Methods: The adherence of yeasts to HSC-3 cells was determined as described by Samaranayake et al. (1994). The cells were incubated with three oral isolates of C.albicans either in the presence of the drug, or pre-incubated with yeasts and subsequently exposed to the drug. The cytotoxicity was determined by an Alamar Blue assay.
Results: Following a 1-h incubation in the presence of AmBisome or Caspofungin, at 1-256 µg/ml, the adherence of C.albicans to HSC-3 cells was reduced considerably. For example at 16 µg/ml, adherence was diminished by ~34% and 50%, in the presence of AmBisome and Caspofungin, respectively. Candida adherence obtained with Caspofungin in this range was significantly different from the controls (p<0.0005), while AmBisome-mediated inhibition was significant at 4 µg/ml and above. The susceptibility of cell-associated Candida to antifungals was decreased markedly. The reduction in adherence was between 3.5 and 13.1%, when compared to the drug-free controls. AmBisome was not toxic in the range 1-256 µg/ml, Caspofungin in the range 1-64 µg, and free AMB at 1 and 4 µg/ml.
Conclusions: AmBisome and Caspofungin inhibited candidal colonization when present during the “adherence phase” but did not cause detachment of cell-associated yeasts.
This work was supported by funds from the University of the Pacific, Arthur A. Dugoni School of Dentistry, and from Western Dental Services.