It says: "The silver NPs effectively inhibited the growth of the tested yeasts at the concentrations below their cytotoxic limit against the tested human fibroblasts determined at a concentration equal to 30 mg/L of Ag. In contrast, ionic silver inhibited the growth of the tested yeasts at the concentrations comparable to the cytotoxic level (approx. 1 mg/L) of ionic silver against the tested human fibroblasts."
Short story: Lower concentration (ionic) more effective against yeast ( cândida )