Background: Exophiala dermatitidis (EDER) is a black-yeast like fungus, which is increasingly being recognized to cause of a variety of invasive infections. This is in contrast to their limited abundance in the environment. Systemic EDER with central nervous system involvement in healthy patients has been described. Despite worrying clinical pictures associated with EDER, data on its antifungal susceptibility are limited and only a few strains have been tested. Methods: 80 clinical- (C) and 15 environmental strains (E) from the CBS culture collection were used. MICs were determined for amphotericin B (AmB), flucytocine (5FC), fluconazole (FLU), itraconazole (IT), voriconazole (VOR), posaconazole (POS), caspofungin (CAS), and BAL 4815 (BAL). Microdilution testing was done in accordance with CLSI M38-A guidelines in RPMI 1640 MOPS broth with L-glutamine without bicarbonate. Plates were sealed and incubated at 35oC for 72 hours. The MIC was determined visually as the lowest concentration of drug showing absence of growth for AMB, ITC, VOR, POS, and BAL or ≥ 50% growth reduction for 5FC and FLU compared with that of the growth control. For CAS the MEC was microscopically determed. Results: For C strains, MIC90s of AmB, 5FC, FLU, IT, VOR, POS, CAS, and BAL were .25, 2, 8, .5, 1, .125, 4, and .5 mg/L, respectively and for E strains, MIC90s were 2, 2, 16, .25, 1, .125, 8, and .5 mg/L. Conclusions: The majority of strains were susceptible to the tested antifungals. AmB and POS appeared to be the most active drugs. There were no major differences in susceptibility pattern between E and C strains. Differences in MIC90 between the latter two groups of isolates did not differ by more than one dilution except for AmB.
Full conference title:
46th Interscience Conference on Antimicrobial Agents and Chemotherapy
- ICAAC 46th