Susceptibility of Candida albicans biofilms to caspofungin and anidulafungin is not affected by metabolic activity or biomass production

Abstract

Micafungin is more active against biofilms with high metabolic activity; however, it is unknown whether this observation applies to caspofungin and anidulafungin and whether it is also dependent on the biomass production. We compare the antifungal activity of anidulafungin, caspofungin, and micafungin against preformed Candida albicans biofilms with different degrees of metabolic activity and biomass production from 301 isolates causing fungemia in patients admitted to Gregorio Marañon Hospital (January 2007 to September 2014). Biofilms were classified as having low, moderate, or high metabolic activity according XTT reduction assay or having low, moderate, or high biomass according to crystal violet assay. Echinocandin MICs for planktonic and sessile cells were measured using the EUCAST E.Def 7.2 procedure and XTT reduction assay, respectively. Micafungin showed the highest activity against biofilms classified according to the metabolic activity and biomass production (P