Comparison of the Sensititre YeastOne colorimetric antifungal panel with reference M38: a method for testing susceptibility Aspergillus spp. to caspofungin

E. López-Oviedo, C. Martí­n, A. Martos, C. Castro, M. Ramirez, A. Romero, J. Palomares, E. Martí­n-Mazuelos

Author address: 

Seville, ES

Abstract: 

Objective: To compare the in vitro activity of Caspofungin (C) by Sensititre YeastOne® method (S) with that of microdilution reference method (MD) (CLSI, formerly NCCLS M38-A) against Aspergillus spp. Material and methods: The in vitro activity of C has been tested against 15 clinical isolates of Aspergillus (5 A. flavus, 4 A. niger, 3 A. glaucus, 2 A. fumigatus, 1 A. terreus) by the Sensititre YeastOne® colorimetric and the M38-A reference methods. The Sensititre YeastOne® was performed following the manufacture's instructions (range concentrations 0.008-16 mg/l). The MD reference susceptibility testing was performed following the CLSI M38-A document, using drug dilutions from 0.03 to 16 mg/l. Inoculum suspensions for both methods were prepared recovering the conidia from a 7-day culture growth on Potato Dextrose Agar at 35 °C (final inoculum: 0.5-5 x 104 CFU/ml). MECs (Minimal Effective Concentrations) readings were performed at 48 h for MD method following the published by Kurtz et al. (1994, AAC 38: 1480-1489). MECs and MICs readings were performed at 48 h. for S method. The MEC50, MEC90 and range of MEC were calculated for both method; the MIC50, MIC90 and range of MIC were calculated for S method. The level of agreement (percentage of MECs and MICs pairs within a ±2 dilutions range) between S and MD were calculated. C. krusei 6258 and C. parapsilosis 22019 were used as Quality Control strains calculated. Results: MICs and MECs are shown in Table 1. The level of agreement between MECs of S and MECs of MD was 60% and between MICs of S and MECs of MD was 6.6%. The MECs (mg/l) were
2006

abstract No: 

P738

Full conference title: 

16th European Congress of Clinical Microbiology and Infectious Diseases
    • ECCMID 16th (2006)