A Method for the Formation of Candida Biofilms in 96 Well Microtiter Plates and Its Application to Antifungal Susceptibility Testing

Abstract

Fungal infections are an increasing threat to an expanding population of immunocompromised patients. Of these, candidiasis remains the most common, now representing the third to fourth most prevalent infection in US hospitals. Candida albicans remains the major causative agent of candidiasis. Most manifestations of candidiasis are associated with biofilm formation on either host tissues or implanted biomaterials (i.e., catheters), which carries important negative consequences, as cells within biofilms show dramatically increased levels of antifungal drug resistance and protection from host defenses. Here we describe a rapid and robust model for the formation of C. albicans biofilms in vitro using 96 well microtiter plates, which can also be easily adapted for antifungal susceptibility testing. The read-out is colorimetric, based on the reduction of a tetrazolium salt (XTT) by metabolically active cells. This method simplifies biofilm formation, democratizes biofilm research, and provides a framework for the standardization of antifungal susceptibility testing of fungal biofilms.