Biofilm formation and antifungal susceptibility of Candida albicans isolated from respiratory tract

OBJECTIVE To monitor the biofilm formation and antifungal susceptibility of Candida albicans isolated from lower respiratory tract of critically ill patients.METHODS By forming biofilm in cell culture plate in vitro,based on the amount of light blocked passing through the wells,C.albicans isolates were divided into two groups: biofilm-negative isolates and biofilm-positive isolates.The MICs of antifungal drugs against planktonic cells and biofilm-associated adherent cells of 10 isolates were determined respectively.RESULTS Totally 14(26.92%)of 52 isolates were classified as biofilm producer,the other 38(73.08%)isolates were classified as nonbiofilm producer.The MICs of FLU,CASPO and AMB for biofilm-associated adherent cells were much higher than that for planktonic cells.All biofilm-associated adherent cells were resistant to FLU and CASPO(SMIC_80256 μg/ml;16 μg/ml).The MICs of AMB for biofilms of 4 strains were more than 8 μg/ml.CONCLUSION Biofilm formation varies greatly among individual C.albicans isolates.C.albicans biofilm is highly resistant to antifungal agents.