In vitro susceptibilities of clinical isolates of filamentous fungi to new antifungal agents
Abstract number: P1358
Linares M.J., Solís F., Casal M.
Objectives: Anidulafungin(AND) and caspofungin (CAS), two new antifungal agents belonging to the echinocandin, act by inhibiting beta-1,3 glucan synthetase, and display a broad spectrum of action, even against isolates resistant to amphotericin B and fluconazole. A study was made of their action against filamentous fungi.
Methods: A total de 124 strains of the following filamentous fungi species were isolated fron a range of clinical samples: Aspergillus fumigatus (35), Aspergillus terreus (22), Aspergillus flavus (18), Aspergillus niger (16), Fusarium verticilliodes (9), Fusarium oxysporum (6), Scedosporium apiospermum (6), Emericella nidulans (4), Scedosporium prolificans (3), Paecillomyces variotii (3), Fusarium solani (2). The CLSI, (formerly NCCLS) M38-A document for antifungal susceptibility testing of filamentous fungi, broth microdilution method was used. Concentrations assayed for each antifungal agent ranged from 0.03 to 16 mg/ml. C. krusei ATCC 6258 and C. parapsilosis ATCC 22019 were used for quality control. MICs and minimum effective concentrations (MECs) for evaluating anidulafungin and caspofungin against moulds. Anidulafungin and caspofungin MICs(50% inhibition) and MECs (morfological hyphal changes) were determined.
Results: MIC90 results (mg/ml) for the two antifungal were as follows (ADN/CAS): Aspergillus fumigatus (2/8), Aspergillus terreus (2/4), Aspergillus flavus (2/4) Aspergillus niger (4/2), Fusarium verticilliodes (16/16), Fusarium oxysporum (16/8), Scedosporium apiospermum (2/2), Emericella nidulans (0.5/4), Scedosporium prolificans (0.12/0.12), Paecilomyces variotii (0.06/2), Fusarium solani (4/2). The paradoxical effectct was more common with caspofungin than with anidulafungin.
Conclusion: Anidulafungin and caspofungin showed moderate in vitro activity against most of the species tested. Greater activity was displayed against Scedosporium prolificans and Scedosporium apiospermum. Anidulafungin was more active than caspofungin against Aspergillus fumigatus. Aspergillus terreus, Aspergillus flavus and Aspergillus niger showed little sensitivity to either antifungal agent, both of which lacked any in vitro activity agains Fusarium verticilliodes and Fusarium oxysporum.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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