Comparison of the Microscopic MEC, Macroscopic MEC and Spectrophotometrically MIC of Caspofungin for Dermatophytes

E. GEERTSEN, I. M. CURFS, J. W. MOUTON, J. F. G. MEIS

Author address: 

Canisius Wilhelmina Hospital, Nijmegen, Netherlands

Abstract: 

Background: Caspofungin (CAS), a member of the echinocandins, is an antifungal agents which blocks the synthesis of 1,3-β -glucan of the fungal cell wall. Previous studies of the minimum effective concentration (MEC) of CAS against Aspergillus spp. was assessed by macroscopic and microscopic observations. However it is easier to determine the MEC macroscopically, and it would be even better if it can be measured with a spectrophotometer. Therefore the aim of this study was to see if there is a concordance between the results of the microscopic MEC, macroscopic MEC and spectrophotometrically read MIC of CAS for dermatophytes. Methods: The in vitro susceptibility of the species Microsporum canis (4), Microsporum gypseum (2), Trichophyton mentagrophytes (5), and Trichophyton rubrum (6) for CAS was assessed with a broth microdilution (BMD) method (Ferní¡ndez-Torres et al. J Clin Microbiol 2002,40:3999) in three different ways, macroscopic and microscopic (Espinel-Ingrofff J Clin Microbiol 2003,41:401) and spectrophotometrically at 405 nm. Results: The agreements of the comparisons were (see table) ERROR : Conclusions: Spectrophotometrically reading is not an option to determine the MEC. The MEC for Trichophyton ssp. can be determined macroscopically. The MEC for Microsporum sp. has to be assessed microscopically.
2004

abstract No: 

M-1783-200

Full conference title: 

44th Interscience Conference on Antimicrobial Agents and Chemotherapy
    • ICAAC 44th