Increased resistance to antifungal antibiotics ofCandida spp. adhered to silicone

Summary The minimal inhibitory concentrations (MICs) and minimal fungicidal concentrations (MFCs) of amphotericin B, miconazole, ketoconazole, fluconazole, and itraconazole were determined for non-adhered cells and cells adhered to sections of a silicone urinary catheter. The densities of adhered cells were established with cells radiolabeled with tritiated leucine. Well defined MICs and MFCs were established for amphotericin B for representative adhered strains. In contrast, the azoles, especially fluconazole, did not give clear end points and the MICs and MFCs were arbitrarily determined. MFCs for the adhered cells generally were 2- to 5-fold higher than those of non-adhered cells. Techniques that include adhered-cell susceptibilities may be necessary before antifungal regimens for prosthetic device-associated yeast infections are appropriately defined.This paper is dedicated to Professor Herman Jan Phaff in honor of his 50 years of active research which still continues.