Reduced Biocide Susceptibility in Candida albicans Biofilms

Candida biofilm formation is common during infection and environmental growth. We tested the impacts of three biocides (ethanol [EtOH], H2O2, and sodium dodecyl sulfate) on Candida albicans, C. parapsilosis, and C. glabrata biofilms. Higher concentrations of the biocides were required for efficacy against biofilms than for efficacy against planktonic controls. A combination study with two biocides (EtOH and H2O2) and fluconazole demonstrated that the combination had enhanced efficacy. Candida species cause a wide spectrum of diseases, including hospital-acquired and device-associated infections (33). In the hospital setting, Candida persists on colonized individuals and medical equipment (10). When it is growing on a surface, such as a medical device, Candida adapts to a biofilm lifestyle (14, 15, 19, 22). Biofilm formation is a common mode of growth during infection and survival in the environment (11, 15, 19, 22, 34). Biofilms consist of cells attached to a surface and embed-ded in a matrix produced by the organisms (13). Phenotypic changes are associated with biofilm formation, and amon