Biofilmes multiespécies de Candida Albicans associados com streptococcus mitis e streptococcus sanguinis: estudo in vitro e in vivo

• Ano de defesa: 2014
• Autor(a) principal: Domingues, Nádia [UNESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Biofilme; Candida albicans; Streptococcus mutans; Biofilms
• Link de acesso: http://hdl.handle.net/11449/127663; http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/01-09-2015/000843223.pdf

Streptococcus sanguinis and Streptococcus mitis are pioneering colonizers of oral biofilm and can cause bacterial endocarditis. Candida albicans is present in the oral cavity in a commensal manner and also has the ability to form biofilm and cause oral candidiasis. The aim of this study was to evaluate the interactions between C. albicans with S. sanguinis and S. mitis biofilms and their influences in vivo on an experimental invertebrate model of Galleria mellonella. To study the interaction of C. albicans (ATCC 18804) with S. sanguinis (ATCC 7073) and S. mitis (ATCC 4945) monospecies and multispecies biofilms were formed of C. albicans and with micro-organisms (a concentration of 107 cells/ml) in the bottom of a 96-well plate for 48 h, incubated at 37 °C with 5% CO₂. After growth, biofilms were detached, and decimal dilutions were plated on selective media. After incubation for 48 h/37 °C the count of colony forming units per milliliter (CFU/mL) was obtained. Alongside, XTT salt colorimetric assays were carried in order to measure the metabolic activity of isolated and associated C. albicans biofilms, following reading at 492 nm, and the result expressed in absorbance (Abs). In the in vivo study, first the sublethal concentrations of microorganisms were determined, and inoculated into G. mellonella, and the effect of C. albicans, S. mitis and S. sanguinis in caterpillars was observed, evaluating the survival curve. Morphological evaluation of the biofilms was performed by scanning electron microscopy (SEM). The count of CFU/mL and metabolic activity were submitted to normality analisis, and as a normal distribution was observed, the results were statistically analyzed by Student's t test (for two variables) and Tukey (for three or more variables) considering statistical difference at p < 0.05. The G. mellonella survival curves data were analyzed by log-rank method. Streptococci influenced the reduction of biofilms of C. albicans and ....