Species-specific and drug-specific differences in susceptibility of Candida biofilms to echinocandins: characterization of less common bloodstream isolates.
Antimicrob Agents Chemother. 2013 Mar 25;
Authors: Simitsopoulou M, Peshkova P, Tasina E, Katragkou A, Kyrpitzi D, Velegraki A, Walsh TJ, Roilides E
Candida species other than Candida albicans are increasingly recognized as causes of biofilm-associated infections. This is a comprehensive study that compares the in vitro activities of all three echinocandins against biofilms formed by different common and infrequently identified Candida isolates. We determined the activities of anidulafungin (ANID), caspofungin (CAS) and micafungin (MFG) against planktonic cells and biofilms of bloodstream isolates of C. albicans (15 strains), Candida parapsilosis (6), Candida lusitaniae (16), Candida guillermondii (5) and Candida krusei (12) by XTT assay. Planktonic and biofilm MICs were defined as ≥50% fungal damage. Planktonic cells of all Candida species were susceptible to the three echinocandins with MICs ≤1mg/L. By comparison, differences existed in the MIC profiles of biofilms to echinocandins among Candida species. Thus, C. lusitaniae and C. guillermondii biofilms were highly recalcitrant to all echinocandins with MICs ≥32mg/L. In contrast, C. albicans and C. krusei biofilms exhibited relatively low MICs to all three echinocandins (MICs ≤1mg/L). While C. parapsilosis biofilms exhibited generally high MICs to echinocandins, MFG exhibited the lowest MICs against these isolates (4mg/L). A paradoxical growth effect was observed with CAS concentrations ranging from 8 to 64mg/L against albicans and parapsilosis biofilms but not against C. krusei, C. lusitaniae or C. guillermondii. While non-albicans Candida planktonic cells are susceptible to all echinocandins, there are drug- and species-specific differences in susceptibility among biofilms of various Candida species with C. lusitaniae and C. guillermondii exhibiting high MIC profiles to the three echinocandins.
PMID: 23529739 [PubMed - as supplied by publisher]