Fungal Biofilms

• They are responsible for a broad spectrum of microbial infections in the human host [1] • Candida albicans and Candida parapsilosis biofilms are relatively resistant to fluconazole, amphotericin B, nystatin, voriconazole and others [2]. • Aspergillus fumigatus biofilms are relatively resistant to itraconazole and, to some extent, to caspofungin [3]. • Cryptococcal biofilms are unaffected by fluconazole and voriconazole [4] and biofilms of Trichosporon asahii display elevated resistance to amphotericin B, caspofungin, voriconazole, and fluconazole [5]. • Azole and amphotericin B therapies are ineffective against Pneumocystis carinii biofilms [6]. • Biofilm-associated resistance mechanisms have been characterized in C. albicans and A. fumigatus and include drug binding by ECM [7] and production of persister cells [8, 9]. • C. albicans transcription factor Efg1, a global regulator of cell surface protein genes and hyphal formation [10] is required for biofilm formation as well [11, 12]. • C. albicans cell surface proteins have been reviewed authoritatively [13] • Increases in ERG gene expression as well as multi-drug resistance transporters has been correlated with increased azole resistance in Candida albicans patient isolate samples [14], though their contribution to biofilm-specific azole resistance has not been detected in mature biofilms [15]. Antifungal susceptibility of Candida biofilms: unique efficacy of amphotericin B lipid formulations and echinocandins. Specific antibody to Cryptococcus neoformans glucurunoxylomannan antagonizes antifungal drug action against cryptococcal biofilms in vitro.