Activities of Systemically Administered Echinocandins against In Vivo Mature Candida albicans Biofilms Developed in a Rat Subcutaneous Model

This study addresses the effects of micafungin, caspofungin, and anidulafungin against Candida albicans biofilms developed in a subcutaneous catheter rat model system. Doses of 5, 10, and 30mg/kg (of body weight)/day (the last only for micafungin) were given intravenously for 5, 7, and 10 days. All three echinocandins caused a significant reduction of the Candida cell numbers on the implanted catheters and are thus promising for the treatment of biofilm-related infections. The formation of Candida biofilms makes the removal and/orreplacement of infected devices often compulsory (1). Nev-ertheless, the potent activity of the currently licensed echino-candins on mature biofilms has been demonstrated in vitro (2, 3). Moreover, caspofungin could be particularly useful against catheter-related infectionswhenused as a lock solution alone or in combination with systemic administration (4, 5). Recently, we demonstrated that anidulafungin is also active in vivo against ma-ture C. albicans biofilms when administered intraperitoneally in an avascular subcutaneous rat model (6). In contrast, micafungin was found to be fairly ineffective against C. albicans biofilms de-veloped in a denture stomatitis model in rodents (7). As a direc