Effects of Fetal Bovine Serum on Biofilm Formation and Cell Attachment of Candida glabrata

Candida glabrata (Nakaseomyces glabratus) is an opportunistic human fungal pathogen. Candida spp., including C. glabrata, can adhere to surfaces, including the human epithelial mucosa and medical devices, to form biofilms, which can lead to high mortality rates. Heat-inactivated fetal bovine serum (HI FBS) is commonly used as a component in plate-based fungal biofilm experiments as a readily available serum model. However, the effect of HI FBS on C. glabrata biofilm formation in in vitro biofilm assays has not been systematically investigated. The results of crystal violet staining for biomass measurements, XTT reduction for metabolic activity quantification, confocal microscopy of biofilms and growth kinetic measurements showed a negative influence of the HI FBS on cell attachment but not growth rates, which resulted in reduced biofilm formation. These findings identify serum exposure as an important experimental variable in C. glabrata biofilm assays that can potentially disrupt the interaction of cells and abiotic surfaces such as those used in medical device applications.