Optimization of the MTT testing for viability analysis of Candida albicans.

To evaluate the cell viability of Candida albicans with menadion augmented MTT method, we studied the optimal combination of the major conditions by the orthogonal design. The optimized MTT testing was used to evaluate the cell viability of C.albicans isolates that were counted into serial cell concentrations by chemical processing. Additionally,nine species of other yeasts or yeast- like fungi were tested for their viability by the optimized MTT testing. The result showed that the optimal combination of the major conditions involved in menadion- augmented MTT method for Candida albicans was 1.2g/L MTT, 20 mmol/L menadion for 6 hours and measured with spectrophotometer at 570nm. This method was not only sensitive to reflect the change of the Candida albicans viability but also effective to evaluate the viability of other yeasts or yeast- like fungi. The optimized MTT method was a rapid, simple,convenient, and sensitive quantitative assay to evaluate the viability of Candida albicans and other yeast or yeast- like fungi.