis and other species. Candida albicans, C. dubliniensis, Candida tropicalis and Candida krusei (reference strains) were inoculated intravenously in mice. For infection kinetics evaluation, a group of five animals were sacrificed after 6 h, 3, 7, 14 and 21 days. Microbiological evaluations (liver, spleen, kidneys, lungs and brain) and histopathological examination of the kidney were performed. The results of virulence evaluation were analysed using Kaplan-Meier survival analysis (5%). Candida dubliniensis-inoculated mice survived for longer periods compared with those with C. albicans (P = 0.005). No differences were detected in relation to C. tropicalis (P = 0.326) and C. krusei (P = 0.317). Most of the organs were persistently colonised by C. albicans and C. dubliniensis even by day 21. Tendency of C. krusei clearance was observed in all organs. Fungal masses and renal lesions were observed after inoculation of C. albicans, C. dubliniensis and C. tropicalis. Within the limits of the study, data on survival rate and dissemination capacity suggest that C. dubliniensis is less virulent than C. albicans.

The effects of rose bengal- and erythrosine-mediated photodynamic therapy on Candida albicans

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Susceptibility of Candida albicans, Staphylococcus aureus, and Streptococcus mutans biofilms to photodynamic inactivation: an in vitro study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparison of the photodynamic fungicidal efficacy of methylene blue, toluidine blue, malachite green and low-power laser irradiation alone against Candida albicans

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Experimental pathogenicity of Candida albicans and Candida dubliniensis with continuous and discontinuous fringes morphotypes

A possible correlation between the presence of discontinuous fringes and high virulence has been previously suggested. The aim of this study was to compare the pathogenicity of Candida albicans and Candida dubliniensis with continuous and discontinuous fringes morphotypes on mice. For C. albicans, two discontinuous fringe morphotype isolates (PN 69, PN 74), two continuous fringe morphotype isolates (N 60, N 33) and one reference strain were used. For C. dubliniensis, three discontinuous fringe morphotype isolates (97487, 97464, 97519), two continuous fringe morphotype isolates (97040, 98026) and one reference strain were used. Swiss male mice were inoculated with a standardised suspension of the microorganisms and observed for 35 days. The pathogenicity of the isolates was analysed according to parameters proposed previously. Three isolates were considered pathogenic: PN 74, N 60 and 98026. Strain N 60 killed the highest amount of mice (80%). Animals inoculated with C. albicans did not show differences on survival estimate. Candida dubliniensis 98026 was more pathogenic than samples 97464 and 97519. on the other hand, the sample 97487 showed a higher pathogenicity when compared with 97040 (Kaplan-Meier test, P = 0.008). Strains with continuous fringe morphotypes were also associated with Candida sp. virulence in vivo.

In vitro adherence of Candida albicans isolated from patients with chronic periodontitis

Adherence is considered an extremely important virulence factor in yeast. Objective: The aim of this study was to analyze the adherence to epithelial cells of C. albicans isolated from patients with chronic periodontitis in comparison to healthy patients. Material and methods: Candida albicans cells isolated from individuals with chronic periodontitis (n=25) and healthy controls (n=25) were included in this study. Suspensions of C. albicans (10(6) cells/rnL) and epithelial cells (10(5) cells/mL) were mixed and incubated at 37 degrees C for 1 h. The number of yeasts adhered to 25 epithelial cells was counted. Results: The number of C. albicans cells adhered to epithelial cells was statistically higher in the chronic periodontitis group than in the control group (Student's t-test, p=0.000). Conclusion: The results of the present study suggest a higher Candida adherence of samples isolated from patients with chronic periodontitis.

Influence of artificial saliva in biofilm formation of Candida albicans in vitro

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)