title: Exopolysaccharide matrix of developed Candida albicans biofilms after exposure to antifungal agents.
abstract: This study aimed to evaluate the effects of fluconazole or nystatin exposure on developed Candida albicans biofilms regarding their exopolysaccharide matrix. The minimal inhibitory concentration (MIC) against fluconazole or nystatin was determined for C. albicans reference strain (ATCC 90028). Poly(methlymethacrylate) resin (PMMA) specimens were fabricated according to the manufacturer's instructions and had their surface roughness measured. Biofilms were developed on specimens surfaces for 48 h and after that were exposed during 24 h to fluconazole or nystatin prepared in a medium at MIC, 10 x MIC or 100 x MIC. Metabolic activity was evaluated using an XTT assay. Production of soluble and insoluble exopolysaccharide and intracellular polysaccharides was evaluated by the phenol-sulfuric method. Confocal laser scanning microscope was used to evaluate biofilm architecture and percentage of dead/live cells. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. The presence of fluconazole or nystatin at concentrations higher than MIC results in a great reduction of metabolic activity (p<0.001). At MIC or 10 x MIC, fluconazole showed high amounts of intracellular polysaccharides (p<0.05), but did not affect the exopolysaccharide matrix (p>0.05). The exposure to nystatin also did not alter the exopolysaccharide matrix at all the tested concentrations (p>0.05). Biofilm architecture was not affected by either of the antifungal agents (p>0.05). Nystatin promoted higher proportion of dead cells (p<0.05). It may be concluded that fluconazole and nystatin above the MIC concentration reduced the metabolic activity of C. albicans biofilms; however, they were not able to alter the exopolysaccharide matrix and biofilm architecture.
authors: Department of Prosthodontics and Periodontology, Piracicaba Dental School, UNICAMP - University of Campinas, Piracicaba, SP, Brazil.
authors: Wander José
authors: WJ
authors: da Silva
authors: Letícia Machado
authors: LM
authors: Gonçalves
authors: Jayampath
authors: J
authors: Seneviratne
authors: Nipuna
authors: N
authors: Parahitiyawa
authors: Lakshman Perera
authors: LP
authors: Samaranayake
authors: Altair Antoninha
authors: AA
authors: Del Bel Cury
mesh_terms: D000935:Antifungal Agents / Q000008:administration & dosage / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D002176:Candida albicans / Q000187:drug effects* / Q000254:growth & development; D003124:Colorimetry / Q000379:methods; D003470:Culture Media; D015725:Fluconazole / Q000008:administration & dosage / Q000494:pharmacology; D062610:Fungal Polysaccharides / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D025301:Hyphae / Q000187:drug effects; D007202:Indicators and Reagents; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D018613:Microscopy, Confocal; D009761:Nystatin / Q000008:administration & dosage / Q000494:pharmacology; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012995:Solubility; D013499:Surface Properties; D013778:Tetrazolium Salts; D013997:Time Factors
chemical_list: D000935:Antifungal Agents; D003470:Culture Media; D062610:Fungal Polysaccharides; D007202:Indicators and Reagents; D013778:Tetrazolium Salts; C059087:2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-((phenylamino)carbonyl)-2H-tetrazolium hydroxide; D009761:Nystatin; D015725:Fluconazole; D019904:Polymethyl Methacrylate