Paradoxical growth effects of the echinocandins caspofungin and micafungin, but not of anidulafungin, on clinical isolates of Candida albicans and C. dubliniensis.
OBJECTIVE
To analyze the effects of a high concentration of three antifungal substances, the echinocandins anidulafungin, caspofungin, and micafungin, on the growth of Candida spp.


METHODS
The growth of 127 C. dubliniensis isolates and 103 C. albicans isolates cultured in medium containing anidulafungin, caspofungin, or micafungin was analyzed using a broth microdilution test according to the guidelines of the CLSI M27-A2 [NCCLS (1997), Wayne, PA]. The final concentrations of all three echinocandins ranged from 0.125 to 64 microg/L.


RESULTS
The different effects of these three antifungal substances on C. albicans cells in comparison to C. dubliniensis cells were quite distinct. When both Candida species were grown in the presence of anidulafungin only a trailing effect was observed. Micafungin induced an Eagle effect in C. dubliniensis only (63%), while caspofungin induced this effect in the majority of C. dubliniensis isolates (90%) and in only a few C. albicans isolates (14%).


CONCLUSIONS
Based on our observations, anidulafungin has effects that are different from the ones produced by micafungin and caspofungin. Whether this different response to high concentrations of echinocandins is based on genetic or phenotypic differences between C. albicans and C. dubliniensis has to be determined in future experiments.
Department of Internal Medicine, Div. Oncology and Hematology, Charité Universitätsmedizin Berlin, Charité Campus Mitte, Charitéplatz 1, 10117 Berlin, Germany.
M
M
Fleischhacker
C
C
Radecke
B
B
Schulz
M
M
Ruhnke
D000077612:Anidulafungin; D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects* / Q000254:growth & development*; D000077336:Caspofungin; D054714:Echinocandins / Q000494:pharmacology*; D006801:Humans; D055666:Lipopeptides; D008074:Lipoproteins / Q000494:pharmacology*; D000077551:Micafungin; D008826:Microbial Sensitivity Tests
D000935:Antifungal Agents; D054714:Echinocandins; D055666:Lipopeptides; D008074:Lipoproteins; D000077612:Anidulafungin; D000077336:Caspofungin; D000077551:Micafungin