Curcumin-mediated photodynamic inactivation of Candida albicans in a murine model of oral candidiasis

In vitro investigations of curcumin-mediated photodynamic therapy (PDT) are encouraging, but there is a lack of reliable in vivo evidence of its efficacy. This study describes the photoinactivation of Candida albicans in a murine model of oral candidiasis, using curcumin as a photosensitizer. Forty immunosuppressed mice were orally inoculated with C. albicans and after five days, they received topical curcumin (20, 40 and 80 μM) and illumination with LED light. The use of curcumin or light alone were also investigated. Positive control animals did not receive any treatment and negative control animals were not inoculated with C. albicans. The number of surviving yeast cells was determined and analyzed by ANOVA and Tukey's post-hoc test (α = 0.05). Histological evaluation of the presence of yeast and inflammatory reaction was also conducted. All exposures to curcumin with LED light caused a significant reduction in C. albicans viability after PDT, but the use of 80 μM curcumin associated with light was able to induce the highest log10 reduction in colony counts (4 logs). It was concluded that curcumin-mediated PDT proved to be effective for in vivo inactivation of C. albicans without harming the host tissue of mice. © 2013 ISHAM.

Anti-Candida properties of urauchimycins from actinobacteria associated with Trachymyrmex ants

After decades of intensive searching for antimicrobial compounds derived from actinobacteria, the frequency of isolation of new molecules has decreased. To cope with this concern, studies have focused on the exploitation of actinobacteria from unexplored environments and actinobacteria symbionts of plants and animals. In this study, twenty-four actinobacteria strains isolated from workers of Trachymyrmex ants were evaluated for antifungal activity towards a variety of Candida species. Results revealed that seven strains inhibited the tested Candida species. Streptomyces sp. TD025 presented potent and broad spectrum of inhibition of Candida and was selected for the isolation of bioactive molecules. From liquid shake culture of this bacterium, we isolated the rare antimycin urauchimycins A and B. For the first time, these molecules were evaluated for antifungal activity against medically important Candida species. Both antimycins showed antifungal activity, especially urauchimycin B. This compound inhibited the growth of all Candida species tested, with minimum inhibitory concentration values equivalent to the antifungal nystatin. Our results concur with the predictions that the attine ant-microbe symbiosis may be a source of bioactive metabolites for biotechnology and medical applications. © 2013 Thais D. Mendes et al.

Effectiveness of disinfectants used in hemodialysis against both Candida orthopsilosis and C. parapsilosis sensu stricto biofilms

Biofilms have been observed in the fluid pathways of hemodialysis machines. The impacts of four biocides used for the disinfection of hemodialysis systems were tested against Candida parapsilosis sensu stricto and Candida orthopsilosis biofilms generated by isolates obtained from a hydraulic circuit that were collected in a hemodialysis unit. Acetic acid was shown to be the most effective agent against Candida biofilms. Strategies for effective disinfection procedures used for hemodialysis systems should also seek to kill and inhibit biofilms. Copyright © 2013, American Society for Microbiology. All Rights Reserved.

Methods for obtaining reliable and reproducible results in studies of Candida biofilms formed in vitro

Biofilm formation is one of the most important attributes for virulence in Candida species and contributes to increased resistance to antifungal drugs and host immune mechanisms. These features have led to the development of several methodologies to reproduce a sessile community in vitro that can be used to study the development of a biofilm, its interaction with other microorganisms and the environment, and its susceptibility to available antifungal agents and also to search for new therapy strategies. The purpose of this review is to describe the most commonly used methods to study Candida biofilms in vitro, to discuss the benefits and limitations of the different methods to induce biofilm formation, and to analyse the architecture, viability and growth kinetics of Candida biofilms. © 2013 Blackwell Verlag GmbH.

Antifungal activity of silver nanoparticles in combination with nystatin and chlorhexidine digluconate against Candida albicans and Candida glabrata biofilms

Although silver nanoparticles (SN) have been investigated as an alternative to conventional antifungal drugs in the control of Candida-associated denture stomatitis, the antifungal activity of SN in combination with antifungal drugs against Candida biofilms remains unknown. Therefore, the aim of this study was to evaluate the antifungal efficacy of SN in combination with nystatin (NYT) or chlorhexidine digluconate (CHG) against Candida albicans and Candida glabrata biofilms. The drugs alone or combined with SN were applied on mature Candida biofilms (48 h), and after 24 h of treatment their antibiofilm activities were assessed by total biomass quantification (by crystal violet staining) and colony forming units enumeration. The structure of Candida biofilms was analysed by scanning electron microscopy (SEM) images. The data indicated that SN combined with either NYT or CHG demonstrated synergistic antibiofilm activity, and this activity was dependent on the species and on the drug concentrations used. SEM images showed that some drug combinations were able to disrupt Candida biofilms. The results of this study suggest that the combination of SN with NYT or CHG may have clinical implications in the treatment of denture stomatitis. However, further studies are needed before recommending the use of these drugs safely in clinical situations. © 2013 Blackwell Verlag GmbH.

Anti-Candida targets and cytotoxicity of casuarinin isolated from Plinia cauliflora leaves in a bioactivity-guided study

In addition to the bio-guided investigation of the antifungal activity of Plinia cauliflora leaves against different Candida species, the major aim of the present study was the search for targets on the fungal cell. The most active antifungal fraction was purified by chromatography and characterized by NMR and mass spectrometry. The antifungal activity was evaluated against five Candida strains according to referenced guidelines. Cytotoxicity against fibroblast cells was determined. The likely targets of Candida albicans cells were assessed through interactions with ergosterol and cell wall composition, porosity and architecture. The chemical major component within the most active antifungal fraction of P. cauliflora leaves identified was the hydrolysable tannin casuarinin. The cytotoxic concentration was higher than the antifungal one. The first indication of plant target on cellular integrity was suggested by the antifungal activity ameliorated when using an osmotic support. The most important target for the tannin fraction studied was suggested by ultrastructural analysis of yeast cell walls revealing a denser mannan outer layer and wall porosity reduced. It is possible to imply that P. cauliflora targeted the C. albicans cell wall inducing some changes in the architecture, notably the outer glycoprotein layer, affecting the cell wall porosity without alteration of the polysaccharide or protein level. © 2013 by the authors.

Effect of diamond-like carbon thin film coated acrylic resin on candida albicans biofilm formation

Purpose: The purpose of this study was to evaluate the effect of diamond-like carbon thin films doped and undoped with silver nanoparticles coating poly(methyl methacrylate) (PMMA) on Candida albicans biofilm formation. The control of biofilm formation is important to prevent oral diseases in denture users. Materials and Methods: Forty-five PMMA disks were obtained, finished, cleaned in an ultrasonic bath, and divided into three groups: Gc, no surface coating (control group); Gdlc, coated with diamond-like carbon film; and Gag, coated with diamond-like carbon film doped with silver nanoparticles. The films were deposited using a reactive magnetron sputtering system (physical vapor deposition process). The specimens were characterized by optical profilometry, atomic force microscopy, and Rutherford backscattering spectroscopy analyses that determined differences in chemical composition and morphological structure. Following sterilization of the specimens by γ-ray irradiation, C. albicans (ATCC 18804) biofilms were formed by immersion in 2 ml of Sabouraud dextrose broth inoculated with a standardized fungal suspension. After 24 hours, the number of colony forming units (cfu) per specimen was counted. Data concerning biofilm formation were analyzed using ANOVA and the Tukey test (p < 0.05). Results: C. albicans biofilm formation was significantly influenced by the films (p < 0.00001), reducing the number of cfu, while not affecting the roughness parameters (p > 0.05). The Tukey test showed no significant difference between Gdlc and Gag. Films deposited were extremely thin (∼50 nm). The silver particles presented a diameter between 60 and 120 nm and regular distribution throughout the film surface (to Gag). Conclusion: Diamond-like carbon films, doped or undoped with silver nanoparticles, coating the base of PMMA-based dentures could be an alternative procedure for preventing candidosis in denture users. © 2013 by the American College of Prosthodontists.

Analysis of inteins in the Candida parapsilosis complex for simple and accurate species identification

Inteins are coding sequences that are transcribed and translated with flanking sequences and then are excised by an autocatalytic process. There are two types of inteins in fungi, mini-inteins and full-length inteins, both of which present a splicing domain containing well-conserved amino acid sequences. Full-length inteins also present a homing endonuclease domain that makes the intein a mobile genetic element. These parasitic genetic elements are located in highly conserved genes and may allow for the differentiation of closely related species of the Candida parapsilosis (psilosis) complex. The correct identification of the three psilosis complex species C. parapsilosis, Candida metapsilosis, and Candida orthopsilosis is very important in the clinical setting for improving antifungal therapy and patient care. In this work, we analyzed inteins that are present in the vacuolar ATPase gene VMA and in the threonyl-tRNA synthetase gene ThrRS in 85 strains of the Candida psilosis complex (46 C. parapsilosis, 17 C. metapsilosis, and 22 C. orthopsilosis). Here, we describe an accessible and accurate technique based on a single PCR that is able to differentiate the psilosis complex based on the VMA intein. Although the ThrRS intein does not distinguish the three species of the psilosis complex by PCR product size, it can differentiate them by sequencing and phylogenetic analysis. Furthermore, this intein is unusually present as both mini- and full-length forms in C. orthopsilosis. Additional population studies should be performed to address whether this represents a common intraspecific variability or the presence of subspecies within C. orthopsilosis. Copyright © 2013, American Society for Microbiology. All Rights Reserved.

Comparison of the effect of rose bengal- and eosin Y-mediated photodynamic inactivation on planktonic cells and biofilms of Candida albicans

Candida albicans is an opportunistic yeast that can cause oral candidosis through the formation of a biofilm, an important virulence factor that compromises the action of antifungal agents. The objective of this study was to compare the effect of rose bengal (RB)- and eosin Y (EY)-mediated photodynamic inactivation (PDI) using a green light-emitting diode (LED; 532 ± 10 nm) on planktonic cells and biofilms of C. albicans (ATCC 18804). Planktonic cultures were treated with photosensitizers at concentrations ranging from 0.78 to 400 μM, and biofilms were treated with 200 μM of photosensitizers. The number of colony-forming unit per milliliter (CFU/mL) was compared by analysis of variance and Tukey's test (P ≤ 0.05). After treatment, one biofilm specimen of the control and PDI groups were examined by scanning electron microscopy. The photosensitizers (6.25, 25, 50, 200, and 400 μM of EY, and 6.25 μM of RB or higher) significantly reduced the number of CFU/mL in the PDI groups when compared to the control group. With respect to biofilm formation, RB- and EY-mediated PDI promoted reductions of 0.22 log10 and 0.45 log10, respectively. Scanning electron microscopy showed that the two photosensitizers reduced fungal structures. In conclusion, EY- and RB-mediated PDI using LED irradiation significantly reduced C. albicans planktonic cells and biofilms. © 2013 Springer-Verlag London.

Efeito fotodinâmico da curcumina em micelas de cetrimida sobre cepas de candida susceptíveis e resistentes a fluconazol

Pós-graduação em Biociências e Biotecnologia Aplicadas à Farmácia - FCFAR

Susceptibilidade antifúngica, produção de biofilme e caracterização do gene ALS3 em isolados de Candida albicans e não-albicans do hospital das clínicas, UNESP, Botucatu

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

Efeitos da terapia fotodinâmica in vitro em biofilmes formados por Candida albicans, Staphylococcus aureus e Streptococcus mutans

Pós-graduação em Biopatologia Bucal - ICT

Presença de Candida, staphylococcus, enterobacteriaceae e pseudomonadaceae na cavidade bucal de pacientes HIV positivos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Associação de enterococcus faecalis, candida albicans e escherichia coli em canais radiculares e avaliação dos efeitos de extratos naturais sobre os microrganismos e endotoxinas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ação in vitro do extrato glicólico de gengibre e medicamentos sobre Candida albicans, Enterococcus faecalis, Escherichia coli e sua endotoxina em canais radiculares

Pós-graduação em Odontologia Restauradora - ICT