Characterization of Candida albicans and Staphylococcus aureus polymicrobial biofilm on different surfaces

Staphylococcus aureus and Candida albicans have been co-isolated from biofilm-associated diseases such as denture stomatitis, periodontitis, and burn wound infections, as well as from medical devices. However, the polymicrobial biofilm of both microorganisms has not been fully characterized. To characterize the polymicrobial biofilm of C. albicans and S. aureus in terms of microbial density, synergy, composition, structure, and stability against antimicrobials and chemical agents. Crystal violet assay was used to measure the biofilm formation. Scanning electron microscopy and confocal microscopy were used to analyze the structure and chemical composition of the biofilms, respectively. Supplemented media with fetal bovine serum (FBS) decreased the biofilm formation of S. aureus and the polymicrobial biofilm. For C. albicans, depending on the culture media, the addition of glucose or FBS had a positive effect in biofilm formation. FBS decreased the adhesion to polystyrene wells for both microorganisms. Supplementing the media with glucose and FBS enhanced the growth of C. albicans and S. aureus, respectively. It seems that C. albicans contributes the most to the adhesion process and to the general structure of the biofilms on all the surfaces tested, including a catheter model. Interestingly, S. aureus showed a great adhesion capacity to the surface of C. albicans in the biofilms. Proteins and β-1,6-linked polysaccharides seem to be the most important molecules in the polymicrobial biofilm. The polymicrobial biofilm had a complex structure, with C. albicans serving as a scaffold where S. aureus adheres, preferentially to the hyphal form of the fungus. Detection of polymicrobial infections and characterization of biofilms will be necessary in the future to provide a better treatment. Staphylococcus aureus y Candida albicans son aislados conjuntamente de infecciones asociadas a la formación de biopelículas, tales como periodontitis, estomatitis e infecciones provenientes de quemaduras, así como en dispositivos médicos. Sin embargo, la biopelícula formada por ambos microorganismos no ha sido completamente caracterizada. Caracterizar la biopelícula de C. albicans y S. aureus en cuanto a densidad microbiana, sinergismo, composición, estructura y estabilidad frente a agentes químicos y antimicrobianos. El análisis de la formación de biopelícula se realizó mediante el ensayo de cristal violeta. Se analizó la composición química y la estructura de las biopelículas m