Optimization of growth conditions for test fungus cultures used in direct bioautographic TLC detection. 3. Test fungus:Candida albicans

Abstract

Summary Optimum conditions have been established for culture of the fungus Candida albicans (ATCC 90028) for microbial detection of zones in direct bioautographic TLC. Bioluminescent ATP assay is a highly sensitive method for optimizing the viability of Candida albicans test fungus in bioautographic TLC detection. A suspension of microbes (OD 600nm = 0.5–0.7, in Mueller–Hinton broth with 5% glucose) in the log phase of growth can be used for dipping TLC plates. On the basis of our results with Candida albicans, we can differentiate between microbiostatic (bacteriostatic or fungistatic) and microbiocidal (bactericidal or fungicidal) effects on TLC plates. Our micrographs clearly show the borders of inhibition zones in bioautograms. This technique leads to new possibilities in studies of the interactions between microbes and antimicrobial compounds on bioautographic silica gel TLC plates by using scanning electron microscopy. In this paper we describe an optimization procedure for bioautographic TLC detection.