Interaction between XTT Assay and Candida Albicans or Streptococcus Mutans Viability

Abstract

Background: Methods based on metabolic activity and cell viability, such as XTT reduction assay and counting colony-forming units (CFU), have been frequently used for biofilm evaluation. The association between the metabolic activities experiments with counting CFU is labor-intensive that need to be done separately. Thus, the aim of this study was to evaluate the effects of XTT salt, and other compounds used to XTT reduction assay on the cell viability of Candida albicans and Streptococcus mutans biofilms. Material and Methods: C. albicans or S. mutans was formed on a microtiter plate. After 48 h, the mature biofilm, to evaluate the effect of these different compounds of XTT on cell viability, the biofilms were divided into five experimental groups (n = 5). The plates were incubated for 3 h in dark conditions at 37°C. The cell viability was evaluated by counting the number CFU mL-1. Results: The results obtained for C. albicans and S. mutans showed differences between the incubation solutions for both microorganisms, however, the differences remained >106 CFU mL1. Conclusion: These findings indicate that the XTT salt and the compounds used for the XTT reduction assay did not exhibit any effect on cell viability of the microorganisms tested.