Use of a new gelling agent (Eladium©) as an alternative to agar-agar and its adaptation to screen biofilm-forming yeasts.

The incidence of yeast-induced infections has increased in the last decade, mainly because of the increasing number of immunodeficient patients. Since biofilm production is believed to be responsible for fungal virulence, we propose screening yeasts of various genera in order to determine their ability to form biofilms. This is an important issue because yeast cells that form biofilms are particularly resistant to anti-fungal agents used in human patients. For screening, we used Eladium©, a new polysaccharide produced by a Rhizobium sp., as an alternative gelling agent to agar. We also established the conditions necessary to detect biofilm formation. The adapted medium provides the missing link between liquid and solid media. Its advantages include enhancement of growth of microorganisms and facilitation of quick and easy monitoring of biofilm formation.