Comparison of various methods used to detect biofilm production of Candida species.

Purpose: The biofilm of organisms can be considered as a virulence factor because of the resistance towards antimicrobial agents. Formation of Candida biofilms are observed in blood, mucosal surface and most medical devices i.e. nonliving objects in patient's body. The study was undertaken to conclude the most sensitive and specific test for detection of biofilm formation.

Materials And Methods: Quantitative measurement of biofilm formation was assessed by three methods- 1) XTT reductionassay, 2) Percentage Transmission (%T) and 3) Crystal Violet assay in microtitre plate for 425 Candida isolates.

Results: Out of 425 Candida strains, XTT reduction assay gave 72 Biofilm positive strains accounting for 16.94 %. The percentage transmission (% T) method gave 56 strains Biofilm positive (13.17 %) and Crystal violet assay gave 50 positive strains (11.76 %). Compared to Percentage Transmission (% T) and Crystal violet method, XTT reduction assay gave maximum percentage of Biofilm positivity.

Conclusion: In comparison of 3 methods used for detection of biofilm formation, XTT reduction assay was the most sensitive and specific method.