Improvement Of XTT Assay Used To Compare Different Candida Biofilms

Objective: the aim of this study was to compare the cells activity using 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay modified with the addition of glucose of different Candida species biofilms. Methods: (Candida albicans ATCC 90028; Candida albicans SC5314; Candida dubliniensis MTA 646; Candida krusei ATCC L252; Candida krusei CAM L25; Candida parapsilosis ATCC 22019; Candida parapsilosis H46b; Candida tropicalis ATCC 13803 and Candida tropicalis CAM L21) were allowed to develop biofilm in polystyrene substrata. Different time points (adhesion, 24 and 48 hours) were compared. Biofilms activity were measured by XTT reduction assay with addition of 200 mM glucose to its formulation and compared to XTT without glucose addition. Results: XTT assay with 200 mM glucose showed reliable and consistent readings in comparison with the XTT assay without glucosegave p<0.001) correlating to biofilm development adhesion at 24 and 48 hours. Conclusion: the addition of 200mM of glucose to XTT decreased the varability of the readings and yield more accurate data. However different species of Candida canxt be compared using XTT assay since the metabolic activity is proper for each Candida. Supported by Capes.